JP2001305601A - Photometer for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately perform exposure arithmetic operation even when an error is generated in a luminance value outputted from a photometer. SOLUTION: This photometer 2 detects subject light in photometric areas 320a to 320e (figure 3) respectively and transmits photometry output to an MCU1. The MCU1 obtains the luminance values BV1(a) to BV1(e) corresponding to the respective photometric areas. A range binder 3 picks up an object image by the object light in image pickup areas 330a to 330c (figure 3) respectively and stores image data in a memory 34. The MCU1 reads out the image data from the memory 34 and obtains the luminance values BV2(a) to BV2(c) corresponding to the respective image pickup areas from the image data. When a difference between the luminance values obtained in the corresponding photometric area and the corresponding image pickup area is equal to or above a specified value K, the MCU1 calculates an exposure control luminance value BV(M) by making the luminance value by the photometer 2 in the corresponding area ineffective and using the luminance value by the range binder 3 in the corresponding area instead of the luminance value. The MCU1 decides a control diaphragm value and a control shutter time by using the exposure control luminance value BV(M).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photometer for a camera for measuring the brightness of a subject.

[0002]

2. Description of the Related Art Silicon photo diodes (hereinafter referred to as SPDs) are widely used as light receiving sensors in photometric devices for cameras. In this light receiving sensor, an SPD and a peripheral circuit are sealed in one package to form an IC. Generally, when light of a long wavelength such as infrared light is incident on a silicon semiconductor, the light enters the inside of the semiconductor as the wavelength of the incident light is longer. When light enters the inside of the semiconductor, the PN junction of the circuit may become a photodiode, which may cause an error in the circuit operation. For example, when a light receiving sensor outputs a detection signal at an output level corresponding to the amount of incident light, if strong infrared light enters the peripheral circuit of the light receiving sensor, the detection signal level output from the light receiving sensor becomes Errors may occur. In order to prevent errors caused by infrared light as described above, the peripheral circuit of the light receiving sensor is shielded from light with aluminum or the like, or an infrared light cutoff filter is provided to attenuate infrared light. Measures have been taken to prevent infrared light from being incident on the device.

[0003]

However, if strong light such as sunlight is incident, infrared light spills into peripheral circuits of the light receiving sensor and an error occurs in a detection signal of the light receiving sensor, so that correct exposure calculation cannot be performed. There was a problem.

It is an object of the present invention to provide a method for detecting an error even when strong infrared light is incident on a photometric photoelectric conversion element and an error occurs in a detection signal.
An object of the present invention is to provide a photometric device for a camera capable of performing an exposure calculation.

[0005]

The present invention will be described with reference to FIGS. 1, 3 and 7 showing one embodiment. (1) The first aspect of the present invention uses a first photoelectric conversion element 21 that outputs a first photoelectric conversion signal according to the luminance of an object scene to be photographed, and a first photoelectric conversion signal using the first photoelectric conversion signal. And a calculating means 1 for performing the above-described exposure calculation. Then, a second photoelectric conversion element 31 that outputs a second photoelectric conversion signal corresponding to a light beam from the object scene, and whether a difference between the first photoelectric conversion signal and the second photoelectric conversion signal is equal to or greater than a predetermined value Determining means 1 for determining whether or not the camera is operating, and control means 1 for performing a predetermined camera operation based on the determination result by the determining means 1
With the provision of the above, the above-described object is achieved. (2) According to a second aspect of the present invention, in the photometric device for a camera according to the first aspect, there is provided a distance measuring unit 3 that receives a light beam from a subject field and calculates information on a distance to a subject. The second photoelectric conversion element 31 is provided in the distance measuring means 3. (3) According to a third aspect of the present invention, in the photometric device for a camera according to the first or second aspect, the control means 1 changes a part of the exposure calculation when the determination means 1 determines that the value is equal to or more than a predetermined value. The operation means 1 is controlled so as to perform the operation. (4) According to a fourth aspect of the present invention, in the photometric device for a camera according to the third aspect, the first photoelectric conversion element includes a plurality of light receiving areas 320a, 320b, 320c, 320d, and 320e in a shooting screen. Has, the determination means, the plurality of light receiving areas 320a, 320b, 320c, 320d,
320e, the light receiving areas 330a, 330b,
A photoelectric conversion signal corresponding to the light receiving regions 320a, 320b, and 320c substantially equal to 330c is set as a first photoelectric conversion signal, and a difference from the second photoelectric conversion signal is determined. (5) According to a fifth aspect of the present invention, in the photometric device for a camera according to the fourth aspect, the determining means 1 changes a light receiving area used for the determination according to at least one of a focal length and a photographing distance of the photographing lens. It is characterized by doing. (6) According to a sixth aspect of the present invention, in the photometric device for a camera according to any one of the third to fifth aspects, the control means 1 comprises:
The exposure calculation is performed by replacing one of the value of the first photoelectric conversion signal and the value used for the exposure calculation calculated using the first photoelectric conversion signal with another value smaller than the original value. It is characterized in that the arithmetic means 1 is controlled. (7) According to a seventh aspect of the present invention, in the photometric device for a camera according to the sixth aspect, the control means 1 replaces a value of the first photoelectric conversion signal with an upper limit value at which exposure can be calculated. It is characterized in that the calculation means 1 is controlled to perform the exposure calculation. (8) According to an eighth aspect of the present invention, in the photometric device for a camera according to the sixth aspect, the control unit 1 replaces a value of the first photoelectric conversion signal with a value of the second photoelectric conversion signal. It is characterized in that the calculation means 1 is controlled so as to perform a predetermined exposure calculation. (9) According to a ninth aspect of the present invention, in the camera photometric device according to the sixth aspect, the control means 1 comprises a plurality of light receiving areas.
The arithmetic means 1 is controlled to perform a predetermined exposure calculation by replacing a value obtained by performing a weighting operation on each of the plurality of first photoelectric conversion signals received at 320a to 320e with an upper limit value at which exposure calculation is possible. I do. (10) According to a tenth aspect of the present invention, in the photometric device for a camera according to any one of the first to ninth aspects, the second photoelectric conversion element is substantially equal to the light receiving area 620b of the first photoelectric conversion element. At least two or more light receiving areas S11 to S16 in the light receiving area
The determination means determines an average value of two or more photoelectric conversion signals corresponding to the two or more light receiving regions S11 to S16 as a second photoelectric conversion signal and determines a difference from the first photoelectric conversion signal. It is characterized by doing. (11) According to an eleventh aspect of the present invention, in the photometric device for a camera according to any one of the first to ninth aspects, the second photoelectric conversion element is substantially equal to the light receiving region 620b of the first photoelectric conversion element. At least two or more light receiving areas S11 to S16 in the light receiving area
The determination means determines the difference between the maximum value of the two or more photoelectric conversion signals corresponding to the two or more light receiving areas S11 to S16 as the second photoelectric conversion signal and the first photoelectric conversion signal. It is characterized by doing. (12) According to a twelfth aspect of the present invention, in the photometric device for a camera according to any one of the first to eleventh aspects, the distance measuring means 3 determines whether or not information on distance can be calculated.
Control means 1 includes a second determination means 1
Is determined to be impossible to calculate, and when the determination means 1 determines that the difference between the first photoelectric conversion signal and the second photoelectric conversion signal is equal to or greater than a predetermined value, the calculation means changes a part of the exposure calculation. 1 is controlled.

