JP2001100087A - Multispot range finder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multipoint range finder which performs a highly precise range finding processing by deciding the position of a main subject image in a photographic picture plane and performing a sure focus detecting processing for the main subject image. SOLUTION: This range finder is equipped with a store type area sensor 12 which light-receives a two-dimensional area in a detection picture plane, a mean luminance arithmetic means which calculates the mean luminance of the two-dimensional area according to the output of the area sensor, an area deciding means which detects a continuous area having a luminance difference of more than a given value from the mean luminance value calculated by the mean luminance arithmetic means as to the output of the area sensor, and a focus detecting means which detects the focus state in the detection picture plane according to the output of the area sensor at least in the given area detected by the area deciding means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multipoint distance measuring device,
Specifically, it is provided in a camera or the like that performs photographing, and can determine the main subject image in the detection screen, and can surely and accurately perform focus detection processing at a ranging point where the determined main subject image is located. The present invention relates to a multipoint distance measuring device.

[0002]

2. Description of the Related Art Conventionally, cameras for taking photographs, etc.
For example, in a camera or the like that obtains an image by exposing a desired subject image using a film for photographing, a photographing operation is performed to automatically perform a focus adjustment operation on a main subject. Various means have been proposed for determining the main subject image within the range of the screen.

For example, in a camera disclosed in Japanese Patent Application Laid-Open No. Hei 5-249369, an image signal based on a subject image acquired by a charge accumulation type image sensor (AF sensor) for focus adjustment has a high luminance portion and a low luminance portion. When it is detected that the main subject such as a person is separated from the distribution, it is determined that the screen configuration is such that a main subject such as a person is positioned in front of a bright background. In this case, the integration time of the AF sensor is set to a long time. By performing the integration calculation process again, the focus detection process is performed with emphasis on the low luminance portion.

According to this, the automatic focus adjustment operation can be reliably performed on a main subject image such as a person without being affected by the brightness (luminance) of the background.

[0005]

However, in the means disclosed in Japanese Patent Laid-Open No. Hei 5-249369, the focus state is detected by a pair of line sensors, so that the detection area is small. For this reason, for example, a subject image having a high contrast, that is, a large luminance difference may be erroneously recognized as a subject in which a high luminance portion and a low luminance portion are distributed.
In such a case, reliable automatic focus detection processing cannot be executed.

[0006] Further, when the high luminance portion does not enter the detection area, the means cannot determine that the main object such as a person has a screen configuration in front of a bright background. Will be. In such a case, the desired main subject may be erroneously recognized, or the focus detection processing may be repeated without obtaining the detection result. As a result, the exposure operation is performed from the release instruction through the focus detection processing. Becomes longer, so-called release time lag increases, which causes a hindrance to the operability of the camera. Also, in this case,
Further, a state where a focus detection result cannot be obtained, that is, a state where distance measurement cannot be performed may be caused.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned point, and an object of the present invention is to reliably determine a position of a main subject image in a shooting screen and to obtain a desired main subject image. It is an object of the present invention to provide a multi-point distance measuring apparatus capable of performing a focus detection process reliably and performing a highly accurate distance measurement process.

[0008]

In order to achieve the above object, a multipoint distance measuring apparatus according to a first aspect of the present invention comprises: a storage area sensor for receiving a two-dimensional area in a detection screen; An average luminance calculating means for calculating an average luminance of the two-dimensional area based on the output; and a luminance difference of a predetermined value or more based on the average luminance value calculated by the average luminance calculating means among the outputs of the area sensor. Area determining means for detecting a continuous area having the same, and focus detecting means for detecting a focus state in a detection screen based on an output of the area sensor in at least a predetermined area detected by the area determining means. It is characterized by.

The multipoint distance measuring apparatus according to the second invention is
An accumulation-type area sensor that receives a two-dimensional area in the detection screen, an average luminance calculating unit that calculates an average luminance of the two-dimensional area based on an output of the area sensor, and a light emitting unit that emits illumination light, Area discriminating means for detecting, in a two-dimensional area in the detection screen, an area in which the luminance difference between the time when the illumination light is emitted by the light emitting means and the time when the illumination light is not emitted exceeds a predetermined value; And a focus detecting means for detecting a focus state in a detection screen based on an output of the area sensor in an area detected by the means.

A multipoint distance measuring apparatus according to a third aspect of the present invention is the multipoint distance measuring apparatus using an area sensor, wherein an average luminance calculating means for calculating an average luminance value based on an output of the area sensor is provided. A region discriminating unit that detects a continuous region in which the luminance difference from the average luminance value calculated by the average luminance calculating unit is equal to or more than a predetermined value, and a main subject is identified according to a detection result by the region discriminating unit. Means for determining a distance measuring point in the detection screen.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a main block diagram showing the configuration of a camera provided with a distance measuring device according to the first embodiment of the present invention.

The camera 1 according to the present embodiment includes a distance measuring device (to be described in detail later) including an AF area sensor 12 and a distance measuring optical system 14, a focus lens 10a contributing at least to focus adjustment, and a variable power operation. A photographing optical system 10 comprising a plurality of lenses including a zoom lens 10b contributing to (zoom operation) and transmitting a light flux from a subject (hereinafter, referred to as a subject light flux) to form a subject image at a predetermined position; A focus lens driving unit 13 that drives the lens 10a in a direction along the optical axis of the photographing optical system 10, a focus lens encoder 15 that generates a predetermined pulse signal according to the amount of movement of the focus lens 10a, and a zoom lens 10b Imaging optical system 10
Lens drive unit 22 for driving in the direction along the optical axis of
And a film for performing drive control for moving the film, such as an automatic feeding operation (auto load) and an automatic winding and rewinding operation of a roll-shaped photographic film (not shown) loaded in the camera 1. A drive unit 21; a shutter drive unit 16 for controlling the drive of a shutter mechanism (not shown) for adjusting the amount of exposure to the film;
, That is, a camera posture detecting unit 24 for detecting whether the photographing screen is in the vertical position or the photographing screen is in the horizontal position. A photometric device including a photometric light receiving element 23a that converts and generates a predetermined photocurrent signal, a photometric unit 23 that receives an output signal of the photometric light receiving element 23a and performs predetermined signal processing, and performs a distance measuring operation. When necessary, a strobe light emitting unit 20a for emitting auxiliary light for distance measurement or for emitting auxiliary illumination light for performing an exposure operation, and a strobe circuit unit 20 for controlling light emission of this strobe light emitting unit 20a and charging. And a liquid crystal display device (L
(CD) and the like, and a display unit 19 for displaying various information in the camera 1 so as to be visually identified, and a release button (not shown) which is an operation button used when a shooting operation is performed. An interlocking two-stage switch,
A first release switch (hereinafter, referred to as 1RSW) 17 that is turned on by the operation of the first stage, receives the signal and generates an instruction signal for instructing execution of photometry and distance measurement performed prior to the exposure operation; A second release that is turned on by the operation of the second stage following the operation of the first stage of the button, and in response thereto, generates an instruction signal for instructing execution of the exposure operation and the winding operation of one frame of the film. A switch (hereinafter referred to as 2RSW) 18;
The microcomputer 11 is a control means for controlling these various components and their electric circuits.

The microcomputer 11 includes a ROM 11b in which various sequence programs for controlling various operations of the camera 1 are stored in advance, and a central processing unit (hereinafter referred to as a central processing unit) for controlling a series of operations in accordance with the sequence programs stored in the ROM 11b. A CPU 11a, a RAM 11c serving as a work area for temporarily storing various data and performing various arithmetic processing, and the like, and receiving an analog signal from the AF area sensor 12 and converting it into a digital signal. A / D converter 11d and unique correction data different for each camera, such as focus detection calculation and photometry calculation.
It has an EEPROM 11e and the like in which unique correction data and the like necessary for performing an exposure calculation and the like are stored in advance.

The microcomputer 11 controls the integration operation of the AF area sensor 12, controls the reading of the sensor data as described above, and performs a predetermined operation on the sensor data output from the AF area sensor 12. The processing is performed, and a predetermined distance measurement calculation processing is performed based on the processing.

A microcomputer 11 as a focus detecting means
Receives the output from the AF area sensor 12 and performs a predetermined distance measurement calculation process. The microcomputer 11 receives the calculation result and generates a predetermined drive signal based on the calculation result. An output is provided to the focus lens driving unit 13. As a result, the focus lens 10a moves by a predetermined distance, and a predetermined focus adjustment operation is performed. At this time, the microcomputer 11 controls the position of the focus lens 10a by monitoring the output of the focus lens encoder 15.

Further, the microcomputer 11 receives a photometric output signal (analog signal) from the photometric section 23, converts the signal into a digital signal by an A / D converter 11d, and then converts the digitized photometric signal for analog measurement. A photometric calculation process for calculating an appropriate exposure value based on the signal is performed.

The distance measuring apparatus according to the present embodiment has a photographic optical system 10
A distance measuring optical system 14 for transmitting a part of the subject light flux transmitted through the lens to form a subject image for focus detection, and receiving the focus detecting subject image formed by the distance measuring optical system 14 An AF area sensor 12 or the like, which is an electric charge accumulation type area sensor that generates an electric signal and outputs the generated signal as sensor data, includes a so-called distance measuring method for measuring a distance to a subject. An external light passive system is applied.

The AF area sensor 12 is constituted by a plurality of light receiving elements, for example, photodiodes, which are two-dimensionally arranged in a horizontal direction and a vertical direction on a light receiving surface for receiving a part of the light beam of the object. A light receiving element group 12a that performs photoelectric conversion processing on the light flux, a processing circuit 12b that receives an output from the light receiving element group 12a, performs predetermined signal processing, and generates sensor data in a predetermined form,
It is composed of a stationary light removing unit 12c and the like that receive an output from the light receiving element group 12a and remove the stationary light component.

Here, the detailed configuration of the AF area sensor 12 will be described below. FIG. 2 is a main part block configuration diagram showing a main part of the configuration of the AF area sensor 12 in the camera 1.

As described above, the AF area sensor 12
It comprises a light receiving element group 12a, a processing circuit 12b (not shown in FIG. 2), a fixed pattern noise removing unit 12f, and the like. The output from the light receiving element group 12a is transmitted to the processing circuit 12b via the fixed pattern noise removing unit 12f and the like.

That is, the light receiving element group 12a is composed of a plurality of light receiving elements 12aa arranged two-dimensionally as shown in FIG. 2, and each light receiving element 12aa is provided with a photodiode 12ab for generating a charge by incident light. And an amplifier 12ac that converts the charge generated by the photodiode 12ab into a predetermined voltage, amplifies and outputs the same. In addition, the above-mentioned stationary light removing unit 12c
Are provided inside the amplifier 12ac for each pixel.

The output of the amplifier 12ac is supplied to the processing circuit 1
2b, the vertical shift register 12d and the horizontal shift register 12e, and the fixed pattern noise elimination unit 1
This is output as a predetermined image signal via 2f or the like. The fixed pattern noise is
This is noise generated due to variations in the amplifier 12ac for each pixel.

FIGS. 3 and 4 conceptually show the positional relationship between the distance measuring optical system and the AF area sensor which constitute the distance measuring device in the camera 1. FIG.

The distance measuring optical system 14 includes a pair of light receiving lenses 14.
a of this pair of light receiving lenses 14
a receives the light beam from the subject 100 and divides it into two subject images, which are divided into two light receiving element groups 1 of the AF area sensor 12.
This serves as a so-called separator lens for forming an image on the light receiving surface 2a.

For this purpose, the pair of light receiving lenses 14a
As shown in FIGS. 3 and 4, they are arranged so as to be substantially parallel to each other with a predetermined interval, that is, a base line length B, and to be arranged in a direction substantially orthogonal to the light beam from the subject.

In the distance measuring apparatus of the present embodiment having the above-described configuration, the distance to the subject is measured by using the principle of triangulation. That is, as shown in FIGS. 3 and 4, the focal length of the light receiving lens 14a = f, the light receiving lens 14a
Where L is the base line length of B, and the relative position difference x between the two images formed by the pair of light receiving lenses 14a (see FIG. 4), the distance L to the subject is: L = (B · f) / x.

On the other hand, the photographing optical system 10 of the camera 1 has
The zoom lens is applied as described above. Therefore, when the focal length of the photographing optical system 10 is changed by performing the zoom operation, the detection area (distance measurement area) of the AF area sensor 12 also changes accordingly.

FIG. 5 is a diagram conceptually showing the relationship between the detection area of the AF area sensor 12 and the photographing screen area when the focal length of the photographing optical system 10 is changed. In FIG. 5, an area indicated by reference symbol W (an area within a range indicated by a dotted line)
Is an AF area sensor 1 used for focus detection processing when the photographing optical system 10 is arranged on the widest angle side (wide side).
2, the light receiving surface of the light receiving element group 12a (hereinafter, referred to as a light receiving element group 12a).
A predetermined area within a distance measurement area, which is indicated by reference symbol A), is shown. An area indicated by reference symbol T (an area within a range indicated by a solid line) is defined by the photographing optical system 10 at the most telephoto side (tele side). 2 shows a predetermined area in a distance measurement area (reference numeral A) used for focus detection processing when the area is disposed. The area indicated by the symbol S (the area within the range indicated by the one-dot chain line) is used for focus detection processing when the imaging optical system 10 is located at a position having an intermediate focal length, that is, a standard position (standard position). The figure shows a predetermined area in the distance measurement area (symbol A).

In the camera 1 provided with the distance measuring apparatus of the present embodiment, the photographing optical system 10 and the distance measuring optical system 14 are separately arranged, and receive the light beam of the subject at each position. The so-called external light distance measurement method is used. As a result, parallax (parallax) exists between the photographing screen actually photographed by the photographing optical system 10 and the ranging area of the AF area sensor 12 on which the image formed by the ranging optical system 14 is formed. Will occur. Therefore, in consideration of such parallax, in the distance measuring apparatus of the present embodiment, an area used for performing the focus detection processing according to the focal length information (zoom information) of the imaging optical system 10 is defined. I have to.

