Non-uniform clocking system for area imaging device

A method for transferring to a serial output of a shift register a two dimensional array of pixels including image and non-image regions and organized as a plurality of rows comprising a fixed number of pixels each, the method comprising the steps of:

• classifying as image pixels each pixel that falls within the image region of the two dimensional array;
• classifying as non-image pixels each pixel that falls outside the image region of the two dimensional array;
• shifting the plurality of rows of pixels sequentially into the shift register;
• for each row, coupling the non-image pixels out of the shift register at a first rate and coupling the image pixels out of the shift register at a second rate that is slower than the first rate;
• classifying as recovery pixels each non-image pixel that is proximate to an image pixel in the two dimensional array;
• and
• coupling the non-image pixel proximate to the image pixel at a third rate to reduce image distortion.

An area imaging device for displaying an active image region of an area image sensor, the area imaging device comprising:

• a horizontal shift register including a plurality of charge transfer cells one of which is coupled to a serial output;
• a plurality of vertical shift registers, each including a plurality of charge transfer cells and each coupled to one of the charge transfer cells of the horizontal shift register;
• a plurality of photo-sensors, each of which is associated with a charge transfer cell of one of the plurality of vertical shift registers to form the area image sensor;
• and
• a state machine coupled to at least one clock sequencer and the area image sensor for tracking an origin for each pixel datum and coupling the pixel datum from the horizontal shift register at a first, second, or third rate according to whether or not the pixel datum originated in an active image area, a non-image area, or a recovery area of the area image sensor, the second rate is slower that the first rate, each clock sequencer used to clock a respective image area.