Dedicated hardware processor and corresponding system-on-chip design for real-time laser speckle imaging

Abstract

Laser speckle imaging (LSI) is a noninvasive and full-field optical imaging technique which produces two-dimensional blood flow maps of tissues from the raw laser speckle images captured by a CCD camera without scanning. We present a hardware-friendly algorithm for the real-time processing of laser speckle imaging. The algorithm is developed and optimized specifically for LSI processing in the field programmable gate array (FPGA). Based on this algorithm, we designed a dedicated hardware processor for real-time LSI in FPGA. The pipeline processing scheme and parallel computing architecture are introduced into the design of this LSI hardware processor. When the LSI hardware processor is implemented in the FPGA running at the maximum frequency of 130 MHz, up to 85 raw images with the resolution of 640×480 pixels can be processed per second. Meanwhile, we also present a system on chip (SOC) solution for LSI processing by integrating the CCD controller, memory controller, LSI hardware processor, and LCD display controller into a single FPGA chip. This SOC solution also can be used to produce an application specific integrated circuit for LSI processing.

Correcting speckle contrast at small speckle size to enhance signal to noise ratio for laser speckle contrast imaging

“…With advancements in the last decade [3][4][5][6][7][8][9], LSCI has been widely applied to map blood flow in skin, cortex and brain in animals with high spatiotemporal resolution [10][11][12][13][14][15], and has been used for preclinical applications [16][17][18][19]. A speckle pattern is generated from random interference of the laser light scattered from a rough surface, and is usually spatially blurred during an exposure time due to motion of the scattering particles.…”