JP2003241073A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a photographic lens focus on an object aimed by a user. <P>SOLUTION: First of all, the object to be focused on is placed in the center of a photographic picture frame, then, the image data on the object placed in the center area is obtained by an imaging device 3 and the obtained image data is stored. Next, all the image data in the photographic picture frame is obtained, and in the case a part similar to the stored data on the image in the center area exits in all the image data, the photographic lens 2 is focused on a point outputting the similar image data. In the case the similar part does not exit, the photographic lens 2 is focused on the object in the center area. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera capable of focusing on a subject intended by a user.

[0002]

2. Description of the Related Art In recent years, digital cameras have become widespread, but it is difficult to obtain a photograph with the desired focus for focusing. For example, in a scene in which subjects having various spatial frequencies and distances are mixed in the screen such as the shooting scene 10 in FIG. 1, a miscellaneous subject different from the main subject may be in focus. Also, you can not check it on a small monitor with a built-in camera,
For the first time, I often realized that the surrounding main subject was out of focus and the main subject was out of focus only after printing the image or checking it on a large monitor after the shooting. . For this reason, further improvement was required so that focusing could be performed more accurately.

Among such focusing techniques, by displaying the focusing state on the camera,
A technique has been proposed that allows a user to check the focus adjustment state. Japanese Patent Laid-Open No. 10-48733 discloses a technique for making it possible to confirm the state of focusing.
Some cameras, such as the camera disclosed in Japanese Patent Publication, superimpose a focus point along with a distance measuring point in a viewfinder screen.

Further, as another focusing technique, there is a focus lock technique disclosed in Japanese Patent Laid-Open No. 1-307711.

[0005]

However, the above-mentioned Japanese Unexamined Patent Application Publication No.
The camera disclosed in 0-48733 is not sufficient for the user to confirm the focus state.
In addition, since the focusing state is displayed superimposed on the viewfinder screen, it may be difficult to see other displays on the viewfinder screen. In addition, since frames that are not actually shot are also displayed in the viewfinder screen,
It could also cause confusion for users. In other words, there is a demand for a technique that allows the subject to be focused more directly to be known at what position and how the subject is displayed, and that enables accurate focusing.

The present invention has been made in view of the above circumstances, and makes it possible to confirm whether or not the focus state is assumed by the user, and to focus on the focus state assumed by the user. It is an object of the present invention to provide a camera with excellent operability that can be achieved.

[0007]

In order to achieve the above object, a camera according to the present invention comprises an image sensor for obtaining object image data, and a storage means for storing the object image data obtained by the image sensor. In a camera equipped with the above, the subject image data of the central portion of the image sensor is stored in advance in the storage means, the subject image data is acquired again when the photographing lens is focused, and the subject image data acquired again is It is characterized in that a portion similar to the subject image data of the central portion stored in the storage means is detected from the inside, and focusing is performed using the contrast signal in the image data of the similar portion.

That is, according to the camera of the present invention, the subject image data of the central portion is stored in advance before focusing, and the subject image data at the time of focusing is similar to the subject image data of the central portion. By detecting the image data and focusing on the subject that outputs similar image data, it is possible to focus on the subject that is assumed by the user.

In order to achieve the above object, the camera according to the present invention comprises an image sensor for obtaining object image data, a storage unit for storing the object image data obtained by the image sensor, and the image sensor. In a camera including a display unit that displays an image based on the acquired subject image data, image data of the central portion of the image sensor is stored in the storage unit in advance, and the subject image is adjusted when the photographing lens is focused. Re-acquiring data, detecting a portion similar to the image data stored in the storage means from the re-acquired subject image data, and displaying the subject image of the portion on the display means. Is characterized by.

That is, according to the camera of the present invention, the focus state of the camera can be confirmed by enlarging and displaying the subject that outputs image data similar to the subject image data in the central portion.