In this case, correction data relating to the distance measurement area position corresponding to the change in the focal length of the photographing optical system 10 is stored in the EEPROM 11e in advance. These data are stored in the microcomputer 11 when the camera 1 is started.
After the initialization is performed, the data is loaded onto the RAM 11d (see step S1 in FIG. 6 described later).

The microcomputer 11 refers to the correction data and determines an appropriate distance measurement area to be used for focus detection processing from all the detection areas of the AF area sensor 12 in accordance with the zoom operation. I have.

In this manner, the microcomputer 11 refers to the focal length of the photographing optical system 10 set at that time and the correction data of the distance measuring area corresponding to the photographing screen at that time, and performs the focus detection processing. The sensor data in the unnecessary area is skipped, and only the sensor data in the area necessary for performing the focus detection processing is read out and read out from the RAM 11c.
To be stored. As a result, the RAM 11
Only necessary data is stored in c.

Also, separately from this, the microcomputer 11
A setting signal of the read range of the area sensor 12 may be output, and only the sensor data necessary for performing the focus detection processing may be output to the RAM 11c.

The operation of the camera 1 configured as described above will be described below. FIG. 6 is a flowchart showing a main operation flow of the camera 1 and showing a main routine of the microcomputer 11.

First, when a battery (not shown) serving as a power source is loaded in the camera 1, a main power switch (not shown) is turned on by a photographer (user of the camera). When a predetermined operation is performed, the microcomputer 11 of the camera 1 reads out and executes a predetermined sequence program stored in advance in its internal ROM 11b. Thus, the camera 1 starts its operation.

First, in step S1 of FIG. 6, each of the constituent blocks of the camera 1 is initialized, and
Predetermined data stored in the ROM 11e is read out and expanded in the RAM 11c.

Next, in step S2, the microcomputer 1
1 confirms the state of the 1RSW 17 and waits until the 1RSW 17 is turned on. Here, when it is confirmed that the 1RSW 17 has been turned on, the next step S
In step S3, a predetermined distance measurement process (hereinafter, referred to as AF process; see FIGS. 7 and 8; details will be described later) is performed, and at the same time, the next step S4 is performed.
, Ie, a predetermined photometric operation is performed to execute the exposure calculation process.

Subsequently, in step S5, the microcomputer 1
1 confirms the state of the 2RSW 18. Here, when the microcomputer 11 confirms that the 2RSW 18 is in the on state, the process proceeds to the next step S6.
In, a predetermined exposure operation is performed. When the exposure operation is completed, the process proceeds to step S7, in which the photographed film is wound up and the next unphotographed frame is placed at a predetermined position, ie, one frame of the film. After performing the winding operation for one minute, the process returns to the above-described step S2, and the 1RSW1
Then, the process waits for the input of an instruction signal from 7 or the like, and the subsequent processes are repeated.

On the other hand, in the above-described step S2, the microcomputer 11 monitors the states of the other switches at the same time as checking the state of the 1RSW 17. That is, if it is confirmed in step S2 that the 1RSW 17 is in the OFF state, and if the microcomputer 11 detects an input signal from a switch other than the 1RSW 17 and the 2RSW 18 in step S8, the process proceeds to step S8. Proceeding to the process of S9, in this step S9,
The microcomputer 11 performs a predetermined process according to the input instruction signal (SW input).

For example, when the instruction signal confirmed by the microcomputer 11 in step S8 is a signal for instructing a zoom-up operation or a zoom-down operation by a zoom switch (not shown) for performing a magnification change operation. In step S9, a process corresponding to the input instruction signal, that is, a predetermined process for performing a zoom-up operation or a zoom-down operation is executed. When the execution of these predetermined processes is completed, the above-described step S2
And the subsequent processing is repeated.

Next, the AF processing when the camera 1 executes the automatic focusing operation will be described below.
The AF process is a process corresponding to step S3 in FIG. FIG. 7 is a flowchart showing a subroutine of the AF process of the camera 1. FIG. 8 is a timing chart when the AF processing of the camera 1 is performed.

As described above, when the microcomputer 11 confirms the ON state of the 1RSW 17 in step S2 of FIG. 6, the process of the next step S3, that is, the AF process is executed. That is, the flowchart in FIG. 7 corresponds to the AF processing in step S3 in FIG.

When the process proceeds to the subroutine of the AF processing, in step S11 shown in FIG. 7, first, the microcomputer 11 controls the AF area sensor 12 to execute a predetermined integral calculation processing. In this case, the microcomputer 11
Outputs a predetermined integration control signal. Upon receiving the integration control signal, the AF area sensor 12 outputs a monitor signal corresponding to a peak output (brightest pixel output) within a predetermined range in the distance measurement area. In response to this, the AF area sensor 12 outputs a peak signal within the range of the designated distance measurement area to the microcomputer 11.

The microcomputer 11, which is a control means, adjusts the integration time (accumulation time) so that the amount of light received by the light receiving element group 12a of the AF area sensor 12 becomes appropriate while referring to the above-mentioned monitor signal (FIG. 8). (See (A) and (B)).

Subsequently, in step S12, the microcomputer 11 outputs a read clock (CLK) signal to the AF area sensor 12, and reads sensor data (pixel data) from the AF area sensor 12. Then, after receiving this, it is converted into a digital signal by the A / D converter 11d and then stored in the RAM 11c (FIG. 8).
(See (C) and (D)).

Next, in the processing after step S13,
The microcomputer 11 determines the state of the subject image on the shooting screen, that is, the shooting scene, based on the sensor data stored in the RAM 11c. First, in step S13, a subroutine of "night scene determination processing" (details will be described later; see FIG. 12) for determining whether or not the shooting scene is a night scene (see FIG. 9 described later). Then, in step S14, it is determined whether or not the scene is a night scene. If the microcomputer 11 determines that the shooting scene is a night scene based on the sensor data of the AF area sensor 12, the microcomputer 11 proceeds to the next step S1.
Then, in step S15, a predetermined AF process for performing an appropriate automatic focus adjustment operation according to the night scene scene, that is, [night scene AF process] is performed, and then the process proceeds to the next step S20.

On the other hand, if it is determined in step S14 that the scene is not a night scene, the process proceeds to step S1.
In step S16, the process proceeds to a subroutine for determining a backlight scene (a backlight determination process, which will be described later in detail; see FIG. 18). Then, in step S17, it is determined whether or not the scene is a backlight scene. Here, if it is determined that the scene is a backlight scene, the process proceeds to the next step S18, and in this step S18, a predetermined [backlight A] for appropriately performing the automatic focusing operation in the backlight scene.
F processing], and then proceeds to the next step S20.

If it is determined in step S17 that the scene is not a backlight scene, step S1 is executed.
In step S19, the normal AF process [normal AF process] is performed, and then the process proceeds to the next step S20.

After completion of any one of the "night scene AF process", the "backlight AF process", and the "normal AF process" as described above, the process proceeds to step S20. The microcomputer 11
The drive control of the focus lens 10a is performed via the focus lens drive unit 13 based on the respective focus detection results (distance measurement results) obtained by the [night view AF process], the [backlight AF process], and the [normal AF process]. When a series of AF processes is completed, the process returns to the above-described main routine of FIG. 6 (return). The processing of [pre-flash emission] shown in FIG. 8E will be described later.

Next, the "night scene determination process" of the above-described AF process will be described. This [Night scene determination processing] corresponds to the processing of steps S13 to S15 in FIG. 7 described above.

FIG. 9 is a diagram showing an example of a photographing screen in a typical night scene scene. In a normal case, the night view scene is, for example, a portion where the entire photographing screen has low brightness (the area indicated by the symbol L in FIG. 9; a hatched portion). This refers to a state in which subject images having brightness (regions indicated by reference numeral H in FIG. 9) are scattered.

When taking a photograph using a camera or the like, there is a case where the main subject 101 such as a person is photographed against the night scene scene as described above (FIG. 9).
reference).

FIG. 10 is a view three-dimensionally showing sensor data obtained by the AF area sensor 12 in the shooting scene shown in FIG. FIG. 11 shows the areas of a continuous high-luminance portion (region indicated by reference numeral H) and a continuous low-luminance portion (region indicated by reference numeral L) in the photographing screen shown in FIG. It is a distribution diagram showing the relationship of.

As shown in FIGS. 10 and 11, when a photographing scene as shown in FIG. 9, that is, when a person or the like is photographed against a night scene scene, the luminance distribution in the photographing screen is
The following features are seen. That is, (1) the overall brightness is low, (2) the high-luminance portion is small in area and scattered over the entire screen, (3) ) The low luminance portion occupies a large area in the entire screen.

Therefore, by taking these facts into consideration, it is possible to determine whether or not the shooting scene is a night scene based on the sensor data obtained by the AF area sensor 12.

FIG. 12 is a flowchart showing a subroutine of "night scene judgment processing". When the processing shifts to [Night Scene Determination Processing] in FIG. 12, first, in step S21, the microcomputer 11 (the average luminance calculating means)
An average value of the luminance data of each pixel is calculated based on the sensor data of the entire detection area of No. 2 and the integration time, and a comparison is made as to whether the calculated average luminance value is smaller than a predetermined value. . Thereby, it is determined whether or not the shooting scene is in a low luminance state. Here, when it is determined that the calculated average luminance value is lower than the predetermined value,
On the other hand, when it is determined that the calculated average luminance value is higher than the predetermined value, the process proceeds to step S31.

In step S21 described above, it is determined that the average luminance is lower than the predetermined value, and the process proceeds to step S22. In step S22, it is determined whether or not high-luminance parts are scattered in the photographic scene. Is detected, the distribution of pixels that will be high-luminance parts is detected.

That is, the microcomputer 11 (area determining means)
Detects the distribution of pixels having a value larger than a predetermined value in the sensor data, and determines the area of the continuous region (the area of the high-luminance portion) in which the distribution of the detected pixel data occurs continuously. It is determined whether there are many things smaller than the value. Here, if the area of the continuous region in which the distribution of the pixel data of the high-luminance part is continuous is small, the area is determined to be a night scene, and the process proceeds to step S23. Is determined to be a normal shooting scene (normal scene)
It proceeds to the process of 31. Thus, the above-described step S
When both the conditions in step 21 and step S22 are satisfied, it is determined that the scene is a night scene.

If it is determined that the scene is a night scene, in step S23, the microcomputer 11 controls the strobe light emitting unit 20a via the strobe circuit unit 20 to perform a preliminary light emitting operation (strobe pre-lighting operation; ( FIG.
(E), and at the same time, the AF area sensor 12 is controlled to execute the integral calculation processing.

In this case, the strobe light emitting section 20a
Is reflected by the subject, and the reflected light beam is received by the AF area sensor 12 (see FIGS. 8A, 8B, and 8E). Then, the integration calculation processing by the AF area sensor 12 at this time is performed by the normal A described in step S11 of FIG.
This is the same as the integral calculation process in the F process.

Next, in step S24, the microcomputer 11 reads out sensor data from the AF area sensor 12 (see FIG. 8C), and reads this from the A / D converter 11.
d into a digital signal, which is then stored in the RAM 11c.
To be stored.

In the next step S25, the microcomputer 1
1 is the sensor data stored in the RAM 11c after being read out in step S12 of FIG. 7 described above, that is, the sensor data acquired by the normal integration operation performed without performing the pre-emission operation, and The difference from the sensor data obtained by the integration calculation processing involving the pre-light emission operation performed in step S23 is calculated.
The details of this calculation will be described later (see FIGS. 19 to 22).

Subsequently, in step S26, it is checked whether or not the result of the calculation in step S25, that is, the difference between the sensor data due to the presence or absence of the pre-lighting operation is equal to or larger than a predetermined value. Here, if the difference between the sensor data is equal to or more than the predetermined value, the area of the region having the difference is calculated, and if the area is equal to or more than the predetermined value, the process proceeds to step S27. On the other hand, when it is determined that the difference between the sensor data is not more than the predetermined value, or when the area of the sensor data is smaller than the predetermined width even if the difference between the sensor data is more than the predetermined value, the process proceeds to step S30.

FIG. 13 shows a possible photographic scene in which there is a difference in sensor data between the presence and absence of the pre-emission operation. In other words, in a background scene composed of a low-luminance part in a photographing screen and a photographing scene in which a person or the like is arranged near the center in front of the background, FIG.
In the shaded area, there is a difference between the sensor data obtained when the pre-emission operation is performed and the sensor data obtained when the pre-emission operation is not performed. Therefore,
This area is an object for performing the focus detection process, that is, a distance measurement area (denoted by a symbol As).

Next, in step S27, the microcomputer 1
1 executes a predetermined distance measurement calculation based on sensor data in an area having a difference (the area indicated by oblique lines in FIG. 13; the selected distance measurement area As). The ranging calculation performed here is a general ranging calculation. That is, the operation corresponding to the equation (1) is performed.

Next, in step S28, it is determined whether or not the distance measurement result calculated in step S27 is a value indicating a short distance than a predetermined distance value. here,
When it is determined that the distance measurement result is a short distance, the process proceeds to the next step S29.

In this step S29, the microcomputer 1
1 sets a so-called [night scene portrait mode] in which a photographing mode in which an optimal exposure can be obtained for a scene in which a main subject 101 such as a person (see FIG. 9) is photographed against a night scene is set. Ends the sequence (return). In the [Night Scene Portrait Mode], the light emission of the strobe light emitting unit 20a is controlled so that the main subject 101 (see FIG. 9) located relatively short to the subject is properly exposed, and the brightness is low. This is a shooting mode in which the exposure time is set to be long so that an appropriate exposure is obtained even for a night scene as a background.

