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Global Shutter Imaging

High-speed, smear-free still image capture is the hallmark of Teledyne DALSA's Falcon cameras. Applications such as traffic management, metrology and robotics inspection all need to image fast-moving objects without smear or distortion. To meet this need, Teledyne DALSA offers true global shutter CMOS and interline transfer CCDs. With both technologies, the sensor has the ability to electronically shutter itself and "stop the action."

To stop the action, the camera starts and stops exposure of all pixels in an array simultaneously, under electronic control. This functionality requires specific design features, and not all sensors have them. Full-frame CCDs require mechanical shutters or strobing to achieve this result, introducing more cost and complexity into the vision system. Frame-transfer CCDs may not provide the speed required, or may be difficult to cost-justify due to the extra silicon required for the storage area. Standard rolling-shutter CMOS sensors distort images of moving objects because they only read out one line of their arrays at a time—by the time they read the next line, the object has moved. This distortion is a major obstacle for machine vision applications such as automated sorting or defect inspection—objects that that should be a "pass" are judged as "fail" because the image fed into the pattern-matching algorithms is distorted. For example, instead of valid round holes, the system would see unacceptable ellipses.

But interline CCDs and true global shutter CMOS sensors are ideally suited to imaging fast-moving objects. They capture crisp images without smear or distortion by electronically shuttering all pixels simultaneously even at short exposure times. Teledyne DALSA's Falcon cameras (Camera Link) and Genie and Genie TS cameras (GigE) both provide true global shuttering.

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