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A frequency-shift interference fringe locking system was established to enhance the contrast of holographic grating profile and to decrease the phase shift of exposure interference fringe caused by the external environment. According to the composition and the working principle of the system, the moire pattern occurrence condition in the measuring system and its dependence on the phase change of interference fringe were analyzed and the selection method for photodetectors was given. On the basis of the system accuracy, the digital control system was self-designed including A/D conversion digit. A optical frequency shifting method was used to regulate the fringe phase, and an acousto-optic modulator was taken to correct the frequency shifter of the interference fringe movement in real time. The experimental results illustrate that the system can offer a sampling frequency of 5 kHz and can restrain the interference fringe drift and low-frequency moving below 10 Hz. The 3 value of the phase shift is below 0.12 rad, which means its phase is within 0.02 interference fringe period. The system can lock the phase of the exposure interference fringe effectively in real time, and can satisfy the requirements of the holographic grating lithography better.

On the basis of the UMHexagonS algorithm used in the Joint Model(JM) for H.264,a new fast algorithm on integer pixel motion estimation was proposed to improve the video encoding characteristics.A new order of checking predicted Motion Vector(MV) was proposed in the predicting starting search point to promote the accuracy of starting search point.Then,a self-adaptive global search method was proposed for the global search,by which the unsymmetrical-cross search and uneven multi-hexagon-grid search could be skipped based on the relationship between two predicted MVs with highest accuracy,and the feasibility and accuracy of this judging method was verified through tests on a number of different sequences.Meanwhile,an improved 5×5 search method was presented according to the distribution of best MV relative to the starting search point and a new early termination technique for sub-macroblock was added to further reduce the cost of motion estimation without additional computation.According to the experiment results,the proposed algorithm reduces the total number of search points by 83.80% and the Peak Signal to Noise Ratio(PSNR) about 0.021 dB on average and increases an average increment of 0.46% on equivalent bitrates as compared with that of original UMHexagonS algorithm.With a negligible performance degradation,the proposed algorithm reduces the computation of motion estimation effectively and offers a well-distributed effect on sequences with different motion intensities.

SPIHT and NLS(Not List SPIHT) are efficient image compression algorithms,but the algorithms application is limited by the shortcomings of the poor error resistance and slow compression speed in the aviation areas.In this paper,the error resilience and the compression speed were improved.The remote sensing images were decomposed by Le Gall5/3 wavelet,and wavelet coefficients were indexed,scanned and allocated by the means of family blocks.The bit-plane importance was predicted by bitwise OR,so the N bit-planes can be encoded at the same time.Compared with the SPIHT algorithm,this modified algorithm is easy implemented by hardware.The experiments results show that the PSNR of reconstructed images was increased about 0.2 to 0.6 db and the speed was 4~6 times faster than the SPIHT encoding process.The speed can be further improved via virtue of the parallelism and pipelining,when it is implemented by the hardware.