A multiwavelength midinfrared quasi-phase-matched (QPM) difference frequency generation (DFG) scheme is proposed based on a segmented temperature controlling technique for the uniform grating periodically poled lithium niobate (PPLN). The QPM DFG output performances have been investigated under the fixed pump and signal wavelength conditions, respectively. Our theoretical results show that when the pump wavelength is fixed at 1.08 μm, three idler QPM bands, located at 3.46, 3.50, and 3.57 μm, have been obtained, where the temperatures of the three PPLN segments with the same length are set at 20°C, 70°C, and 100°C. However, when the signal wavelength is fixed at 1.58 μm, six idler QPM bands, located at 2.95, 3.06, 3.14, 3.63, 3.72, and 3.83 μm, have been achieved with the same crystal temperature distribution of 20°C, 70°C, and 100°C.
On the base of analyzing the dual-channel systems, a single-channel dual-band false color night imaging principium
based on inter-frame compensation is proposed to realize originally dual-channel dual-band on single-channel system
with a raster filter setting forward. Single channel double spectrum low light level system can receive stripe image
included two spectrum information of low light level in single channel by stripe filter slice. On the aspect of the
dual-band low light level images separation and compensation, the technique of spectrum separation and compensation
reconstruction were researched, the stripe low light level images were obtained from the scenery actual imaging with the
'long' wave information and the 'short' wave information in turn. The sample block compensation method based on the
correlation of the gray space and the inter-frame compensation methods were designed to compensate the split dual-band
images. The simulation experimental study of the dual-band low light level image separation and the compensation
technique were done, the results indicate that the above methods in the single channel dual-spectrum color low light level
system have applied effectively, and have achieved the goal of the dual-band low light level image separation and the
Proc. SPIE. 6149, 2nd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies
KEYWORDS: Target detection, Infrared detectors, Infrared imaging, Digital signal processing, Image segmentation, Field programmable gate arrays, Signal processing, Infrared radiation, Target recognition, Binary data
In the technique on the detecting and the identifying of infrared target, the infrared target and the background can be distinguished by the difference of the gray-scale, i.e. the difference in temperature between them. Firstly, FPGA was used to pre-treat the infrared image including the threshold segmentation of two-apex and the threshold segmentation of maximum between-cluster variance. Secondly, the figure of the target was obtained, and then the binary image was transferred to the DSP which identified it. The high efficiency of FPGA in simple-shape computing of digital signal processing was stood out.