In the section of the means for solving the above-mentioned problems, the present invention is associated with the drawings of the embodiments in order to explain the present invention in an easy-to-understand manner, but the present invention is not limited to the embodiments. is not.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. -First Embodiment- FIG. 1 is a block diagram illustrating an outline of a photometry control unit of a camera according to a first embodiment of the present invention. In FIG.
The photometry control unit of the camera is a microcomputer
1), a photometric device 2, a distance measuring device 3, a switch 4, and a memory 5. The MCU 1 includes a program for controlling the camera, and the MCU 1 controls the entire sequence of the camera including the photometry control described in the present embodiment.

The photometric device 2 includes an SPD 21 and a peripheral circuit 22 sealed in a transparent mold package (not shown),
This is a photometric device that has a logarithmic compression amplifier 23 and an amplifier 24 and measures the subject brightness (field brightness) in the shooting area.
When an activation signal is input from the MCU 1 to the photometric device 2, S
The PD 21 generates a photocurrent according to the amount of incident light, and the photocurrent is converted by the peripheral circuit 22 into a voltage signal. The voltage signal is further converted by the logarithmic compression amplifier 23 into a voltage signal having a linear characteristic with respect to the amount of incident light, amplified by the amplifier 24 with a predetermined gain, and then transmitted to the MCU 1 as a photometric output.

FIG. 2 is a diagram showing the relationship between the output voltage output from the photometric device 2 to the MCU 1 and the subject brightness. In FIG. 2, the horizontal axis represents the luminance and the vertical axis represents the output voltage, and the output voltage changes linearly as the luminance of the subject increases. The MCU 1 calculates the luminance using the output voltage sent from the photometric device 2. In FIG. 2, when the subject luminance exceeds a predetermined value, that is, when the peripheral circuit 2 of the SPD 21
When sunlight directly enters the camera 2 or very strong infrared light enters the camera, the output voltage of the photometric device 2 increases, and the output voltage becomes the same as when the subject luminance is extremely low. The state indicated by 29 in FIG. 2 is a state in which an error has occurred in the output of the photometric device 2.

The distance measuring device 3 includes an image pickup device 31 such as a CCD.
And a processing circuit 32 and a memory 34, and is a distance measuring device for detecting a distance from a camera to a subject. MCU1
When the start signal is input to the distance measuring device 3 from the
1 accumulates charges according to the amount of incident light, and the accumulated charges are taken out to the processing circuit 32. The processing circuit 32 amplifies the image signal to a predetermined multiple gain by an amplifier (not shown) and outputs the amplified signal. The image data is stored in the memory 34 corresponding to the pixel position of the image sensor 31. The image data stored in the memory 34 is read by a CPU (not shown) and used for a distance measurement process. This image data does not have a measurable luminance range and accuracy as much as the data from the photometric device 2, but is read out by the instruction of the MCU 1 and transmitted to the MCU 1 as luminance information. In addition, the distance measuring device 3
Even when strong infrared light as described above is incident on the image sensor 31, an error does not occur in the luminance information.

The switch 4 outputs an operation signal to the MCU 1 when a release button (not shown) of the camera is operated. The memory 5 stores information necessary for exposure calculation performed by the MCU 1.

The photometric processing performed by the above-described camera will be described. FIG. 3 illustrates a region where the photometric device 2 detects subject light and a region where the distance measuring device 3 inputs an image signal based on subject light for distance measurement, on a photographing screen of the camera according to the first embodiment. FIG. In FIG. 3, an area where the photometric device 2 detects subject light, that is, a photometric area is
A section 320a located at the center left of the shooting screen, a B section 320b located at the center, a C section 320c located at the center right, a D section 320d located at the top, and an E section 320e located at the bottom. Area. In addition, an area in which the distance measuring device 3 inputs an image signal based on subject light, that is, an imaging area, is located at an area 330a located on the left side of the area 330 indicated by a dashed line at the center of the imaging screen, and is located at the center. There are three regions, a region 330b and a region 330c located closer to the center right. Among them, the photometric device 2
The position and size of the photometric areas 320a to 320c on the shooting screen by the
About 330c. That is, in the first embodiment, the position and the size of the region common to both the photometric region of the photometric device 2 and the imaging region of the distance measuring device 3 are substantially the same.

