Driver Design Of Intelligent Light Pen Coordinate Measuring System

The light pen portable coordinate measuring system based on photogrammetry technology possesses many advantages such as light and portable device, fast and flexible construction, simple operation, precision of proper level, not been affected by differences of surface been measured.The light pen portable coordinate measuring system has shown some shortage along with the development of measuring technology. All of light-emitting diodes (LED) on the light pen have the same on/off status and brightness. The brightness of imaging on the CCD camera will be influenced by difference of distance between LED and camera and luminance fluctuation of LEDs during the measuring process. So the measurement precision of system will be influenced. The CCD camera in the current measuring system is only used to capture the image of light pen. Processing of image must be operated by the computer, so the system is very complex. The performance of portability and flexibility are needed to improve.The light pen coordinate measuring system is improved according to the questions described above. The adjustable light pen in the measuring system is designed to replace traditional light pen. Intelligent camera which is researched and designed to replace the traditional CCD camera in the measuring system is used to capture the image of light pen and process the image data. The main work includes the following aspects:1. The current light pen coordinate measuring technology and intelligent camera are introduced.2. The adjustable light pen is designed to realize the function that the on/off status and brightness of LEDs on the light pen are adjustable.3. The project of intelligent camera in the measuring system is researched and designed. MT9M001 which is a CMOS image sensor controlled by DM642 is used to capture the Raw image. The Raw image data are stored to external extended SDRAM and fetched by DM642 to process. The image which is processed is display on the screen via SAA7121H of video encoder.4. The driver of intelligent camera is designed in the article. It mainly includes the 5. Debug for the system. The experiments show that: the function of adjustable light pen has implemented. The brightness and on/off status of light-emitted diodes on the light pen can be adjusted according to the requirement. The image of light pen can be captured by intelligent camera and display. The improvement is provided after analyzing for the system designed in the article. The DSP can be embedded with the real-time operate system of DSP/BIOS. The software are divided into several tasks scheduled by operate system to satisfy the real time requirement.