JPH05196989A - Camera - Google Patents

Abstract

PURPOSE:To obtain an optimum density on the skin parts of a person, etc., by specifying the positions of the person, etc., in a picture, extracting the face part with reflectance, and controlling an exposure based on the face part. CONSTITUTION:A reflectance calculating part calculates the reflectance of photometric areas A12, A19, and A25-A 27, corresponding to each range-finding point of a main object candidate area MA, and sends the reflectance signals of each area to a flesh color extracting part. It compares the reflectance signals of each area with a reference value recorded in advance. The reference value is the fresh color data of the face part of the person, the face part area FA of the person is extracted, and a signal showing the photometric area A12 where the face part area FA is located, is sent to an exposure control part. Then, the exposure control part calculates a light value(LV), based on the object brightness signal of the photometric area A12 and film sensitivity, and when a releasing button is further, depressed in a half-depressed state, a diaphragm driving part and a shutter driving part are operated, and the photometric area A12 is photographed with an optimum exposure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera, and in particular, even when an object having different reflectance is present near a main subject,
The present invention relates to a camera adapted to photograph a main subject with an appropriate exposure.

[0002]

2. Description of the Related Art In a conventional camera, there is a method of performing exposure control according to the amount of reflected light during flash photography.

[0003]

However, even with such a camera, when there is an object with extremely high reflectance near the main subject, it is impossible to perform accurate exposure control due to the adverse effect of the reflected light of the object. There's a problem.

The present invention is intended to solve the above problems, and it is an object of the present invention to provide a camera capable of eliminating the influence of an object having high reflectance near a main subject. And

[0005]

In order to achieve the above object, the present invention sets a large number of distance measuring points and photometric areas corresponding thereto in a two-dimensional arrangement and measures the distances of the respective distance measuring points. A means for measuring each photometry area, and a means for extracting, as the main subject candidate, the shortest distance measurement data and the points having the distance measurement data within a certain range from the shortest distance measurement data among the distance measurement data of each distance measurement point. , A light emitting device, a means for emitting light before photographing, detecting reflected light due to light emission of a photometric area corresponding to a main subject candidate area, and obtaining a reflectance thereof, a reflectance of the main subject candidate area and a preset main subject And means for extracting the skin area of the main subject by comparing with the reflectance of the subject, and means for controlling the exposure by the photometric data of the extracted skin area.

According to another invention, in the camera of the above invention, a strobe device is used as a light emitting device, and a plurality of pre-flashes for gradually changing the light emission amount are performed, and the exposure control means is
The reflectance is linearly predicted on the basis of the relationship between the light emission amount and the reflected light amount at each stage of the pre-light emission, and the strobe light emission amount and the exposure amount at the time of shooting are controlled using this. Another invention is that the above-mentioned camera uses invisible light when performing pre-emission.

[0007]

When the photograph is taken, first, the distance measuring data for each distance measuring point is detected. Then, of the distance measurement data, the distance measurement point having the shortest distance measurement data from the camera and the distance measurement data within a certain range from the shortest distance measurement data is extracted as the main subject candidate area. Next, for each photometric area corresponding to this main subject candidate area, the reflectance for each photometric area is obtained from the brightness before flash emission and the brightness at the time of flash emission. Then, the skin area of the main subject is extracted by comparing this reflectance with the preset reflectance of the skin portion of the main subject. Exposure control is performed during shooting based on the photometric data of the skin area.

[0008]

FIG. 2 shows a camera for performing focus control and exposure control based on multipoint distance measurement information. The light projecting unit 11 is
The light source unit 12 for generating spot-like infrared light is provided. When the release button 13 is half pressed, the controller 14 controls the light source unit 12 and the two-dimensional scanning unit 15,
Irradiation light 16 is projected toward the shooting scene 10. The light source unit 12 emits light intermittently and sequentially illuminates the distance measuring points SP1 to SP15 in the shooting scene 10. FIG. 3 shows an example of the arrangement of the photometric areas and distance measuring points. The screen is divided into a 7 × 5 matrix and the photometric area A is divided.
1 to A35 are set. Furthermore, the photometric areas A9 to A13 and A16 to A2 located at the center of the shooting scene.
0, A23 to A27, distance measuring points SP1 to SP1
5 is set.