The photometric device 2 includes the above photometric areas 320a to 320a.
SPD 21 (FIG. 1) corresponding to each area of 320e,
The photometric output corresponding to each area is sent to MCU1. The MCU 1 has a photometry area 3 input from the photometry device 2.
Exposure calculation is performed as follows using the five photometric results corresponding to 20a to 320e. The MCU 1 detects a voltage value of a voltage signal of each photometry area input from the photometry device 2 using an A / D converter (not shown) built in the MCU 1,
The luminance is obtained from the detected voltage value. Since the relationship between the voltage value and the luminance has a linear relationship as shown in FIG. 2 by the operation of the logarithmic compression amplifier, when the voltage value is detected, the luminance value is uniquely obtained. The plurality of luminance values obtained corresponding to the plurality of photometric regions 320a to 320e are respectively BV1 (a), BV1
(b), BV1 (c), BV1 (d), and BV1 (e) are stored in the memory in the MCU1.

The distance measuring device 3 includes the above-described image pickup areas 330a to 330a.
The image data stored in the memory 34 corresponding to each area of 330c is sent to the MCU 1 as luminance information corresponding to each area. The MCU 1 calculates the luminance from the image data. The relationship between the image data and the luminance is stored in a memory in the MCU 1 in advance. MCU1 is
The three luminance values corresponding to the image data of the areas 330a to 330c input from the distance measuring device 3 are BV2 (a) and BV2, respectively.
(b) and BV2 (c) are stored in the memory in the MCU1.

The MCU 1 calculates the differences D (a) to D (c) of the luminance values in the photometry area of the photometry device 2 and the imaging area of the distance measurement device 3 in an area having substantially the same position and size between the two. It is calculated using (1) to (3).

D (a) = | BV1 (a) −BV2 (a) | (1) D (b) = | BV1 (b) −BV2 (b) | (2) D (c) = | BV1 ( c) −BV2 (c) | (3) When all of the calculated differences D (a) to D (c) are less than the predetermined value K, the luminance value obtained by the photometric device 2 and the distance measuring device 3 is Since they almost match, it is considered that the error caused by the strong infrared light in the photometric device 2 does not occur. In this case, the MCU 1 includes a plurality of brightness values BV1 (a), BV1 (b), BV1 (c), BV1 (d),
By performing predetermined weighting associated with each of the photometric regions 320a to 320e using BV1 (e), an exposure control brightness value BV (M) is calculated using the following equation (4).

BV (M) = BV1 (a) × K1 + BV1 (b) × K2 + BV1 (c) × K3 + BV1 (d) × K4 + BV1 (e) × K5 (4) where BV1 (a) to BV1 (e) Brightness values corresponding to the photometric areas 320a to 320e, K1 to K5 are weighting coefficients, K1 + K2 + K3 + K4 +
K5 = 1.

On the other hand, when at least one of the differences D (a) to D (c) calculated from the luminance value by the photometric device 2 and the luminance value by the distance measuring device 3 is equal to or larger than a predetermined value K, the photometric device Since the brightness values obtained by the light measuring device 2 and the distance measuring device 3 are different from each other, it is considered that the error caused by the strong infrared light as described above occurs in the light measuring device 2. For example, in the case where the difference D (b) is equal to or greater than the predetermined value K, for example, it is considered that an error has occurred in the luminance value due to the photometric region 320b (FIG. 3) located at the center of the shooting screen. The MCU 1 converts the luminance value BV1 (b) from the photometric device 2 into the luminance value BV
2 (b), the exposure control brightness value BV is calculated using the following equation (5).
Calculate (M).

BV (M) = BV1 (a) × K1 + BV2 (b) × K2 + BV1 (c) × K3 + BV1 (d) × K4 + BV1 (e) × K5 (5) However, BV1 (a), BV1 (c) ~ BV (e) is the photometric area 320a-3
The luminance value corresponding to 20e, BV2 (b) is the luminance value corresponding to the imaging region 330b, K1 to K5 are weighting coefficients, K1 + K2 + K3 + K4 + K5
= 1.

In other words, when it is considered that an error due to strong infrared light occurs in the photometric device 2, the luminance value of the relevant region by the photometric device 2 is invalidated, and instead of this luminance value, the corresponding region is measured. The exposure control brightness value BV (M) is calculated using the brightness value of the distance device 3.

The MCU 1 performs a predetermined calculation using the exposure control brightness value BV (M) calculated as described above and the sensitivity value SV of the film to be used, and obtains a control aperture value AV and a control shutter time during shooting. (Speed) Calculate TV.

FIGS. 4 and 5 are flow charts for explaining the flow of the exposure determining process which is started by operating the switch 4 of the camera according to the first embodiment.
In step S101 of FIG. 4, the MCU 1 sends a control signal to the photometric device 2 to start photometric processing. In the following step S102, the photometric device 2 sets each photometric area 320a
Photometry is performed corresponding to .about.320e, and a voltage signal for each area is sent to the MCU1. In step S103, the MCU 1 obtains a luminance value from the voltage signal for each area transmitted from the photometric device 2, and calculates BV1 (a) and BV1 respectively.
(b), BV1 (c), BV1 (d), and BV1 (e) are stored in the memory in the MCU1.

In step S104, the MCU 1 sends a control signal to the distance measuring device 3 to start the distance measuring process. In the following step S105, the distance measuring device 3 performs a distance measuring process.
Image data captured by the image sensor 31 (FIG. 1) in the distance measurement process is stored in the memory 34 in the distance measurement device 3. In the following step S106, the MCU 1 stores the image data stored in the memory 34 in the areas 330a to 33a.
The data corresponding to 0c is read as luminance information, and the luminance values obtained from the luminance information are represented by BV2 (a), BV2 (b), and BV2, respectively.
(c) is stored in the memory of the MCU1.

In step S107, the differences D (a) to D (c) of the luminance values obtained by the photometric device 2 and the distance measuring device 3 in each area are calculated by the above equations (1) to (3). It is determined whether or not each of the differences is smaller than a predetermined value K. If it is determined that all of the brightness value differences D (a) to D (c) are smaller than the predetermined value K (Y in step S107), the process proceeds to step S1.
08, and at least one of the brightness value differences D (a) to D (c).
Are determined to be equal to or greater than the predetermined value K (N in step S107).
Then, the process proceeds to step S109.