On the other hand, if it is determined in step S28 that the distance measurement result is not a short distance, or as described above, in step S26, the difference between the sensor data due to the presence or absence of the pre-light emission operation does not exceed a predetermined value. In this case, the microcomputer 11 sets a normal [night scene mode] for photographing a normal night scene, that is, a night scene, and then ends a series of sequences (return). This [Night Scene Mode]
This is a shooting mode in which light emission of the strobe light emitting unit 20a is prohibited, and an exposure time is set long so that an appropriate exposure is obtained for a night scene with low luminance.

On the other hand, in step S21 described above, it is determined that the average luminance value of the entire photographic screen is higher than the predetermined value, or in step S22, the average luminance value of the entire photographic screen is lower than the predetermined value. Despite this, it is determined that no high-luminance parts are scattered, and step S31
In step S31, the distance measurement calculation process is performed for each predetermined region set in advance. Then, after the distance measurement result on the short distance side is selected from the distance measurement result, a shooting mode suitable for performing normal shooting is set, and a series of sequences is terminated (return).

When the appropriate photographing mode is automatically set for the photographing scene at that time based on the sensor data of the AF area sensor 12 in this manner, this series of [Night Scene Judgment Processing] sequence is terminated. [AF processing] in FIG.
Return to subroutine (return).

The processing of step S21 in the subroutine [Night scene determination processing] shown in FIG. 12 will be described in more detail below. That is, FIG. 14 is a flowchart showing another subroutine of the "night view determination process". In order to describe the process of step S21 in FIG.
This is shown in detail by each of steps 41 to S45. Note that the steps after step S23 are completely the same as the processing in FIG. 12 described above, and thus these processings are represented by the same step numbers. Hereinafter, only different portions will be described.

First, in step S41, the microcomputer 11 calculates the average value of the luminance data of each pixel based on the sensor data of the entire detection area of the AF area sensor 12 and the integration time, and calculates the average value as the calculation result. The luminance value is compared with a predetermined threshold value Bth. Here, when it is determined that the average luminance value <the threshold value Bth,
On the other hand, when it is determined that the average luminance value ≧ the threshold value Bth, the process proceeds to step S31.

In step S41, it is determined that the average luminance value is lower than the threshold value Bth, and the process proceeds to step S42. In step S42, a pixel having a luminance higher than the predetermined value (larger value) is obtained. The number of continuous areas in which data is continuously distributed is counted, and a count value = Sa is set.

Subsequently, in step S43, the number of continuous areas in which pixel data having a lower luminance (smaller value) than a predetermined value is continuously distributed is counted, and the count value = Sb is set.

Then, in step S44, the count value Sa of the high luminance area is compared with a predetermined judgment value = m. The determination value m is a unique default value stored in the EEPROM 11e in advance, and is a value developed in the RAM 11c when the camera 1 is started. Where Sa
If> m is satisfied, the process proceeds to step S45; otherwise, the process proceeds to step S31.

Subsequently, in step S45, the count value Sb of the low luminance area is compared with a predetermined judgment value = n.
This determination value n is determined in advance by the EEPR similarly to the determination value m described above.
This is a unique default value stored in the OM 11e, and is a value developed in the RAM 11c when the camera 1 is started. Then, when Sb <n holds,
The process proceeds to step S23, and if not satisfied, the process proceeds to step S31. Therefore, when the conditions of Sa> m and Sb <n are satisfied, it is determined that the average luminance of the photographed scene at the time of acquiring the sensor data is low and high luminance parts are scattered. The processing after step S23 is exactly the same as the processing in FIG. 12 described above.

Next, the [backlight determination processing] of the above-described AF processing will be described. This [backlight determination processing] corresponds to the processing of steps S16 to S18 in FIG. 7 described above.

FIG. 15 is a diagram showing an example of a photographing screen in a typical backlight scene. In a normal case, a backlight scene refers to a shooting scene in which a high-luminance area such as the sky or the sea (the area indicated by reference numeral H in FIG. 15) is arranged on the background of the main subject 101 such as a person. . In this case, the area occupied by the main subject 101 such as a person in the photographing screen is distributed as an area where the luminance based on the corresponding pixel data is medium luminance (the area indicated by the symbol M in FIG. 15). In the photographing screen, there is almost no low-luminance area.

FIG. 16 shows a three-dimensional distribution of sensor data acquired by the AF area sensor 12 in the case of a backlight scene shown in FIG.
That is, in a backlight scene, as shown in FIG. 16, a high-luminance portion region H serving as a background and a medium-luminance region M occupied by the main subject 101 are distributed in the shooting screen.
The average luminance of the entire screen tends to be relatively high. FIG. 17 shows a luminance histogram in the case of this backlight scene, that is, a distribution of each pixel of the sensor data.

FIG. 18 is a flowchart showing a subroutine of [backlight determination processing]. Step S55
The processes in steps S59 and S61 correspond to the processes in steps S23 to S27 and step S31 of the above-mentioned [night scene determination process] in FIGS. 12 and 14, and substantially the same processes are executed. Will be done.

As shown in FIG. 18, when the process proceeds to the subroutine of the "reverse determination process", first in step S51, the microcomputer 11 determines each of the data based on the sensor data of the entire detection area of the AF area sensor 12 and the integration time thereof. An average value of the luminance data of the pixels is calculated, and it is determined whether or not the average luminance value is larger (higher) than a predetermined value, that is, whether the photographic scene is in a high luminance state. here,
If it is determined that the calculated average luminance value is higher than the predetermined value, the process proceeds to the next step S52, while if it is determined that the average luminance value is lower than the predetermined value, the process proceeds to step S61. Proceed to processing.

In step S52, pixel data having relatively low luminance, that is, distribution of a medium luminance area is detected.
Further, after extracting pixel data within a predetermined luminance range from the above, the process proceeds to the next step S53. here,
As the specified predetermined luminance range, the region of the middle luminance portion in the photographed scene shown in FIG. 15 = the luminance value corresponding to the peak value of the number of pixels of M = the predetermined luminance value centered on Bvp =
The predetermined range is within the range of ± ΔBv (see FIG. 17).

Subsequently, in step S53, after calculating the area = Sn of the continuous area in which the extracted pixel data within the above-mentioned predetermined luminance range (± ΔBv centered on Bvp) is continuously distributed, The process proceeds to the next step S54.

In step S54, the area of the continuous region = Sn within the above-mentioned predetermined luminance range (± ΔBv around Bvp) and a predetermined judgment value (judgment threshold)
= Snth. This predetermined determination value = Sn
th is a unique default value stored in the EEPROM 11e in advance, and the RAM 11c
Is the value that is expanded to And here, Sn> S
When nth holds, the shooting scene at this time is:
It is determined that the scene is a backlight scene in a backlight state, and step S5
Proceed to step 5.

That is, in the case of the backlight scene shown in FIG. 15, the area occupied by the main subject 101 = Sn occupies a relatively large area with respect to the entire photographing screen. Therefore, the relationship of Sn> Snth is established, and it is determined that the scene is a backlight scene.

In step S54, S
If n> Snth is not established, it is determined that the shooting scene at this time is not a backlight scene but a normal light state, and the process proceeds to step S61.

In step S55, the integration calculation process is performed by the AF area sensor 12 with the pre-light emission operation. In this [backlight determination process],
The AF area sensor 12 simultaneously performs the integral calculation processing while removing the steady light by operating the steady light removing unit 12c (see FIGS. 8A, 8B, and 8E).

After reading out the sensor data (see step S11 in FIG. 7) generated by the AF area sensor 12 in step S56, the process proceeds to step S57.
, The difference between the sensor data obtained by the normal integration operation without the pre-emission operation and the sensor data obtained by the integration operation with the pre-emission operation is calculated. The means for this calculation will be described in detail below.

FIG. 19 is a diagram three-dimensionally showing the distribution of sensor data obtained by the AF area sensor 12 when the integral calculation process involving the pre-flash operation is performed in the shooting scene shown in FIG. .

In this case, the reflected light from the subject 101 such as a person at a position relatively close to the camera 1 becomes large, and the reflected light from a long-distance subject as the background becomes small. A subject light beam that can be received by the sensor 12 is as shown in FIG.

The procedure for calculating the difference between the sensor data obtained by the normal integration operation without the pre-emission operation and the sensor data obtained by the integration operation with the pre-emission operation is as follows.

That is, the sensor data of the whole area of the photographing screen acquired by the AF area sensor 12 in the desired photographing scene is analyzed, and the sensor data of the area occupying the largest area in the whole area is standardized. After the conversion, the difference at the same position of the sensor data between the normal time and the pre-light emission is calculated.

The above-described photographing scene in FIG. 15 will be described as an example. First, in the photographing scene in FIG. 15, normalization is performed on sensor data (see step S11 in FIG. 7) obtained by performing a normal integration operation. Performs data arithmetic processing.

In this case, the average value of the sensor data in the area indicated by the symbol H in FIG. 16 is defined as the reference value of the normalized data. Then, after obtaining a coefficient k1 having such a ratio that the average value x1 is adjusted to r0 near the center of the dynamic range of the sensor data, all the sensor data are multiplied by the coefficient k1.

K1 = r0 / x1 FIG. 20 shows a three-dimensional distribution of the sensor data (normalized data at the time of normal integration) calculated thereby.

Next, the normalized data calculation process is similarly performed on the sensor data by the integration calculation process accompanied by the pre-light emission operation. 19 from the sensor data at the time of pre-flash
Is defined as the reference value of the normalized data of the sensor data in the area indicated by the symbol H. Then, after obtaining a coefficient k2 having such a ratio that the average value x2 is adjusted to r0 near the center of the dynamic range of the sensor data, the coefficient k2 is multiplied by all the sensor data.

K2 = r0 / x2 FIG. 21 shows a three-dimensional distribution of the sensor data (normalized data at the time of pre-emission integration) calculated in this way.

In this way, the sensor data obtained by the normal integration operation without the pre-emission operation and the sensor data obtained by the integration operation with the pre-emission operation are standardized, Based on this, the difference between the same positions in the entire screen area is calculated. FIG. 22 shows a three-dimensional distribution of the sensor data (difference data) calculated in this way.

FIG. 22 is a diagram three-dimensionally showing the distribution of the difference data Δd of the sensor data calculated by the above-described calculating means with respect to the sensor data obtained by the AF area sensor 12.

In the above example, the AF area sensor 1
Although the predetermined arithmetic processing is performed on all the sensor data that can be obtained in step 2, the present invention is not limited to this. For example, only the sensor data within a predetermined range may be used.

In the above-described example, the normalization of all sensor data is calculated based on the region occupying the largest area in the sensor data during normal integration. However, the present invention is not limited to this. The standardized data may be similarly calculated based on the sensor data at the time.

Returning to FIG. 18, in the next step S58, the microcomputer 11 determines that the difference data Δd has a predetermined value d.
It is determined whether there is an area larger than th. Here, the area Sm of a continuous area in which pixels having the difference data Δd equal to or larger than the predetermined value dth are continuously distributed, that is, the area indicated by the symbol M in FIG. 22 is calculated. If the area Sm is equal to or larger than the predetermined value Smth, it is determined that the main subject image exists in this area, and this area is set as a distance measurement area. That is, the distance measurement area indicated by reference symbol As in FIG. 23 is a target for which the distance measurement calculation processing is performed.

A predetermined judgment value (judgment threshold) =
Smth is a unique default value stored in advance in the EEPROM 11e.
1c.

On the other hand, if it is determined in step S58 that the difference data Δd is not larger than the predetermined value dth, or if the area Sm is not larger than the predetermined value Smth even if the difference data Δd is larger than the predetermined value dth, The process proceeds to step S61.

In the next step S59, a predetermined distance measurement calculation process for the same distance measurement area As is performed. In this way, in order to specify the position of the main subject image and reflect this information in the exposure, in the next step S60,
The photographing mode is set to a so-called backlight mode for photographing a main subject image such as a person in a backlight state.

Then, the sequence of this series of [backlight determination processing] is completed (return), and the flow proceeds to the above-described processing of step S20 in FIG. That is, the aforementioned step S59
Microcomputer 11 based on the result of the distance measurement calculation process in
Executes a lens driving process of driving the focus lens 10a via the focus lens driving unit 13.

The photometric operation in the backlight mode (FIG. 6)
In step S4), photometric data of the photometric sensor area corresponding to the position of the main subject image is employed.
Alternatively, the brightness data obtained from the sensor data of the AF area sensor 12 may be taken into account as a photometric value. Furthermore, a predetermined exposure calculation process (photometric operation) may be performed based on the brightness value obtained from the sensor data of the AF area sensor 12.

Here, as means for exposure calculation processing in a backlight scene, that is, means for obtaining an appropriate exposure value for a main subject image in a backlight state, for example, auxiliary illumination light is emitted by flash light emission means during an exposure operation. There is a means for irradiating the main subject. In this case, for a subject such as a person at a relatively short distance from the camera, that is, for a main subject in a backlight state, an image having an appropriate exposure value can be obtained by the auxiliary illumination light of the flash light emitting means. Since the auxiliary lighting does not affect its background,
An image with a normal exposure value will be obtained. In this manner, the exposure operation in step S6 in FIG. 6 is performed so that the main subject in the backlight state is appropriately exposed.

On the other hand, if it is determined that the scene is not a backlight scene,
When the process proceeds to step S61 in FIG. 18, normal AF processing is performed in step S61.
In other words, a predetermined distance measurement calculation process is performed for each predetermined predetermined area, and the distance measurement result closest to the short distance is selected.

