US Patent 8165351 Method of structured light-based measurement

A method of determining the distance to an object can use a video inspection device comprising a first light emitter and a second light emitter, wherein the first light emitter can emit light through an opening with at least one shadow-forming element. The method can comprise capturing at least one first emitter image with the first light emitter activated and the second light emitter deactivated, capturing at least one second emitter image with the second light emitter activated and the first light emitter deactivated, determining a first plurality of luminance values of the pixels in the at least one first emitter image, determining a second plurality of luminance values of the pixels in the at least one second emitter image, determining the brightness ratios of the second plurality of luminance values to the first plurality of luminance values, and determining an object distance using the brightness ratios.