JAI RMC-4200GE User Manual

Contents

JAI RMC-4200GE User Manual Manual pdf 28 page image

RM/TM-4200GE Series28 OperationTable 4 Asynchronous Mode ChartAsyn No Shutter Async Preset and Prog. Shutter PWCaA <1 line <1 line 6 clkaB 9.5 line (n+1) lines + 1024 clk Pulse width + 1024 clkaC 1024 clkPIV Fixe Expo PIV PWC UnitpA 6 6pB 200 200pC 160 160 PixelpD 320 320pE 20 20pF 1 1 Frame3.4 Dynamic Range ControlFigure 21. Output and BloomingThe typical interline transfer CCD has fixed noise levels based on dark current (thermal or KT noise), patternnoise, and the operating clock speed. In general, the level of the 20 MHz pixel clock CCD at room temperatureis around 20 to 50 electrons. The maximum capacity of CCD charges is limited by the well capacity atsaturation. The range is limited by the structure and the pixel size.The TM-4200GE uses a CCD with 7.4 μm x 7.4 μm pixels and a two-phase vertical shift register structure. Thewell capacity is 40,000 electrons. The theoretical dynamic range is 40,000:30 = 1333:1 (60 dB).A typical CCD camera does not use the full dynamic range due to the nominal gain and the output specificationsuch as RS-170. The typical CCD camera’s gain is set at 16 to 22 dB and the RS-170 video level is 714 mV. Using20 dB gain for the calculation, CCD output is limited to 714/10 = 71.4 mV. Since the CCD’s saturation voltage is400 mV to 500 mV, it uses less than 1/5 of the full dynamic range.Machine vision and outdoor applications cannot afford to miss image information behind the saturation, whichis why the dynamic range adaptation is critical.3.4.1 Programmable Look-Up Table (LUT) and Knee ControlThe TM-4200GE has a built-in LUT (look-up table) for dynamic range control.