As described above, according to the first embodiment, in the night view scene, the flash light emitting means emits light of the amount of light that provides an appropriate exposure for the determined main subject, and A proper exposure is obtained even for the background of the luminance part, so that noise reduction in the low luminance part and latitude and color reproducibility in the high luminance part are improved, so that even a night scene is better. Photographic images can be obtained.

In a backlight scene, a medium luminance region having relatively low luminance is detected, it is determined that a main subject is present in the detected medium luminance region, and the exposure value is set with emphasis on this region. Is performed, so that the influence of the luminance of the background portion where the desired main subject image does not exist and is high in luminance is removed, and the desired main subject, for example, a person or the like is photographed with an appropriate exposure. Is to be executed. Therefore, the main subject can be photographed with an appropriate exposure, and a good photographic image can be obtained.

Then, the position of the main subject image in the photographing screen is reliably determined, the focus detection process is performed on the desired main subject image reliably, and a highly accurate ranging process (AF process) is executed. Therefore, comfortable operability can be secured.

[0113] In the camera 1 equipped with the distance measuring device of the first embodiment, the [backlight determination processing] is performed in order to obtain all pixel data (sensor data) that can be obtained by the light receiving element group 12a of the AF area sensor 12. Data) to perform signal processing. In this case,
Number (number of pixels) of each light receiving element constituting light receiving element group 12a
As the number increases, the capacity of sensor data tends to be enormous. When the data capacity of the sensor data increases, the time required to execute various calculations also increases, so the time required for performing a predetermined calculation in response to the generation of a command signal for executing the process and ending a series of processes is described. And the time lag increases accordingly. When the time lag increases in this way, the operability of the camera itself is impaired.

Therefore, for example, the light receiving surface (entire ranging area) of the light receiving element group 12a of the AF area sensor 12 is divided into a plurality of predetermined blocks, and the sensor data in each of the divided blocks is added to perform predetermined processing. Means for reducing the amount of sensor data that can be obtained by treating the pixel data as one piece of pixel data may be considered. If the capacity of the sensor data can be reduced in this way, it can contribute to speeding up the calculation, thereby solving the above-described problem of the time lag.

In this case, the AF area sensor 1
In the case where the photographing optical system is a zoom lens capable of changing the magnification when dividing the light receiving surface (the entire ranging area) into a plurality of predetermined blocks, the size of the unit block to be divided (the number of pixels of the block or Regardless of the focal length)
If it is defined to be always constant, the sensor data amount when the shooting angle of view is set to the wide wide angle side and the sensor data amount when the shooting angle of view is set to the telephoto side where the shooting angle of view is narrower than this The former means that the sensor data amount increases due to a change in the focal length, and the time required for the arithmetic processing using the sensor data also greatly changes.

Therefore, a modified example corresponding to this will be described below. First, the light receiving surface of the AF area sensor 12 is equally divided by a predetermined unit block (the number of pixels of one block or the light receiving area), and the size (area) of this one block is determined by a photographing optical system that is set each time photographing is performed. If the setting is made to be variable according to the focal length of the camera, it is possible to prevent a change in the focal length of the photographing optical system from causing a large change in the time required for the corresponding arithmetic processing. Can be.

FIG. 24 is a view showing a first modification of the first embodiment, in which the entire area of the light receiving surface of the light receiving element group 12a of the AF area sensor 12 is divided into predetermined unit blocks. FIG. 6 is a conceptual diagram showing the light receiving area according to the focal length of the photographing optical system with respect to all the light receiving areas of the AF area sensor 12 at the same time.

In FIG. 24, the area indicated by the reference symbol W is A when the photographing optical system is disposed on the short focus (wide angle; wide) side.
The light receiving area of the F area sensor 12 (in this case, the entire light receiving area corresponds).

As described above, on the short focus side, the number (pixel number) of the light receiving elements 12aa of the AF area sensor 12 corresponding to the photographing screen increases. Therefore, for example, 2 pixels × 2 pixels = 4 pixels are defined as one divided block, and the four pixels included in this block are added and processed to be treated as one pixel data.

The addition processing of the sensor data performed here is an arithmetic processing performed by the microcomputer 11 based on information such as the focal length of the photographing optical system. In addition, separately from this, a predetermined instruction signal from the microcomputer 11 is received, and A
It is also conceivable to perform analog addition processing in the processing circuit on the F area sensor 12 side. As the analog addition processing means, a means for performing addition processing based on a charge level generated by a photodiode or the like, a means for performing addition processing on a voltage output of a pixel amplifier circuit, and the like are conceivable.

On the other hand, in FIG. 24, the area indicated by the symbol T is the light receiving area of the AF area sensor 12 when the photographing optical system is arranged on the long focal point (telephoto side: telephoto side) (in this case, near the center part). Corresponds to the predetermined light receiving area).

As described above, the number of the light receiving elements 12aa (the number of pixels) of the AF area sensor 12 corresponding to the photographing screen at that time is smaller on the long focal length side than on the short focal length side. . Therefore, the sensor data of one pixel is directly handled as pixel data of one pixel.

In this way, the capacity of sensor data handled on the short focus (wide) side and the long focus (tele) side does not change, and the calculation time greatly changes depending on the difference in focal length. Nothing.

In the above example, four pixels are set as one block. However, the setting of the number of pixels is not limited to this, and the total number of pixels of the AF area sensor 12 and the focal length of the photographing optical system are not limited to this. The present invention can be applied with various changes depending on various conditions such as a magnification and a magnification.

Alternatively, the same effect can be obtained by reducing the sensor data capacity by performing a predetermined thinning process or the like on all sensor data that can be obtained by the AF area sensor 12, for example. Can be.

By the way, as a modified example of performing the [backlight determination processing] in the camera 1 equipped with the distance measuring device of the first embodiment, the following means (second modified example)
Is also conceivable. That is, this is a means for determining the shape of a main person or the like in consideration of the shape of the main subject image and the area (size) occupied by the main subject image in the shooting screen.

In this case, for example, taking a person as an example of the main subject, the shape thereof is substantially circular in a portion corresponding to the face and the head, and substantially rectangular in a portion corresponding to the body. .

In the case where the main subject is a person, the size of the person naturally differs depending on the age and the individual, but the size of the person image formed on the light receiving surface of the AF area sensor 12 is obvious. The size can define a substantially standard size according to the distance to the subject.

Therefore, in the present modification, standard person size data (hereinafter referred to as subject data) corresponding to the distance to the subject is prepared in advance in the EEPROM 11e or the like, and the subject data and the AF By comparing the size of the image formed on the light receiving surface of the area sensor 12 with the size of the image, it is determined whether or not the main subject image is a person.

FIG. 25 is a diagram showing a second modification of the above-described first embodiment. When performing the [backlight determination process] in the camera 1, the main subject image when the main subject is a person is shown. FIG. 6 is a diagram for explaining a means for determining the state of the image.

As shown in FIG. 25, when the distance measuring apparatus of the present modification is arranged so as to face a main subject 100 such as a person, a light beam from the main Through the distance measuring optical system 14, thereby forming a subject image, and a main subject image 101 is formed on the light receiving surface of the AF area sensor 12.

Here, the width dimension of the subject itself, which is a portion corresponding to the head of the person and substantially parallel to the light receiving surface of the AF area sensor 12, is indicated by a reference symbol Wh, and similarly, the portion corresponding to the body portion is shown. The width of the subject itself (specifically, the person 100
Is represented by reference symbol Ws. Also, a distance measuring optical system 1
The distance from the object 4 to the subject is indicated by a symbol L,
The distance between the light receiving surface 4 and the light receiving surface of the AF area sensor 12, that is, the focal length of the distance measuring optical system 14 is indicated by a symbol f.

At this time, in the human image 101 on the light receiving surface of the AF area sensor 12, the image width Whh of the portion corresponding to the head and the image width Wss of the portion corresponding to the body are expressed as follows. Can be. Whh = Wh × f / L Wss = Ws · f / L As described above, if predetermined subject data corresponding to the distance to the subject is prepared in advance in the EEPROM 11 e or the like, this data and the AF area sensor 12 are used. By comparing data such as the shape and size (dimensions) of the subject image based on the acquired sensor data, it can be determined whether the subject image is a human image. Note that the process of determining whether or not the subject is the main subject based on the shape of the subject image and the like is hereinafter referred to as a shape determination process.

FIG. 26 is a flowchart showing the sequence of [backlight determination processing] in this modification, which is a sequence to which the above-described shape determination processing is added. The operation when the “light determination process” in this modification is performed will be described below with reference to this flowchart.

First, in step S71, block data is created by adding the read sensor data according to the focal length information. The processing performed here is
This is the processing described in the first modified example (see FIG. 24).

Next, in step S72, brightness data for each block is created from the block data created in step S71, and an average brightness is calculated based on the created all brightness data.

Subsequently, in the next step S73, it is determined whether or not the average luminance of all sensor data is higher than a predetermined value. Here, if it is determined that the average luminance is higher than the predetermined value, the process proceeds to the next step S74. If it is determined that the average luminance is lower than the predetermined value, the process of step S86 is performed. Proceed to.

In step S74, since it is determined that the luminance is high, a process of extracting luminance data of a block within a predetermined luminance range is performed.
In the next step S75, the area of the continuous block luminance data is calculated, and this is set as area = Sn.

Next, in step S76, the area = Sn calculated in step S75 is compared with a predetermined determination value Snth. If Sn> Snth holds, the process proceeds to the next step S77, and
If n> Snth is not satisfied, that is, if Sn ≦ Snth, the process proceeds to step S86.

In step S77, a shape discriminating process is performed to determine whether or not the image of the extracted area is substantially circular. Here, when it is determined that the shape of the image of the extracted area is substantially circular, the process proceeds to the next step S78, and when it is determined that the image is not substantially circular, the process proceeds to step S82. Proceed to processing.

Here, the details of the shape determination processing will be described. The regions extracted in the above steps S74 and S75 are a region P (area = Sc) and a region Q (area = Sd) (see FIG. 25). Here, means for performing pattern matching with a predetermined image is generally used to determine the shape of the image.

That is, in the extracted area, the radius of the circular shape where the area = Sc can be specified from the area = Sc of the image of the area P. Therefore, this is set as a reference circle, the degree of correlation between the image of the extracted area and the reference circular image is calculated, and if the degree of correlation is higher than a predetermined value, it is determined to be a circle.

In step S78 in FIG. 26, since the shape of the image of the region extracted by the determination in step S77 is determined to be substantially circular, the image of this substantially circular region (circular area) is determined. The length Whh in the width direction is calculated.

Next, at step S79, the relationship between the calculation result at step S78 described above, that is, the relationship between the width Whh of the substantially circular region in the width direction and the predetermined determination values W1 and W2 stored in advance in the EEPROM 11e is given by the following equation. W1 <Whh <
It is determined whether or not the relationship is W2. Here, W1
If the relationship <Whh <W2 is established, the process proceeds to the next step S80, and if the relationship is not established,
Proceed to step S86.

In step S80, the circular region P
After setting at least one ranging area As (see FIG. 27) in (see FIG. 25), predetermined ranging calculation processing is performed on this ranging area to create ranging data. When a plurality of distance measurement areas are set, predetermined distance measurement calculation processing is executed for each distance measurement area, and the plurality of distance measurement results are subjected to, for example, the closest selection processing or averaging. One distance measurement data is created by performing processing and the like.

Then, in step S81, after setting the shooting mode of the camera to the backlight scene mode, a series of [backlight determination processing] sequence is terminated (return).

On the other hand, if it is determined in step S77 that the shape of the image of the extracted area is not substantially circular, the process proceeds to step S82. It is determined whether or not the image has a substantially rectangular shape. In the shape determination process in this case, substantially the same process as the substantially circular shape determination process performed in step S77 described above is performed. That is, the shape discrimination processing performed in step S82 is performed on the area Q in FIG.

If it is determined in step S82 that the image of the extracted area is substantially rectangular, the process proceeds to the next step S83, and if it is determined that the image is not substantially rectangular. , The process proceeds to step S86.

In step S83, the length Wss in the image width direction of the extracted area, that is, the substantially rectangular area (rectangular area) is calculated. In the next step S84, the calculation result in step S83 described above, that is, the substantially rectangular The relationship between the length Wss in the width direction of the shape region and the predetermined determination values W3 and W4 stored in the EEPROM 11e in advance is W3.
It is determined whether <Wss <W4. Here, when the relationship of W3 <Wss <W4 holds,
The process proceeds to the next step S85, and if the same relationship is not established, the process proceeds to a step S86.

In step S85, at least one distance measurement area is set in the rectangular area Q (see FIG. 25), and a predetermined distance measurement calculation process is performed on this distance measurement area to generate distance measurement data. When a plurality of distance measurement areas are set, predetermined distance measurement calculation processing is executed for each distance measurement area, and the plurality of distance measurement results are subjected to, for example, the closest selection processing or averaging. One distance measurement data is created by performing processing and the like. And step S
The process proceeds to 81, where the shooting mode of the camera is set to the backlight scene mode, and then a series of [backlight determination processing] sequence is terminated (return).

On the other hand, as described above, (1) when it is determined in step S73 that the average luminance of all sensor data is lower than a predetermined value, (2) in step S73
At 76, Sn> Snth does not hold (Sn ≦ S
nth), (3) In the above-described step S79, when the relationship of W1 <Whh <W2 is not established,
(4) In the above step S77, it is determined that the shape of the image of the extracted region is not substantially circular, and the shape of the image of the region extracted in step S82 is not substantially rectangular. If determined,
(5) In the above step S84, W3 <Wss <
If the relationship of W4 is not established, step S8
In step S86, the routine proceeds to step S86, in which a normal distance measurement calculation process, that is, a predetermined distance measurement calculation process is executed for each of the divided distance measurement areas, and a plurality of calculation results obtained by the closest distance selection are selected. After one distance measurement data is created by performing processing, averaging processing, etc., a series of [backlight determination processing] sequence is terminated (return). Note that, in this case, the shooting mode is not switched, and the normal shooting mode is maintained.

