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slothfulxtx / diff-gaussian-rasterization

Differentiable gaussian rasterization with depth, alpha, normal map and extra per-Gaussian attributes, also support camera pose gradient
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Question about renderCUDA #4

Closed zhanglk9 closed 4 months ago

zhanglk9 commented 8 months ago

Thanks for your great job! I want to know why added the accum_rea = last_alpha + (1.f - last_alpha) * accum_rea; dL_dalpha += (1 - accum_rea) * dL_dpixel_alpha; in renderCUDA backward.cu You know that in the gaussian-splatting's code ,this isn't be added. and how can I get the formula about this part.

slothfulxtx commented 7 months ago

Hi, We wanna support the gradient back-propagation of alpha map supervision. Sometimes we have the ground truth alpha map of the scene, and we may compute the l1 loss between the predicted alpha map and GT.