Linpeng Cheng

Abstract

Interpixel coupling (IPC) is an electronic crosstalk where a pixel couples signal charges to its neighbors capacitively. It is a deterministic process, whereas diffusion crosstalk is stochastic. It will smooth normal image signal as well as Poisson noise. As a result, the conversion gain will be underestimated by the photon transfer method. However, the capacitive coupling has not received much attention until Andrew Moore and Gert Finger recently studied its potential effect on the measurement of responsive detective efficiency of image detector arrays in both theory and observation. This thesis continues to investigate this electronic effect. The potential impact of capacitive coupling on the photometric measurement is first simulated. Methods based on inverse filer and Wiener filer are tested to correct this coupling impact. It appears that the signal loss can be restored to reasonable accuracy by applying the pseudo-inverse filter, provided that we have full knowledge of interpixel coupling. New methods to measure the IPC value are proposed and tested based on the cosmic ray events and hot pixels, where the dark frame data sampled up-the-ramp are used. By these two methods, the coupling effect of a hybrid HgCdTe array is studied. The coupling magnitude is measured at different detector temperatures. It shows that the IPC magnitude decreases with increasing temperature. The IPC dependencies on the center pixel intensity and background are also checked: the magnitude becomes smaller when the target pixel event gets stronger, while the trend reverses with the change of background level. Finally, the possible impact on read noise, i.e. noise correlation with adjacent pixels, is examined based on the dark frames from the infrared HgCdTe and Si-PIN arrays. The initial results indicate that the read noise component is not affected by the capacitive coupling between pixels, in the sense that read noise is uncorrelated to neighboring pixels, as compared to the neighbor-correlated Poisson noise due to interpixel capacitance.

Library of Congress Subject Headings

Metal oxide semiconductors, Complementary--Design and construction; Crosstalk; Electronic circuits--Noise; Optical detectors--Design and construction; Imaging systems--Design and construction

Publication Date

1-1-2009

Document Type

Thesis

Department, Program, or Center

Chester F. Carlson Center for Imaging Science (COS)

Advisor

Figer, Donald

Advisor/Committee Member

Ninkov, Zoran

Comments

Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works. Physical copy available through RIT's The Wallace Library at: TK7871.99.M44 C436 2009

Campus

RIT – Main Campus

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