Further, in order to achieve the above object, the camera according to the present invention is a camera equipped with an image pickup means for obtaining a subject image signal, and in the central portion of the photographing screen in response to the first operation prior to the photographing operation. Subject image signal is acquired, the subject image signal is obtained again by the image pickup means in response to a second operation subsequent to the first operation, and the subject image signal of the central portion is obtained from the obtained subject image signal again. It is characterized in that a portion similar to is extracted, and focus control at the time of shooting is performed based on the subject image signal of the extracted similar portion.

That is, according to the camera of the present invention, it is possible to perform a process of extracting a similar portion by dividing the operation between the first operation and the second operation.

In order to achieve the above object, the camera according to the present invention comprises an image pickup means for picking up a subject image signal and a distance measuring means for measuring the subject distance in an optical path different from that of the image pickup means. In the camera provided, the object image signal and the object distance signal of the central portion in the image capturing screen are acquired by the image capturing means and the distance measuring means prior to the image capturing operation, and at the time of image capturing, the object image signal and the object distance signal of the central portion It is characterized in that the focusing control of the taking lens is performed according to and.

That is, according to the camera of the present invention, the similar portion can be detected using the image signal and the distance signal of the subject.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a block diagram of an electronic circuit inside a camera according to a first embodiment of the present invention.
Shown in.

The electronic circuit inside the camera according to the first embodiment includes a CPU 1, a photographing lens 2, an image pickup device 3, a photographing lens drive circuit (LD) 4, a focus determination circuit 5,
An image processing circuit 6, a memory 6a, an LCD driver 7, a display device (LCD) 8, switches such as a release button 9a, a focus position confirmation switch 9b, and a focus position adjustment switch 9c, and a strobe light emitting section 12 are provided. There is.

The CPU 1 is an arithmetic control unit composed of a one-chip microcomputer or the like, and operates a built-in program in accordance with the operation state of each switch such as the release button 9a to drive the LD 4, the focus determination circuit 5, the image processing circuit. 6, LC
The operation control of the entire camera including the control of the D driver 7 is performed.

The photographic lens 2 captures an image of a subject by the image sensor 3
It is a lens for forming an image on the top.

The image pickup device 3 converts an image of a subject formed through the taking lens 2 into an image signal which is an electric signal. Further, this image signal is digitally converted into image data. Then, this image data is input to the focus determination circuit 5.

The LD 4 is a circuit for driving the taking lens 2.

The focus determination circuit 5 detects the focus position based on the image data input from the image pickup device 3 under the control of the CPU 1. This focus position detection method is
First, image data of a subject is measured while controlling the extension of the taking lens 2 via the LD 4, and a component corresponding to a predetermined spatial frequency is extracted from the image data. Then, the peak position of the subject contrast is detected from the extracted component by the focus determination circuit 5, and focusing is performed based on the detected peak position.

A focusing method for measuring the subject contrast and detecting the focus position while controlling the extension of the taking lens 2 is called "mountain climbing AF". In this method, the taking lens 2 is driven and controlled. However, there is a drawback that it takes time to perform contrast measurement.

With the taking lens 2 in the focus position detected by the focus determination circuit 5, the image pickup device 3
Image data is acquired again, and the acquired image data is input to the image processing circuit 6. If the exposure is insufficient at this time, the CPU 1 also performs control such that the strobe light emitting unit 12 emits light to supplement the light.

The image processing circuit 6 subjects the input image data to various image processing such as compression. This image-processed image can be stored in the memory 6a or displayed on the LCD 8. At this time, CP
U1 controls the LCD driver 7 to display an image on the LCD 8. Furthermore, when the focus state confirmation function described later is activated, only a specific portion of the image pickup device 3 is selected via the image processing circuit 6, and the image of the specific portion is cut out and enlarged and displayed on the LCD 8. It controls the LCD driver 7.

FIG. 2A shows how a user handles a camera having such a configuration. On the back of the camera 30,
The LCD 8 is provided, and is controlled by the CPU 1 so as to switch the display image according to the operation of the release button 9a, the focus position confirmation switch 9b, the focus position adjustment switch 9c and the like.

The release button 9a is composed of two switches, a 1st release switch and a 2nd release switch. Then, by pressing the release button 13 halfway down, the 1st release switch is turned on and the image data of the central area is extracted from the image data acquired by the image sensor 3 and stored in a RAM (not shown). The second release switch is turned on by the pressing operation to focus the taking lens 2, and the captured image is stored in the memory 6a.

