How to set focal length of demo codes

[hongsukchoi]

Hi, thanks for the excellent work.

I want to ask about how you set the focal length of a mesh renderer.
In the demo codes, you set it to 1000 and it works well on the sample FreiHAND images.
However, when I test on other images, I have to set the focal length to 5000 for good projection.
Is there any math or reason behind setting the focal length? Thanks.

And by the way, the model does not perform bad on left hands as you've written in the demo README.
You can flip the input image of a left hand and assume it as a right hand.

[kevinlin311tw]

We empirically set focal length to 1000, following GraphCMR implementation. I wonder if you could provide an example that requires focal length=5000 for a good projection? I would like to check this issue. Thanks.

Thanks a lot for your brilliant solution! I didn't think of flipping the image 🤣

[hongsukchoi]

This image required me focal length to be 5000.
height: 720, width: 1040
If you want, I can send you the source video.

[canghaiyunfan]

@hongsukchoi How to render on the original image? I try to do it by affine transform, but failed.

[hongsukchoi]

You can do it by adjusting the intrinsic params of the virtual camera you are using to project.

https://github.com/hongsukchoi/3DCrowdNet_RELEASE/blob/3d84d17797e353aaf49acfd8087637eca2877292/demo/demo.py#L205