IEEE Journal of Solid-State Circuits · 2006 · 80 citations · 22 references
EngineeringComputer EngineeringElectrical EngineeringComputer VisionSensorsSystem-on-chip DesignCmos Circuit DesignDigital Image ProcessingImage ProcessingImage SensorsLow-noise Circuit DesignSensor IntegrationCmos Image SensorsDynamic RangeParameter CalibrationPixel PitchReadoutResponse TimeSensor Dynamic RangeSignal-to-noise Ratio
A CMOS image sensor that can operate in both linear and logarithmic mode is described. Two sets of data are acquired and combined in the readout path to render a high dynamic range image. This is accomplished in real-time without the use of frame memory. A dynamic range in excess of 120 dB was achieved at 26 frames/s (352times288-array). The system addresses the problems of high fixed pattern noise (FPN), slow response time, and low signal-to-noise ratio (SNR) in logarithmic mode. FPN has been effectively reduced by single and two parameter calibration, the latter achieving FPN of 2% per decade. A novel on-chip method of deriving a reference point has been implemented. The system is fabricated in a 0.18-mum 1P4M process and achieves a pixel pitch of 5.6 mum with 7 transistors per pixel
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