During the intermittent irradiation of the irradiation light 16, the reflected light 18 reflected by the subject 17 enters the incident position detecting means, for example, the image area sensor 20 through the lens 19. The presence or absence of the subject 17 is detected depending on whether or not the reflected light 18 is incident on the image area sensor 20, and the position of the subject 17 is detected from the scanning position of the irradiation light and the incident position of the reflected light at the time of detecting the subject. It

The two-dimensional scanning unit 15 scans the light source 12 two-dimensionally and intermittently emits the light source 12 when positioned at each of the distance measuring points SP1 to SP15. The controller 14 includes a pulse counter, and detects the scanning position of the light source 12 with respect to the shooting scene 10, that is, the position on the shooting screen by counting the drive pulses sent to the scanning unit 15. This screen position signal is the position / distance detection circuit 2
Sent to 6. The light source 12 may be made to intermittently emit light and be intermittently scanned at a constant pitch, or the light source 12 may be made to continuously emit light to scan the shooting scene in a line.

The position / distance detection circuit 26 obtains the position where the reflected light 18 is incident from the time-series signal of the image area sensor 20, and from the relationship between this incident position and the screen position,
The position and distance of the subject on each of the distance measuring points SP1 to SP15 are detected, and signals of the subject position and distance (hereinafter,
Dn (referred to as distance measurement data) (n indicates each distance measurement point,
Value of 1 to 15) is sent to the main subject detection unit 30.
The main subject detection unit 30 has the distance measuring points SP1 to SP.
Of the 15 distance measurement data, the distance measurement point having the shortest distance data and the distance measurement point within a certain range from the shortest distance data are determined as the main subject, and focus control is performed based on the distance measurement data of these points. .. That is, the shortest distance data among the distance measuring points SP1 to SP15 is dmin.
In this case, if (dn-dmin) <ε, the distance measuring point n is determined to be the main subject. However, ε is a certain threshold value.

After determining the main subject, the main subject detecting section 30 uses the shortest distance data as the lens setting section 32.
Send to. The lens setting unit 32 adjusts the focus of the taking lens 33 based on the shortest distance data. As a result, autofocus is performed on the main subject.

Further, the main subject detecting section 30 receives the distance measuring point data indicating the main subject area from the reflectance calculating section 34.
Send to. In the reflectance calculation section 34, as shown in FIG. 3, the shooting scene is divided into a 7 × 5 matrix, and the photometry section 35
The subject brightness data is detected for each area. The photometric unit 35 includes a lens 36 and an image area sensor 37. The reflectance calculation unit 34 uses the photometry unit 35 to determine the subject brightness for each photometry area as the flash unit 3.
8 before pre-flashing and during pre-flashing are detected twice, and this photometric data is stored in the memory 34a for each photometric area.
Remember. First, the photometric unit 35 uses the release button 13
When is pressed halfway, the first subject brightness (BV0) is measured for each of the photometric areas A1 to A35, and this photometric data is sent to the reflectance calculation section 34. Next, the controller 14 causes the strobe device 38 to pre-light. During the pre-flash, the photometric unit 35 determines the second subject brightness (BV
1) is metered and sent to the reflectance calculation section 34.

The reflectance calculating section 34 includes a strobe device 38.
From the lens set unit 32, and the photographing magnification (M) from the lens setting unit 32. Then, the reflectance calculation unit 34
Is an actual area S covering each photometric area of the photometric unit 35 based on the photographing magnification (M), and the unit area that has reached the subject by the area S, the distance d to the subject, and the flash emission amount A0. The amount of strobe light A1 per
Calculate by

[Number 1] A1 = A0 × (1 / d 2) × Ka However, as constant Ka is determined by the flash device 38, the reflectance calculating section 34, the flash reflected light B1 per unit area from the subject, the formula Calculated according to 2.

## EQU00002 ## B1 = (BV1-BV0) .times.Kb / S where Kb is a constant obtained experimentally, whereby the reflectance calculation unit 34 calculates the reflectance R by Equation 3.

## EQU00003 ## R = B1 / A1

The reflectance calculating section 34 sends the obtained reflectance R for each photometric area to the skin color extracting section 40. Skin color extraction unit 40
Compares the preset reference value with the reflectance R for each photometric area, and when these reflectances R are within the range of the reference value, the photometric area of the reflectance within this range is selected. Judge as human skin. Then, the photometric area is sent to the exposure control unit 41 as a skin color area. It should be noted that the reference value is previously obtained as a reflectance of human skin by an experiment and is stored in the memory 40a.

