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Laser Doppler Blood Flow Imaging Using a CMOS Imaging Sensor with On-Chip Signal Processing
Electrical Systems and Optics Research Division, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD, UK
School of Medicine, University of Southampton, University Road, Southampton SO17 1BJ, UK
* Author to whom correspondence should be addressed.
Received: 25 July 2013; in revised form: 6 September 2013 / Accepted: 9 September 2013 / Published: 18 September 2013
Abstract: The first fully integrated 2D CMOS imaging sensor with on-chip signal processing for applications in laser Doppler blood flow (LDBF) imaging has been designed and tested. To obtain a space efficient design over 64 × 64 pixels means that standard processing electronics used off-chip cannot be implemented. Therefore the analog signal processing at each pixel is a tailored design for LDBF signals with balanced optimization for signal-to-noise ratio and silicon area. This custom made sensor offers key advantages over conventional sensors, viz. the analog signal processing at the pixel level carries out signal normalization; the AC amplification in combination with an anti-aliasing filter allows analog-to-digital conversion with a low number of bits; low resource implementation of the digital processor enables on-chip processing and the data bottleneck that exists between the detector and processing electronics has been overcome. The sensor demonstrates good agreement with simulation at each design stage. The measured optical performance of the sensor is demonstrated using modulated light signals and in vivo blood flow experiments. Images showing blood flow changes with arterial occlusion and an inflammatory response to a histamine skin-prick demonstrate that the sensor array is capable of detecting blood flow signals from tissue.
Keywords: laser Doppler; blood flow; CMOS; imaging sensor; full field
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He, D.; Nguyen, H.C.; Hayes-Gill, B.R.; Zhu, Y.; Crowe, J.A.; Gill, C.; Clough, G.F.; Morgan, S.P. Laser Doppler Blood Flow Imaging Using a CMOS Imaging Sensor with On-Chip Signal Processing. Sensors 2013, 13, 12632-12647.
He D, Nguyen HC, Hayes-Gill BR, Zhu Y, Crowe JA, Gill C, Clough GF, Morgan SP. Laser Doppler Blood Flow Imaging Using a CMOS Imaging Sensor with On-Chip Signal Processing. Sensors. 2013; 13(9):12632-12647.
He, Diwei; Nguyen, Hoang C.; Hayes-Gill, Barrie R.; Zhu, Yiqun; Crowe, John A.; Gill, Cally; Clough, Geraldine F.; Morgan, Stephen P. 2013. "Laser Doppler Blood Flow Imaging Using a CMOS Imaging Sensor with On-Chip Signal Processing." Sensors 13, no. 9: 12632-12647.