The predetermined determination values W1, W2, W3, and W4 read out from the EEPROM 11e in the above-described steps S79 and S84 are determined based on the distance range where the person (subject) in the backlit state exists in the shooting screen, for example, the shooting range. The value is set in consideration of the range of the magnification ratio 1/30 to 1/80 and also considering individual differences.

On the other hand, after the distance measurement data is created in step S80 or step S85, the following processing may be further performed. That is,
After the distance measurement data is created, the distance measurement data Ls, the length of the substantially circular region in the image width direction = Whh, and the length of the substantially rectangular region in the image width = Wss are stored in the EEPROM 11e in advance. It is checked against predetermined subject data, that is, data of the image width Wha of the part corresponding to the head and the data of the image width Wsa of the part corresponding to the body. By doing so, it is possible to more reliably improve the ranging accuracy.

That is, Wha + ΔW1h <Wh · Ls / f <Wha + ΔW2h Wsa + ΔWls <Ws · Ls / f <Wsa + ΔW2s where the sign ΔW1h · ΔW2h · ΔW1s · ΔW2s
Represents coefficients each indicating an allowable range. Only when such a relationship is established, the selected ranging area is adopted.

According to the second modification, the following effects are also obtained. FIG. 28 is a configuration example of a shooting screen in a case where a non-main subject exists closer than the main subject.

The configuration of the photographing screen shown in FIG. 28 is such that, for example, in a backlight state, a main subject image (person, etc.) 101 is arranged substantially at the center, and another rough subject is located at a position closer to the subject image 101. This shows a case where the (non-main subject 110) is located.

In such a case, the shape of the non-main subject 110 is not substantially circular, and its size is different from that of the human image 101, that is, since it is closer than the human image 101, the width of the Since the length in the direction is larger than each of the predetermined image widths Whh and Wss of the human image 101, the image of this area is not extracted, and the area corresponding to the human image 101 is reliably extracted. It becomes.

Therefore, even in the case of such a photographic screen configuration, the distance measurement area is reliably set for the human image 101, and a predetermined focus detection process is executed based on this.

Next, as a third modified example of the “backlight determination process” in the camera 1 including the distance measuring device of the first embodiment, an area determination value Snt for performing the backlight determination process is described.
Means for setting h and the main subject determination value Smth to different values depending on the position in the shooting screen may be considered.

FIG. 29 is a diagram showing the relationship between the position of the photographing screen and the judgment threshold value in the third modification.
As shown in FIG. 29, the determination threshold value is set so as to be small in a substantially central portion of the photographing screen, and to be large in a peripheral portion.

Usually, as a configuration of a photographing screen when photographing, a main subject such as a person tends to be arranged near a substantially central portion of the photographing screen. Therefore, it is considered that the backlight determination processing is facilitated by setting the determination threshold value in the substantially central portion of the photographing screen smaller than that in the peripheral portion. In addition, if the area of the region used for performing the backlight determination process is reduced, the data capacity to be handled is reduced, so that there is an effect that the process can be speeded up easily.

Separately from this, the area determination value Snth and the main subject determination value Smt for performing the backlight determination processing are described.
Means for changing h in accordance with various shooting modes is also conceivable.

For example, in a portrait mode mainly used for photographing a person, a composition in which a main subject image of a person or the like is arranged substantially near the center of a photographing screen is generally used. At this time, the main subject image often occupies a relatively large area with respect to the entire area of the shooting screen. Therefore, in such a case, the determination value Snth
By setting Smth smaller than in other shooting modes, that is, landscape mode, macro mode, etc., it is possible to facilitate backlight determination processing and contribute to speeding up the processing.

On the other hand, when the main subject is a person or the like, there are many compositions in which the main subject image is arranged at a position near the lower side of the shooting screen, and the upper side is mainly the background. At this time, since the background portion is occupied by the high luminance region, it is considered that it is relatively easy to detect this region. Therefore, a fourth modified example in which such composition information (position information of the main subject image in the shooting screen and the like) is added to determine whether or not the scene is a backlight scene is also conceivable.

In a normal case, the photographing screen of the camera 1 is usually set to have a rectangular shape. Therefore, when photographing is performed, a desired composition is determined by landscape shooting in which a rectangular shooting screen is horizontally long and vertical shooting in which a rectangular shooting screen is vertically long. Will be.

FIGS. 30 and 31 show examples of compositions when photographing is performed with a person or the like as a main subject. FIG. 30 shows an example of horizontal position photographing.
Is an example in the case of vertical shooting.

As shown in FIGS. 30 and 31, an area serving as a background in the case of horizontal position shooting, ie, a detection area Asa, and an area serving as a background in the case of vertical position shooting, ie, a detection area Asb
And a different position.

In consideration of this, in the present modification, prior to the determination of the shooting scene, whether the shooting screen is in the horizontal position or the vertical position is detected, and the detection is performed in the direction of the shooting screen. The detection area is set accordingly.

For this purpose, the camera 1 of the present modified example includes a camera posture detecting section 24 for detecting the posture of the camera 1 at the time of photographing.
(See FIG. 1). Then, the camera posture detection unit 24 detects whether the photographing screen of the camera 1 is in the vertical position or the horizontal position, and sets the position of the detection area based on the direction of the photographing screen detected thereby. I am trying to do it.

Here, the operation in the [backlight determination processing] of this modification will be described below with reference to the flowchart of FIG. The [backlight determination process] of this modification is a sequence of the [backlight determination process] of the above-described second modification (FIG. 26).
) Is added to the above-described processing, that is, the processing of determining the length and width of the shooting screen and the processing of determining the luminance of the detection area according to the direction of the shooting screen. Therefore, the description of the portions described in the second modification will be omitted, and only different portions will be described.

In the backlight determination processing, the processing in steps S71 to S85 determines that the target photographing screen is a backlight scene. After the focus detection processing in a predetermined distance measurement area is performed, the processing proceeds to step S91. move on.

In this step S91, the attitude of the camera 1 is detected by the camera attitude detector 24 first. Here, if it is determined that the shooting screen of the camera 1 is in the horizontal position, the process proceeds to the next step S92. If it is determined that the shooting screen is in the vertical position, the process proceeds to step S92. The process proceeds to S94.

In step S92, since the photographing screen is in the horizontal position, the area Asa shown in FIG. 30 is set as a detection area (also referred to as a detection area).
The average luminance value at sa is calculated.

Subsequently, in step S93, it is determined whether or not the average luminance value of the detection area Asa calculated in step S92 is equal to or greater than a predetermined luminance value, that is, whether or not the luminance is high. Here, if it is determined that the brightness is high, the shooting scene is determined to be a backlight scene, and the process proceeds to step S81. Also,
If it is determined that the brightness is not high, step S86
Proceed to processing. The processing after step S86 is as described above (see FIG. 26).

On the other hand, if it is determined in step S91 that the shooting screen of the camera 1 is not in the horizontal position but in the vertical position, the process proceeds to step S94.
In this step S94, the area Asb shown in FIG.
Is set as a detection area, and an average luminance value in the detection area Asb is calculated.

Subsequently, in step S95, it is determined whether or not the average luminance value of the detection area Asb calculated in step S94 is equal to or higher than a predetermined luminance value, that is, whether or not the luminance is high. Here, if it is determined that the brightness is high, the shooting scene is determined to be a backlight scene, and the process proceeds to step S81. Also,
If it is determined that the brightness is not high, step S86
Proceed to processing. The processing after step S86 is as described above (see FIG. 26).

As described above, according to the above-described fourth modification, the processing for confirming the luminance in the background area is added, so that it is possible to more reliably and accurately determine whether or not the scene is a backlight scene. .

By the way, with regard to the [Night Scene Judgment Processing],
In the first embodiment described above, it is determined whether or not the scene is a night scene by detecting whether or not high-luminance portions are scattered. Five modifications are also conceivable.

In a normal case, in a night scene (see FIG. 9), a high contrast image tends to be formed because the luminance difference between the high luminance portion and the low luminance portion is large. That is,
The features of the night view scene are as follows: (1) the overall brightness is low (the average brightness is low); and (2) the sum of the contrast (absolute value of the brightness difference) in the shooting screen is greater than a predetermined value. They tend to be large (high contrast). Therefore, it can be considered that it is easy to determine whether or not the scene is a night scene by detecting a portion having a high contrast in the shooting screen.

FIG. 33 is a diagram three-dimensionally showing a contrast distribution based on sensor data of a night scene (FIG. 9) obtained by the AF area sensor of the camera provided with the distance measuring device of the first embodiment. It is.

The contrast of the image is determined by the individual pixel data (sensor data) obtained by the individual light receiving elements 12aa of the light receiving element group 12a of the AF area sensor 12, and
After calculating the absolute value (contrast value) of the difference between the pixel data (sensor data) in the peripheral portion for each pixel, the sum is calculated by summing the contrast values of all the pixels in a predetermined area.

It should be noted that, as shown in FIG. 33, the cross-sectional shape on the distribution diagram of the original sensor data after the contrast calculation processing with respect to the cross-sectional shape (reference M) is indicated by the reference character N. . In other words, it is shown that the highest contrast is obtained at the boundary between the high luminance area and the low luminance area.

Next, the operation at the time of performing the [night scene judgment processing] based on the contrast value of the photographing screen is as shown in the flowchart of FIG. FIG. 34 shows steps S21 and S22 in the sequence of the “night scene determination process” (FIG. 12) in the first embodiment.
Steps S101 and S1
02 is different.

That is, in the present modified example, when the processing shifts to the [night scene judgment processing] of FIG. 34, first in step S101,
The average value of the luminance data of each pixel is calculated based on the sensor data of the entire detection area of the AF area sensor 12 and the integration time, and the calculated average luminance value is calculated from a threshold value Bth representing a predetermined luminance value. Is also compared. Thereby, it is determined whether or not the shooting scene is in a low luminance state. Here, when it is determined that the calculated average luminance value is lower than the predetermined value Bth, the process proceeds to the next step S102, while it is determined that the calculated average luminance value is higher than the predetermined value Bth. If so, the process proceeds to step S31.

In step S101 described above, it is determined that the average luminance is lower than the predetermined value Bth, and step S1 is executed.
02, in this step S102,
The above-described predetermined contrast calculation is performed on the entire shooting scene, and the calculation result is a predetermined threshold value Ct.
h is compared. Here, the predetermined value C
If it is determined that the contrast is higher than th, it is determined that the scene is a night scene, and the process proceeds to step S23. If it is determined that the contrast is low,
It is determined that the scene is not a night scene but a normal shooting scene (normal scene), and the process proceeds to step S31.

Thus, the above-described step S101 is performed.
Is satisfied, that is, when both the average luminance <Bth and the condition in step S102, that is, the contrast value> Cth are satisfied, it is determined that the scene is a night scene. When it is determined that the scene is a night scene, a series of processes from step S23 is performed. In addition, about a series of processes after this step S23,
Since the processing is exactly the same as the processing described with reference to FIG. 12, a detailed description thereof will be omitted. According to the fifth modified example as described above, it is possible to reliably determine the night scene scene.

Next, a sixth modification of the above-described first embodiment will be described. In the sixth modification, the case where the shooting scene is as shown in FIG.
25 to S27, that is, a case where it is determined whether the shooting mode to be set when it is determined that the scene is a night scene scene is the “night scene portrait mode” or the normal “night scene mode” is set. It will be described (FIGS. 19 to 2)
2).

FIG. 35 is a diagram three-dimensionally showing sensor data obtained by integration calculation processing by the AF area sensor 12 when a pre-emission operation of causing the strobe light emission unit 20a to emit light is performed on the shooting scene of FIG. It is.

FIG. 36 shows sensor data obtained by comparing sensor data without pre-emission with sensor data with pre-emission in the photographed scene of FIG. 9 and extracting only a part having a difference between the two. FIG. 3 is a diagram showing three-dimensionally.

Here, when comparing the two sensor data, for example, means for normalizing the two data at the peak luminance value and calculating the corresponding sensor data or the difference for each area is used.

In the night view scene as shown in FIG. 9, when a main subject such as a person is present at a position relatively close to the camera (position at a short distance), as shown in FIGS. 35 and 36. There is a difference in image data obtained depending on the presence or absence of strobe light. Then, it can be inferred that the main subject exists in the part (area) having the difference. Therefore, in this case, the photographing mode is set to [Night scene portrait mode], and the area having this difference, that is, FIG.
An area indicated by a symbol As of No. 3 is set as a distance measurement area, and a predetermined distance measurement calculation process is executed in this distance measurement area As.

On the other hand, in the night scene scene, if there is no subject such as a person at a position close to the camera, there is no difference in the obtained image data depending on the presence or absence of strobe light emission. Therefore, in this case, the normal [Night Scene Mode] is set. In this case, the scene of the night view itself is considered to be the main subject, so that the focus adjustment operation may be set to an infinite distance.

As described above, in the present modification, when it is determined that the shooting scene is a night scene scene, the [Night scene portrait mode] and the normal [Night scene mode] among the shooting modes suitable for night scene shooting are switched. To do so.

According to this, a more appropriate photographing mode is automatically switched according to the photographing scene, so that a good photographing result can always be obtained.

In the case where the shooting scene is as shown in FIG. 9, switching of the shooting mode to be set when it is determined that the scene is a night scene, that is, [Night scene portrait mode] or the normal [Night scene mode] is performed. As for the switching determination processing of whether or not to set to [], a seventh modified example shown below can be considered as means different from the above-described example.

