Based on the existed ways of 2-D reconstructed images by spatial light modulator (SLM), the methods to enhance the reconstructed quality of 3-D images are investigated in this paper. Based on the diffraction theory, the effects of a lattice SLM with a limited fill factor on the reconstructed images are analyzed. Through adding the phase of the convergent spherical wave, the two focused planes of reconstructed images and the multi-order beams caused by the lattice structure of the SLM can be separated spatially. Therefore, the spatial filter is used to eliminate the influences of higher-orders diffraction beams and zero-order light of reconstructed images, respectively. A holographic optoelectronic display system based on liquid crystal spatial light modulator (LC-SLM) is set up to demonstrate this method.
A dual-channel fusion system of visual and infrared images based on color transfer The increasing availability and deployment of imaging sensors operating in multiple spectrums has led to a large research effort in image fusion, resulting in a plethora of pixel-level image fusion algorithms. However, most of these algorithms have gray or false color fusion results which are not adapt to human vision. Transfer color from a day-time reference image to get natural color fusion result is an effective way to solve this problem, but the computation cost of color transfer is expensive and can’t meet the request of real-time image processing. We developed a dual-channel infrared and visual images fusion system based on TMS320DM642 digital signal processing chip. The system is divided into image acquisition and registration unit, image fusion processing unit, system control unit and image fusion result out-put unit. The image registration of dual-channel images is realized by combining hardware and software methods in the system. False color image fusion algorithm in RGB color space is used to get R-G fused image, then the system chooses a reference image to transfer color to the fusion result. A color lookup table based on statistical properties of images is proposed to solve the complexity computation problem in color transfer. The mapping calculation between the standard lookup table and the improved color lookup table is simple and only once for a fixed scene. The real-time fusion and natural colorization of infrared and visual images are realized by this system. The experimental result shows that the color-transferred images have a natural color perception to human eyes, and can highlight the targets effectively with clear background details. Human observers with this system will be able to interpret the image better and faster, thereby improving situational awareness and reducing target detection time.