Genie Monochrome Series-GigE Vision Camera Technical Specifications • 95Example: An acquisition system has a 512 x 512 element, 10μm pixel pitch area scan camera, a lens with aneffective focal length of 45mm, and requires that 100μm in the object space correspond to each pixel in the imagesensor. Using the preceding equation, the object distance must be 450mm (0.450m).ODmmmm 4510010 =μμ )450.0(450 mmmOD =Sensor Handling InstructionsThis section reviews proper procedures for handling, cleaning, or storing the Genie camera. Specifically the GenieCCD sensor needs to be kept clean and away from static discharge to maintain design performance.Electrostatic Discharge and the CCD SensorCameras contain charge-coupled device (CCD) image sensors, which are metal oxide semiconductor (MOS) devicesand are susceptible to damage from electrostatic discharge (ESD).Electrostatic charge introduced to the sensor window surface can induce charge buildup on the underside of thewindow that cannot be readily dissipated by the dry nitrogen gas in the sensor package cavity. When charge buildupoccurs, surface-gated photodiodes (SGPDs) may exhibit higher image lag or a highly non-uniform response, withsome pixels displaying a much higher response when the sensor is exposed to uniform illumination. The chargenormally dissipates within 24 hours and the sensor returns to normal operation.Important: Charge buildup will affect the camera’s flat-field correction calibration. To avoid an erroneouscalibration, ensure that you perform flat-field correction only after a charge buildup has dissipated over 24 hours.Protecting Against Dust, Oil and ScratchesThe CCD window is part of the optical path and should be handled like other optical components, with extremecare.Dust can obscure pixels, producing dark patches on the sensor response. Dust is most visible when the illuminationis collimated. The dark patches shift position as the angle of illumination changes. Dust is normally not visible whenthe sensor is positioned at the exit port of an integrating sphere, where the illumination is diffuse.Dust can normally be removed by blowing the window surface using a compressed air blower, unless the dustparticles are being held by an electrostatic charge, in which case either an ionized air blower or wet cleaning isnecessary.Oil is usually introduced during handling. Touching the surface of the window barehanded will leave oily residues.Using rubber finger cots and rubber gloves can prevent oil contamination. However, the friction between the rubberand the window may produce electrostatic charge that may damage the sensor.Scratches can be caused by improper handling, cleaning or storage of the camera. When handling or storing theGenie camera without a lens, always install the C-mount protective cap. Scratches diffract incident illumination.When exposed to uniform illumination, a sensor with a scratched window will normally have brighter pixelsadjacent to darker pixels. The location of these pixels changes with the angle of illumination.
