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1 <?xml version="1.0" encoding="utf-8"?> |
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2 <!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. --> |
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3 <!-- This component and the accompanying materials are made available under the terms of the License |
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4 "Eclipse Public License v1.0" which accompanies this distribution, |
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5 and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". --> |
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6 <!-- Initial Contributors: |
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7 Nokia Corporation - initial contribution. |
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8 Contributors: |
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9 --> |
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10 <!DOCTYPE concept |
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11 PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
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12 <concept id="GUID-60DBA025-8FA0-5DF2-90D0-744A016998EE" xml:lang="en"><title>Panoramic |
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13 Stitching Guide</title><prolog><metadata><keywords/></metadata></prolog><conbody> |
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14 <p>This document introduces you to the panoramic stitching functionality. </p> |
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15 <section id="GUID-3333CA2A-EF84-5E7B-B9BE-8FF00523897F-GENID-1-8-1-18-1-1-5-1-6-1-12-1-4-1-3-1-4-1-3-1-2-2"><title>Purpose</title> <p>Panoramic |
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16 stitching involves combining a collection of images into a single image. </p> </section> |
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17 <section><title>Panoramic stitching overview</title> <p>The panorama image |
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18 is created by stitching a collection of several separate image into one large |
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19 image. The panoramic stitching process is done by, </p> <ul> |
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20 <li id="GUID-0DA59FD4-B817-5B51-8E83-F56FC42E1675"><p>image registration </p> </li> |
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21 <li id="GUID-74941275-9681-51AB-B1FB-4F0829B47075"><p>cylindrical projection |
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22 of images </p> </li> |
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23 <li id="GUID-70E87CA6-B8BC-5CE9-A545-FC3782A81A69"><p>image blending. </p> </li> |
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24 </ul> <p>The panoramic stitch can be done eihter interactively by using camera |
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25 viewfinder, for tracking the camera movements or by stitching pre-captured |
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26 images together. </p> <p><b>Introduction |
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27 about the panoramic stitching</b> </p> <p>The <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> stitches |
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28 a set of images into a single panorama image. The input to <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> is |
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29 a collection of high resolution images together with some guidance on the |
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30 relative positioning between the images expressed by <xref href="GUID-27BD164A-9283-3BE0-A0BF-A475539D86EA.dita"><apiname>CPanoramaTransform</apiname></xref> instances. </p> <p>For |
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31 the panorama creation, the most common use is rendering a full size panorama |
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32 image to the device file system. </p> <p>The high level steps to use <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> are |
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33 shown below: </p> <ul> |
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34 <li id="GUID-EF02A22B-B4B1-5E97-97E7-F09DE26DA93A"><p>To construct <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref>, |
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35 use <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita#GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4/GUID-39BE88C3-C617-3AF8-A13D-CEC60AE798B1"><apiname>CImagePanorama::NewL()</apiname></xref> which loads the image panorama |
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36 plugin. </p> </li> |
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37 <li id="GUID-690408AF-782D-5E67-93BC-238EBCBD0C20"><p>To initialise <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref>, |
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38 use <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita#GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4/GUID-B6D24921-92B8-3FD8-B666-91C56E1E7984"><apiname>CImagePanorama::InitialiseL()</apiname></xref>. </p> </li> |
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39 <li id="GUID-3E167564-6974-571E-99A0-196A5A18133D"><p>To correct the lens |
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40 parameter use <xref href="GUID-90D79D23-97BC-3EE5-98DD-594DF6EFA0EE.dita"><apiname>TPanoramaLens</apiname></xref>. You need to correct the lens |
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41 for panorama stitching quality. The lens parameters are camera specific. </p> </li> |
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42 <li id="GUID-93217AEB-2AC5-5CCC-B5EE-36E8B99BAA85"><p>To add images to <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref>, |
