Low-uncertainty absolute radiometric calibration of a CCD

Abstract

The use of CCD detectors for radiometric measurements has proven to be very interesting for a variety of fields. This work presents an experimental method for the low-uncertainty calibration of the spectral radiant exposure responsivity of a CCD detector. It contains the description of the experimental setup as well as the analysis of the various sources of uncertainty. The overall result shows that the calibration procedure-related uncertainty is only 0.18% as long as the temperature is kept constant and the field of view is restricted to angles under 13.

Calibrating the Elements of a Multispectral Imaging System

“…In this section we detail the entire process we propose to calibrate radiometrically a monochrome CCD camera, [16][17][18][19][20]22 which mainly involves two steps: studying and correcting the influence of different kinds of noise, and studying the spectral response of the CCD sensor. In the following subsections we show how we developed the necessary steps to accomplish the complete calibration of our camera, and the instrumentation used in each case.…”

“…Several publications describe the types of noise and their influence on CCD camera response. 5,8,13,[16][17][18][19][20][21][22][23][24]29 Detailing the effect of noise on electronic devices is outside the scope of this paper, but it is important to consider the nature of the major noise sources in order to understand how to minimize them.…”

“…By assuring a constant number of registered digital counts and a constant temperature of the sensor (thanks to the cooling system of the camera), we avoided the influence of both parameters on camera noise. 17 We took a series of p =20, 80 150, and 300 frames to study the influence of the number of averaged frames on the minimization of high-frequency temporal noise, which was measured by calculating the residual spatial standard deviation across the whole CCD sensor array. The smaller this residual spatial standard deviation may be, the more temporal noise is removed in the averaging process.…”

“…Several authors [1][2][3][4][5][6]8,[16][17][18][19][20][21][22] have put forward the idea of modeling the pixel response of CCD cameras linearly, i.e.,…”

“…Subsequently we focus on calibrating the CCD camera. 16,17 Additionally, we conduct an exhaustive study into temporal and spatial noise generated by the CCD sensor array and how to remove as much of it as possible. By 'noise' we mean any process that reduces the ideal behavior of the camera's response as far as time and radiant exposure changes 16-24 are concerned.…”