US 4,786,964 AGranted

Electronic color imaging apparatus with prismatic color filter periodically interposed in front of an array of primary color filters

AssigneePolaroid Corporation

InventorsWilliam T. Plummer, Hugh R. MacKenzie

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Abstract

Apparatus for improving the quality of an electronic image generated by a charge coupled device (CCD) array that senses scene images through a colored optical filter. The apparatus includes a prism or prismatic filter movable into and out of the path of image-containing light rays impinging on the color filter overlying the CCD array that alternately shifts the scene image between color filters of the CCD array that absorb particular scene image colors and those that transmit these colors to their associated CCDs while in the case of the prismatic filter absorbing the dominant scene color generated by the colored optical filter. Scene image signals generated by a CCD array in this manner are processed such that their spatial relationship with respect to the sensed scene image is precisely monitored and electronically counter-shifted for subsequent scene image reconstruction. By shifting the scene image between individual CCDs having different color optical filters, most of the CCDs in the CCD array can generate image signals for two different scene colors or scene color combinations and thereby improve the image resolving capabilities and/or the color balance of electronic images generated by the CCD array.

Electronic imaging apparatus for producing an enhanced image of a scene comprising:

an array of photosensitive elements, with each of said elements producing an electrical signal indicative of the intensity of light incident thereon;
an array of primary color filters, with each of said filters having a respective one of at least three given primary colors, said filter array being fixedly positioned in an overlying relationship to said photosensitive element array such that each of said filters is operably associated with a respective one of said photosensitive elements, and said filter array in its entirety being structured to normally pass light which is weighted in favor of one of said given primary colors;
means for focusing image-carrying light rays from a scene onto said photosensitive element array through said filter array;
means for causing light rays from each of a plurality of areas of said scene to pass through a first respective one of said filters onto the associated photosensitive element to produce a first electrical signal representative of the corresponding scene area, and for subsequently causing said light rays from each of said plurality of scene areas to pass through a filter element interposed in front of said filter array, said filter element being structured to filter out said one of said given primary colors, and then causing said filtered light rays from each of said plurality of scene areas to be redirected to pass through a second respective one of said filters onto the associated photosensitive element to produce a second electrical signal representative of the corresponding scene area, said second respective filter being structured to filter out any primary color other than said one of said given primary colors which is passed by said first respective filter;
and
means for at least temporarily storing said first and second electrical signals representative of each of said plurality of scene areas, whereby the stored signals may be later manipulated to produce an enhanced image of said scene.

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Abstract

Claims6