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43 use <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita#GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4/GUID-B6591C30-F990-3D75-B9F3-922D41A5F1A1"><apiname>CImagePanorama::AddFileL()</apiname></xref>,<xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita#GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4/GUID-19FBD32E-9B1F-38B0-963A-B361737818D2"><apiname>CImagePanorama::AddBufferL()</apiname></xref> or <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita#GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4/GUID-66509DE8-2DBA-3FE0-8495-32E4256FA939"><apiname>CImagePanorama::AddImageL()</apiname></xref>, providing a hint on relative positioning or translation of the images through <xref href="GUID-27BD164A-9283-3BE0-A0BF-A475539D86EA.dita"><apiname>CPanoramaTransform</apiname></xref>. |
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44 This transform only needs to be approximate. </p> </li> |
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45 <li id="GUID-B445F73C-2910-56DE-B03D-2637ECED0963"><p>To make the stitched |
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46 image available call <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita#GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4/GUID-A098A70C-050C-3592-BC37-E849A81890F2"><apiname>CImagePanorama::RenderL()</apiname></xref>. </p> </li> |
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47 <li id="GUID-B68A2C77-F19A-5999-82C1-F433269DAACB"><p>The <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> instance |
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48 can then be deleted. </p> </li> |
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49 </ul> <p><b> Introduction |
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50 about the CVFTracker</b> </p> <p> <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> is used to |
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51 track viewfinder images to aid in capturing a panorama. The usage of <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> are |
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52 demonstrated as follows: </p> <ul> |
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53 <li id="GUID-3496F712-4FCD-5E89-BFEE-5AA6A22A1DA0"><p>The <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> output |
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54 is used for providing feedback and guidance to you, on how to move the camera |
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55 while capturing a panorama. </p> </li> |
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56 <li id="GUID-BDBC8A06-B2F8-507C-81F7-E2F344A94FEA"><p>The <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> is |
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57 used as an aid for the stitching process in the <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref>. |
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58 The input to the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> is a rapid flow of raw images |
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59 from the viewfinder of the camera. The output is the movement of the camera. </p> </li> |
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60 </ul> <p>The high level steps to use the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> are |
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61 shown below: </p> <ul> |
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62 <li id="GUID-5C25D0C8-49E1-5514-A90C-2B8A026D20CC"><p>To create <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref>, |
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63 use the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita#GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352/GUID-AE92A41F-388D-338C-A80E-C0B16DF3BDDC"><apiname>CVFTracker::NewL()</apiname></xref>. The <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita#GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352/GUID-AE92A41F-388D-338C-A80E-C0B16DF3BDDC"><apiname>CVFTracker::NewL()</apiname></xref> is |
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64 used to load the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> plugin. </p> </li> |
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65 <li id="GUID-ECE3D707-B871-5EC5-A04D-CA2A632BECC6"><p>To initialise <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref>, |
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66 use <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita#GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352/GUID-5E441486-3333-3B4F-81F3-3A86AE541CF8"><apiname>CVFTracker::InitialiseL()</apiname></xref>. </p> </li> |
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67 <li id="GUID-54FEF93A-68BB-5EFB-8DE4-21F6562DCF11"><p>To reset <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref>, |
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68 use <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita#GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352/GUID-AE707DEA-4747-3A1A-8C6F-8163F1DF0584"><apiname>CVFTracker::Reset()</apiname></xref>. </p> </li> |
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69 <li id="GUID-32F88242-4EDD-54C7-8D7A-574015A197F4"><p>To perform the image |
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70 registration, use <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita#GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352/GUID-AB58BBEB-5EAE-3E2A-A94E-F59334402A2B"><apiname>CVFTracker::RegisterImageL()</apiname></xref>. </p> </li> |
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71 <li id="GUID-01DDC476-9596-55A1-B296-13877DB41B67"><p>To destroy the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref>, |
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72 use <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita#GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352/GUID-C2B64F7D-04D8-324A-BD84-C588503881BC"><apiname>CVFTracker::~CVFTracker()</apiname></xref>. </p> </li> |
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73 </ul> <p><b>Camera |
