DIFFERENTIAL ELECTRONIC IMAGING SYSTEM

A differential electronic imaging system has a diode array camera and a plurality of A/D processing circuits connected to the respective diode pixel elements in parallel. The A/D processing circuits are operated in successive frame periods including a first partial period for processing an object-plus-FBP image and a second partial period for processing a fixed background pattern (FBP) image, in order to derive digital differential image data representing the object image alone. The use of parallel processing eliminates the bottleneck of conventional serial processing of the pixels of the image plane, and permits better sensitivity and image resolution. The use of the A/D processing circuits for direct conversion of the object-plus-FBP image minus the FBP image in each frame period eliminates readout noise, high frequency noise errors, FBP drift errors, and storage requirements for the FBP image. Other features include a chopper section synchronized to the clock cycle for each frame period, which also selectively controls a laser source for applications of the system as a target locator.