METHOD AND APPARATUS FOR EXTENDING THE DYNAMIC RANGE OF AN ELECTRONIC IMAGING SYSTEM

A method and apparatus is disclosed for extending the dynamic range of an electronic imaging system to permit the use of lower cost, lower resolution devices to digitize and process the analog image signal generated by an electronic image sensor. Multiple images captured at different exposure levels are stored in a framestore. An electronic data processing unit then compares the pixels from the image captured at a normal exposure level to preselected exposure ranges to determine if the pixel is underexposed or overexposed. If the pixel is underexposed, the pixel is replaced with a corresponding pixel from an image captured at a higher exposure level. If the pixel is overexposed, the pixel is replaced with a corresponding pixel from an image captured at a lower exposure level. A two level optimization routine is employed, wherein median exposure valves are used to compensate for subject motion.