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74 requirements </b> </p> <p>The camera requirements for the <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> and <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> are |
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75 as follows, </p> <ul> |
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76 <li id="GUID-C83A6919-C7BB-55C9-9D60-80EDAE0D4458"><p>The camera must provide |
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77 low resolution images (in the order of 160 by 120 up to 320 by 240 resolution) |
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78 as the raw format at a high frame rate to the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> and |
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79 high resolution captured images to the <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref>. </p> </li> |
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80 <li id="GUID-EF41F660-AAEE-5D31-A014-FD6C39C42C5E"><p>For the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref>, |
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81 it is better to have good frame rate than to have high resolution input images. </p> </li> |
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82 <li id="GUID-810B06D2-D45F-5E7C-BC62-88AEE0B0A071"><p>The use of large <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> images |
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83 can cause a lower frame rate on slow devices, and do not give accurate tracking |
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84 for the view finder. </p> </li> |
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85 <li id="GUID-DA5C3ED7-550D-5E4E-AD5A-E9119A56D8FB"><p>The optimal size of |
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86 images is a tradeoff between the panorama quality and the time for rendering |
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87 the panorama. </p> </li> |
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88 </ul> </section> |
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89 <section><title>How to use Panoramic Stitching</title> <p>This section contains |
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90 some code snippets to show, how Panoramic stitching is accessed in several |
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91 situations. </p> <p><b>Basic |
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92 stitching </b> </p> <p>The basic stitching is demonstrated by a simple example |
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93 of stitching four JPEG images into a single JPEG image providing an approximate |
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94 translation between each image: </p> <p> </p> <codeblock id="GUID-304B7755-B05B-5BAE-884A-44A0500ABF37" xml:space="preserve"> |
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95 |
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96 TSize imageSize(1200, 1000); |
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97 |
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98 TDirection direction = EPanoramaDirectionRight; |
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99 |
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100 //Lens parameters or internal camera characteristics should be available for the |
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101 //specific camera module in use. Here we use default values. |
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102 TPanoramaLens lens; |
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103 |
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104 //Create transform. A transform is an approximate offset between each image. |
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105 CPanoramaTransform* panTrans = CPanoramaTransform::NewL(); |
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106 CleanupStack::PushL(panTrans); |
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107 |
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108 //Create panorama object.This stitches the individual images together. |
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109 CImagePanorama* panImage = CImagePanorama::NewL(); |
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110 CleanupStack::PushL(panImage); |
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111 |
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112 //Create panorama engine and set the lens and size |
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113 panImage->InitializeL(imageSize, lens, direction); |
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114 |
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115 //Each file added is provided with an approximate translation. |
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116 //In this case there are 4 images. |
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117 panTrans->SetTranslationL(TPoint(0, 0), imageSize); |
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118 panImage->AddFileL(KTestFileName1, *panTrans); |
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119 |
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120 panTrans->SetTranslationL(TPoint(900, -30), imageSize); |
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121 panImage->AddFileL(KTestFileName2, *panTrans); |
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122 |
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123 panTrans->SetTranslationL(TPoint(900, 60), imageSize); |
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124 panImage->AddFileL(KTestFileName3, *panTrans); |
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125 |
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126 panTrans->SetTranslationL(TPoint(400, -30), imageSize); |
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127 panImage->AddFileL(KTestFileName4, *panTrans); |
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128 |