The exposure control unit 41 calculates the exposure amount based on the subject brightness of the photometric area which is the skin color area. A film sensitivity signal is input to the exposure control unit 41,
Based on this and the subject brightness signal in the skin color area, the light value (L
V) is calculated, and the diaphragm drive unit 43 and the shutter drive unit 44 are calculated.
Program control. Further, as is well known, the exposure control unit 41 includes a subject brightness determination circuit 45, and automatically emits light from the strobe device 38 in synchronization with the shutter mechanism 46 when the subject brightness in the skin color area is low.

A known diaphragm mechanism 47 and shutter mechanism 46 are arranged behind the taking lens 33. Each of these mechanisms 46 and 47 operates when the release button 13 is pushed further from the half-pressed state, and exposes the negative film 48.

Next, the operation of this embodiment will be described with reference to FIGS. 4 and 5. In FIG. 4, the solid line indicates the main subject A.
Is shown. Hold the camera and press the release button halfway down. First, each distance measuring point SP of the shooting scene 10
The ranging data of 1 to SP15 is detected. Then, based on this distance measurement data, the main subject detection unit 30 extracts a distance measurement point having the shortest distance data from the camera and the distance data within a certain range from this shortest distance data as a main subject candidate area. For the shooting scene shown in FIG. 4, the distance measuring points SP4, SP9, SP13 to 15 are extracted as main subject candidate areas MA (hatched portions by parallel lines in the figure). Each distance measurement point signal of the main subject candidate area MA is sent to the reflectance calculation section 34.

The reflectance calculating section 34 is provided with the photometric areas A12, A corresponding to the respective distance measuring points of the main subject candidate area MA.
19, the reflectances of A25 to A27 are calculated using the above-mentioned mathematical expressions 1 to 3, and the reflectance signals of the respective areas are calculated to be the skin color extraction unit 40.
Send to. The skin color extraction unit 40 compares the reflectance signal of each area with a reference value recorded in advance. The reference value is the skin color data of the human face portion, and as a result, the human face portion area FA (hatched portion by the intersecting line in the figure) is extracted as shown in FIG. Then, a signal indicating the photometric area A12 in which the face area FA is located is sent to the exposure controller 41. The exposure control unit 41 is in the photometric area A1.
Based on the subject luminance signal of 2 and the film sensitivity, the light value (L
V) is calculated. When the release button 13 is further pressed from the half-pressed state, the diaphragm drive unit 43 and the shutter drive unit 4
4 is activated, and shooting is performed with the optimum exposure amount for the photometric area A12.

In the main subject area determination process, if there is no area that can be regarded as the main subject at the distance measuring point having the shortest distance data, the main subject area is detected for the distance measuring point having the next distance data. The determination process of is repeated. When the main subject area cannot be finally detected, the exposure control may be performed by the data of the distance measuring point having the normal shortest distance data.

Further, in the above embodiment, the face area of the main subject is specified by the reflectance of the main subject candidate area. However, in addition to this, the face area of the main subject is experimentally determined according to the photographing distance and the photographing magnification of various subjects. Alternatively, the reflection pattern may be stored as data, and the most similar reflection pattern according to the shooting distance and the shooting magnification at the time of shooting may be found to specify the main subject.

Further, in the above embodiment, the light emission for detecting the reflectance is performed only once, but the pre-emission for preventing red eye is used to detect the reflectance from the photometric data at the time of several times of light emission. You may do so. In this case, the reflectance is linearly predicted based on the relationship between the amount of light emission and the amount of reflected light at each stage of pre-light emission. Thereby, the reflectance can be calculated with high accuracy. In addition, a small amount of light is sufficient for detecting the reflectance, and infrared light may be used instead of visible light. In this case, it is possible to take a picture in a natural state without causing the person to be photographed to feel uncomfortable.

Further, as the camera information at the time of shooting, distance measuring data for each distance measuring point, light measuring data for each light measuring area at the time of non-light emission and light emission, various information such as aperture, shutter speed, shooting distance and shooting magnification May be recorded, and these pieces of information may be sent to the printer side to perform more accurate exposure control during printing.

[0024]

As described above, according to the present invention,
The shooting scene is measured at a number of points, and light is measured for each area corresponding to the distance measurement points. First, the position of a main subject such as a person on the screen is specified by the distance measurement data, and then the face area is determined by the reflectance. Since the main part such as the above is extracted and the exposure control is performed based on this main part, the skin part such as the face part of the main subject such as a person can be finished to the optimum density. For example, even when wearing white clothes or black clothes, the face density can be optimally adjusted without being affected by the color tone of these clothes.

