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# Final Project - PowerPoint PPT Presentation

Final Project. 601410058 黃啟承. High Dynamic Range. 使 真實世界場景的亮暗對比，正確呈現在影像上。 現今多使用不同曝光度 的影像來產生 HDR image 。. approach.

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## PowerPoint Slideshow about 'Final Project' - miach

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### Final Project

601410058

• 使真實世界場景的亮暗對比，正確呈現在影像上。

• 現今多使用不同曝光度的影像來產生HDRimage。

• Reference : Paul E. Debevec , Jitendra Malik, Recovering high dynamic range radiance maps from photographs, Proceedings of the 24th annual conference on Computer graphics and interactive techniques, p.369-378, August 1997

• 這篇使用不同曝光量照片來恢復成像過程的response function，從已知response function可以將多張影像合成單一影像。

film response recovery

• film reciprocity equation

• Zij where i is a spatial index over pixels and j indexes over exposure times ∆tj, E is the irradiance.

• Assume ∫ is invertible, and taking the natural logarithm

• ;

• Define , so

• recovering g only requires recovering the finite number of values that g(z) can take since the domain of Z.

• minimize the following quadratic objective function

• Zmin and Zmax be the least and greatest pixel values (integers), N be the number of pixel locations and P be the number of photographs

• use

• introduce the additional values that g(z) can take since the domain of constraint

• introduce a weighting function w(z) to emphasize the smoothness and fitting terms toward the middle of the curve.

• Now,

• We obtain values that g(z) can take since the domain of

• we reuse the weighting function in Equation 4 to give higher weight to exposures in which the pixel’s value is closer to the middle of the response function

• Equation 4 :

result values that g(z) can take since the domain of

• Source exposure times (32, 16, 8, 4)

• Source values that g(z) can take since the domain of exposure times (2, 1, 1/2, 1/4)

• Source values that g(z) can take since the domain of exposure times (1/8, 1/16, 1/32, 1/64)

• Source values that g(z) can take since the domain of exposure times (1/128, 1/256, 1/512, 1/1024)

• Output values that g(z) can take since the domain of

• 藍色的部分為原本影像既有

programs values that g(z) can take since the domain of