[jviolette123]

Suppose your camera was a somewhere in mid-field.

If the camera were looking directly at the backboard, that is, your rectangle is in the center of the field of view, then you would get a large reading for the pixel count, indicating you are close to the backboard.

If the camera were looking off to the side, then your rectangle is at the edge of the field of view. The rectangle would be smaller by up to 25% in pixel count than at the center. Any calculation based on that smaller number would say that you are farther than you really are.

The answer you get at the same distance depends on where the backboard is in the field of view. You can correct for that after the fact, or you can correct the image in the first place. We chose to correct the image.