[Brief description of drawings]

FIG. 1 is a flowchart showing an exposure control procedure of a camera of the present invention.

FIG. 2 is a schematic diagram showing a camera of the present invention.

FIG. 3 is an explanatory diagram showing an example of a photometry area and distance measurement points in the same camera.

FIG. 4 is an explanatory diagram showing extraction of main subject candidate areas.

FIG. 5 is an explanatory diagram showing extraction of a face portion of a main subject.

[Explanation of symbols]

 10 Shooting Scene 11 Projection Section 30 Main Subject Detection Section 34 Reflectance Calculation Section 38 Strobe Device 40 Skin Color Extraction Section 41 Exposure Control Section

[Procedure amendment]

[Submission date] July 14, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

The position / distance detection circuit 26 obtains the position where the reflected light 18 is incident from the time-series signal of the image area sensor 20, and from the relationship between this incident position and the screen position,
The position and distance of the subject on each of the distance measuring points SP1 to SP15 are detected, and signals of the subject position and distance (hereinafter,
Dn (referred to as distance measurement data) (n indicates each distance measurement point,
Value of 1 to 15) is sent to the main subject detection unit 30.
The main subject detection unit 30 has the distance measuring points SP1 to SP.
Of the 15 distance measurement data, the distance measurement point having the shortest distance data and the distance measurement point within a certain range from the shortest distance data are determined as the main subject, and focus control is performed based on the distance measurement data of these points. .. That is, the shortest distance data among the distance measuring points SP1 to SP15 is dmin.
In this case, if (dn-dmin) <ε, the distance measuring point n is determined to be the main subject candidate area . Where ε
Is a certain threshold.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

After determining the main subject candidate area , the main subject detecting section 30 sends the shortest distance data to the lens setting section 32. The lens setting unit 32 adjusts the focus of the taking lens 33 based on the shortest distance data. As a result, autofocus is performed on the main subject candidate area .

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

Further, the main subject detecting section 30 sends distance measurement point data indicating the main subject candidate area to the reflectance calculating section 34. In the reflectance calculation unit 34, as shown in FIG. 3, the shooting scene is divided into a 7 × 5 matrix, and the photometric unit 35 detects subject brightness data for each area. The photometric unit 35 includes a lens 36 and an image area sensor 37. The reflectance calculation section 34 detects the subject brightness of each photometric area by the photometric section 35 twice, before the flash unit 38 pre-flashes and during pre-flashes, and outputs the photometric data for each photometric area. In the memory 34a. First, when the release button 13 is pressed halfway down, the photometric section 35 determines each of the photometric areas A1 to A1.
For each 35, the first subject brightness (BV0) is measured,
This photometric data is sent to the reflectance calculation section 34. Next, the controller 14 causes the strobe device 38 to pre-light.
The photometry unit 35 measures the second subject brightness (BV1) during this pre-emission, and sends it to the reflectance calculation unit 34.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

Further, as the camera information at the time of shooting, distance measuring data for each distance measuring point, light measuring data for each light measuring area at the time of non-light emission and light emission, various information such as aperture, shutter speed, shooting distance and shooting magnification the record, sending the information to the printer, may be carried out with high precision exposure control by time print.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03B 7/16 9224-2K 15/05 7139-2K

Claims (3)

[Claims] 1. A means for measuring a plurality of distance measuring points and corresponding light measuring areas in a two-dimensional arrangement, measuring each distance measuring point and measuring each light measuring area, and measuring distance of each distance measuring point. Among the data, the shortest distance measurement data and a means for extracting a point having distance measurement data within a certain range from the shortest distance measurement data as a main subject candidate, a light emitting device, and a main subject candidate area which is caused to emit light before photographing. Extracts the skin area of the main subject by comparing the reflectance of the main subject candidate area with the preset reflectance of the main subject by detecting the reflectance of the light emitted from the corresponding photometric area. And a means for controlling exposure based on the extracted photometric data of the skin area. 2. The camera according to claim 1, wherein the light emitting device is a strobe device, and pre-flashing is performed a plurality of times to change the flashing amount stepwise, and the exposure control means is a flashing amount for each stage of the pre-flashing. And a reflected light amount thereof, the reflectance is linearly predicted, and the stroboscopic light emission amount and the exposure amount at the time of shooting are controlled by using the camera. 3. The camera according to claim 1, wherein:
A camera characterized by using invisible light when performing pre-emission.