Patent attributes
A computer, including a processor and a memory, the memory including instructions to be executed by the processor to acquire a first image by illuminating a first object with a first light beam, determine a first measure based on a first number of pixels corresponding to the first object in the first image and determine a relative distance measure by comparing the first measure based on the first number of pixels corresponding to the first object to a second measure based on a second number of pixels corresponding to a second object in the first image. The instructions can include instructions to modify the first measure of pixel values based on the relative distance measure, perform a comparison of the modified first measure of pixel values to a third measure of pixel values determined from a second image of a second object, and when the comparison determines that the first measure is equal to the third measure of pixel values within a tolerance, determine that the first object and the second object are a same object.