The features of two-dimensional CCD imaging arrays have led to widespread use of these devices as quantitative optical and x-ray image sensors. In this paper we discuss the desirable attributes that a general purpose digital CCD camera system should have to exploit these capabilities and provide applications flexibility. These include wide dynamic range, flexible readout format and high speed clocking and data acquisition. The ability to digitally sum a number of successive image frames increases the dynamic range and reduces array cooling requirements in intensified-CCD and x-ray applications. We discuss the ways in which these goals have been achieved through the architecture of the DCS-2 Digital Camera System. The system consists of a camera head and controller connected by a datalink over which control information and image data are transmitted. Camera operation is controlled by a Micro-programmable Control Unit (MCU) in response to commands received from the controller over the serial channel in the datalink. The MCU controls all aspects of the CCD readout including integration time and generation of clock signals. The CCD video signal undergoes correlated double sampling and is digitized and transmitted to the controller over the parallel channel in the datalink on a pixel-sequential basis. The instrument controller is based around a microcomputer system with floppy and Winchester disk storage. Successive image frames received from the camera head are summed directly into the Summation Video Memory (SVM). The SVM is a novel three-port design which provides ports for the camera and computer and which also provides an output signal to drive a real-time display monitor. A menu-driven software package provides an interactive environment for control of the CCD readout configuration and image acquisition.
S. K. Babey,
C. D. Anger,
B. D. Green,
"Digital Charge Coupled Device (CCD) Camera System Architecture", Proc. SPIE 0570, Solid-State Imaging Arrays, (11 December 1985); doi: 10.1117/12.950306; https://doi.org/10.1117/12.950306