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Radiometric calibration with illumination change for outdoor scene analysis. CVPR 2008 Advisor: Prof. H.Y. Lin Reporter: Annie Lin Date: 2009-8-11 . Outline . Introduction W e change the illuminance , no exposure for radiometric response function
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Radiometric calibration with illumination change for outdoor scene analysis CVPR 2008 Advisor: Prof. H.Y. Lin Reporter: Annie Lin Date: 2009-8-11
Outline • Introduction • We change the illuminance , no exposure for radiometric response function • The steps of radiometric calibration • Experiments • Conclusion
Auto-exposure Introduction Fixed exposure • Past: change exposure • Now: wish a actual scene radiance • Lambertian surface • Group pixels with same behaviors • Same exposure • Change illuminance , make different light • Problem: • change in intensity -> change both exposure & illuminance • Solves: • Model the illumination variation according to the motion ofsun, deal with outdoor scenes • Steps: • 1. Radiometric calibration • 2. Introduce a method for computing the camera response function, using images with illumination change • 3. Develop methods for computing the exposure value for each image in a sequence
Compute the radiometric response function with illumination change If 2 points have the same surface normal (same light conditions ,behavior) Response functionf transforms Const. Response function with different illumination
Finding pixels with same lighting conditions Cluster pixels with the same lighting conditions n pixels selected for a cluster (at time t) How much support the pixel i –dot product between dit and dit+1 -> remove pixels with the worst support(crossing line)
Radiometric response function estimation Same cluster l, time t
Exposure estimation 1. Modeling the illumination with the motion of the sun
2. Exposure estimation Uy = 0 Different exposure Illuminance Not to use pixel value when the pixels fall into shadow regions
Auto- exposure Fixed exposure The method of this paper