Half-Through The Lens Phase Difference Of Digital Camera System Without Reflector

There are two different structures of digital camera:ordinary digital camera which images directly through the lens to reach the image sensor and digital single lens reflex (DSLR) camera which use the structure of single-lens reflex. DSLR's structure is complex and it must equip with expensive large size image sensor, but DSLR have the following three advantages:1. A large number of lenses has been developed for previous film SLR camera, and most of these lenses can be directly used in DSLR camera, so DSLR have great advantages of ownership.2. Optical viewfinder through the lens has the features of high resolution, real-time display and High brightness display. These features have obvious advantages over the ordinary digital camera use LCD viewfinder or external optical viewfinder.3. The camera have the structure of single-lens reflex use phase difference AF that faster than contrast AF was used in ordinary camera, so SLR can meet higher shooting needs. These three advantages make large size image sensors was equipped in DSLR worth. What's more, this makes DSLR camera have the better image quality much than ordinary camera use small size image sensors. Of course, this also makes the price of SLDR camera expensive and its appearance cumbersome.On the other hand, the reversal of reflector produces a greater shock and sound when DSLR is shooting, it affects image clarity and some usage in quiet Occasions. At the same time, in order to get high quality image, the requirements of reflector's mechanical structure is very high. In addition, the reflector makes the imaging plane to be away from the edge of lens design, it limits lens design. With the rapid development of semiconductor technology, the production cost of large size image sensor decreased rapidly, so some higher-end ordinary cameras are also equipped with a large image sensor and lens can be replaced. These higher-end ordinary cameras can also use the existing lenses which were designed for SLR camera on the basis of without shortcomings of single-lens reflex structure, and with the progress of LCD viewfinder, the necessity of optical viewfinder is dropping. All of these represent important trends of the current digital camera technology. But because of without single-lens reflex structure, these kinds of camera can only use contrast AF which is slower than phase difference AF. So, AF performance has become the decisive factor that this kind camera can replace the single-lens reflex structure camera or not.The paper discusses a new digital camera system without reflector. The system uses main lens and main image sensor to find a view and execute exposure parameter detection. Through combining Auxiliaty I(?) and auxiliary image sensor, the system can use phase difference metho The system can avoid vibration and big size caused by the reflector and has the same speed of single-lens reflex camera.This paper reviews the history of the development of cameras, and make a brief introduction of the future development trend of digital cameras. Next introduces the system structure and working principle of digital camera and DSLR, and the principle of phase difference AF and contrast AF. Detailed analyzes the working principle and design ideals of the phase difference AF camera system without reflex. Finally, through the camera's live view function, the paper discusses a validation platform solution for this new camera system and researches deeply the imaging algorithm for extracting the difference which is the most critical algorithm in validation platform solution. Image matching based on gray and image matching based on Feature are discussed.