compute_rays

giant.ray_tracer.rays:

giant.ray_tracer.rays.compute_rays(model, rows, cols, grid_size=1, temperature=0, image_number=0)[source]

Compute rays passing through the given row, col pairs for the given camera in the camera frame.

The rays are assumed to start at the origin of the camera frame (0, 0, 0). The directions are formed by calls to CameraModel.pixels_to_unit() and are generate all at once. The pixel values corresponding to the generated rays are returned second as a 2xn array.

When creating the rays, you can specify how many rays per pixel you want to generate (evenly distributed in a square subpixel pattern) using the grid_size argument. The result will be

   1  2        grid_size
+------ ... ------+
|                 |
|                 |
|  x  x ... x  x  | 1
|                 |
|                 |
|  x  x ... x  x  | 2
...             ...
|  x  x ... x  x  | grid_size -1
|                 |
|                 |
|  x  x ... x  x  | grid_size
|                 |
|                 |
+------ ... ------+

where +-| indicates the bounds of the pixel, and x indices subpixel locations for the rays (with even spacing between each sub-pixel location and the edges of the pixel.

Parameters:

  • model (CameraModel) – A camera model object which is used to set the direction for the rays

  • rows (Sequence | ndarray) – An array like list of rows to generate rays through (paired with cols). If there are only 2 elements then it is assumed that this is a min, max pair (inclusive on both sides) and you want to generate rays for every pixel between min and max

  • cols (Sequence | ndarray) – An array like list of cols to generate rays through (paired with rows). If there are only 2 elements then it is assumed that this is a min, max pair (inclusive on both sides) and you want to generate rays for every pixel between min and max

  • grid_size (int) – The number of rays per edge of pixel (sqrt of number of rays). There will be grid_size*grid_size rays evenly distributed through the area of each pixel pair requested

  • temperature (Real) – The temperature of the image the rays are being computed for passed to CameraModel.pixels_to_unit()

  • image_number (int) – The number of the image the rays are being created for pass to CameraModel.pixels_to_unit()

Returns:

The rays passing through the requested pixels in the camera frame and the subpixel locations

Return type:

Tuple[Rays, ndarray]