Electronic still camera capable of compensating for variations in luminance levels within a field being photographed

• US 5,101,276 A
• Filed: 09/05/1991
• Issued: 03/31/1992
• Est. Priority Date: 03/16/1989
• Status: Expired due to Term

• Current Assignee: Konica Corporation (Konica Minolta Inc.)
• Original Assignee: Konica Corporation (Konica Minolta Inc.)
• Inventors: Ohta, Yoshitaka
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Metjahic, Safet
• Application Number:
  US07/758,447
• Time in Patent Office: 208 Days
• Field of Search: 358/213.31, 358/213.19, 358/213.29, 358/909, 358/209, 358/213.24
• US Class Current: 348/221.1
• CPC Class Codes: H04N 1/2112 using still video cameras
• CPC Class Codes: H04N 1/215 Recording a sequence of still pictures, e.g. burst mode
• CPC Class Codes: H04N 2101/00 Still video cameras
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene
• CPC Class Codes: H04N 25/53 Control of the integration time
• CPC Class Codes: H04N 25/715 using frame interline transfer [FIT]

Abstract

An electronic still camera wherein exposures of different exposure times are accomplished at overlapped timings by controlling sweeping and reading operations of two fields to be exposed by the image pickup device, independently of each field so that the images thus exposed are recorded. Two images are recorded by exposing an object in conformity to one specific and another luminances if the luminance difference is large. When a plurality of images are to be continuously recorded by varying exposure conditions, signals of second and later images are recorded only at its region, in which signal levels are within a proper range, but are outside of the proper range in the preceding image. Luminance area detecting devices for detecting each area of a photographic frame, divided according to luminance level of image pickup signals detected by an image pickup device during photographing under a set condition are provided, and exposure control devices for controlling the exposure at the time of photographing so that a luminance region occupying a large area detected may take a proper signal level are provided.

Claims

1. An electronic still camera comprising

image pick-up means for photographing a single object to generate a plurality of images having different exposure times,

means for controlling sweeping and recording operations for each of at least two fields of differing light luminances exposed to said image pick-up device, said sweeping and reading operations for each of said fields being conducted independently whereby, exposures having different exposure times corresponding to said light luminances are generated in a continuous or overlapped manner, and

means for recording the exposed images.

2. An electronic still camera comprising a photometric element for detecting a luminance of an object,

means to automatically adjust exposure with reference to a specific luminance when luminance level varies over the luminance of said object,

means for selecting at least two characteristic luminance region within the luminance distribution of said object obtained by said photometric element,

means for determining an exposure condition suitable for each of said selected luminance regions, and

means for automatically bracketing, on the basis of said exposure conditions.

3. An electronic still camera for digitizing video signals to record them on a recording medium, said apparatus comprising,

photometric means for detecting a luminance of an object being photographed,

means for automatically adjusting exposure with reference to a luminance distribution of said object,

means for selecting at least two characteristic luminance region from said luminance distribution,

means for determining an exposure condition suitable for each selected luminance region,

means for automatically bracketing, based on a plurality of exposure conditions corresponding to each of said selected luminance regions,

memory means for recording images, and

discriminating means, whereby signals of second and subsequent images are recorded only when signal levels are within a proper range based on a corresponding luminance region, but are outside the proper range of the image corresponding to the proceeding image.

4. An electronic still camera for digitizing video signals comprising a photometric element for reading a luminance distribution of an object to be photographed,

means for selecting at least two characteristic luminance region from said luminance distribution,

means for determining an exposure condition suitable for each of the selected luminance regions,

means for automatically bracketing on the basis of said exposure conditions, and

means for continuously recording at least a first to third image based on said exposure condition, the first image being recorded under an intermediate exposure condition corresponding to an intermediate luminance region, the second and third images being recorded over and under said intermediate exposure condition, respectively,

memory means, and

discriminating means, for discriminating between generated signals whereby said second image is recorded in said memory only in regions corresponding to black-blanked regions in said first image, and said third image is recorded only in regions corresponding to white blanked regions of said first image.

5. An exposure control device for a camera comprising means for selecting at least two characteristic luminance regions along a luminance distribution of a photographic frame, said luminance regions being divided according to a luminance level of an image pick up signal detected by an image pick-up device during photography under a set condition, and exposure control means for controlling exposure at a time a photograph is taken so that a luminance distribution on the object being photographed can be adjusted for so that a proper signal level can be achieved.

6. The exposure control device of claim 5 wherein said luminance area detecting means detects the area of each luminance level on the basis of a plurality of photographic exposures made under different exposure conditions.

7. The exposure control device of claim 5 wherein a plurality of luminance regions along said luminance distribution are detected by said luminance area detecting means, said exposure control device further comprising photographic control means for adjusting the exposure of the luminance regions to proper signal levels during a plurality of photographic exposures made under different exposure conditions.

8. The exposure control device of claim 5 wherein a level of luminance regions at proper signal level detected by said luminance area detecting means are less than a predetermined value, said device further comprising photographic control means for generating a plurality of photographic exposures at varying exposure conditions.