A Hardware-Efficient Architecture for Accurate Real-Time Disparity Map Estimation

Emerging embedded vision systems utilize disparity estimation as a means to perceive depth information to intelligently interact with their host environment and take appropriate actions. Such systems demand high processing performance and accurate depth perception while requiring low energy consumption, especially when dealing with mobile and embedded applications, such as robotics, navigation, and security. The majority of real-time dedicated hardware implementations of disparity estimation systems have adopted local algorithms relying on simple cost aggregation strategies with fixed and rectangular correlation windows. However, such algorithms generally suffer from significant ambiguity along depth borders and areas with low texture. To this end, this article presents the hardware architecture of a disparity estimation system that enables good performance in both accuracy and speed. The architecture implements an adaptive support weight stereo correspondence algorithm that integrates image segmentation information in an attempt to increase the robustness of the matching process. The article also presents hardware-oriented algorithmic modifications/optimization techniques that make the algorithm hardware-friendly and suitable for efficient dedicated hardware implementation. A comparison to the literature asserts that an FPGA implementation of the proposed architecture is among the fastest implementations in terms of million disparity estimations per second (MDE/s), and with an overall accuracy of 90.21%, it presents an effective processing speed/disparity map accuracy trade-off.