Morphological automatic Landolt C orientation detection

A method and apparatus are provided for automatically assessing a resolution of an optical sensor. An image is obtained from the sensor. The obtained image is thresholded to generate a binary image of black and white pixels using a first threshold value. A target area is selected from the binary image. The first threshold value is increased to generate a second threshold value. The target is thresholded using the second threshold value. At least one pixel is tagged at a center of the target area. Pixels surrounding a tagged pixel are processed, tagging white pixels. If a tagged pixel is at an edge of the target area, an orientation of an object in the target area is determined based on that edge. And, if no pixel is tagged at the edge of the target area, the second threshold value is decreased and the thresholding, tagging, and processing steps are repeated.