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129 //The image size can be obtained before rendering (if required) |
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130 TSize size; |
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131 panImage->CurrentImageSizeL(size); |
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132 |
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133 //view the output image |
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134 panImage->RenderL(KTestBSOutputFileName); |
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135 |
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136 CleanupStack::PopAndDestroy(2); //panTrans, panImage |
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137 |
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138 </codeblock> <p>The main steps for using <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> are |
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139 as follows, </p> <ol id="GUID-D6872BA3-A3DF-566A-83AF-527870CBE997"> |
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140 <li id="GUID-FB378114-769F-5404-BD20-8886D538191F"><p>create <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> </p> </li> |
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141 <li id="GUID-D8A28AFC-4D37-59C4-91D9-92F4898F2302"><p>some approximate transform |
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142 information for each image pair </p> </li> |
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143 <li id="GUID-146D95D7-14DE-57CA-96DA-45959EB895A4"><p>add each images to <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> </p> </li> |
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144 <li id="GUID-FF479A52-24E3-5D0B-A821-44127DA5B60C"><p>render the output (for |
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145 example to the file) </p> </li> |
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146 <li id="GUID-0ADBEE3F-AA60-5787-92A0-C421D4EA8731"><p>delete the objects used. </p> </li> |
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147 </ol> <p> <b>Note:</b> The following points must be noted by you: </p> <ul> |
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148 <li id="GUID-D3EB4190-4B2B-5760-8E6C-D19DAFF439DF"><p>The lens parameters |
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149 are not resolution dependant. It is enough to calibrate once for each camera |
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150 model and no need to recalibrate for each resolution. For best accuracy, use |
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151 the highest resolution possible when calibrating with a calibration tool. </p> <p>The |
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152 approximate translations in x co-ordinate and y co-ordinate ( as dx, dy) must |
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153 be compliant with the value of direction. </p> </li> |
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154 </ul> <p><b>A |
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155 camera application example</b> </p> <p>The <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> is |
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156 used in a camera application. The example is more complicated than the previous |
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157 example. In this example <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> provides the approximate |
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158 transform between the captured images. </p> <p><b>Viewfinder |
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159 image tracking </b> </p> <p>The <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> generates |
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160 panorama images. The application starts the process and then use the camera |
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161 for capturing the images. The <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> will give an indication |
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162 when to capture the high resolution images, which will later be stitched into |
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163 a panorama image. </p> <p>The <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> plays an important |
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164 role for getting the camera movement. The high level steps to use the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> in |
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165 the <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> for a camera application, are shown |
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166 below: </p> <ol id="GUID-B6357C9E-1510-53C8-856B-2C06C7A6A69C"> |
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167 <li id="GUID-54C90419-08DE-5406-BBF1-37C0B59FCA26"><p>To create the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> object |
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168 and load the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> plugin, use <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita#GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352/GUID-AE92A41F-388D-338C-A80E-C0B16DF3BDDC"><apiname>CVFTracker::NewL()</apiname></xref>. </p> </li> |
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169 <li id="GUID-D3E16606-ED81-5702-9F4F-9B19754D4768"><p>To create <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> object |
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170 and load the <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> plugin, use <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita#GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4/GUID-39BE88C3-C617-3AF8-A13D-CEC60AE798B1"><apiname>CImagePanorama::NewL()</apiname></xref>. </p> </li> |
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171 <li id="GUID-E5C6B072-64FE-554F-BAC4-8850E15B841D"><p>To create the <xref href="GUID-27BD164A-9283-3BE0-A0BF-A475539D86EA.dita"><apiname>CPanoramaTransform</apiname></xref> object |