The focus position confirmation switch 9b is a switch for operating a distance measuring point confirmation function, which will be described later, and the focus position adjustment switch 9c is for fine adjustment of the focus position at the selected focus adjustment point. It is a switch.

The user selects the distance measuring point selection mark 80 in the image 8a displayed on the LCD 8 as shown in FIG.
However, by checking which subject is marked, it is possible to confirm that the focus state is as intended. Here, the image pickup device 3 is configured as shown in FIG.
The description will be continued assuming that there are three focus detection areas b and 3c, but the number of areas is not limited to three, and may be five or seven including one point in the center.

By thus providing a plurality of focus detection areas, it becomes possible to detect the focus position not only when there is a subject in the center but also in a scene where the subject is not in the center of the screen as shown in FIG. In addition, a method in which focusing can be performed by enabling distance measurement at a plurality of points on the screen is called “multi-AF method”.
Due to the side effect of using the F method, the distance measurement point selection mark 80 may be aligned with the tree 11b that was not originally intended to be focused as shown in FIG. 2B. If the shooting sequence is continued in such a state, the tree 11b will be focused instead of the person 11a, so some measure is required.

Therefore, in the present embodiment, the release button 9a is configured to be pushed in two steps.
Such a scene is dealt with by applying a so-called focus lock technique, which is a technique of dividing the shooting sequence into two stages according to the operation state of.

First, the user points the photographing lens 2 toward the person 11a so that the main subject, for example, the person 11a, which is going to be focused, is in the center of the photographing screen. After that, the camera according to the present embodiment performs the operation according to the flowchart of FIG. 4 and corresponds to the above scene.

When the main switch (not shown) of the camera is turned on, the operation of the flow shown in FIG.
U1 operates the image sensor 3 to acquire image data of a subject (step S1). Next, a captured image is displayed on the LCD 8 based on the image data acquired by the image sensor 3 (step S2). At the same time, the distance measuring point selection mark 80 is displayed in the center of the LCD screen. It should be noted that these displays are displayed on the LCD 8 as well as on a finder (not shown) of the camera. In this state, C
For PU1, the release button 9a was pressed halfway.
It is determined whether or not the st release switch is turned on (step S3). If it is determined that the 1st release switch is not turned on, the process returns to step S1.

When it is determined that the 1st release switch is turned on, the image pickup device 3 is detected in step S1.
The image data of the main subject in the central area 3b, for example, the image of the person 11a is extracted from the image data acquired by (step S4). This image data becomes the image data of the main subject selected by the user in the current state. Note that, in general, the image data of the main subject has a higher output level than the image data of the other parts, and therefore, the acquisition of the image data of the main subject is performed by, for example, outputting a certain level or more in the central area 3b. It suffices to extract only the image data of. Next, the extracted image data of the main subject is stored in a RAM (not shown).
(Step S5).

After the storage of the image data of the main subject is completed,
The user can select the arrow a in FIG.
Move the camera direction as shown by. In this state, the CPU 1 determines whether or not the release switch 9a has been fully pressed to turn on the second release switch (step S6).

When it is determined that the 2nd release switch is not turned on, the 1st release switch is turned on.
It is determined whether or not it remains (step S7). 1s
When it is determined that the t-release switch is turned off, the process returns to step S1. When it is determined that the 1st release switch remains ON, the arrow a in FIG.
By changing the orientation of the camera as shown by, the user can freely change the composition. Note that FIG.
Although the arrow a is shown as only one direction in the above, it is a matter of course that the direction of the camera can be changed in the opposite direction.

When the orientation of the camera is changed, CP
U1 operates the image sensor 3 again to acquire the image data of all the subjects in the photographing screen (step S20). Then, RA is selected from all the subject image data in this shooting screen.
Image data similar to the image data of the main subject stored in M is detected (step S21). Hereinafter, such an operation of detecting similar image data will be referred to as an object search.

