The Design Of A High-speed Linescan CCD Camera

Studied in this thesis is the design of line-sain CCD camera cable of performing high-speed image capturing.An embedded line-scan CCD camera design scheme is proposed in this thesis to fulfill the requirements of its intended applications. Based on state-of-art technologies, DSPs, CPLDs, as well as advanced CCD image sensors are combined together to construct the camera. This thesis mainly includes camera hardware design and analysis, image processing algorithms, prototypeing, and testing.The camera structure and construction principles are presented in this thesis. Various working modes are proposed to meet different application needs; the principles and opti-electric papameters of various types of solid statte imaging sensors are given and their noise sources are analyzed; and the camera analog front end circuits are described. Based on camera's timing and control requirements, a camera control solution is proposed and its major functions are implemented within a CPLD device. In addition, DSP is employed to implement other camera functions. TI's C6000 series DSP is used for this purpose. A flowchart is given to describe its working procedures. The interface between the camera and frame grabber on PC is provided by interface circuits, whose principles and implementations are also given in this thesis.A key part in the camera is its CCD sensor. Discussed in this thesis are the imaging principles of CCD sensors, CDS circuits, how CDS can be used to reject noises, and what mechanisms are behind those noises. Some analytical results are also presented.In the camera design, programmable logic devices are used to implement high-speed part of circuits, especially, CCD clock generators and access control modules for FIFO, dual-port RAM, and flash memory. A detail descript ion about FIFO dual access operationsis given too.Also discussed in this thesis is some image processing algorithms used with line scanHICCD sensors. The characteristics of the the images obtained from CCD sensors are analyzed; algorithms are then introduced, mainly, to neutralize noise effects and other interferences.To verify the feasibility of the proposed design, the design is prototyped and extensively tested to investigate its characteristics and any potential problems. Details about prototyping and testing are presented in this thesis. This includes how to select ICs for particular functions, the design of PCB, and the constructions of PCBs.Finally, the design, anlysis, testing, and other procedures leading to the prototype are summarized and the perspectives of future high-speed cameras in machine vision fields are indicated.