FIG. 37 is a diagram showing the relationship between the luminance in the photographing scene of FIG. 9 and the number of pixels or areas corresponding thereto. Focusing on the relationship between the luminance and the number of pixels or areas corresponding to the luminance based on the sensor data acquired by the AF area sensor 12, the following tendency is observed in a normal night scene. In other words, when (1) the distribution of the low luminance area and the high luminance area is biased, while the distribution of the medium luminance area is small, and (2) there is a main subject at a short distance, The brightness distribution is different between the sensor data when the light emission operation is performed and the sensor data when the pre-light emission operation is not performed, and when the pre-light emission operation is performed compared to the sensor data when the pre-light emission operation is not performed. (3) When there is no main subject at a short distance, there is almost no difference in the luminance distribution regardless of the presence or absence of the pre-emission operation. Absent.

In consideration of such a tendency, the following criterion can be defined. That is, (1) when the distribution of the high luminance area and the low luminance area is uneven and the distribution of the medium luminance area is small, it is determined that the scene is a night scene, and the normal [night scene mode] is set. (2) If there is a difference in the luminance distribution when comparing the respective sensor data obtained according to the presence or absence of the pre-emission operation, the main subject such as a person against a night view is present at a short distance. Set to [Night scene portrait mode] suitable for portrait shooting in night scene scenes,
(3) If there is no difference in luminance distribution when comparing the respective sensor data obtained depending on the presence or absence of the pre-light emission operation, it is determined that the scene is a normal night scene scene in which only a night scene as a landscape is photographed, Set to [Night Scene Mode].

FIG. 38 shows the sequence of the "night scene determination process" of the present modification when the above-described determination criteria are defined.
This will be described below with reference to the flowchart of FIG. First, in step S111, the number of pixels having a luminance higher than a predetermined value is counted for an area (distance measurement area) within a predetermined range corresponding to the shooting screen, and this is counted as a count value BH.
C.

Next, in step S112, similarly, the number of pixels having a medium luminance value larger than a predetermined value is counted for a predetermined range of an area (ranging area) corresponding to the photographing screen, and this is referred to as a count value BMC. I do.

Subsequently, also in step S113, similarly, the number of pixels having a luminance lower than the predetermined value is counted in a predetermined range area (distance measuring area) corresponding to the photographing screen, and this is counted by the count value BLC. And

In steps S114 to S116, each count value BHC / BMC counted as described above
-Each of the BLCs is compared with a predetermined determination value a, b, c.

That is, in step S114, the count value BHC is compared with a predetermined determination value a, and the value of BHC>
If the relationship a is established, the process proceeds to the next step S115, and in this step S115, the count value BM
C is compared with a predetermined determination value b. Here, if the relationship of BMC <b is established, the process proceeds to the next step S116, and in this step S116, the count value BLC
Is compared with a predetermined determination value c, and if the relationship of BLC> c is established, the process proceeds to the next step S117.

Thus, BHC> a, BMC <
If both of b and BLC> C are satisfied, it is determined that the shooting scene is a night scene.

When it is determined that the scene is a night scene, as described above, in the next step S117,
A pre-emission operation for causing the strobe light emission unit 20a to emit light is performed, and the integration calculation process is performed by the AF area sensor 12. Subsequently, in step S118, sensor data is read from the AF area sensor 12.

Next, in step S119, the number of pixels having medium luminance is counted based on the sensor data of the predetermined distance measurement area, and this is set as a count value BMCa.

In step S120, the count value BMCa is compared with a predetermined value b. here,
When the relationship of BMCa> b is established, it is determined that the main subject is present with the night view as the background, and the process proceeds to the next step S121. Also, BMCa> b
If the relationship is not established, it is determined that the scene is a normal night scene, and the process proceeds to step S124.

In step S121, an area in which the number of pixels having medium luminance is increased is set as a distance measurement area, a predetermined distance measurement calculation process is performed, and the flow advances to the next step S122.

In step S122, it is determined whether or not the distance to the subject is short based on the result of the distance measurement calculation in step S121. Here, if it is determined that the subject exists at a short distance, the process proceeds to step S12.
On the other hand, if it is determined that the subject is a normal night view scene where the subject is not at a short distance, the process proceeds to step S124.
Proceed to processing.

If it is determined in step S122 that the subject exists at a short distance, and the process proceeds to step S123, in this step S123, the photographing mode is set to [Night Scene Portrait Mode] and a series of [Night Scene Portrait Mode] is set. Judgment process] is terminated (return).

On the other hand, when it is determined in step S120 and step S122 that the scene is a normal night scene, and the process proceeds to step S124, the process proceeds to step S1.
At 24, the shooting mode is set to the normal "night scene mode", and the sequence of the "night scene determination process" is terminated (return).

If the relationship of BHC> a is not established in step S114, if the relationship of BMC <b is not established in step S115, if the relationship of BLC> c is not established in step S116, In either case, it is determined that the scene is a normal shooting scene (normal scene), and the process proceeds to step S125. Then, in step S125, a distance measurement calculation process is performed for each predetermined region set in advance.
Then, the distance measurement result on the short distance side is selected from the distance measurement result, and a shooting mode suitable for performing normal shooting is set. Then, a series of sequences is terminated (return).

As described above, also in the seventh modified example, a good photographing result can be always obtained by automatically switching to an appropriate photographing mode according to a photographing scene.

By the way, in the camera provided with the distance measuring apparatus of the first embodiment and the modifications thereof, when it is determined that the scene is a night scene, the shutter speed value is decreased in a normal case. Usually, the exposure amount is controlled. Therefore, if the photographer holds the camera 1 with his / her hand or the like, good photographing results may not be obtained due to camera shake or the like. In such a case,
It is desirable to take a picture with the camera 1 fixed by using a tripod or the like.

Therefore, when the photographic scene is determined to be a night scene scene as described above, the shutter speed based on the exposure value calculated by the photometric means or the like is a relatively slow shutter speed, and camera shake or the like occurs. When the situation becomes easy, the display unit 19 (see FIG. 1) or the like is used to display information to that effect, thereby giving a predetermined warning to the photographer of the camera 1. Should be issued. As the warning display, for example, a warning index displayed on the light receiving surface of the display unit 19 is displayed, and the warning indicator is displayed in a blinking manner. Alternatively, a sounding means capable of generating a warning sound or the like may be provided, and a warning may be issued by using a beep sound or a sound by the sounding means.

The exposure value determined by the photometric means is determined according to the shooting scene. In addition, the condition of the film loaded in the camera 1, that is, the film sensitivity and the like are also taken into consideration. Is common.

Therefore, in a situation where the proper exposure value is a low shutter speed value, a film having a higher sensitivity can obtain the same exposure value as a faster shutter speed value. It is well known.

Therefore, as described above, when the scene is determined to be a night scene, and the shutter speed value for realizing the appropriate exposure value at that time becomes a relatively slow shutter speed, information indicating that the use of the high-sensitivity film is promoted. May be displayed or sounded as a warning display by the display unit 19 or a warning sound by the sounding means. Also, apart from this,
The film sensitivity information etc. that is appropriate for the shooting scene
Means for displaying on the display unit 19 is also conceivable.

When the information prompting the user to exchange the film is provided by the camera 1, the user of the camera performs a predetermined halfway rewind operation or the like of the film currently loaded in the camera 1. Then, by taking this out of the camera and loading a high-sensitivity film appropriate for the shooting scene at that time, shooting can be continued without hindrance.

The used film loaded in the camera is rewound in the course of photography, taken out of the camera, and loaded again in the camera at a later date. A function that winds up to the top of the frame and allows it to be reused continuously, a so-called mid-film change function (MRC; midroll change function)
Are generally put into practical use.

By the way, as a method of a distance measuring device used for a camera or the like for taking a photograph, for example, an infrared ray or the like is irradiated toward a desired subject, and the reflected light is received to determine the distance to the subject. In addition to the so-called active type distance measuring device that measures the distance and the so-called passive type distance measuring device that calculates the distance to the subject from the amount of shift between the pair of subject images formed by the pair of light receiving lenses, the active type and the passive type So-called hybrid type distance measuring device, which is configured by combining two distance measuring devices with the method, and switches between them according to the subject distance.
Various types of distance measuring devices are generally put into practical use.

Therefore, the camera provided with the distance measuring apparatus according to the second embodiment of the present invention is not only a hybrid combination of the active system and the passive system, but also employs both systems to obtain a photographic screen. A camera to which a so-called super combination distance measuring device adapted to detect a main subject image in is applied.

The camera provided with the distance measuring device of the present embodiment has substantially the same configuration as that of the first embodiment.
The only difference is the method of the applied distance measuring device. Therefore, for the same configuration as the first embodiment described above,
A detailed description of the configuration will be omitted, and only different points will be described below.

FIG. 39 is a main block diagram showing the main components of a camera provided with the distance measuring apparatus of this embodiment. FIG. 3 shows a configuration of a camera provided with the distance measuring device of the present embodiment.
9 will be described below.

As shown in FIG. 39, the distance measuring apparatus applied to this camera includes an AF area sensor 12A and a distance measuring optical system 1
4A and the like. The distance measuring optical system 14A is
It is provided on the front side of the camera, and is constituted by a pair of light receiving lenses 14Aa and the like for transmitting a light flux from the object 100 to form two object images, and by a pair of light receiving lenses 14Aa of the distance measuring optical system 14A. The formed subject image is arranged at a predetermined position so as to form an image on the light receiving surface of the AF area sensor 12.

The AF area sensor 12A includes the distance measuring optical system 1
A pair of subject images formed by a pair of 4A light receiving lenses 14Aa are respectively received, and a pair of light receiving element groups 12Aa for performing a photoelectric conversion process on the pair of subject images and an output from the pair of light receiving element groups 12a are received. A / A which converts the output from the pair of light receiving elements 12a into a digital signal and outputs the digital signal to the microcomputer 11A arranged at a predetermined position inside the camera, and a stationary light removing unit 12Ac for performing processing for removing the stationary light component. D converter 12Af and a pair of light receiving element groups 12
It is configured by a processing circuit (not shown) that receives the output from a and performs other necessary signal processing and the like to generate sensor data in a predetermined form.

The pair of light receiving element groups 12Aa is composed of a plurality of light receiving elements such as photodiodes arranged two-dimensionally in the horizontal and vertical directions on the light receiving surface of the subject light beam.

The steady light removing means 12Ac is controlled by the microcomputer 11A together with the strobe light emitting means 20A, and emits illumination light from the strobe light emitting section 20Aa whose light emission is controlled by the strobe light emitting means 20A. When the steady light removing means 12Ac is operated, the DC light signal which is constantly incident is removed from the output signals from the pair of light receiving element groups 12Aa. Therefore, the pair of light receiving element groups 12Aa at this time
Is an output signal based only on the pulsed light beam from the strobe light emitting unit 20Aa.

The distance measuring apparatus according to the present embodiment thus configured is controlled by the microcomputer 11A on the camera side. Further, the microcomputer 11A controls the strobe light emitting section 20Aa via the strobe light emitting means 20A as described above.

On the other hand, in the camera provided with the distance measuring device of the present embodiment, an audio signal generating means 25 is further provided.
1A.

Further, inside the microcomputer 11A, the CPU, ROM, RAM, and EE are stored as in the first embodiment.
In addition to the members such as the PROM 11e, it further includes a pattern determination unit 11Af for analyzing an image pattern of a subject image formed on the light receiving surfaces of the pair of light receiving elements 12Aa of the AF area sensor 12A.

In the present embodiment configured as described above, the luminous flux from the subject 100 is processed as follows. That is, the subject luminous flux transmitted through the pair of light receiving lenses 14Aa first enters the light receiving surfaces of the pair of AF area sensors 12A, that is, the light receiving element group 12Aa. Then, the light receiving element group 12Aa performs predetermined signal processing so that the optical subject image formed on its own light receiving surface is subjected to predetermined signal processing, that is, photoelectric conversion processing so as to become an electrical image signal. And outputs it to the A / D converter 12Af. Then, the image signal converted into a digital signal by the A / D converter 12Af is transmitted to the microcomputer 11A.

At this time, the microcomputer 11A controls the steady light removing means 12Ac as necessary to operate it, and controls the strobe light emitting section 20Aa via the strobe light emitting means 20A to emit predetermined illumination light to the object. In some cases. For example, when the shooting scene is a night scene, the AF process involving the pre-emission operation is performed. In such a case, the reflected light of the illumination light flux from the strobe light emitting unit 20Aa by the subject enters the AF area sensor 12 via the distance measuring optical system 14, and A
In the subject image formed on the light receiving surface of the F area sensor 12A, an output signal of an area indicated by reference numeral 101 in FIG. 40 (a portion indicated by oblique lines in FIG. 40), that is, a steady incidence by the action of the steady light removing means 12Ac. Then, an output signal based on only the pulse light of the strobe light emitting unit 20Aa is output from the AF area sensor 12A.

FIG. 40 is a diagram showing an image area corresponding to an output signal from the AF area sensor when the steady light removing means and the strobe light emitting means are operated.

The microcomputer 1 receives the output signal and receives the output signal.
1A is a pattern discriminating means 11Af included in the self.
Performs a pattern analysis of the image formed on the light receiving surface of the AF area sensor 12A. If it is determined, for example, that the object is a human figure based on the analysis result, it is estimated that the object is the main subject.

FIG. 41 is a flowchart showing the sequence of the AF processing in the camera provided with the distance measuring apparatus of the present embodiment. This AF process is an AF process in the main routine in the above-described first embodiment, that is, a process corresponding to step S3 in FIG.

First, when the flow shifts to the AF processing, step S1 is executed.
At 31, the microcomputer 11A operates
In addition to controlling the strobe light emitting unit 20Aa via 0A, the flash unit 20A controls the AF area sensor 12A to perform integral calculation processing involving a pre-flash operation. At this time, the stationary light removing means 12Ac is operated at the same time.

