Call rescale_output_resolution before early return

[pierotofy]

Hello 👋

While looking through the splatfacto implementation, I noticed that in the case of an early exit in the forward pass due to a zero radii sum the camera does not get rescaled back to its original dimensions. I think this might be a mistake? I haven't found a dataset where the condition occurs, but it seems correct to make sure the camera is rescaled back before returning.

[chungmin99]

in the case of an early exit in the forward pass due to a zero radii sum the camera does not get rescaled back

Thank you for catching it! This condition can actually happen quite frequently when there's no gaussians in front (e.g., due to cropping + moving the camera away from the cropbox).

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The fix looks great, but I'm just wondering if we can remove duplicate code, by moving the camera rescaling logic (L745, and L763) before the radii check (L738):

nerfstudio/nerfstudio/models/splatfacto.py

Lines 737 to 747 in c5520fb

	tile_bounds,
	) # type: ignore
	if (self.radii).sum() == 0:
	rgb = background.repeat(int(camera.height.item()), int(camera.width.item()), 1)
	depth = background.new_ones(*rgb.shape[:2], 1) * 10
	accumulation = background.new_zeros(*rgb.shape[:2], 1)
	# rescale the camera back to original dimensions before returning
	camera.rescale_output_resolution(camera_downscale)
	return {"rgb": rgb, "depth": depth, "accumulation": accumulation}

And we can change rgb = background.repeat(int(camera.height.item()), int(camera.width.item()), 1) to rgb=background.repeat(H, W, 1).

... unless there's any dependence on the camera object I'm missing between L750-760.

[jb-ye]

Thanks for catching the issue. Instead of adding this line to early return, could you move the line later to an earlier position: right after project_gaussian() call. We no longer need camera after that.

[jb-ye]

You can test your code by enabling --pipeline.model.num_downscales=2 because currently it is set to zero by default.

[jb-ye]

lgtm