Feature Extraction Acceleration to Stabilize Execution Time for Real-Time Applications in Low-Cost Embedded Systems

摘要

Extracted features are widely used for image processing. Many research endeavors have been undertaken to extract significant features of fast moving images. Appropriate algorithm processing is necessary to extract features and provide features to the other modules in real time with low-cost embedded systems. The features from accelerated segment test (FAST) algorithm is renowned for feature extraction. FAST is composed of simple arithmetic operators. In this study, FAST is employed to implement the hardware accelerator in a field-programmable gate array for small embedded systems. Meanwhile, the threshold value in FAST affects the number of extracted features and the execution time. The precarious execution time makes it difficult for the system to schedule the timing of system functions and thus degrades the performance. An appropriate method is necessary to stabilize the execution time. A dynamic threshold controller in a FAST hardware accelerator is thus proposed to enable a stable execution time. A proportional integral controller composed of an adder, subtractor, and shifter is applied for low design implementation costs. The proposed approach occupies 2,263 slice flip-flops, 3,498 look-up tables, and 17 block RAMs in a Xilinx Virtex 5 FX field-programmable gate array. It requires 3.87 ms for continuous 800 x 480 images from the KITTI benchmark.