# US 4,397,545 A · Exposure control method

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- Number: US 4,397,545 A
- Document ID: US4397545A
- Status: Granted
- Kind: A
- Application number: 06/258,699
- Filed: 1981-04-29
- Granted: 1983-08-09
- Earliest claimed: 1980-04-30
- Assignees: Fuji Photo Film Co., Ltd.
- Inventors: Takaaki Terashita
- Web page: https://patentgrep.com/patent/US4397545A

## CPC

- G03B 27/72: Controlling or varying light intensity, spectral composition, or exposure time in photographic printing apparatus
- Y10S 358/906: Hand-held camera with recorder in a single unit
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

An exposure control method in which an exposure value for a designated or particular original picture is determined using in combination photometric values or exposure controlling characteristic values of a designated original picture and photometric values or exposure controlling characteristic values of at least one other original picture which is weighted with relativity to the designated original picture. With this method, pictures of similar or continuous scenes are reproduced with a uniform density and color. The method may be applied to photographic film, particularly, motion picture films, VTR photographing operations or picture printing operations.

## Claims

### Claim 1

In a picture processing method of the type comprising the steps of determining exposure data for a particular picture to be processed, correcting said exposure data in accordance with exposure data of at least one other picture to obtain corrected exposure data, and processing said particular picture in accordance with said corrected exposure data, the improvement characterized in that said correcting step comprises:
determining the degree of similarity between said particular picture and said at least one other picture;
weighting the exposure data of said at least one other picture in accordance with the determined degree of similarity to obtain weighted exposure data; and
combining said particular picture exposure data and weighted exposure data to obtain said corrected exposure data.

### Claim 2 (depends on 1)

The processing method as claimed in claim 1, wherein said exposure data comprises an exposure value, said weighted exposure data comprises a weighted exposure value and said corrected exposure data comprises a corrected exposure value, and said processing step comprises the step of printing a color print of said particular picture in accordance with said corrected exposure value, the improvement characterized in that said combining step comprises combining said particular exposure value and said weighted exposure value according to the equation:
X.sub.0 =[K.sub.0 X.sub.0 '+K.sub.1 X.sub.1 '+K.sub.i X.sub.i ']/[K.sub.0 +K.sub.1 +K.sub.0 ]
where X.sub.0 is said corrected exposure value, X.sub.0 ' is the determined exposure value for said particular picture, K.sub.1 X.sub.1 '-K.sub.i X.sub.i ' are weighted exposure values of a plurality of other pictures, and K.sub.0 and K.sub.1 -K.sub.i are constants representing the degree of similarity between said particular picture and each of said plurality of other pictures.

### Claim 3 (depends on 1)

The processing method as claimed in claim 1, wherein said exposure data comprises an exposure controlling characteristic value, said weighted exposure data comprises a weighted exposure controlling characteristic value and said corrected exposure data comprises a corrected exposure controlling characteristic value, said combining step comprising combining said weighted exposure controlling characteristic values according to the equation:
(Y.sub.0).sub.m =[K.sub.0 (Y.sub.0).sub.m '+K.sub.1 (Y.sub.1).sub.m '++K.sub.i (Y.sub.i).sub.m ']/(K.sub.0 +K.sub.1 ++K.sub.i)
where m is an integer, (Y.sub.0).sub.m is the corrected exposure controlling characteristic value, (Y.sub.0).sub.m ' is the exposure controlling characteristic value determined for said particular picture, K.sub.1 (Y.sub.1).sub.m '-K.sub.i (Y.sub.i).sub.m ' are weighted exposure controlling characteristic values of a plurality of other pictures, and K.sub.0 -K.sub.i are weighting coefficients indicating the degree of similarity between said particular picture and said plurality of other pictures.

### Claim 4 (depends on 3)

The processing method as claimed in claim 3, wherein said processing step comprises printing a color print of said particular picture in accordance with an exposure value X, said method further comprising the step of calculating said exposure value X according to the equation: ##EQU4## where k.sub.0 -k.sub.m are constants.

### Claim 5 (depends on 2, 3, 4)

The processing method as claimed in any one of claims 2, 3 or 4, wherein said step of determining said degree of similarity between said particular picture and said at least one other picture comprises the step of determining a degree of similarity XX given by the expression: ##EQU5## where D.sub.R, D.sub.G and D.sub.B are red, green and blue densities of a photometric point, where values without apostrophes correspond to said designated frame to be printed and those with apostrophes correspond to other frames.

### Claim 6 (depends on 5)

The processing method as claimed in claim 5, wherein said weighting step comprises determining values for K.sub.0 -K.sub.i according to: K.sub.0 =1.1;
when XX>4.0, K.sub.i =1.0
when 4.0.gtoreq.XX>3.0, K.sub.i =0.8,
when 3.0.gtoreq.XX>2.0, K.sub.i =0.6,
when 2.0.gtoreq.XX>1.0, K.sub.i =0.4,
when 1.0.gtoreq.XX>0, K.sub.i =0.2, and
when 0.0.gtoreq.XX, K.sub.i =0.

### Claim 7 (depends on 1)

The processing method as claimed in claim 1, wherein said step of determining said exposure data of said particular picture comprises the step of scanning said particular picture to obtain photometric values of a plurality of measurement positions, determining a plurality of transmission density characteristics from said photometric values for said particular and said at least one other picture, and calculating said degree of similarity in accordance with the comparison of said plurality of transmission density characteristics from said particular and at least one other picture.

### Claim 8 (depends on 2, 3, 4)

The processing method as claimed in any one of claims 2, 3 or 4, wherein said weighting step further comprises the step of adjusting said weighting coefficients in accordance with the proximity in time of the taking of said particular picture and the taking of said at least one other picture.

### Claim 9 (depends on 2, 4)

The processing method as claimed in any one of claims 2 or 4, wherein said exposure data of said particular and said at least one other pictures are measured from a single strip of film, said weighting step further comprising the step of adjusting said weighting coefficients in accordance with the distance between said particular picture and said at least one other picture along said strip of film.