DEVICE AND METHOD FOR CONTROLLING THE CONTRAST IN AN IMAGE OBSERVATION SYSTEM PROVIDED WITH AN MCP IMAGE INTENSIFIER

摘要

An image observation system comprises an image intensifier provided with an MCP. It further comprises an image converter to convert the output image of the image intensifier into a video signal or a visible image. When the contrast range in the image formed by the image converter is large the voltage applied across the MCP is increased and the gain of the image converter is reduced. When the contrast range in the image formed by the image converter is small the voltage applied across the MCP is reduced and the gain of the image converter is increased. In this way the contrast in the image is controlled by the darker portions of the observed scene instead of by the brighter portions.