In step S108, the exposure control brightness value BV (M) is calculated using the above equation (4), and the exposure control brightness value BV (M) is calculated.
By performing a predetermined calculation using (M), the control aperture value AV and the control shutter time (speed) TV at the time of photographing are determined, and the processing in FIG. 4 ends.

The replacement process performed in step S109 will be described with reference to the flowchart of FIG. In step S151 of FIG.
Photometric device 2 determined to be equal to or greater than predetermined value K from (a) to D (c)
Are replaced with the brightness values BV2 (a) to BV2 (c) of the distance measuring device 3 obtained in the corresponding area. For example, when all the differences D (a) to D (c) are determined to be equal to or greater than the predetermined value K, the brightness values BV1 (a) to BV1 (c)
Are replaced with the brightness values BV2 (a) to BV2 (c), respectively.

Then, an exposure control calculation value BV (M) is calculated using the replaced luminance value. Note that, in the above equation (5), the luminance value BV1 (b) obtained by the photometric device 2
Since the formula is an example in which the exposure control brightness value BV (M) is calculated by substituting for (b), the corresponding term is set as the brightness value by the distance measuring device 3 at the time of actual processing. Subsequent step S15
In 2, the MCU 1 performs a predetermined calculation using the exposure control luminance value BV (M), determines the control aperture value AV and the control shutter time (speed) TV at the time of shooting, and ends the processing of FIG.

According to the first embodiment described above,
The following effects can be obtained. (1) The subject light is detected in each of the photometry areas 320a to 320e of the photometry device 2, and the brightness value BV1 corresponding to each photometry area is detected.
(a) to BV1 (e) are obtained. Imaging area 330a of ranging device 3
At 330c, a subject image is captured, and luminance values BV2 (a) to BV2 (c) corresponding to each imaging region are obtained. With respect to a region common to both the photometry region of the photometry device 2 and the imaging region of the distance measurement device 3, that is, a region having substantially the same position and size, the difference between the luminance values obtained in the corresponding photometry region and the imaging region is calculated. If it is determined that the value is equal to or larger than the predetermined value K, the luminance value of the corresponding area by the photometer 2 is invalidated. And
Instead of the luminance value to be invalidated, the distance measuring device 3 in the corresponding area
Exposure control brightness value BV (M) is calculated using the brightness value according to. Therefore, even if an error due to the strong infrared light occurs in the photometric device 2, since the luminance value of the photometric device 2 in the corresponding area is not used, it is possible to prevent the photographing from failing by removing the appropriate exposure. (2) The luminance value is obtained from the image data for distance measurement taken by the distance measurement device 3 and the difference from the luminance value obtained by the light measurement device 2 is obtained using this luminance value. In addition to this, it is not necessary to provide a new photometric device for obtaining a luminance value, so that it is possible to suppress an increase in size and cost of the camera.

Second Embodiment In a second embodiment, the distance measuring device 3 has a plurality of image pickup regions corresponding to a light measuring region where light is measured by the light measuring device 2. FIG.
FIG. 9 is a diagram illustrating a region where the photometric device 2 performs photometry and a region where the distance measuring device 3 captures image data for distance measurement on the photographing screen of the camera according to the second embodiment. In FIG. 6, the photometry device 2 performs photometry in two areas: an A section 620a located on the left side of the center of the shooting screen, and a B section 6 located in the center.
20b and a C section 620c located on the right side of the center. Further, the imaging area imaged by the distance measuring device 3 is a rectangular area 630 indicated by a dotted line in the center of the imaging screen. The imaging region 630 is subdivided into a plurality of regions as described later, and image data is imaged for each subdivided region.

FIG. 7A is an enlarged view of a portion where the photometry area by the photometry device 2 and the imaging area by the distance measurement device 3 in FIG. 6 overlap, and FIG. 7B is a view centering on the photometry area 620b. It is the figure which expanded the part made into further. In FIG. 7A, the imaging region 630 is equally divided into a region s1 to a region s26. Among them, the imaging region s3 to the imaging region s8 correspond to the photometry region 620a, and the imaging region s11 to the imaging region s16 correspond to the photometry region 620b.
And the imaging region s19 to the imaging region s24 correspond to the photometry region 620
Corresponds to c. Taking the photometry area 620b of FIG. 7B as an example, the areas s11, s12, s13, s14, s15, s1 of the imaging area 630
Six areas 6 correspond to the photometry area 620b. Therefore, the luminance value B measured in the photometric area 620b of the photometric device 2
According to V1 (b), BV2 (s11), BV2 (s12), BV2 (s13), BV2 (s14), BV2 are respectively obtained by the imaging areas s11 to s16 of the distance measuring device 3.
Six luminance values of (s15) and BV2 (s16) are obtained.

In the second embodiment, when a plurality of luminance values are obtained by the distance measuring device 3 corresponding to one luminance value by the photometric device 2, the maximum value is obtained from the plurality of luminance values. The difference between the brightness values is calculated.

FIG. 8 is a flow chart for explaining the flow of an exposure determination process which is started when the switch 4 is operated in the camera according to the second embodiment. In step S201 of FIG. 8, the MCU 1 sends a control signal to the photometric device 2 to start photometric processing. In the following step S202, the photometric device 2 sets each of the photometric regions 620a to 620a.
Photometry is performed in response to 0c, and a voltage signal for each area is sent to the MCU1. In step S203,
The MCU 1 obtains a luminance value from the voltage signal for each area transmitted from the photometric device 2, and calculates BV1 (a), BV1 (b), and BV1 respectively.
(c) is stored in the memory of the MCU1.

In step S204, the MCU 1 sends a control signal to the distance measuring device 3 to start the distance measuring process. In the following step S205, the distance measuring device 3 performs a distance measuring process.
Image data captured by the distance measuring device 3 in the distance measuring process is as follows:
It is stored in the memory 34 in the distance measuring device 3. In the following step S206, the MCU 1 determines that the imaging areas s3 to s8 and the imaging areas s11 to s among the image data stored in the memory 34.
16. Read data corresponding to the imaging areas s19 to s24. A luminance value is obtained from the read data, and a luminance value BV2 (s3) to BV2
The maximum value of (s8) is BV2 (a) max, and the brightness values BV2 (s11) to BV2 (s16)
Is the maximum value of BV2 (b) max, and the maximum value of the brightness values BV2 (s19) to BV2 (s24) is BV2 (c) max, and BV2 (a) max, BV2 (b) max, BV2
(c) Each max is stored in the memory in the MCU1.

