Automatic follow-up focus detecting device and automatic follow-up device

• US 5,204,749 A
• Filed: 03/20/1992
• Issued: 04/20/1993
• Est. Priority Date: 05/25/1984
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Fujiwara, Akihiro, Iwasaki, Youichi, Kaneda, Naoya, Takei, Masahiro, Toyama, Masamichi, Amikura, Takashi
• Primary Examiner(s): ADAMS JR, RUSSELL E
• Application Number:
  US07/860,289
• Time in Patent Office: 396 Days
• Field of Search: 358/227, 358/125, 354/400-409, 352/140
• US Class Current: 348/352
• CPC Class Codes: G01S 3/7865 using correlation of the live video image with a stored image
• CPC Class Codes: H04N 23/635 Region indicators; Field of view indicators
• CPC Class Codes: H04N 23/673 based on contrast or high frequency components of image signals, e.g. hill climbing method
• CPC Class Codes: H04N 23/675 comprising setting of focusing regions

Abstract

An automatic follow-up focus detecting device comprises means for shiftably setting a follow-up field; extracting means for extracting a feature of an object in relation to the follow-up field; storing means for storing the extracted feature; detecting means for detecting a relative shift between the object and the device on the basis of the feature of the object extracted by the extracting means and the feature stored by the storing means; and shifting means for shifting a distance measuring field following the object according to the relative shift.

Claims

1. An automatic follow-up focus detecting device comprising:

means for shiftably setting a follow-up field;

extracting means for extracting a feature of an object in relation to the follow-up field;

storing means for storing said extracted feature;

detecting means for detecting a relative shift between said object and the device on the basis of the feature of said object newly extracted by said extracting means and the feature stored by said storing means; and

shifting means for shifting a distance measuring field following said object according to said relative shift between said object and the device.

5. A video camera according to claim 1, wherein said first control means is arranged to detect a shift of said image by comparing the output of said detecting means at different timings.

6. A video camera according to claim 5, and further comprising integrating means for integrating the outputs of said detecting means, wherein said first control means is arranged to detect the shift of the image by comparing the signals smoothed by said integrating means.

2. A video camera, comprising:

(A) a photographing optical system for photographing an object and for focusing an image of the object on an image sensing plane;

(B) image sensing means for converting the image of the object on said image sensing plane into an image sensing signal;

(C) area setting means for setting a detecting area for extracting a feature of said image of the object on said image sensing plane;

(D) detecting means for detecting the feature of said image from said image sensing signal corresponding to said detecting area, and for putting out corresponding signals;

(E) first control means for detecting a variation of said image of the object on the basis of an output of said detecting means and for controlling said area setting means so that said detecting area follows the variation of said image of the object; and

(F) second control means for varying a size of said detecting area in response to a focal length of said photographing optical system.

3. A video camera according to claim 2, wherein said detecting means detects a color signal component in said image sensing signal.

4. A video camera according to claim 2, wherein said detecting means includes normalizing means for effecting normalization on the basis of a luminance, in order to prevent the signal representing the feature of the image extracted from said image sensing signal from being subjected to an influence of a brightness.

7. A video camera according to claim 2, wherein said detecting area is a focus detecting area.

8. A video camera, comprising:

(A) a photographing optical system for photographing an object and for focusing an image of the object on an image sensing plane;

(B) image sensing means for converting the image of the object on said image sensing plane into an image sensing signal;

(C) area setting means for setting a detecting area for extracting a feature of said image of the object on said image sensing plane;

(D) detecting means for detecting the feature of said image from said image sensing signal corresponding to said detecting area, and for producing outputs;

(E) first control means for detecting a variation of said image of the object on the basis of an output of said detecting means and for controlling said area setting means so that said detecting area follows the variation of said image of the object; and

(F) second control means for varying a size of said detecting area in response to a distance between said object and the video camera body.

9. A video camera according to claim 8, wherein said detecting means includes normalizing means for effecting normalizing on the basis of a luminance, in order to prevent the signal representing the feature of the image extracted from said image sensing signal from being subjected to an influence of a brightness.

10. A video camera according to claim 8, wherein said first control means is arranged to detect a shift of said image by comparing the outputs of said detecting means at different timings.

11. A video camera, comprising:

(A) image sensing means for converting the image of the object on said image sensing plane into an image sensing signal;

(B) area setting means for setting a detecting area for extracting a feature of said image of the object on said image sensing plane;

(C) detecting means for detecting the feature of said image from said image sensing signal corresponding to said detecting area, and for producing an output;

(D) control means for detecting a variation of said image of the object on the basis of an output of said detecting means and for controlling said area setting means so that said detecting area follows the variation of said image of the object; and

(E) adjusting means for manually varying a size of said detecting area.

12. A video camera according to claim 11, wherein said control means includes a memory for storing the output of said detecting means and it is arranged to detect a shift of said image by comparing the output of said detecting means at different timings.

13. A video camera according to claim 11, wherein said detecting means includes normalizing means for effecting normalization on the basis of a luminance in order to prevent the signal representing the feature of the image extracted from said image sensing signal from being subjected to an influence of a brightness.

14. A video camera, comprising:

(A) area setting means for setting a detecting area for detecting a feature of an image in a picture plane;

(B) detecting means for detecting the feature of said image in said detecting area from the image signal;

(C) control means for detecting a variation of said image on the basis of an output of said detecting means and for controlling said area setting means so that said detecting area follows the variation of said image when the variation of said image comes beyond a predetermined threshold value; and

(D) means for varying said threshold value.

15. A video camera according to claim 14, wherein said threshold value determines a non-sensitive band for the shift of said detecting area.

16. A video camera according to claim 14, wherein said detecting area is a focus detecting area.