Yingen Xiong and Kari Pulli Download our panorama software httpstoreovicomcontent51491 Outline Introduction What is the problem Why do we need color correction Related work ID: 359626
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Slide1
Color Matching of Image Sequences with Combined Gamma and Linear Corrections
Yingen Xiong
and Kari Pulli
Download our panorama software :
http://store.ovi.com/content/51491
Slide2
OutlineIntroductionWhat is the problem? Why do we need color correction?Related workColor correction with color matchingProblem expressionColor matching by gamma correctionColor mean matching by gamma correction
Combination of gamma and linear correctionsApplications and resultsConclusions
2Slide3
Introduction: Mobile Panorama System3
Image registration
Image warping
or
Image blending
Image capturing
camera
Color correction
Image labeling
Object editing
Panorama viewing
Download our panorama software:
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Slide4
What is the Problem?Image parameters (focus, exposure, WB) change for each imageChanges in illumination lead to different exposure levels The same objects in different frames may have different apparent colors4Slide5
Panorama Stitching without Color Correction
Stitching artifacts ; visible seams; bad color transitions
5Slide6
Color Correction to Reduce Color Differences Perform color correction before panorama stitching6Slide7
Related WorkLinear-model-based color correctionColor correctionLuminance correctionPolynomial mapping and others
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sRGB color space
Tian
et al. 2002
YCbCr color space
Ha et al. 2007
Linearized RGB color space
Xiong and Pulli 2009
Histogram mapping
Zhang et al. 2001
Linearized RGB color space
Meunier and Borgmann 2000
sRGB color space
Brown and Lowe 2007
Pham and Pringle 1995
Polynomial mappingSlide8
Color Correction using Linear ModelOriginal source images with different colorsSimple, fast, color saturation, low quality8Slide9
Efficient Color Correction is Needed Avoid saturation problemsReduce color differences9Slide10
Color Matching with Gamma Correction10Slide11
Color Matching with Gamma Correction11Slide12
Color Mean Matching with Gamma Correction12Slide13
Color Mean Matching with Gamma Correction13Slide14
Combination of Gamma and Linear Correction14Slide15
Combination of Gamma and Linear Correction15Slide16
Comparison of the Results 16Slide17
Applications and Result AnalysisApplication environmentImplemented in a mobile panorama imaging systemRuns on several mobile devicesNokia N900, N8, N95, …
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Nokia N95 8G
ARM 11
332 MHz processor
128MB
RAM
ARM Cortex A8 600 MHz processor
256MB RAM
768MB virtual memory
3.5 inch touch display
Nokia
N900
Nokia
N8Slide18
Computation TimeComputational time for color correction:5 images: 0.37, 1.08, 1.86 seconds
10 images: 0.97, 1.56, 4.12 seconds
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ResolutionTime for 5 Images (sec.)
Time for 10 Images (sec.)
A
B
C
DAB
CD
1280x9600.373.30
2.486.15
0.976.965.44
13.372048x1536
1.086.724.70
12.501.56
14.4410.4626.46
2576x19361.86
15.9812.25
30.094.1235.63
29.3469.09
A: color correction, B image labeling, C: image blending, D: image stitchingSlide19
Color and Color Mean matchingSlide20
Gamma Correction in Different Color SpacesSlide21
Different Color Correction21Local linear correction in sRGB
Local linear correction in
YCbCr
Global linear correction in
sRGB
Color matching with gamma correction
Color matching with gamma mean correctionSlide22
Different Color Correction22
Local linear correction in
sRGB
Local linear correction in
YCbCr
Global linear correction in
sRGB
Color matching with gamma correction
Color matching with gamma mean correctionSlide23
Image Sequences with Random Order23Slide24
More Examples24Slide25
ConclusionsColor correction with color matching Gamma correction for luminanceLinear correction for chrominanceImplementationRuns on mobile phones, high qualitydownload from http://store.ovi.com
to your N8 / N900AdvantagesNo color saturation problems during color correction
Good color transitions for the whole image sequenceEfficient (fast) execution25Slide26
Thank You26Slide27
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Questions?
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http://store.ovi.com/content/51491