CHAPTER 2 NEW FUNCTIONS2-87COPYRIGHT © 2001 CANON INC. 2000 2000 2000 2000 CANON iR8500/7200 REV.1 AUG. 20015.2 Analog Image Processing5.2.1 OutlineAnalog image processing is performed by the CCD/AP PCB, which has the followingmajor functions:[1] Drives the CCD.[2] Corrects the gain in the CCD output, corrects offset.[3] Performs A/D conversion of CCD output.F02-502-015.2.2 Driving the CCDThe machine’s CCD sensor is a single-line linear image sensor, and is composed of 7450pixel photo cells.The signals subjected to phtoconversion in the light-receiving segment are sent out in twotypes of analog signals: even-number (EVEN) pixels and odd-number (ODD) pixels.F02-502-02 CCD Block DiagramCCDAnalog signalprocessing unit· Gain correction· Offset correctionA/DconversionA/DconversionAnalog imagesignalDigital image signalCCD/AP PCBCCD drivecontrolReadercontrollerPCB8J6002J6001J5003J5002Even-number pixelsOdd-number pixelsEven-numberpixelsOdd-numberpixels Digital image signal8CCD control signalA12VA5VGain/offsetcorrection dataShift registerLight receivingsegment(photodiode)Shift registerOutput bufferOutput bufferGateGate123456Odd-number pixel dataEven-number pixel data
