Abstract: Improved linear sensor array and scanner apparatus and operating methods to reduce noise and streaking in a digitized image produced by the scanner. The scanner uses a charge coupled device linear sensor array having a pair of sensor output channels, each for processing one half of the array sensor elements which are interleaved with the other half of the sensor elements. To provide a reference, the CCD outputs are read a plurality of times with the system on but no article in scanning position, with the multiple readings for each sensor element being averaged to provide an average reference level therefor. These averages are stored in digital form, each to provide a calibration factor (multiplier) for the corresponding readings of the array during scanning of an article. During scanning, the output corresponding to each sensor element is multiplied by the corresponding calibration factor to normalize each output to a common reference.