In step S207, differences D (a) to D (c) of the luminance values obtained by the photometric device 2 and the distance measuring device 3 in each area are calculated by the following equations (6) to (8). It is determined whether or not each of the differences is smaller than a predetermined value K.

D (a) = | BV1 (a) −BV2 (a) max | (6) D (b) = | BV1 (b) −BV2 (b) max | (7) D (c) = | BV1 (c) -BV2 (c) max | (8)

The differences D (a) to D (c) of the luminance values are all equal to a predetermined value K.
When it is determined that the brightness is smaller (Y in step S207), the process proceeds to step S208, and at least one of the brightness value differences D (a) to D (c) is determined to be equal to or more than the predetermined value K (step S207).
N) and the process proceeds to step S209.

In step S208, the exposure control brightness value BV (M) is calculated using the above equation (4), and the exposure control brightness value BV (M) is calculated.
By performing a predetermined calculation using (M), the control aperture value AV and the control shutter time (speed) TV at the time of photographing are determined, and the processing in FIG. 8 ends. In the second embodiment, since the photometric device 2 has three photometric regions, the weighting coefficients K4 and K5 are set to 0 in the above equation (4).

The replacement process performed in step S209 is performed in the same manner as in the flowchart of FIG. 5 according to the first embodiment. However, in FIG.
Luminance values BV2 (a) to BV2 (c) ”are replaced with“ luminance values BV2 (a) max to BV2 (c) max by distance measuring device 3 ”. Therefore, for example, the difference D
When it is determined that (c) is equal to or greater than the predetermined value K, the luminance value BV1 (c) obtained by the photometric device 2 is changed to the luminance value BV2 (c) max obtained by the distance measuring device 3.
Is replaced by

According to the second embodiment described above,
The distance measuring device 3 has a plurality of imaging regions corresponding to the light measuring region of the light measuring device 2 in a region common to the light measuring region of the light measuring device 2 and the imaging region of the distance measuring device 3. Therefore, a plurality of luminance values are obtained by the distance measuring device 3 corresponding to the luminance values obtained by the photometric device 2. Further, when calculating the difference between the brightness values obtained in the corresponding photometry area and the imaging area, the difference between the brightness values is calculated by taking the maximum value from among a plurality of brightness values by the distance measuring device 3. As described above, the distance measuring device 3 is configured such that an error does not occur in luminance information even when strong infrared light is incident. As a result, even if an error due to the strong infrared light occurs in the photometric device 2, the exposure calculation is performed using the maximum luminance value of the corresponding region by the distance measuring device 3, so that, for example, it is appropriate for a scene having a large contrast. It is possible to prevent the photographing from being failed due to a large exposure.

Third Embodiment In the third embodiment, when a plurality of brightness values are obtained by the distance measuring device 3 corresponding to one brightness value by the photometric device 2, a plurality of brightness values are obtained. And the difference between the luminance values is calculated.

FIG. 9 is a flowchart illustrating the flow of an exposure determination process that is started when the switch 4 is operated in the camera according to the third embodiment. Steps S206a and S207a in comparison with the second embodiment.
Therefore, the description will focus on the processing of both steps.

In step S206a, the MCU 1 determines that the image pickup area of the image data stored in the memory 34
Data corresponding to s3 to s8, imaging areas s11 to s16, and imaging areas s19 to s24 are read. The luminance value is obtained from the read data, the average value of the luminance values BV2 (s3) to BV2 (s8) is BV2 (a) ave, and the average value of the luminance values BV2 (s11) to BV2 (s16) is BV2 (b) ave. , Brightness value B
The average value of V2 (s19) to BV2 (s24) is BV2 (c) ave, and BV2
(a) ave, BV2 (b) ave, and BV2 (c) ave are respectively stored in the memory in the MCU1.

In step S207a, differences D (a) to D (c) of the luminance values obtained by the photometric device 2 and the distance measuring device 3 in each area are calculated by the following equations (9) to (11).
It is determined whether each of the calculated differences is smaller than a predetermined value K.

D (a) = | BV1 (a) −BV2 (a) ave | (9) D (b) = | BV1 (b) −BV2 (b) ave | (10) D (c) = | BV1 (c) -BV2 (c) ave | (11)

The differences D (a) to D (c) of the luminance values are all equal to a predetermined value K.
When it is determined that the brightness is smaller (Y in step S207a), the process proceeds to step S208, and at least one of the brightness value differences D (a) to D (c) is determined to be equal to or more than the predetermined value K (step S20).
7) N) and the process proceeds to step S209.

The replacement process performed in step S209 is performed in the same manner as the flowchart of FIG. 5 according to the first embodiment. However, in FIG.
Luminance values BV2 (a) to BV2 (c) ”are read as“ luminance values BV2 (a) ave to BV2 (c) ave by the distance measuring device 3 ”, respectively. Therefore, for example, the difference D
When it is determined that (b) is equal to or more than the predetermined value K, the luminance value BV1 (b) of the photometric device 2 is changed to the luminance value BV2 (b) ave of the distance measuring device 3.
Is replaced by

According to the third embodiment described above,
Unlike the second embodiment, when calculating the difference between the luminance values obtained in the corresponding photometry area of the photometry device 2 and the imaging area of the distance measurement device 3, the average value of the plurality of brightness values by the distance measurement device 3 is used. To calculate the difference between the brightness values. As a result, even if an error due to strong infrared light occurs in the photometric device 2, the exposure calculation is performed using the average luminance value of the corresponding area by the distance measuring device 3. Therefore, for example, the proper exposure is increased in a backlight scene or the like. It is possible to prevent the photographing from failing when the user removes the camera.