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172 and set or get the values, use the <xref href="GUID-27BD164A-9283-3BE0-A0BF-A475539D86EA.dita#GUID-27BD164A-9283-3BE0-A0BF-A475539D86EA/GUID-ADB1D55B-CEA7-3151-B6E2-14F165F8BB9F"><apiname>CPanoramaTransform::NewL()</apiname></xref>. </p> </li> |
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173 <li id="GUID-FD68A411-E492-5492-88FD-E7A7307113F7"><p>To create and set the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref>, <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref>, |
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174 and <xref href="GUID-27BD164A-9283-3BE0-A0BF-A475539D86EA.dita"><apiname>CPanoramaTransform</apiname></xref> functions for the Image Processor |
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175 Adaptation Plug-in objects, use <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita#GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352/GUID-5E441486-3333-3B4F-81F3-3A86AE541CF8"><apiname>CVFTracker::InitialiseL()</apiname></xref> and <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita#GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4/GUID-B6D24921-92B8-3FD8-B666-91C56E1E7984"><apiname>CImagePanorama::InitialiseL()</apiname></xref> respectively.</p> </li> |
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176 <li id="GUID-A605F836-474D-55D4-A326-9AC8B0F8F86B"><p>To get a translation |
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177 value from a viewfinder image, register an image by using <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita#GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352/GUID-AB58BBEB-5EAE-3E2A-A94E-F59334402A2B"><apiname>CVFTracker::RegisterImageL()</apiname></xref>. |
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178 This will return translation information as a CPanoramaTransform object. </p> </li> |
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179 <li id="GUID-8E6E35D9-B20A-5BA2-987F-1A3447DEA146"><p>Check the right time |
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180 to capture the next image by using <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita#GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352/GUID-945FF7AD-31E5-3C6A-AD89-F1A5FC225B9D"><apiname>CVFTracker::IsTimeToCapture()</apiname></xref>. </p> </li> |
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181 <li id="GUID-A490A649-B910-5E1C-B317-EC5627547EF7"><p>Reset the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> for |
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182 the next image, using <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita#GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352/GUID-AE707DEA-4747-3A1A-8C6F-8163F1DF0584"><apiname>CVFTracker::Reset()</apiname></xref>. </p> <p>In order |
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183 to capture many images to be stitched into a single panorama image, repeat |
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184 the steps 5, 6 and 7. </p> </li> |
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185 </ol> <fig id="GUID-7F48B2F5-D65B-52EC-8412-F3F56A5EE8E8"> |
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186 <image href="GUID-470FAFE8-2246-5E91-9F01-6CC95F975E54_d0e310270_href.jpg" placement="inline"/> |
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187 </fig> <p><b>Panorama |
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188 stitching </b> </p> <p>The <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> helps to decide when |
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189 to capture each of the full resolution images using the camera. The images |
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190 can then be passed to CImagePanorama and the stitching is done. The high level |
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191 steps to do panorama stitching are listed below: </p> <ol id="GUID-763005A3-4098-534F-9CA1-E2F8654C95BD"> |
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192 <li id="GUID-6866E73F-F1F7-53C8-BA64-8AF448318C53"><p>Capture the next image |
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193 using the camera, then add the image to the <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> by |
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194 using <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita#GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4/GUID-66509DE8-2DBA-3FE0-8495-32E4256FA939"><apiname>CImagePanorama::AddImageL()</apiname></xref> or <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita#GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4/GUID-201D0607-2D25-3B1D-B449-7A61419BB0C8"><apiname>CImagePanorama::AddFileL</apiname></xref>, |
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195 passing in the <xref href="GUID-27BD164A-9283-3BE0-A0BF-A475539D86EA.dita"><apiname>CPanoramaTransform</apiname></xref> object obtained from |
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196 the CVFTracker. </p> </li> |
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197 <li id="GUID-BC35AEEF-206E-5830-909E-07F645C2E063"><p>When all images have |
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198 been captured you can render the stitched image to file, image buffer, CFbsBitmap |
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199 or image frame using <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita#GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4/GUID-A098A70C-050C-3592-BC37-E849A81890F2"><apiname>CImagePanorama::RenderL()</apiname></xref>. </p> </li> |
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200 </ol> <fig id="GUID-B5F7149F-1FB9-535E-9212-7C9E23B9347B"> |
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201 <image href="GUID-A8C80AA1-42CF-5866-B223-FCE1AEC9DF63_d0e310320_href.jpg" placement="inline"/> |
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202 </fig> <p><b>User Interface</b> </p> <p>Provide a good user interface (UI) application |
