Complementary metal-oxide-semiconductor imaging array with laser Doppler blood flow processing

A fully integrated complementary metal-oxide-semiconductor 16 X 1 linear photodetector array with on-chip signal processing for applications in laser Doppler blood flow imaging has been designed and tested. Analog circuitry is used to provide the transimpedance amplifier, amplification of the modulated (ac) component, and antialiasing filter at each pixel, and also multiplexing of the 16 pixels. Digital signal processing is used to implement the lowpass, bandpass, and frequency-weighted filters, along with the signal averaging conventionally implemented as discrete components in laser Doppler blood flow imaging. The sensor demonstrates good agreement with simulation at each design stage. The measured optical performance of the array is demonstrated using modulated light signals and a vibrating test structure. As the first iteration of the chip, this 16 X 1 linear array provides an opportunity to evaluate the feasibility of full-field laser Doppler blood flow imaging with on-chip processing, with a view to providing a design that is scalable to a larger linear array or 2-D imaging array. (C) 2008 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.2993318]