An Energy-Efficient, Resource-Efficient and High Frame-Rate End-to-End Pedestrian Detector Using HOG-SVM for Intelligent Edge Devices

This paper proposes a Histogram of Oriented Gradients-Support Vector Machine (HOG-SVM) based pedestrian detector with an end-to-end fully-pipelined architecture to achieve a high frame rate by improving the throughput, and reduce the power consumption by minimizing the data movement. To further improve the energy efficiency under the high frame rate, a bit-width pruning method is used to remove the gray-scale converter's redundant data bit width, and a block-score normalization is employed to significantly reduce the normalizer's required divisions. The reduced computation amount also saves the hardware overhead while maintaining the same calculation accuracy. Besides, a modeling and analysis method of the SVM-classifier-Multiply-ACcumulate (MAC) array is proposed to further improve the energy efficiency and save the logic resources, by optimizing the array size with a hardware utilization of 98.4% while maintaining the same throughput. The FPGA implementation results of
$640\times 480$
video show a high frame rate of up to 439 fps @143 MHz and a high energy efficiency of 0.76 nJ/pixel with 46.7% fewer LUTs, 22.4% fewer registers, 88.3% fewer DSPs, compared to the state-of-the-art design. The ASIC implementation in 55 nm also confirms a high energy efficiency of 0.35 nJ/pixels at 613 fps and 200 MHz as well as a hardware overhead of 177 k gates and 108 Kbits SRAM.