Research And Implementation Of Single Channel Millimeter Wave Coding Imaging Theory

In order to overcome the shortcomings that the signal-to-noise ratio is low and the imaging time is long of the single channel millimeter wave imaging system, this thesis combined the Hadamard transform theory and millimeter wave imaging and then built a single channel millimeter wave coding imaging model. Simultaneously measure of multi pixel with a single detector (millimeter-wave radiometer) is realized through the use of encoding measurement baffle. Coding and decoding algorithm program and a signal sampling and processing board that based on DSP and FPGA were designed. The primary contributions of this paper are listed as follows.This paper designed the single channel millimeter-wave imaging system and established the corresponding mathematical model which based on the analysis of passive millimeter-wave imaging and Hadamard transform theory. After comparison and analysis of several typical encoding matrixs, the left cyclic S matrix is employed in the system, meanwhile, fast Hadamard transform which based on symmetric π transform is adopted as the decoding algorithm of the system.In this thesis, advantages and disadvantages of reentry motion measurement baffle, linear motion measurement baffle and rotary motion measurement baffle are discussed. Based on that, according to actual application requirements, we designed the rotary motion measurement baffle which based on 31*33 orders left cyclic S matrix.On the basis of a millimeter wave image existed, coding measurement algorithm and fast Hadamard decoding algorithm based on symmetric π transform were accomplished using C language. The simulation verifies the correctness of the imaging model. Then we analysised the computational complexity of the decoding algorithm, and successfully migrated it on an image processing hardware platform which taking DM643 as the core processor.At last, we designed a dual core architecture embedded image processing board which consists of TMS320DM6437 and XC3S1600E. The board mainly implements the functions of data sampling, decoding, control of baffle’s motion and display.