How to choose the variacne of 2D Mip Filter ?

[garrisonz]

Thanks for your great work! I understand more about 3dgs from your work!

In 6.1 Implementation, We choose the variance of our 2D Mip filter as 0.1, approximating a single pixel

My questions: How to deduce from a single pixel to 0.1 value？ By the way, what is the unit of 0.1?

In my understande: In computeCov2D function, cov[0][0] += kernel_size; means the scale (or unit) of kernel_size and cov should be the same, because they can add together. cov is the covariance in ray space. So the unit of 0.1 should be the unit in ray space. But why 0.1 in $(x_0, x_1)$ plane of ray space occupies a aingle pixel?

From Fig. 8 ray space. of EWA Splatting

Thanks!

[chensiyuan030105]

[niujinshuchong]

Hi, the variance of the 2D Gaussian filter is choose to approximate a box filter with a pixel size. We choose the value of 0.1. Here is a figure showing a box filter with 1 pixel wide and three Gaussian filters with different variances: 0.1, 0.3, 1.