Based on this detection result, the above step S
It is determined whether or not there is image data similar to the main subject image data stored in the RAM among all the subject image data in the photographing screen acquired in 20 (step S22). If it is determined that the image data similar to the main subject image data stored in the RAM exists in the image data acquired in step S20, the process shown in FIG.
As shown in (C), the display position of the distance measuring point selection mark 80 is changed to the position of the subject that outputs image data similar to the main subject image data stored in the RAM (step S23), and the process proceeds to step S25. move on.

On the other hand, if it is determined in step S22 that there is no image data similar to the main subject image data stored in RAM in all the subject image data in the photographing screen, for example, In the case of image data of a contrast subject or image data that changes such as ocean waves, or when there is no image data stored in the RAM in the shooting screen, the distance measurement point selection mark 80
Without changing the display position of (step S24), the process directly proceeds to step S25.

The user looks at the image displayed on the LCD 8 and confirms whether the composition is his or her favorite. Then, according to the confirmation result, the focus position confirmation switch 9b
Alternatively, the focus position adjustment switch 9c is operated. CPU1
Determines whether or not the focus position confirmation switch 9b or the focus position adjustment switch 9c has been operated by the user (step S25). When it is determined that these switches are not operated, the process directly returns to step S6. On the other hand, when it is determined that these switches are operated, the display position of the distance measuring point selection mark 80 is changed according to the operation of the switches (step S2).
6). Then, the image data of the subject on which the distance measurement point selection mark 80 is located is overwritten and stored in the RAM (step S27), and the process returns to step S6.

In the determination in step S6, 2nd
When it is determined that the release switch has been turned on, the image sensor 3 is operated again in the current state to acquire the image data of all the subjects in the shooting screen (step S).
8). Then, the object search is performed to detect image data similar to the main subject image data stored in the RAM from all the subject image data in the photographing screen (step S9). Based on this result, it is determined whether or not there is image data similar to the subject image data stored in the RAM among all the subject image data in the photographing screen acquired in step S8 (step S).
10).

When it is determined that the image data similar to the subject image data stored in the RAM exists, the similar image data is extracted (step S11), the process proceeds to step S14 and is acquired. Mountain climbing A using image data
Start F. Before entering the mountain climbing AF, see FIG.
As in (C), a state in which the distance measuring point selection mark 80 is aligned with a subject that outputs similar image data may be displayed. After checking the result, the focus position adjustment switch 9c or the like is used to focus. The position may be finely adjusted. Note that these processes are omitted here.

On the other hand, if it is determined in step S10 that there is no image data similar to the subject image data stored in the RAM, a warning is displayed or a warning sound is issued (step S10). S12), object image data of the central area 3b in which the main object is highly likely to exist is acquired (step S13), and step S1
Proceed to step 4 to start hill climbing AF.

After the hill-climbing AF in step S14 is started, the CPU 1 determines whether or not the hill-climbing AF is completed (step S15). If it is determined that the hill-climbing AF is not finished, step S is performed until the hill-climbing AF is finished.
The determination of 15 is repeated. On the other hand, when it is determined that the hill-climbing AF is completed, the exposure operation is performed (step S1).
6) The photographed image is stored in the memory 6a.

After the exposure operation and the image storage in the memory 6a, it is determined whether or not the focus position confirmation switch 9b or the focus position adjustment switch 9b is operated, that is, whether or not the focus state confirmation function is operated. (Step S
17). When it is determined that the focus state confirmation function is operated, the focused subject is enlarged and displayed on the LCD 8 as shown in FIG. 2D (step S18).
On the other hand, when it is determined that the focus state confirmation function is not operated, the operation of this flow is ended.

The enlarged display in step S18 may be performed before the exposure operation in step S16. By doing so, the user can confirm the focus point, the facial expression of the subject, and the like by this enlarged display before photographing. If the release operation is continued while the focus position is incorrect as shown in FIG. 2B, the tree 11b, which is not originally intended, is enlarged as shown in FIG. 2E. It can be prevented further.

Further, if the selected point is out of focus, a warning is given and then the LCD
8 Change the pointed position, and climb A in step S14
By starting from F, it may be possible to perform shooting with an emphasis on photo opportunities.

