| With the rapid development of laser and liquid crystal technology, display technology has also been developed very fast. Laser display and three-dimensional (3D) display have become an important part of modern display technology. But there are lots of problems which prevent these technologies becoming popular in the market, for example, the image quality is very poor in laser display because of speckle, the cross talk and lack of film sources make the auto-stereoscopic can’t go into families. Speckle is a phenomena which is result from laser’s high coherence, it reduce the resolution of images. To reduce speckle, the model of speckle in laser display system has been established, the influence of laser source’s statistical properties on speckle have been studied, the feature of speckle in laser projection system has also been studied, and two kinds of speckle suppression methods have been proposed based on the features. Speckle contrast is the basement of speckle reduction and speckle sensing technology, but the contrast measurement hasn’t been standardized. The influence of parameter of CCD has been investigated and the images of speckle photo by CCD are also been analyzed and the noise caused by spatial light modulator (SLM) and color filter array (CFA) are suppressed by algorithms. Auto-stereoscopic is the development trend of3D display, the multi-view point has lots of advantages such as low cross-talk, high sense of depth, but lack of film sources makes it not be popular. To fix this problem we developed a single projection3D display system using laser resource.The main research works are as follows:1. Laser speckle theory is introduced in detail, the statistical properties are analyzed and the influence of laser coherence properties on speckle has been studied. It has been proved that when the sinusoidal of the angle between two incoherence light sources is less than the number aperture of imaging system, the coherence between the two light sources is the least. And the dependencies between speckle and projection screen is analyzed, after theoretical simulation and experimental verification, it has been proved that the speckle contrast is inversely proportional to the thickness of rear projection screen, 2. The characteristic of speckle in laser projection system has been analyzed, the most common methods of speckle suppression have been summarized. And it is proved that when speckle is reduced with diffuser, the speckle contrast is inversely proportional to the square root of the spot illuminated on the diffuser. On this basis, the set up using piezoelectric ceramics (PZT) and dielectric elastomer actuators (DEAs) vibrating the diffuser in the larger projection display system have been designed, and the speckle contrast is reduced to0.06and0.1, which satisfied people’s watching needs. And in the smaller projection display system, electronic controls Polymer Dispersed Liquid Crystal (PDLC) and liquid crystal modulates spatial polarization state have been proposed, the theoretical simulation and experimental have been verified, these methods can be supplement of the current speckle reduction methods.3. To resolve the problem of speckle measurement standardization, we test the relationship between parameter of charge-coupled device (CCD) such as f-number, distance, angle, integration time, defocus and speckle contrast in experiment. To simulate human eyes’characteristic an eye model is designed with Zemax and the influence of eyes on speckle is also analyzed. Thus a standardized speckle measurement system is set up with human eyes’ property. The noise in the image shoot by this system has also been suppressed, including removing the array noise which is result from the SLM by Fourier translation, the suppression of the noise introduced by the CFA and experiment is also verified. And a new evaluation criteria is introduced to judge the image clarity.4. The principle of auto-stereoscopic display and glasses-stereoscopic display are introduced clearly, the advantage of auto-stereoscopic in reducing cross-talk, enhancing depth sensing are analyzed. A new algorithm is developed to solve the question that lack of multi-view point movie. This algorithm is based on SIFT algorithm and depth calculation algorithm, and it achieve to change two-view point figure into multi-view point figure. To meet the needs of family life, a single projection3D display system using laser resource is developed; the performance of key element such as SLM, LC polarizer, rear screen is analyzed. The shortage of this system is also analyzed and the theoretical solutions is put forward which can guide the next stage’s experiment work.Highlights of the dissertation are as follows:1. A new algorithm is developed to change two-view point figure into multi-view point figure. A single chip rear projection display system with the laser resource is built, the shortage of this system is also analyzed and the theoretical solutions is put forward which can guide the next stage’s experiment work. The principle of speckle in laser projection display system has been analyzed, the influence of the location of laser and the laser spot’s size illuminated on the diffuser on speckle are derived in theoretical and verified in experiment, the result can guide the design of projection system.2. It’s first time to propose electronic controls PDLC and change polarization of LC to reduce speckle, experiment has been verified. The suppression effect, the requirement of LC’s parameter and the improvement of the system can be achieved from experiment.3. Simulating the human eyes and the influence of characteristic on speckle is analyzed. The influence of CCD’s parameter on speckle measurement has been qualified from experiment. A standardized speckle measurement system is set up with human eyes’ property. The noise in the image shoot by this system has also been suppressed and a new evaluation criteria is introduced to judge the image clarity. |
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