Fourth Embodiment FIG. 10 is a flowchart illustrating the flow of an exposure determination process that is started by operating the switch 4 in the camera according to the fourth embodiment. In the fourth embodiment, a new step S106b is added between steps S106 and S107 in the flowchart of FIG. 4 according to the first embodiment.

When the distance measuring device 3 is a passive type autofocus, distance measurement cannot be generally performed under the following conditions. This is the case where there is no contrast difference (difference in light quantity), the light quantity is small even if the light beam for distance measurement returns to the camera side, or the case where an extremely bright object is to be photographed. If the amount of light incident on the light receiving element for distance measurement is too large or too small, distance measurement may not be performed. In the fourth embodiment, even if luminance information is obtained, it is determined whether or not distance measurement can be performed using image data for distance measurement processing captured by the distance measurement device 3, and it is determined that distance measurement cannot be performed. In this case, the difference between the luminance value by the photometric device 2 and the luminance value by the distance measuring device 3 is calculated.

In step S106b of FIG. 10, it is determined whether or not the distance was measured by the distance measuring device 3. When it is determined that the distance measurement has been performed (Y in step S106b), the process proceeds to step S106.
Proceeding to 108, an exposure calculation is performed. On the other hand, when it is determined that the distance measurement could not be performed (N in step S106b),
Proceeding to 107, the difference D (a) of the luminance value for each region obtained by the photometric device 2 and the distance measuring device 3 as described above
It is determined whether D (c) is calculated and whether the calculated difference is smaller than a predetermined value K.

According to the fourth embodiment described above,
It is determined whether or not the distance was measured by the distance measuring device 3 (step S10).
6b) If the distance cannot be measured, the process proceeds to step S107, and the difference between the luminance value by the photometric device 2 and the luminance value by the distance measuring device 3 is calculated. When the incident light amount for distance measurement is extremely large and distance measurement cannot be performed by the distance measurement device 3, there is a high possibility that an error occurs in the luminance value of the photometry device 2. Therefore, by performing the processing of step S107 only when the distance measurement cannot be performed by the distance measuring device 3, the amount of calculation can be reduced as compared with the case of performing the processing of step S107 unconditionally. The processing speed time can be reduced.

Fifth and Sixth Embodiments The processing of step S106b described above is added to the flowcharts according to the second and third embodiments, respectively, and the fifth and sixth embodiments shown in FIG. The flowchart of the exposure determining process according to the embodiment and the flowchart of the exposure determining process according to the sixth embodiment shown in FIG. 12 are obtained. The processing other than the addition of step S106b is the same as the processing in FIGS. 8 and 9, respectively.

According to the fifth and sixth embodiments, as in the fourth embodiment, the amount of calculation can be reduced as compared with the case where the processing in step S107 is performed unconditionally. Time can be reduced.

-Seventh Embodiment- In the first embodiment, when a negative determination is made in step S107 of FIG. 4, the replacement process shown in the flowchart of FIG. 5 is performed. Can be performed. Step S25 in FIG.
1, a predetermined value K of the brightness value differences D (a) to D (c)
The luminance values BV1 (a) to BV1 by the photometric device 2 determined as above
One of (c) is replaced with a predetermined value BV ′ stored in the memory 5 (FIG. 1) in advance. For example, the difference D (a)
Is determined to be equal to or greater than the predetermined value K, the luminance value BV1 (a) is
Replace with BV '. Note that the predetermined value BV ′ corresponds to a luminance value obtained when a strong light such as sunlight is measured.

Using the replaced predetermined value BV ', an exposure control calculation value BV (M) is calculated in the same manner as in the above equation (5). The above equation
(5) is a calculation formula in which the exposure control brightness value BV (M) is calculated by replacing the brightness value BV1 (b) by the photometry device 2 with the brightness value BV2 (b) by the distance measurement device 3. Therefore, at the time of actual processing, the corresponding term is set to the predetermined value BV '. Subsequent step S
In step 252, the MCU 1 performs a predetermined calculation using the exposure control brightness value BV (M) to determine the control aperture value AV and the control shutter time (speed) TV at the time of shooting, and ends the processing in FIG. .

According to the seventh embodiment described above,
When the difference between the luminance values obtained in the corresponding photometry region and the imaging region in the region common to the photometry region of the photometry device 2 and the imaging region of the distance measurement device 3 is determined to be equal to or greater than the predetermined value K,
Exposure calculation is performed using an exposure control brightness value BV (M) calculated using a predetermined value BV ′ in place of the brightness value of the photometry device 2 in the corresponding area. Therefore, even if an error due to the strong infrared light occurs in the photometric device 2, since the luminance value of the photometric device 2 having the error is not used, it is possible to prevent a failure in photographing by removing the appropriate exposure.

The above-mentioned predetermined value BV 'may have a plurality of values according to the distance from the camera to the subject detected by the distance measuring device 3 and the focal length of the taking lens. For example, an optical system for guiding the subject light to the photometric device 2,
When parallax exists between the optical system that guides the subject light to the distance measuring device 3, the difference between the luminance values of the light measuring device 2 and the distance measuring device 3 depends on the subject distance and the focal length due to the influence of the parallax. May change. Since the predetermined value BV ′ has a plurality of values according to the subject distance and the focal length, it is possible to suppress an error due to the influence of parallax.

The predetermined value BV 'may have a different value depending on the photometry area. Photometric device 2 described above
When parallax exists between the optical systems of the distance measuring device 3 and the parallax, the difference between the luminance values of the light measuring device 2 and the distance measuring device 3 may change depending on the light measuring region due to the influence of the parallax. Since the predetermined value BV ′ has a different value depending on the photometry area, it is possible to suppress an error due to the influence of parallax.

Eighth Embodiment The replacement process can be performed as shown in the flowchart of FIG. In step S351 of FIG.
Is used to calculate the exposure control brightness value BV (M), the exposure control brightness value is set to a predetermined value BVc. The predetermined value BVc corresponds to an exposure control brightness value obtained when measuring strong light such as sunlight. In the following step S352, the MCU 1 performs a predetermined calculation using the predetermined value BVc to determine the control aperture value AV and the control shutter time (speed) TV at the time of shooting, and ends the processing in FIG.

