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

• US 4,786,964 A
• Filed: 02/02/1987
• Issued: 11/22/1988
• Est. Priority Date: 02/02/1987
• Status: Expired due to Fees

• Current Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Original Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Inventors: Plummer, William T., MacKenzie, Hugh R.
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/009,934
• Time in Patent Office: 659 Days
• Field of Search: 358/41, 358/43, 358/44, 358/213, 358/28, 358/55, 358/75
• US Class Current: 348/270
• CPC Class Codes: H04N 23/125 Colour sequential image capture, e.g. using a colour wheel
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 25/48 Increasing resolution by shifting the sensor relative to the scene

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.

Claims

1. 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.

2. The apparatus of claim 1 wherein each of the photosensitive element in said array of photosensitive elements is a charge-coupled device.

3. The apparatus of claim 3 wherein the colors of the colors filters in said array of primary color filters are yellow green and cyan.

4. The apparatus of claim 3 wherein said filter element interposed in front of said filter array is a prismatic magenta filter of the subtractive type.

5. The apparatus of claim 4 wherein said prismatic magenta filter is mounted for rotation on a wheel having an opening therethrough with said filter and said opening being alternately interposed in front of said filter array.

6. The apparatus of claim 4 wherein said prismatic magenta filter is mounted for translation on a support member having an opening therethrough overlying said filter array with said filter being periodically interposed in front of said filter array.