An Efficient High-Throughput Structured-Light Depth Engine

Abstract

In this article, an efficient high-throughput depth engine is proposed to generate high-quality 3-D depth maps for speckle-pattern structured-light depth cameras. A dynamic-binarization (DB) method is introduced with a significant reduction of computational complexity in contrast to the sum-of-absolute-distance (SAD) method. The depth map evaluation shows good robustness compared with other window-based correlation methods. Parallel architecture and reuse of intermediate results are employed for efficient hardware implementation. Our design is verified on a field-programmable gate array (FPGA) and implemented in the SMIC 55-nm CMOS technology, achieving a frame rate of 1731.77 fps ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$640\times480$ </tex-math></inline-formula> ) with an area efficiency of 3.75 fps/KGE. The proposed engine shows a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.71\times $ </tex-math></inline-formula> promotion of area efficiency in contrast to the SAD-based implementation. In addition, the subpixel estimation algorithm deployed in postprocessing is optimized for efficient hardware implementation, reducing the gate count by 69.2% without significant performance loss.