Lockheed Martin Corporation

James S Howard

Glenn L Kehley

Steven J Pratt

Robert M Krohn

Mark D Goodwin

Santosh Kumar

Thomas Musa

Methods and apparatus for detecting a blockage in the field-of-view of a camera in an image capture system by monitoring changes in the quality of images captured by the camera. As an image is acquired by the camera, intensity values for pixels in the acquired image are determined and stored in a data structure in memory of the camera. Image statistics are calculated based in part on the intensity values for pixels in the currently acquired image and at least some previous images acquired by the camera. If the image statistics satisfy at least one predetermined alert criterion, an alert is triggered. In response to triggering an alert, an alert sensor included as part of the camera is activated to indicate to a user of the image capture system that a possible blockage in the field-of-view of the camera has been detected.

Automatic detection of blocked field-of-view in camera systems

A new and improved line scan camera achieves the proper framing of the image field of view by using a first test card to calibrate the true bottom and leading edge portions of the test card which simulate the true bottom and leading portions of an article being scanned or photographed. Still further, the architecture of the electronic chip incorporated within the charge coupled device (CCD) of the camera effectively divides the linear array of pixels into a plurality of channels, and amplifier gain and black offset adjustments are made with respect to exposure levels, characteristic of the pixels disposed at the channel boundaries, under different degrees of input whiteness signals applied to a test card of a predetermined color shade, so as to achieve channel-to-channel seam matching. Subsequently, correction factors are effectively superimposed upon substantially all of the exposure levels characteristic of substantially all of the pixels comprising the line scan of the line scan camera such that true uniform exposure levels are in fact achieved.

Automatic calibration and built-in diagnostic procedures for line scan cameras

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Endicott, NY, United States of America

James S Howard