Thus, in the next step S132, the AF area sensor 12A outputs the image 1 shown in FIG.
01, that is, the strobe light emitting section 20Aa
Only the pattern signal (hereinafter, referred to as reflected signal light) due to the reflected light beam of the illumination light is extracted as the sensor data,
The data is output to the microcomputer 11A.

Subsequently, in step S133, the microcomputer 11A receives the sensor data extracted in step S131, and determines the shape of the signal based on the reflected signal light by the pattern determining means 11Af. Here, when the pattern of the reflected signal light is determined to be a main subject such as a predetermined person, after detecting the position of the main subject in the ranging area corresponding to the shooting screen, the next step is performed. The process proceeds to S134. The detection of the subject position performed here is performed by determining whether the intensity of the image signal forming the pattern of the reflected signal light is at a predetermined level or by determining whether the image signal has a predetermined contrast. Done.

In step S134, A to be executed
A selection is made as to whether the F processing is of the active type or of the passive type. That is, the above-described step S
If it is determined in 133 that the contrast of the image signal has not reached the predetermined level, the process proceeds to the next step S137 to execute the AF process by the active method.

In step S137, the illumination operation is performed again by the strobe light emitting section 20Aa, and the integral operation is performed with the stationary light removing means 12Ac acting. In step S138, the active AF is performed.
Execute the process. In this case, the area of the image based on the sensor data extracted in the previous integration calculation process, that is, the area of the image 101 shown in FIG. Is performed.

Next, in step S139, the microcomputer 11A controls the audio signal generating means 25 to output audio information in a first audio pattern indicating that active AF processing has been performed. Then, a series of sequences ends (return).

On the other hand, in the above-mentioned step S133,
It is determined that the intensity of the reflected signal light has not reached the predetermined level (weak), and the process proceeds to step S134, where it is selected to execute the AF process by the passive method, and the process proceeds to step S135. Proceed to processing.

At step S135, a passive AF process is executed. Also in this case, the area of the image (the area of the image 101 in FIG. 40) based on the sensor data extracted in the previous integration calculation processing is set as the distance measurement point, and the predetermined calculation processing is focused on this distance measurement point. Perform

Next, in step S136, the microcomputer 11A controls the audio signal generating means 25 to output audio information in the second audio pattern indicating that the passive AF process has been performed. Then, a series of sequences ends (return).

On the other hand, in the above-mentioned step S133,
The pattern of the reflected signal light extracted in the process of step S132 does not match the pattern shape of a predetermined person or the like,
If it is determined that the subject is not the main subject, step S
Proceed to 140.

At step S140, the microcomputer 1
1A executes AF processing by either active method or passive method distance measuring means in consideration of luminance information and the like. In this case, a predetermined calculation process is performed with emphasis on the distance measurement point, with the vicinity of the center of the screen where the object is most likely to be arranged in the shooting screen as the distance measurement point.

Next, in step S141, the microcomputer 11A controls the audio signal generating means 25 to
The audio information is output in the third audio pattern indicating that the F processing (the normal hybrid AF processing using either the active method or the passive method) has been performed. Then, a series of sequences ends (return).

As described above, according to the second embodiment,
The AF processing of the active method and the passive method are simply combined in a hybrid manner to perform not only the distance measurement operation according to the situation of the shooting scene, but also the AF processing accompanied by the flash pre-flash operation such as a night scene scene. When this is done, the main subject image in the shooting screen is detected, so that more reliable AF processing can be executed.

Also, after each AF process is executed, audio information is generated by the audio signal generating means 25 according to the process, which contributes to improving the operability of the camera user. Can be.

In recent years, an electric image signal generated by subjecting an optical subject image to photoelectric conversion by an image pickup device such as a CCD separately from a camera or the like for taking a photograph using a conventional film. A so-called electronic imaging device (hereinafter, referred to as an electronic camera), which is capable of recording on a predetermined recording medium as digital data or the like in a predetermined form, is widely used.

An image obtained when a night view scene is photographed by using such a conventional electronic camera or the like is caused by, for example, a so-called color skipping phenomenon in a high luminance portion or deterioration of the S / N ratio. There is a tendency for unnaturalness to be seen in the entire image taken by the camera.

Further, in an image obtained as a result of shooting in a backlight scene, a phenomenon may be seen in which a low-luminance portion of a main subject such as a person is so-called blackened by the influence of a high-luminance portion serving as a background. .

In order to solve these problems, it is conceivable to apply the distance measuring apparatus of the present invention. A third embodiment described below is an example in which the present invention is applied to an electronic camera or the like.

FIG. 42 is a main block diagram showing the configuration of an electronic camera provided with the distance measuring apparatus according to the third embodiment of the present invention.

The electronic camera 50 has a photographic optical system 51 composed of a plurality of lenses and the like for transmitting a subject light beam O to form a subject image at a predetermined position, and an optical system formed by the photographic optical system 51. C to convert subject image into electrical signal
An imaging element 53 which is a photoelectric conversion element such as a CD, and an imaging optical system 51 provided between the imaging optical system 51 and the imaging element 53;
Aperture section 52 that regulates the amount of light of subject light flux O passing through the imaging element 53 and a CDS section 54 that receives an output signal of the imaging element 53 and performs correlated double sampling or the like to remove a predetermined reset noise or the like. And a sample-and-hold circuit (hereinafter, referred to as an S / H unit) 55, and the CDS unit 54
And an A / D converter 56 for converting an output signal (analog signal) output via the S / H unit 55 into a digital signal
And a process processing unit 57 that receives the digital signal from the A / D circuit 56 and performs various image processing and the like, and receives an output signal (image signal) from the process processing unit 57 and temporarily stores it. Temporary memory 6 such as DRAM
3 and a signal equivalent to the image signal stored in the temporary memory 63 is subjected to a compression process or the like so as to be in an optimal form for recording on the recording medium 65, and is converted into data. A compression / decompression unit 64 which reads out the compressed data recorded in the form, performs a decompression process on the compressed data so as to become a signal of a predetermined form, and stores it in the temporary memory 63;
A recording medium 65 such as a magnetic recording medium or a semiconductor memory for recording image data of a predetermined form and a signal processed by the process processing unit 57 are used to measure subject brightness and the like, and to adjust an exposure amount suitable for a shooting scene. Metering section 61 for setting the aperture setting value and the like, and an aperture control section 62 for controlling the driving of the aperture section 52 in response to a predetermined value and the like set by the metering section 61.
And so on.

The process processing section 57 includes an AGC / γ correction section 58 for performing processing such as automatic gain control, a night scene scene determination section 59 for determining whether or not the shooting scene is a night scene scene, and a shooting scene scene. Is constituted by various circuits such as a backlight scene determination unit 60 that determines whether or not the scene is a backlight scene.

The operation of the electronic camera 50 thus configured will be described below. The subject light beam O transmitted through the photographing optical system 51 is regulated to a predetermined incident amount by the diaphragm unit 52, then enters the image sensor 53, and forms a subject image on the light receiving surface thereof. The imaging device 53 receives the incident subject light beam, performs photoelectric conversion on the received subject light beam, and generates an image signal corresponding to the subject image formed by the light beam. The image signal generated by the image sensor 53 is transmitted to the CDS unit 5.
After predetermined signal processing is performed in the S / H unit 4 and the S / H unit 55, the signal is output to an A / D circuit 56, where it is converted into a digital signal.

The image signal thus converted into a digital signal is output to the process processing section 57, and subjected to image processing such as gain control processing and γ conversion processing by the AGC / γ correction section 58. In addition, the night scene determination section 59
The backlight scene determination unit 60 performs a determination process as to whether the shooting scene is a night scene or a backlight scene (details will be described later).

Next, in the photometric unit 61, a predetermined photometric calculation process is executed based on the output of the process processing unit 57, and the optimal setting value of the aperture unit 52 and the electronic shutter speed value of the image sensor 53 are selected for the photographic scene. Is calculated. And
The aperture control unit 6 based on the calculation result by the photometric unit 61
2, the drive control of the aperture section 52 is performed.

On the other hand, the image signal processed by the process processing section 57 is also output to a temporary memory 63, temporarily stored therein, and then output to a compression / decompression section 64, where a predetermined compression is performed. By being processed,
Image data in a form optimal for recording is generated. Then, the image data is output to the recording medium 65 and recorded therein.

FIG. 43 is a flow chart showing the sequence of the "night scene determination process" executed in the electronic camera 50. In the electronic camera 50 provided with the distance measuring device of the present embodiment, the night scene determination section 59 of the process processing section 57 performs the following [night scene determination processing based on the image signal generated by the image sensor 53. Is executed.

As shown in FIG. 43, first, in step S15
In 1, a predetermined integration process is performed by the imaging device 53, and in the next step S <b> 152, a reading process of the image signal generated by the imaging device 53 is performed.
This read processing is performed by the CDS unit 54, S / H unit 55, and A
This includes various signal processings executed in the / D circuit 56 and the like.

Next, in step S153, the night scene determining section 59 of the processing section 57 measures the luminance of the photographed scene. In this case, the night scene determination section 59 assumes that the light receiving surface of the image sensor 53 is divided into a plurality of regions as shown in FIG.
, A process of calculating respective brightness values and calculating an average brightness value of the entire shooting scene is performed.

Subsequently, in step S154, the average luminance value calculated in step S153 is compared with a threshold value Bth representing a predetermined luminance value.
Here, if the relationship of average luminance value <Bth holds, the process proceeds to step S155, and the process proceeds to step S1.
At 55, a comparison is made between the divided area contrast value and a predetermined threshold value Cth. Here, when the relationship of the divided area contrast value> Cth holds, it is determined that the scene is a night scene, and the process proceeds to the next step S155.

Here, the division area contrast value is
This is a value obtained by calculating a difference between the luminance values of the divided area and the peripheral divided areas for each divided area, and calculating the sum of the absolute values of the luminance values corresponding to the divided areas thus calculated.

[0266] In the above step S154,
In the case where the relationship of the average luminance value <Bth is not established, and in the case where the relationship of the divided area contrast value> Cth is not established in the above-described step S155, it is determined that the normal shooting scene (normal scene) is used in any case. After the determination, the series of sequences is terminated (return).

If it is determined that the scene is a night view scene as described above, at step S156, AG
After controlling the setting so as to decrease the gain of the C / γ correction unit 58, a series of sequences is terminated (return).

That is, in a photographing scene in a low luminance state as a whole, such as a night scene, the gain level set by the AGC / γ correction unit 58 is set to be very high. Therefore, in this case, noise (image deterioration) in a low-luminance portion, that is, a dark portion as a night view of the image becomes conspicuous.

Therefore, as described above, in the present embodiment, a process for determining whether or not the shooting scene is a night scene is provided. If it is determined that the scene is a night scene, AGC · γ By performing control to lower the gain level of the correction unit 58, generation of unnecessary noise can be suppressed.

In the [night scene determination process] in the third embodiment described above, as shown in step S156 in FIG. 43, by controlling the AGC / γ correction unit 58 to lower the gain level, Although the image deterioration in the luminance portion is prevented, the following means may be separately provided.

That is, when it is determined in step S155 of FIG. 43 that the scene is a night scene, the compression characteristics of the high-luminance portion in the AGC / γ correction unit 58 are determined by comparing the processing in the case of the normal scene with the processing in the case of the night scene. To improve the color development of the image to be displayed based on the image signal.

FIG. 45 is a diagram showing the relationship between the output luminance signal and the input luminance signal as a result of the signal processing executed by the AGC / γ correction section 58. As shown in FIG. 45, in the case of a normal scene, the output luminance signal with respect to the input luminance signal is output while maintaining a substantially proportional relationship, whereas in the case of a night scene, a high luminance portion is output. , A high-luminance compression process for suppressing an output luminance signal and outputting the input luminance signal is performed.

By doing so, the latitude of the entire photographic scene can be improved, so that it is possible to prevent image deterioration due to the so-called overexposure phenomenon occurring in a high-luminance portion and to improve the color developability. .

Next, the [backlight determination processing] in the present embodiment will be described below. FIG. 46 is a flowchart illustrating a sequence of the “backlight determination process” executed in the present embodiment. In the electronic camera 50 including the distance measuring device of the present embodiment, the backlight scene determination unit 60 of the process processing unit 57 performs the following [backlight determination process] based on the image signal generated by the image sensor 53. Is executed.

As shown in FIG. 46, first, in step S16
In 1, a predetermined integration process is performed by the image sensor 53, and in the next step S <b> 162, a process of reading out the generated image signal is performed.

Next, in step S163, the backlight scene determination section 60 of the process processing section 57 measures the luminance of the photographed scene. The processing in steps S151 to S163 is substantially the same as the processing in steps S151 to S153 in the above-mentioned [night scene determination processing] (see FIG. 43).

Subsequently, in step S164, the average luminance value calculated in step S163 is compared with a threshold value Bgth representing a predetermined luminance value. Here, when the relationship of average luminance value> Bgth holds,
Proceeding to the process of step S165, this step S165
, A process of converting the luminance value in each divided area into a histogram as shown in FIG. 47 is performed.

FIG. 47 shows a luminance histogram created in step S165 described above. The shooting scene at this time is based on the backlight scene shown in FIG. 15 similarly to the brightness histogram of FIG. 17 in the first embodiment described above.

Next, in step S166, FIG.
7 based on the luminance histogram of
By using vq, binarization processing of sensor data is performed. That is, as shown in FIG. 47, in the intermediate luminance portion between the peak value of the middle luminance portion and the peak value of the high luminance portion,
A value corresponding to the luminance value with the smallest number of pixels (the number of blocks = one area of the divided area) is set as the threshold value Bvq, and based on this, the binarization processing of the sensor data (luminance data) is performed. Here, the binarization process is a process in which sensor data having a brightness value higher (bright) than the threshold value Bvq is set to “1”, and sensor data having a lower brightness value (dark) is set to “0”.

