Roper Photometric manual CCD Readout

Page 38

CCD Readout The standard CCD readout sequence is shown in CCD Readout. After an integration, a programmed sequence of changing gate potentials causes all charge packets stored in the parallel register to be shifted one pixel towards the serial register; the first charge packet in each column is shifted into the serial register. Once in the serial register, charge packets are individually shifted toward the output amplifier. The output amplifier produces a signal proportional to the charge in each packet. After the serial register is emptied of charge, a second row of charge packets is shifted in from the parallel register. The process continues until all charge has been shifted out of the parallel register.

 

 

CCD Readout

 

1

2

3

4

The CCD is exposed to light and a charge pattern accumulates in the parallel register.

Charge in the parallel register is shifted one row. The first row is shifted into the serial register.

The first pixel is serially shifted into the output node.

The charge at the out- put node is collected for signal processing.

5

6

7

8

The charge from the next pixel is shifted to the output node.

The charge at the out- put node is collected for signal processing.

Steps 5 and 6 are re- peated until the entire serial register is read out.

Steps 2 through 7 are repeated until the entire parallel register is read out.

All CCD imagers depend on the efficient transport of charge from the photosites to the output amplifier. Because the charge from wells located far from the output amplifier must undergo many hundreds of transfers, the charge transfer efficiency (CTE) is important. A scientific-grade CCD imager exhibits a CTE of 0.99999, where 1.0 is perfect. CTE is of special concern at low charge levels where a small loss of charge can cause significant degradation of the image.

32Advanced Camera Operation Manual

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Contents Page Rev C1 Limited Warranty Roper Scientific Analytical Instrumentation Your Responsibility Table of Contents Index Introduction DescriptionSoftware Roper Scientific Customer Service BeneluxICL Following parameters are illegal Multiple Parameter FunctionsICL Function Syntax Readout / Display Function Definitions ClearparallelclearcountClearuntiltrig Exposeuntiltrig ExposewhiletrigclearfirstPixelreadoutsoffset, ssize, sbin, psize, pbin LoopendPixeldisplayx,y Shiftimagetostorage ScriptbeginScriptendcontinclear Shiftmodeism ShiftmodeisShiftmodeisalt ShiftmodeismaltShutteropen Single Image Example ScriptsOpen the Shutter TDI Time Delay Integration Panorama Ratio Imaging 2-Frame Ratio Ratio Imaging Multi-Frame Ratio CCD ESignal to Begin the Experiment Color SequenceIntermittent Exposure Good Exposure TimeHigh-Speed Spectroscopy Done EXPOSING, NOW ReadoutError Codes Man Pages Class 101 ICL Plexpdisplayscript101Class 101 ICL Plexpinitscript101 Boolean plexpinitscriptvoidClass 101 ICL Plexplisterrscript101 Class 101 ICL Plexpsetupscript101 Class 101 ICL Plexpstartscript101 Boolean Plexpstartscriptint16 hcam, voidptr pixelstreamClass 101 ICL Plexpuninitscript101 Boolean plexpuninitscript voidICL This page intentionally left blank Introduction Theory of Operation Potential WellsCharge Transfer Typical CCD Imager CCD Readout Subarray Readout Binned Readout CCD Architectures CCD ArchitecturesFrame Transfer Variations Resolution Sensitivity CCD Camera ImplementationsThick and Thinned CCDs Sources of Noise FiberopticsSNR Additional Reading This page intentionally left blank Index Page Index Benelux France Germany Japan
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