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203 for the <xref href="GUID-4DBD1F07-42C5-3CD7-B809-A391F315E0D4.dita"><apiname>CImagePanorama</apiname></xref> is crucial. An example of UI design |
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204 is described below, which gives you a robust and easy application for generating |
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205 panorama images. </p> <p><b>How |
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206 to shoot a panorama </b> </p> <p>The steps to be followed for shooting a panorama |
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207 images: </p> <ol id="GUID-8FD3D305-BEAF-5414-BD49-5728C2504256"> |
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208 <li id="GUID-92642922-D0A0-57CD-80A6-03722941E52C"><p>You need to press the |
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209 start button of the camera and need to sweep the camera towards the wanted |
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210 scene. </p> <p> <b>Note:</b> You must try not to move the mobile phone, but |
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211 only rotate it. You see in the below diagram the camera is sweep in a clockwise |
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212 direction from left-to-right. The rotation is made around the imagined axis |
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213 through mobile (axis of rotation in the image). A panorama image covers approximately |
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214 a 100 degree field of view. </p> <fig id="GUID-8562E235-6D10-5097-A888-E27EE6D4E498"> |
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215 <image href="GUID-7B3578A0-7E2E-508A-A355-A39AEE0307AD_d0e310357_href.jpg" placement="inline"/> |
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216 </fig> </li> |
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217 <li id="GUID-16CA0CFB-9D17-573C-9D7B-FEDBCFF4044C"><p> <b>Application Start</b> </p> <p>When |
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218 you launch the application the UI appears as shown in the below diagram. </p> <fig id="GUID-4A6082E2-1B7F-5A48-8FC5-7BC2786987B7"> |
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219 <image href="GUID-0E55E007-913C-56DA-8BEF-7EC00FFCCE51_d0e310373_href.jpg" placement="inline"/> |
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220 </fig> <p>Here the screen area shows the viewfinder image. When you sweep |
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221 the mobile, several images are captured and then the images are stitched to |
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222 create a panorama image. </p> </li> |
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223 <li id="GUID-FE8D49DB-26CC-5546-A05D-B46045894313"><p> <b>Capture a panorama |
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224 image during tracking</b> </p> <p>When you choose to capture a panorama image |
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225 the UI changes, which is shown in the below diagram. </p> <fig id="GUID-930C8F54-4C13-50AC-B700-9D889FFE9DC7"> |
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226 <image href="GUID-9AB5481B-C321-56C9-937D-2397AA80DE8E_d0e310392_href.jpg" placement="inline"/> |
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227 </fig> <p>In the above diagram you see three different boxes named 1, 2 and |
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228 3 which represent the position of the camera. The blue box representation |
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229 changes according to the rotation of the mobile phone. </p> <p>The boxes shown |
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230 in the above diagram is for illustrative purpose, so that it can be down scaled |
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231 for viewfinder image size. The total panorama coverage area box is estimated |
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232 by the number of images for capturing and the overlapping area size. </p> <p>The |
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233 code snippets below shows the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> tracking. </p> <codeblock id="GUID-73381F9D-53D9-505A-888D-464A83B0A352" xml:space="preserve"> |
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234 |
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235 _LIT(KFileOutput, "c:\\ICLExample\\viewfinder%d.mbm"); |
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236 _LIT(KFileCapturedImage, "c:\\ICLExample\\pancapture%d.jpg"); |
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237 TInt i = 0; |
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238 |
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239 TSize imageSize(1200,1000); |
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240 CFbsBitmap* bmp = new (ELeave) CFbsBitmap; |
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241 CleanupStack::PushL(bmp); |
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242 |
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243 // get 1st viewfinder image from camera into bmp (detail excluded) |
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244 TSize bmpSize = bmp->SizeInPixels(); |
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245 |
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246 CPanoramaTransform* panTrans = CPanoramaTransform::NewL();//create panorama transoform |
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247 CleanupStack::PushL(panTrans); |
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248 |
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249 CVFTracker* vfTracker = CVFTracker::NewL(); //create VFTracker and load the plugin |
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250 CleanupStack::PushL(vfTracker); |
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251 |