Subsequently, in step S167, “0” of the sensor data obtained by the above-described binarization processing is set.
Is calculated, and in the next step S168, the area Sn of the continuous area is compared with a predetermined determination value Snth to determine the area S of the continuous area.
It is determined whether or not n is greater than a predetermined determination value Snth. Here, when the relationship of Sn> Snth holds,
That is, if the area Sn of the continuous region is larger than the predetermined value Snth, it is determined that the shooting scene is a backlight scene, and the process proceeds to the next step S169.

For example, in the case of the backlight scene shown in FIG. 15, the image of the photographing screen represented by the binarized sensor data (image signal) is as shown in FIG. FIG. 48 is a diagram showing a luminance distribution for each divided area represented by sensor data obtained by the binarization processing. In this case, the average brightness of the entire shooting screen is in a high brightness state, and in a low brightness portion corresponding to a main subject such as a person, the area S of a region where data “0” is continuous
If the relationship between n and the predetermined value Snth is Sn> Snth, it is determined that the scene is in a backlight scene.

Then, when the flow proceeds to the next step S169,
Here, a predetermined photometric process is performed with emphasis on a low luminance portion. That is, in the luminance bistogram shown in FIG. 47, a photometric calculation process is performed based on data of a portion that is equal to or less than the luminance threshold value Bvq.

On the other hand, if the relationship of average luminance value> Bgth is not established in step S164 or if the relationship of Sn> Snth is not established in step S168, normal photometric calculation processing is performed in step S170. After a predetermined average photometry calculation process is performed on the entire photographing screen, a series of sequences ends (return).

As described above, when the shooting scene is a backlight scene, it is first detected whether or not the shooting scene is in a backlight state, and when it is determined that the shooting scene is a backlight scene, a main subject such as a person is detected. Predetermined photometric processing is performed on the basis of the luminance of the region to be located, that is, the image signal which has been subjected to the binarization processing, with emphasis on the image arranged substantially in the center.

As described above, according to the third embodiment, the same effects as those of the above-described embodiments can be obtained in the electronic camera, and therefore, the electronic image representing a high quality image can be obtained. Data can be easily obtained.

[Supplementary Note] According to the above-described embodiment, the invention having the following configuration can be obtained.

(1) Image detecting means for detecting the luminance distribution in the photographing screen, and the main subject based on the distribution of the area which continuously outputs a luminance value within a predetermined range among the outputs of the image detecting means. And a means for specifying a position.

(2) In the multipoint distance measuring apparatus according to Supplementary Note 1, the luminance distribution is a luminance distribution based on reflected light of light projected by a camera.

(3) Image detecting means for detecting the luminance distribution in the photographing screen, the average luminance information among the outputs of the image detecting means, the area of the area for continuously outputting a predetermined luminance value, and the shape of the area. Means for specifying the position of the main subject based on the result of the determination.

(4) In the multipoint distance measuring apparatus described in Appendix 3, the brightness distribution is a brightness distribution based on reflected light of light projected by a camera.

(5) Image detecting means for detecting the luminance distribution in the photographing screen, average luminance information among the outputs of the image detecting means, and the area and the shape of the area for continuously outputting a predetermined luminance value. Means for determining a backlight scene based on the determination result and setting an operation mode.

(6) In the multipoint distance measuring apparatus according to Supplementary Note 5, the luminance distribution is a luminance distribution based on reflected light of light projected by a camera.

(7) A multi-point distance measuring apparatus comprising: a determination means for determining a shooting scene; and a control means for switching a method of detecting a main subject position according to the determination result.

[0294]

As described above, according to the present invention, the position of the main subject image in the photographing screen can be reliably determined based on the image signal obtained by the area sensor, and the desired main subject image can be determined with respect to the desired main subject image. It is possible to provide a multi-point distance measuring apparatus capable of performing a focus detection process reliably and executing a high-accuracy distance measurement process.

[Brief description of the drawings]

FIG. 1 is a main block diagram showing the configuration of a camera provided with a distance measuring device according to a first embodiment of the present invention.

FIG. 2 is a main part block configuration diagram showing a main part of a configuration of an AF area sensor in the camera of FIG. 1;

FIG. 3 is a perspective view conceptually showing an arrangement relationship between a distance measuring optical system and an AF area sensor constituting a distance measuring device in the camera of FIG.

FIG. 4 is an arrangement diagram conceptually showing an arrangement relationship between a distance measuring optical system and an AF area sensor constituting a distance measuring device in the camera of FIG. 1;

5 is a diagram conceptually showing a relationship between a detection area of an AF area sensor in the camera of FIG. 1 and a shooting screen area when a focal length of a shooting optical system is changed.

6 is a flowchart showing a main operation flow of the camera in FIG. 1 and showing a main routine of the microcomputer.

FIG. 7 is a flowchart showing a subroutine of AF processing of the camera in FIG. 1;

FIG. 8 is a timing chart when AF processing of the camera in FIG. 1 is performed.

FIG. 9 is a diagram showing an example of a shooting screen in a typical night view scene.

FIG. 10 is a diagram three-dimensionally showing sensor data acquired by an AF area sensor in the shooting scene shown in FIG. 9;

11 is a distribution diagram showing a relationship between each area of a continuous high-luminance part (reference numeral H) and a continuous low-luminance part (reference numeral L) in the photographing screen shown in FIG. 9 and luminance of each part.

FIG. 12 is a flowchart showing a subroutine of “night scene judgment processing” in the camera of FIG. 1;

FIG. 13 is a diagram showing an area of the photographing screen area of the camera of FIG. 1 in which a difference between sensor data obtained when the pre-emission operation is performed and sensor data obtained when the pre-emission operation is not performed;

FIG. 14 is a flowchart illustrating another subroutine of [night scene determination processing] in the camera of FIG. 1;

FIG. 15 is a diagram showing an example of a shooting screen in a typical backlight scene.

FIG. 16 is a diagram showing a three-dimensional distribution of sensor data acquired by the AF area sensor in the case of the backlight scene shown in FIG. 15;

FIG. 17 is a luminance histogram showing a distribution of each pixel of sensor data in the case of the backlight scene of FIG. 15;

FIG. 18 is a flowchart illustrating a subroutine of [backlight determination processing] in the camera of FIG. 1;

FIG. 19 is a diagram three-dimensionally showing a distribution of sensor data obtained by the AF area sensor when performing an integration operation process involving a pre-emission operation in the shooting scene shown in FIG. 15;

FIG. 20 is a diagram showing a three-dimensional distribution of normalized data obtained by normalizing sensor data during normal integration.

FIG. 21 is a diagram three-dimensionally showing a distribution of normalized data obtained by normalizing sensor data at the time of pre-light emission integration.

FIG. 22 is a diagram showing a three-dimensional distribution of difference data calculated based on the normalized data of FIGS. 20 and 21;

FIG. 23 is a view showing a distance measurement area to be subjected to distance measurement calculation processing in the photographing screen of the camera in FIG. 1;

FIG. 24 is a conceptual diagram showing a first modification of the first embodiment of the present invention, in which the entire area of the light receiving surface of the light receiving element group of the AF area sensor is divided into predetermined unit blocks; FIG. 4 is a diagram showing light receiving areas according to the focal length of the imaging optical system with respect to all light receiving areas of the AF area sensor.

FIG. 25 is a diagram illustrating a second modified example of the first embodiment of the present invention and illustrating a means for determining a main subject image when a main subject is a person when performing [backlight determination processing].

FIG. 26 is a flowchart showing the sequence of “backlight determination processing” in a second modification of FIG. 25;

FIG. 27 is a diagram showing a distance measurement area to be subjected to distance measurement calculation processing in the photographing screen of the camera in FIG. 25;

FIG. 28 is a diagram showing a configuration example of a shooting screen when a non-main subject is present at a shorter distance than a main subject.

FIG. 29 is a view showing a third modification of the first embodiment of the present invention, and showing the relationship between the position of a shooting screen and a judgment threshold value.

FIG. 30 shows an example of composition in the case of horizontal position photographing when a photograph is taken with a person or the like as a main subject in a fourth modification of the first embodiment of the present invention, and distance measurement in this case. FIG.

FIG. 31 is a diagram illustrating an example of a composition in the case of vertical shooting when a photograph is taken with a person or the like as a main subject in the fourth modified example of FIG. 30, and also illustrates a ranging area in this case. .

FIG. 32 is a flowchart showing a sequence of [backlight determination processing] in a fourth modification of the first embodiment of the present invention.

FIG. 33 shows a fifth modification of the first embodiment of the present invention, and shows a three-dimensional contrast distribution based on sensor data of a night scene (FIG. 9) acquired by an AF area sensor of a camera (FIG. 1). FIG.

FIG. 34 is a flowchart illustrating a sequence of a “night scene determination process” based on a contrast value of a shooting screen in a fifth modification of the first embodiment of the present invention.

FIG. 35 shows a sixth modification of the first embodiment of the present invention, in which the sensor data obtained by the integral calculation processing of the AF area sensor when performing the pre-emission operation on the shooting scene of FIG. FIG.

FIG. 36 shows a sixth modification of the first embodiment of the present invention, in which there is a difference between sensor data without pre-emission and sensor data with pre-emission for the shooting scene of FIG. 9; The figure which shows the sensor data which extracted only three-dimensionally.

FIG. 37 is a view showing a seventh modification of the first embodiment of the present invention, showing the relationship between the brightness in the shooting scene of FIG. 9 and the number of pixels or areas corresponding to the brightness.

FIG. 38 is a flowchart illustrating a sequence of a “night scene determination process” according to a seventh modification of the first embodiment of the present invention.

FIG. 39 is a block diagram of a main part showing main components of a camera provided with a distance measuring apparatus according to a second embodiment of the present invention.

FIG. 40 is a diagram showing an image area corresponding to an output signal from an AF area sensor when a steady light removing unit and a strobe light emitting unit are operated in the camera of FIG. 39;

FIG. 41 is a flowchart showing a sequence of an AF process in the camera shown in FIG. 39;

FIG. 42 is a main block diagram showing the configuration of an electronic camera including a distance measuring device according to a third embodiment of the present invention.

FIG. 43 is a flowchart showing the sequence of “night scene determination processing” in the camera of FIG. 42;

FIG. 44 is a conceptual diagram showing a divided area in which the light receiving surface of the image sensor in the camera of FIG. 42 is divided into a plurality of regions.

FIG. 45 is a diagram illustrating a relationship between an input luminance signal and an output luminance signal as a result of signal processing performed by the AGC / γ correction unit in the camera of FIG. 42;

46 is a flowchart showing a sequence of [backlight determination processing] in the camera in FIG. 42.

FIG. 47 is a histogram showing luminance values of a photographing screen corresponding to the photographing scene of FIG. 15 in the camera of FIG. 42;

FIG. 48 is a view showing a luminance distribution for each divided area represented by sensor data by binarization processing in the camera of FIG. 42;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Camera 10 ... Photographing optical system 10a ... Focus lens 10b ... Zoom lens 11 / 11A ... Microcomputer 11a ... CPU (Central processing unit) 11b ... ROM 11c ... RAM 11d ... A / D converter 11e ... EEPROM 11Af ... pattern discriminating means 12.12A ... area sensor (image detecting means) 12a ... light receiving element group 12b ... processing circuit 12c ... steady light removing section 12d ... vertical shift register 12e ... horizontal Shift register 12f Fixed pattern noise removing unit 12aa Light receiving element 12ab Photodiode 12ac Amplifier 12Aa Light receiving element group 12Ac Steady light removing means 12Af A / D converter 13 Focus lens drive Section 14 ・ 14A Distance measuring optical system 14a ・ 14Aa ... Light receiving lens 15... Focus lens encoder 16... Shutter drive unit 19... Display unit 20... Lens drive unit 23 Photometry unit 23a Photometric light-receiving element 24 Camera attitude detection unit 25 Audio signal generation unit 50 Electronic camera 51 Photographic optical system 52 Diaphragm unit 53 Image sensor 54 CDS unit 55 S / H unit (sample and hold circuit) 56 A / D circuit (A / D converter) 57 process processing unit 58 AGC / γ correction unit 59 night scene scene determination Unit 60 Backlight scene determination unit 61 Photometry unit 62 Aperture control unit 63 Temporary memory (DRAM) 64 Compression / expansion unit 65 Recording medium

Claims (3)

[Claims] 1. An accumulation type area sensor for receiving a two-dimensional area in a detection screen, an average luminance calculating means for calculating an average luminance of the two-dimensional area based on an output of the area sensor, Area determining means for detecting a continuous area having a luminance difference equal to or greater than a predetermined value based on the average luminance value calculated by the average luminance calculating means in the output; and at least a predetermined area detected by the area determining means. And a focus detecting means for detecting a focus state in the detection screen based on the output of the area sensor. 2. An accumulation type area sensor for receiving a two-dimensional area in a detection screen, an average luminance calculating means for calculating an average luminance of the two-dimensional area based on an output of the area sensor, and emitting illumination light. A light emitting unit that performs light emission, and an area discriminating unit that detects an area in which the luminance difference between when the illumination light is emitted by the light emission unit and when the illumination light is not emitted exceeds a predetermined value in a two-dimensional area in the detection screen. And a focus detecting means for detecting a focus state in a detection screen based on at least an output of the area sensor in an area detected by the area determining means. 3. A multi-point distance measuring apparatus using an area sensor, comprising: an average luminance calculating means for calculating an average luminance value based on an output of the area sensor; and an average luminance value calculated by the average luminance calculating means. Area determining means for detecting a continuous area in which the luminance difference is equal to or greater than a predetermined value; and means for specifying a main subject in accordance with a result of detection by the area determining means and determining a ranging point in a detection screen. A multi-point distance measuring device comprising: