Color video camera with selectively expanded sensitivity

Abstract From the Canadian patent

Primary color filters which also pass infrared are employed in cooperation with a broad spectral response image, sensing apparatus in providing a color video camera which has an extended range of operation at low light levels. The image beam which reaches the image sensing apparatus is selectively controlled by a regulatable infrared filtering device in cooperation with such primary color filters. Upon detecting a normal light level, the infrared filtering device responds by blocking infrared. At low light levels on the other hand, infrared blocking is negated and infrared passes through some or all of the primary color filters to augment the faint visible light components which are imaged …