According to the eighth embodiment described above,
When the difference between the luminance values obtained in the corresponding photometry region and the imaging region in the region common to the photometry region of the photometry device 2 and the imaging region of the distance measurement device 3 is determined to be equal to or greater than the predetermined value K,
Exposure calculation is performed using the predetermined value BVc. Therefore, the weighting calculation of the above equation (5) for calculating the exposure control brightness value BV (M) can be omitted, so that the processing time can be reduced.

In the above description, the photometric device 2 according to the first embodiment measures light in five photometric regions 320a to 320e, and the photometric device 2 according to the second and third embodiments.
Has been described in the three photometric regions 320a to 320c, but the number of photometric regions may not be as described. Further, in the above description, the distance measuring device 3 is
Although the description has been made so that the image data is captured in the three regions 0a to 330c, the number of the imaging regions may not be as described.

The shape of the photometry area by the photometry device 2 and the shape of the imaging area by the distance measurement device 3 need not be the above-described square, but may be a polygon, a circle, or an ellipse. Further, as long as the photometry area and the imaging area partially overlap each other, the shapes and sizes of both areas may not be the same.

In the above-described second and third embodiments, it has been described that the distance measuring device 3 has a plurality of image pickup regions corresponding to the light measuring regions measured by the light measuring device 2. Conversely,
The light metering device 2 may have a plurality of light metering regions corresponding to the image pickup regions picked up by the distance measuring device 3.

The photometric device 2 and the distance measuring device 3 described above
When the difference between the brightness values obtained in step (1) is obtained, the image pickup area of the distance measuring device 3 corresponding to the light measuring area measured by the light measuring device 2 is the distance from the camera detected by the distance measuring device 3 to the subject, and the photographing lens. Has been described as being constant regardless of the focal length. However, as described above, when parallax exists between the optical systems of the photometric device 2 and the distance measuring device 3, the positional relationship between the photometric region and the imaging region depends on the subject distance and the focal length due to the influence of the parallax. May change. In this case, an error due to the influence of parallax can be suppressed by calculating a difference between luminance values in different imaging regions according to the subject distance and the focal length. The positional relationship between the photometry area and the imaging area according to the subject distance and the focal length is stored in one of the memory 5 and the memory in the MCU 1.

In the above description, the weighting operation of the above equation (5) is performed using the luminance values obtained in a plurality of photometric areas, thereby obtaining the exposure control luminance value BV ( M) is calculated, but the present invention can also be applied to a case where a brightness value obtained in one pre-selected photometry area is used as an exposure control brightness value without using a plurality of brightness values. .

In the above description, when the difference between the luminance value of the photometry area by the photometry device 2 and the luminance value of the imaging region by the distance measurement device 3 is equal to or greater than the predetermined value K, the replacement process S109 (S209) is performed in the exposure calculation. ). Instead of performing the replacement process, a warning light may be turned on to notify the photographer or release may be prohibited. That is, the difference between the brightness values of the photometric device 2 and the distance measuring device 3 may be determined, and the camera may perform a predetermined process.

The camera distance measuring device described above
There is also included one that has two systems of light receiving sensors and measures the amount of defocus from the relative positional relationship between the subject images formed on each light receiving sensor. That is, the present invention can be applied to a single-lens reflex camera, an electronic still camera, a lens shutter camera, and an industrial camera.

The correspondence between each component in the claims and each component in the embodiment of the present invention will be described.
1 is an arithmetic unit, a judging unit, a control unit and a second judging unit, the image sensor 31 is a second photoelectric conversion element, the distance measuring device 3 is a distance measuring unit, and photometric regions 320a to 320e and 620a to 620c.
Are in the light receiving region of the first photoelectric conversion element,
0c and S1 to S26 are in the light receiving region of the second photoelectric conversion element,
The brightness values BV1 (a) to BV1 (e) correspond to the value of the first photoelectric conversion signal, and the exposure control brightness value BV (M) corresponds to the weighted value.

[0064]

According to the present invention as described in detail above, the following effects can be obtained. (1) In the photometric device for a camera according to the first to twelfth aspects of the present invention, the first photoelectric conversion signal corresponding to the field luminance by the first photoelectric conversion element and the image capturing by the second photoelectric conversion element. When the difference from the second photoelectric conversion signal according to the light flux from the field is equal to or larger than a predetermined value, a predetermined camera operation is performed. Since the first and second photoelectric conversion elements receive light from the same field, the first and second photoelectric conversion signals normally change in the same manner even if the field brightness changes, and both signals are changed. The difference between them hardly changes. Therefore, by determining when the difference between the two signals is equal to or greater than a predetermined value, for example,
It can be detected that the first photoelectric conversion signal does not change according to the field luminance. (2) In particular, in the invention according to the second aspect, since the configuration using the second photoelectric conversion element provided in the distance measuring means is adopted, compared with the case where the second photoelectric conversion element is newly provided. Thus, the effect of suppressing the increase in size and the increase in cost can be obtained. (3) In particular, in the inventions according to claims 3 to 9, a part of the exposure calculation is changed when the difference between the first and second photoelectric conversion signals is equal to or greater than a predetermined value. Therefore, for example, even when the exposure calculation is not performed correctly due to the fact that the first photoelectric conversion signal is not output according to the field luminance, the exposure calculation can be changed so as to be performed correctly.
The effect of preventing a failure in photographing can be obtained. (4) In particular, according to the twelfth aspect of the present invention, the difference between the first and second photoelectric conversion signals is determined only when it is determined that the information on the subject distance cannot be calculated by the distance measuring means. I did it. Therefore, the amount of calculation can be reduced as compared with the case where the determination is always made, so that the processing time can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an outline of a photometry control unit of a camera according to a first embodiment.

FIG. 2 is a diagram illustrating a relationship between an output voltage output from a photometric device and subject brightness.

