Camera with large dynamic range

• US 5,541,705 A
• Filed: 01/12/1994
• Issued: 07/30/1996
• Est. Priority Date: 01/12/1994
• Status: Expired due to Fees

• Current Assignee: Kenneth C. Kitlas, Michael Kan
• Original Assignee: Kenneth C. Kitlas, Michael Kan
• Inventors: Kitlas, Kenneth C., Kan, Michael
• Primary Examiner(s): Perkey, W. B.
• Application Number:
  US08/180,219
• Time in Patent Office: 930 Days
• Field of Search: 354/432, 354/227.1, 351/45, 351/49, 351/44, 351/158, 250/205, 250/201.1, 2/8, 348/362, 348/363, 348/364, 348/365, 348/216, 348/217
• US Class Current: 396/233
• CPC Class Codes: G03B 17/48 adapted for combination with other photographic or optical apparatus
• CPC Class Codes: G03B 7/28 Circuitry to measure or to take account of the object contrast

Abstract

In accordance with the present invention, an apparatus and method are described which in general provide for an extended dynamic range in light sensitivity for an imaging device. This extended dynamic range is achieved primarily through control of the light intensity level in a image on a pixel by pixel basis.

In one aspect, a multi-faceted light controller is used like a variable iris camera, but on a pixel by pixel basis; thereby achieving a wider range of intensity control.

In another aspect, this system is enhanced by adding another controller outside the feedback loop, before an added output image detector.

In yet another aspect, some or most of the elements of the controlling and detecting system may be integrated into a composite monolithic structure.

Claims

1. A camera arrangement with the following elements and relationships:

an objective lens for gathering initial scene light, a following depolarizing retarder, a following polarizer, at the objective lens focal plane a planar array of light polarization rotation elements, a front field lens in front of and adjacent to the planar array to make the light incident to the planar array parallel, a rear field lens following and adjacent to the planar array, the rear field lens and a relay lens imaging the planar array on two receiving planes via a beam splitter behind the relay lens, a second polarizer acting as an analyzer adjacent or within the relay lens, one of said receiving planes presented as an image source for film or direct visual use, at the second of said receiving planes an image sensor that produces an electrical image-representing signal, the image sensor has correspondingly mapped elements to the planar array, the image-representing signal is brought to a connector for optional video output, a means for controlling the intensity of the image representing signal, the image-representing signal is sent to the planar array controlling the correspondingly mapped light polarization rotation elements, the polarization rotation elements controlling the transmitted scene light that falls on the correspondingly mapped array elements of the image sensor.