Infrared camera ranging system

• US 4,341,447 A
• Filed: 12/01/1980
• Issued: 07/27/1982
• Est. Priority Date: 12/01/1980
• Status: Expired due to Term

• Current Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Original Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Inventors: Biber, Conrad H.
• Primary Examiner(s): ADAMS JR, RUSSELL E
• Application Number:
  US06/211,639
• Time in Patent Office: 603 Days
• Field of Search: 354/25, 354/25 A, 354/195, 356/4
• US Class Current: 396/116
• CPC Class Codes: G01C 3/085 with electronic parallax measurement
• CPC Class Codes: G02B 7/30 using parallactic triangle with a base line

Abstract

A passive infra-red ranging system for a photographic camera or the like includes two infra-red responsive sensors spaced apart a predetermined distance from one another on the camera body. Each sensor includes a plurality of vertically aligned segments which receive a portion of the infra-red radiation emitted from the subject(s) of principal interest. In one embodiment, the segments of the two sensors are scanned in a successive serial manner by scanning circuitry with the composite output of each sensor analyzed to identify the maxima(s) associated with the subject(s) of principal interest. Computing circuitry determines the angular relationship between the subject(s) and each sensor to permit calculation of the distance-to-subject range by triangulation. In another embodiment, one of the two sensors is angularly adjusted until the scanning circuitry detects "coincidence" between the image of a given subject on each sensor thereby permitting computation of the distance-to-subject range by triangulation.

Claims

1. A passive ranging system for photographic apparatus, said system comprising:

means for sensing infrared radiation emitted by one or more subjects in a scene to be photographed, said sensing means including first and second sensor members of given length spaced apart a predetermined distance in a given direction and means for imaging radiation from a subject on said sensor members;

means for comparing the position of the subject image defined by said emitted radiation on each said sensor member as measured along said given direction and, in accordance therewith, determining the separation of said subject images along said given direction and the angular relationship between each sensor member and the subject forming such image; and

means for determining the distance to said subject by triangulation employing said separation of said images and said angular relationship.

2. The system of claim 1 wherein one of said sensor members is mounted for pivotal movement around an axis normal to said given direction and the direction of ranging, and said comparing means includes means for determining the angular position of said one sensor relative to its said axis.

3. The system of claim 1 or 2 wherein said sensor members comprise a plurality of sensing segments arranged in given locations along said given direction.

4. The system of claim 1 wherein said sensor members comprise a plurality of sensing segments arranged in given locations along said given direction, and said comparing means includes means for serially scanning said sensing segments, for recording the radiation response values of each said segment, and means for comparing the values of each of said segments to determine the segments having a maximum value for each image such that, with the given spacing of said sensor members and the given width of said segments, the distance between said images and the angular relationship may be determined.

5. The system of claim 4 wherein said comparing means includes means for identifying and matching the maximum response values of each sensor member to identify the images of the same subject on each sensor member and for then determining the separation of said identified images in accordance with the separation of said sensor members and the segments at which such identified images provide a maxima.

6. A passive ranging system for photographic apparatus, said system comprising:

means for sensing infrared radiation emitted by a subject in a scene to be photographed, said sensing means including first and second sensor members of a given length spaced apart a predetermined distance in a given direction and means for imaging radiation emitted by said subject on said sensor members, one of said sensor members being mounted for pivotal movement around an axis normal to said given direction and the direction of ranging;

means for determining the position of said subject image on each said sensor member as measured along said given direction;

means for comparing the position of the subject image on each said sensor member as measured along said given direction;

means for pivoting said one sensor member until the position of said image thereon substantially corresponds to the position of said image on the other side of said sensor members;

means for determining the separation of said subject images along said given direction and the angular position of said one member; and

means for determining the distance to said subject by triangulation employing said separation of said images and said angular position of said one member.

7. The system of claim 6 wherein said sensor members comprise a plurality of sensing segments arranged in given locations along said given direction, and said comparing means includes means for serially scanning said sensing segments, for recording the radiation response values of each said segment, and means for comparing the values of each of said segments to determine the segments having a maximum value for each image such that, with the given spacing of said sensor members and the given width of said segments, the distance between said images and the angular relationship may be determined.

8. The system of claim 7 wherein said comparing means includes means for identifying and matching the maximum response values of each sensor member to identify the images of the same subject on each sensor member and for then determining the separation of said identified images in accordance with the separation of said sensor members and the segments at which such identified images provide a maxima.