def _get_pytorch3d_camera()

in dataset/co3d_dataset.py [0:0]

• 34 lines of code
• 8 McCabe index (conditional complexity)

    def _get_pytorch3d_camera(self, entry, scale, clamp_bbox_xyxy):
        # principal point and focal length
        principal_point = torch.tensor(
            entry.viewpoint.principal_point, dtype=torch.float
        )
        focal_length = torch.tensor(
            entry.viewpoint.focal_length, dtype=torch.float
        )

        # first, we convert from the legacy Pytorch3D NDC convention
        # (currently used in CO3D for storing intrinsics) to pixels
        half_image_size_wh_orig = (
            torch.tensor(list(reversed(entry.image.size)), dtype=torch.float)
            / 2.0
        )

        # principal point and focal length in pixels
        principal_point_px = (
            -1.0 * (principal_point - 1.0) * half_image_size_wh_orig
        )
        focal_length_px = focal_length * half_image_size_wh_orig
        if self.box_crop:
            assert clamp_bbox_xyxy is not None
            principal_point_px -= clamp_bbox_xyxy[:2]

        # now, convert from pixels to Pytorch3D v0.5+ NDC convention
        if self.image_height is None or self.image_width is None:
            out_size = list(reversed(entry.image.size))
        else:
            out_size = [self.image_width, self.image_height]

        half_image_size_output = torch.tensor(out_size, dtype=torch.float) / 2.0
        half_min_image_size_output = half_image_size_output.min()

        # rescaled principal point and focal length in ndc
        principal_point = (
            half_image_size_output - principal_point_px * scale
        ) / half_min_image_size_output
        focal_length = focal_length_px * scale / half_min_image_size_output

        return PerspectiveCameras(
            focal_length=focal_length[None],
            principal_point=principal_point[None],
            R=torch.tensor(entry.viewpoint.R, dtype=torch.float)[None],
            T=torch.tensor(entry.viewpoint.T, dtype=torch.float)[None],
        )