A CMOS Active Pixel Sensor With Light Intensity Filtering Characteristics for Image Thresholding Application

Author

Huang, Chia-Chin ; Huang, Jalin Ko-Tsung ; Lee, Chi-Wei ; Lin, Chrong Jung

Author_Institution

Inst. of Electron. Eng., Nat. Tsing-Hua Univ., Hsinchu, Taiwan

Volume

12

Issue

5

fYear

2012

fDate

5/1/2012 12:00:00 AM

Firstpage

1289

Lastpage

1293

Abstract

A CMOS image sensor with light intensity filtering feature for realizing image thresholding is proposed. The simple sensing pixel circuit with less than 5 transistors is designed to provide a tunable non-linear photo-response with a peak signal at a specified intensity level. This unique intensity-filtering photo-response characteristic is achieved by the push/pull forces between the n⁺/p photo-diode and a parasitic p⁺/n-well diode on the PMOS control transistor. With proper timing control, tunable intensity filtering transfer functions can be obtained on the unique pixel. Based on the behavior model of the pixel´s photo-response, image thresholding as well as edge detection are successfully demonstrated by this non-linear imager.

Keywords

CMOS image sensors; edge detection; spatial filters; CMOS active pixel sensor; edge detection; image thresholding application; intensity filtering photoresponse characteristic; light intensity filtering; nonlinear imager; timing control; CMOS integrated circuits; Filtering; Logic gates; Partial discharges; Photodiodes; Timing; Transistors; CMOS image sensor; image thresholding; non-linear photo-response; pixel circuit;

fLanguage

English

Journal_Title

Sensors Journal, IEEE

Publisher

ieee

ISSN

1530-437X

Type

jour

DOI

10.1109/JSEN.2011.2170163

Filename

6031894