ISSN : 1796-2048
Volume : 2    Issue : 5    Date : September 2007

FPGA-based Real-time Optical Flow Algorithm Design and Implementation
Zhaoyi Wei, Dah-Jye Lee, and Brent E. Nelson
Page(s): 38-45
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Optical flow algorithms are difficult to apply to robotic vision applications in practice because of their
extremely high computational and frame rate requirements. In most cases, traditional general
purpose processors and sequentially executed software cannot compute optical flow in real time. In
this paper, a tensor-based optical flow algorithm is developed and implemented using field
programmable gate array (FPGA) technology. The resulting algorithm is significantly more accurate
than previously published FPGA results and was specifically developed to be implemented using a
pipelined hardware structure. The design can process 640 × 480 images at 64 fps, which is fast
enough for most real-time robot navigation applications. This design has low resource
requirements, making it easier to fit into small embedded systems. Error analysis on a synthetic
image sequence is given to show its effectiveness. The algorithm is also tested on a real image
sequence to show its robustness and limitations. The resulting limitations are analyzed and an
improved scheme is then proposed. It is then shown that the performance of the design could be
substantially improved with sufficient hardware resources.

Index Terms
Optical flow, FPGA, Motion estimation