Z-AXIS HEIGHT MEASURMENT SYSTEM

This invention concerns an optical system for use with a television camera for detecting the surface location of an object. A preferred optical image having a distinct, unique, recognizable pattern is projected on a surface along a defined path that ultimately falls on an imaging sensor associated with a television camera. The optical configuration causes a maximum light pattern energy to fall on the image sensor when the focal point coincides exactly with the surface of the object being detected. The system is not an automatic focussing system, since best focus is normally considered to be that condition which produces an image of maximum detail and sharpness, and the present invention does not rely on detail or sharpness of image for its operation. The invention can be used as an automatic focussing device if desired, since best focus can be derived as a useful by-product of accurate surface detection. In operation the camera moves in the Z direction through the point of maximum light pattern energy. The Z-axis position of the energy peak value is a function of the optical design. An output signal from the camera is filtered and processed and calculated to the Z-axis height of the camera as a measure of the distance to the object surface being detected.