Although the New Vickers Hardness Tester has integrated with today's high and new technologies, and has been digitalized, automated, intellectualized, and gradually developed into a video-based photoelectric detector, one of the key technologies still be the advanced Optical Imaging Technology. Putting this technology into use, an Optical Image Acquisition System with fine image quality can be designed and created. The key technologies of Vickers Hardness
Tester are discussed in this paper with an example of Anchor Clamp Hardness Photoelectric Detection System including the Special Infinite Image Distance Optical System and Image Processing Software. A Special Infinite Image Distance Optical System composed of high amplification Semi-apochromatic Microscope Objective lens with Flat-field and long working distance and Photographic Objective lens is designed, and taking the advantage of optical device based on the Special Infinite Image Distance Optical System, the image of the shape of impression of a diamond cone can easily be
acquired when it is pressed into Anchor Clamp. Indention image processing are carried out through the self-designed Image Processing Software. At present, this system has been successfully applied to Anchor Clamp Hardness On-line Lossless Automatic Detection Apparatus.