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252 vfTracker->InitializeL(bmpSize); //Create VFTracker and set size |
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253 |
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254 CImagePanorama* panImage = CImagePanorama::NewL(); //create CImagePanorama object |
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255 CleanupStack::PushL(panImage); |
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256 |
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257 TDirection direction = EPanoramaDirectionRight; //assign direction |
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258 |
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259 // Lens parameters or internal camera characteristics should be available for the |
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260 // specific camera module in use. Here we use default values. |
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261 TPanoramaLens lens; |
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262 panImage->InitializeL(imageSize, lens, direction); //initialise size, lens, direction and create panorama engine |
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263 |
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264 // get the first captured image from the camera as a starting point - its name is given in capturedFileName |
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265 TFileName capturedFileName; |
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266 capturedFileName.Format(KFileCapturedImage(),i); |
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267 panImage->AddFileL(capturedFileName, *panTrans); //add the captured image |
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268 |
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269 do |
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270 { |
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271 // give the next camera viewfinder image to the tracker (details ommitted) |
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272 vfTracker->RegisterImageL(*bmp, *panTrans); // register viewfinder image |
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273 |
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274 // check if we have a good overlap with the previous image |
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275 if(vfTracker->IsTimeToCapture(direction, KPanoramaDefaultOverlap)) |
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276 { |
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277 // capture the next image from the camera (details ommitted) |
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278 capturedFileName.Format(KFileCapturedImage(),i); |
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279 |
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280 panImage->AddFileL(capturedFileName, *panTrans); //add the captured image |
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281 vfTracker->Reset(); //reset the VFTracker object |
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282 } |
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283 if ( err != KErrNone ) // some termination condition usually a signal from user |
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284 { |
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285 // no more viewfinder images |
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286 break; |
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287 } |
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288 } |
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289 while (1); |
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290 panImage->RenderL(KTestVFTOutputFileName); // render the stitched image |
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291 CleanupStack::PopAndDestroy(4,bmp); //panTrans, vfTracker, panImage, bmp |
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292 </codeblock> <p>The <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> is passed each viewfinder |
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293 images which it checks and determines whether it is right time to capture |
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294 the next image. In return it provides translation information <codeph>CPanoramaTransform::GetTranslation()</codeph> which |
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295 indicates the shift of the current viewfinder image. </p> <p>The extracted |
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296 information is used to draw the blue rectangle on the screen. If it is time |
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297 to capture, then it triggers the capturing function and restarts the <xref href="GUID-0D12EA24-3BF5-3BEA-B0EA-CEB89D49D352.dita"><apiname>CVFTracker</apiname></xref> again |
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298 for next image. </p> <p> <b>Note:</b> The box representation is used in the |
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299 UI, to help you to take better panorama images. In addition a vibration effect |
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300 can be used to provide additional feedback on when to capture an image. For |
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301 example, when you sweep the mobile phone, it is in tracking mode so it vibrates. |
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302 When the mobile phone is ready to capture, the vibration stops to let you |
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303 know that it must be static for capturing an accurate second image. Then when |
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304 it vibrates again, you must rotate the mobile and until it stop. </p> </li> |
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305 <li id="GUID-C7848E42-74B4-56D2-BB7B-2F20A4D30D32"><p> <b>User interface updating |
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306 details </b> </p> <p>The UI design detail is shown in step by step process. |
