We have devised a new and efficient method of zoom-convergence interlocked control in the moving-parallel axes style stereoscopic camera system. We set up a simple and smart algorithm of our own, which is based on the basic geometry of the stereoscopic camera system. And, instead of making the Look-Up-Table by measuring the zoom value and the convergence at each step, we utilized the lens data sheet, which can be obtained from the lens manufacturer, so that we can secure the accuracy and the handiness without any measuring.
The geometric differences between left and right images are known as a main factor of eye fatigue in the stereoscopic system. We developed a real-time stereoscopic error corrector which can adjust the vertical errors, the disparity, and the size (field of view) errors of HD moving pictures in VCR tape. The main idea of this system is to extract and use only the common area of both images by cropping the left and right images independently. For this system, we developed a realtime HD scaling hardware and stereoscopic error correcting software. We tested the system with the video streams taken by our HD stereoscopic camera. As a result, we confirmed that the developed system could reduce the efforts and time for correcting the stereoscopic errors compared to the other methods. We also developed a real-time zoom-convergence interlocked controller for HD parallel-axis stereoscopic camera using the same hardware. Because it doesn't need motors for parallax move, we could control the convergence more smoothly while locking it with zoom.
We have improved the HD stereoscopic camera system reported last year. Though the previous version shows good performance in many aspects, we felt some more accurate control mechanism should be realized after various types of trial shooting in field. So we have changed several parts of it. For controlling the separation between two cameras and the convergence of the parallel-axis style stereoscopic camera system, we replaced the linear motor system in the first version with small DC motors. And by changing the lens with full-digitally controlled HD lens, we could control both of the lenses more accurately. For the preparation of the real-time image composition with computer graphics, namely mixed-reality, in this version we fixed the updating frequency of the camera parameters to 60 Hz. In addition, for better zoom-convergence interlocked control, we made the look-up table with much more steps so even smoother operation of zoom-convergence control is accomplished. And, we have done subjective evaluation test on the acquired pictures. As we have implemented the function of storing and retrieving the major parameters of the stereoscopic camera, we could precisely analyze the relationship between the result of picture quality assessment and the camera parameters.
We have developed a reliable and practical HD stereoscopic camera system. It consists of a pair of full digital box-type HD video camera, small radius SD class lens, a multiplexer board and some other control boards. The camera is a parallel-axes style. We control the convergence by moving the lens slightly inward which is separated from the camera body. We have used two sets of linear motor modules to control the convergence and the distance between the two cameras precisely. The various camera parameters concerned with stereoscopic view can be displayed in the viewfinder, stored with video and used for studying picture quality improvement and assessment. We have combined zoom control with convergence control for the convenience of stereoscopic image capturing, so we can control them with one knob. They also can be controlled individually. The built-in multiplexer board receives two video signals from the left and right camera, and makes them into one side-by-side image that is compressed in half horizontally and multiplexed two images. After this process we can record the video into a normal VCR, then reconstruct the original two images by demultiplexer, and we can enjoy stereoscopic images.