FIG. 3 is a diagram illustrating a region where a photometric device detects subject light and a region where a distance measuring device captures image data for distance measurement.

FIG. 4 is a flowchart illustrating a flow of an exposure determining process of the camera according to the first embodiment.

FIG. 5 is a flowchart illustrating a replacement process.

FIG. 6 is a diagram illustrating an area where a photometric device of a camera performs photometry and an area where a ranging device captures image data for ranging according to the second embodiment.

7A is an enlarged view of a portion where a photometry area by the photometry device and an imaging area by the distance measurement device in FIG. 6 overlap, and FIG. 7B is a further enlarged view.

FIG. 8 is a flowchart illustrating the flow of a camera exposure determination process according to a second embodiment.

FIG. 9 is a flowchart illustrating a flow of a camera exposure determining process according to a third embodiment.

FIG. 10 is a flowchart illustrating a flow of an exposure determining process of a camera according to a fourth embodiment.

FIG. 11 is a flowchart illustrating a flow of a camera exposure determining process according to a fifth embodiment.

FIG. 12 is a flowchart illustrating a flow of a camera exposure determining process according to a sixth embodiment.

FIG. 13 is a flowchart illustrating a camera replacement process according to a seventh embodiment.

FIG. 14 is a flowchart illustrating a camera replacement process according to an eighth embodiment.

[Explanation of symbols]

1 MCU, 2 Photometer,
3. Distance measuring device, 4. Switch,
5: memory, 21: SPD, 2
2. Peripheral circuit, 23: Logarithmic compression amplifier, 31: Image sensor, 32: Processing circuit, 34: Memory, 320a-
320e, 620a to 620c: photometry area, 330a to 330c, 630: imaging area, BV (M): exposure control luminance value, BV1 (a) to BV1
(e): Luminance value by photometer, BV2 (a) to BV2 (c), BV2 (S1)
BBV2 (S26): brightness value by distance measuring device, S1 to S26: area where imaging area 630 is subdivided

Claims (12)

[Claims] 1. A first photoelectric conversion element for outputting a first photoelectric conversion signal according to the luminance of an object scene to be photographed, and arithmetic means for performing a predetermined exposure operation using the first photoelectric conversion signal A second photoelectric conversion element that outputs a second photoelectric conversion signal according to a light beam from the object scene; and a first photoelectric conversion signal and the second photoelectric conversion. A photometric device for a camera, comprising: a determination unit that determines whether a difference from a signal is equal to or greater than a predetermined value; and a control unit that performs a predetermined camera operation based on a determination result by the determination unit. 2. The photometric device for a camera according to claim 1, further comprising: a distance measuring unit that receives a light beam from the object scene and calculates information on a distance to a subject. Is a photometric device for a camera provided in the distance measuring means. 3. A photometric device for a camera according to claim 1, wherein said control means changes a part of said exposure calculation when said determination means determines that said exposure value is equal to or more than said predetermined value. A photometric device for a camera, characterized by controlling the means. 4. The photometric device for a camera according to claim 3, wherein the first photoelectric conversion element has a plurality of light receiving areas in the photographing screen, and the determining unit determines the number of the light receiving areas. A photoelectric conversion signal corresponding to a light receiving area substantially equal to a light receiving area of the second photoelectric conversion element is set as the first photoelectric conversion signal, and a difference from the second photoelectric conversion signal is determined. Photometric device for a camera. 5. A photometric device for a camera according to claim 4, wherein said determining means changes said light receiving area used for determination according to at least one of a focal length and a photographing distance of a photographing lens. Photometric device for camera. 6. The photometric device for a camera according to claim 3, wherein said control means calculates the value using the value of said first photoelectric conversion signal and said first photoelectric conversion signal. A photometric device for a camera, characterized in that the arithmetic means is controlled so that one of the values used for the exposure calculation is replaced with another value smaller than the original value and the exposure calculation is performed. 7. The photometric device for a camera according to claim 6, wherein said control means performs said predetermined exposure calculation by replacing a value of said first photoelectric conversion signal with an upper limit value at which exposure calculation is possible. A photometric device for a camera, wherein said photometric device is controlled. 8. The photometric device for a camera according to claim 6, wherein the control means replaces the value of the first photoelectric conversion signal with the value of the second photoelectric conversion signal and performs the predetermined exposure calculation. A photometric device for a camera, wherein the computing means is controlled to perform the following. 9. The photometric device for a camera according to claim 6, wherein said control means is capable of performing exposure calculation on a value obtained by weighting a plurality of first photoelectric conversion signals received by said plurality of light receiving areas. A photometric device for a camera, wherein the arithmetic means is controlled so as to perform the predetermined exposure calculation by substituting an upper limit value. 10. A photometric device for a camera according to claim 1, wherein at least two of said second photoelectric conversion elements are located in a light receiving area substantially equal to a light receiving area of said first photoelectric conversion element. Having the above light receiving area, wherein the determination unit sets an average value of two or more photoelectric conversion signals corresponding to the two or more light receiving areas as the second photoelectric conversion signal, A photometric device for a camera, wherein the photometric device determines the difference between the two. 11. The photometric device for a camera according to claim 1, wherein at least two of said second photoelectric conversion elements are located in a light receiving area substantially equal to a light receiving area of said first photoelectric conversion element. Having the above-mentioned light receiving area, wherein the determination unit sets the maximum value of two or more photoelectric conversion signals corresponding to the two or more light receiving areas as the second photoelectric conversion signal, and sets the first photoelectric conversion signal A photometric device for a camera, wherein the photometric device determines the difference between the two. 12. The photometric device for a camera according to claim 1, further comprising: a second determining unit that determines whether the distance measuring unit can calculate the information on the distance. The control unit determines that the second determination unit determines that the calculation is not possible, and then determines that the difference between the first photoelectric conversion signal and the second photoelectric conversion signal is equal to or greater than the predetermined value. A photometric device for a camera, wherein the calculating means is controlled to change a part of the exposure calculation in a case.