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307 They are as follows: </p> <ul> |
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308 <li id="GUID-99D23225-ECF9-5A34-ADAA-4E0A2326D768"><p>The total panorama coverage |
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309 area is divided into four different image areas: </p> <fig id="GUID-0808E657-6313-510C-9EB6-F4D49722229B"> |
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310 <image href="GUID-023D30F0-C1E8-5E09-92AD-C5A7963DCF70_d0e310453_href.jpg" placement="inline"/> |
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311 </fig> </li> |
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312 <li id="GUID-D06A8B59-81EE-5420-A3AE-FB036B7CE3F4"><p>When you choose to capture |
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313 a panorama image the following steps are performed. The first image is captured |
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314 at position 0. The UI looks as follows: </p> <fig id="GUID-A17F50EC-3241-56CA-B96A-59515EAF161B"> |
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315 <image href="GUID-C2D99C88-09C7-55FA-AF95-3F689BA27484_d0e310463_href.jpg" placement="inline"/> |
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316 </fig> </li> |
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317 <li id="GUID-BF4A2D67-EF8D-5F72-B2C2-9DC79E319023"><p>When you rotate the |
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318 mobile phone clockwise, the blue box moves to the right using the translation |
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319 information from <xref href="GUID-27BD164A-9283-3BE0-A0BF-A475539D86EA.dita"><apiname>CPanoramaTransform</apiname></xref>. At the same time the |
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320 vibrator is set on to give direct feedback for the tracking process. When |
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321 the blue box and the grey box (which represent the position to capture the |
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322 next image) coincide, the blue box turns into a filled blue box and the vibrator |
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323 stops. You then known that the next image is captured. At this moment the |
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324 camera must be steady. </p> <p>After second image is captured the blue box |
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325 is moving again and vibrator is set-on. The UI looks as follows: </p> <fig id="GUID-C6E583BB-EE47-52EE-BBFB-D7EE37156C12"> |
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326 <image href="GUID-B985B750-9B42-55ED-B7E4-41B06B44C365_d0e310480_href.jpg" placement="inline"/> |
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327 </fig> <p>Again, you rotate the mobile clockwise until the two boxes coincide |
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328 and vibrator stops; third image then captured. After this, the UI looks as |
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329 follows: </p> <fig id="GUID-FD9D81DA-E675-5C9C-BA6E-4E7DCE6F46D9"> |
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330 <image href="GUID-9E12593C-38EF-5052-A2E8-0AB25EEFF4D0_d0e310488_href.jpg" placement="inline"/> |
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331 </fig> <p>You rotate the mobile phone until the boxes coincide and the fourth |
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332 (last) image is captured. </p> <p> <b>Note:</b> If the mobile phone rotation |
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333 deviates from chosen (clockwise) direction or translates up and down, the |
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334 blue box indicates this, and you must correct the mobile phone for the wrong |
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335 movement. </p> <p>At this point the stitched image can be saved or you can |
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336 reset the camera, to create another panorama image: </p> <fig id="GUID-1A527BEA-0C50-5910-9525-75336C02B2C9"> |
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337 <image href="GUID-8E2303E9-DB60-5F38-A4D4-8BF8F7A1EF9F_d0e310505_href.jpg" placement="inline"/> |
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338 </fig> </li> |
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339 </ul> </li> |
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340 </ol> <p><b>Camera |
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341 calibration </b> </p> <p>In order to produce good panorama images, the internal |
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342 characteristics of the camera is calibrated by the <xref href="GUID-E361A378-76EB-36C9-A949-A5D31D4D1C4C.dita"><apiname>TPanoramaLens()</apiname></xref>. |
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343 The lens parameter such as the distance, the focal length, the principal point, |
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344 the skew, the width and the height are called the intrinsic parameters. </p> <p>The |
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345 camera module supplier should be able to provide this information or there |
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346 are a number of tools to get the camera parameters. A free tool that can be |
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347 used is the calibration functions in <xref href="http://en.wikipedia.org/wiki/Opencv" scope="external">OpenCV</xref>. Typically these tools need an input of images |
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348 of a special reference pattern, for example a checker board like grid, photographed |
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349 from many directions. From that the tools automatically generate all the desired |
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350 lens parameters. </p> </section> |
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351 </conbody></concept> |