Patent ID: 8165351

Claim:
A method of structured light-based measurement for determining the distance from a probe of a video inspection device to an object, wherein the video inspection device has a first light emitter and a second light emitter for emitting light through an opening with at least one shadow-forming element onto the object forming a plurality of shadows on the object when the light emitters are activated, the method comprising the steps of: capturing at least one first emitter image of the object with the first light emitter activated, and the second light emitter deactivated, wherein the first emitter image has a first shadow formed by the at least one shadow-forming element; capturing at least one second emitter image of the object with the second light emitter activated, and the first light emitter deactivated, wherein the second emitter image has a second shadow formed by the at least one shadow-forming element; 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 first plurality of luminance values of the pixels in the at least one first emitter image to the second plurality of luminance values of the pixels in the at least one second emitter image; and determining an object distance using the brightness ratios.