An Active Pixel CMOS separable transform image sensor

• Published in: 2009 IEEE International Symposium on Circuits and Systems (ISCAS) pp. 1281 - 1284
• Main Authors: Chi, Y.M., Abbas, A., Chakrabartty, S., Cauwenberghs, G.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.05.2009
• Subjects: Charge-coupled image sensors; CMOS image sensors; Coupling circuits; Image resolution; Image sensors; Noise reduction; Pixel; Sampling methods; Switched capacitor circuits; Voltage
• ISBN: 1424438276; 9781424438273
• ISSN: 0271-4302
• DOI: 10.1109/ISCAS.2009.5117997

This paper presents a 128 times 128 charge-mode CMOS imaging sensor that computes separable transforms directly on the focal plane. The pixel is a unique extension of the widely reported active pixel sensor (APS) cell. By capacitively coupling across an array of such cells onto switched capacitor circuits, computation of any unitary 2-D transform that is separable into inner and outer products is possible. This includes the Walsh, Hadamard and Haar basis functions. This scheme offers several advantages including multiresolution imaging, inherent de-noising, compressive sampling and lower integration voltage and faster readout. The chip was implemented on a 0.5 mum CMOS process and measures 9 mm 2 in MOSIS' submicron design rules.