Patent US 7,907,796

A method for aligning a tape cartridge accessor with cartridges in cells of a tape cartridge magazine is provided. IR illumination is applied to an object expected to include a desired physical feature. Specular reflections are received from the illuminated object to create an image of the object. Dynamic image thresholding is applied to the image to select an optimum gray scale level of the image expected to include the desired physical feature. Bounding boxes are used to identify the location of the desired physical feature in the thresholded image.