As described above, according to the present invention, the object search is performed before the hill climbing operation is performed for the time-consuming hill climbing AF so that the camera recognizes the subject targeted by the user. The possibility of misjudgment of alignment is reduced.

Further, the release time lag can be shortened because it is not necessary to perform an extra hill climbing operation.

Furthermore, by enlarging and displaying the focused subject after focusing, the user can accurately and easily confirm the focused state. Looking at this display result, if the image is in a disagreeable focus state, it is sufficient to take the image again by taking advantage of the advantages of the digital camera such as easily deleting the taken image data.

[Second Embodiment] A second embodiment of the present invention will be described with reference to FIG. The camera according to the present embodiment uses the image sensor used in the first embodiment for focusing and two light receiving lenses 20a,
Focusing by a so-called external light type triangulation method, in which distance measurement is performed using a positional difference x generated by parallax between two light receiving lenses 20a and 20b of image signals obtained by sensor arrays 21a and 21b via 20b. The above-mentioned object search is performed by using both and. Sensor array 21a,
The image signal obtained at 21b is converted into a digital signal by the A / D conversion unit (A / D) 22 and becomes image data. These image data are input to the CPU 1.

The CPU 1 obtains the above-mentioned x by comparing these two image data, and L is the principle formula of triangulation.
= Subject distance L is calculated from Bf / x. Here, B is a distance between both light receiving lenses, and f is a distance between the light receiving lens 20a and the sensor array 21a or a distance between the light receiving lens 20b and the sensor array 21b.

In this way, based on the obtained object distance L, the CPU 1 causes the photographing lens 2 to pass through the LD 4.
Focus on. After that, when actually taking an image, the CPU 1 also controls the light amount of the strobe light emitting unit 12 based on the light receiving amount of the taking lens 2 and the light receiving amount of the image pickup device 3.

Since the distance measuring device based on the principle of this triangular distance measuring is a known technique, its detailed description will be omitted. Further, focusing using the image sensor 3 has also been described in the first embodiment, so description thereof will be omitted here. It should be noted that in the present embodiment, by omitting the function of enlarging and displaying the focused subject on the LCD in the first embodiment, a camera that displays the distance measuring points and the like in the viewfinder in a superimposed manner Can also be applied to.

Here, in the photographing scene 10, the range 23 monitored by the above-mentioned sensor array for triangulation is shown in FIG.
It is as shown in (B). Therefore, it is possible to perform distance measurement at three points on the screen depending on which area of 24L, 24C, and 24R of the sensor array 21a is used as the distance measurement point.

Here, FIG. 6B shows the sensor array 2
Only one of 1a and 21b (for example, the sensor array 21
a) is shown, and there is actually another one similar to this. Hereinafter, the description will be continued for the sensor array 21a, but the same description can be made for the sensor array 21b. Further, this distance measuring area is not limited to the number of areas of 3 points as in the first embodiment, but may be 5 points or 7 points depending on the way of dividing the area to be used.

FIG. 7 is a front view of the camera having such a configuration. The basic appearance is similar to that of the first embodiment, but the light receiving lens 2 is provided above the taking lens 2.
The difference is that a window 25 for distance measurement which is a window for 0a and 20b is provided. Further, in the present embodiment, since the function of enlarging and displaying the focused subject is omitted, the focus position confirming switch 9b and the focus position adjusting switch 9 are omitted.
c is omitted.

Next, the operation control program of the camera according to the present embodiment having the above configuration will be described with reference to the flowchart of FIG. Also in the present embodiment, the release button 9a is configured to be pushed down in two steps, and the 1st release switch is turned on by a half-press operation to start capturing the central area 24C and start acquiring main subject image data. hand. Further, it is assumed that the second release switch is turned on by full-press operation to start the operation of focusing and storing the captured image in the memory 6a. Also, before starting the operation of this flow, the user is supposed to place the subject to be focused on the center of the shooting screen.

First, when a main switch (not shown) of the camera is turned on, the CPU 1 displays a target mark (frame for distance measurement) in the center of the finder screen (step S70). In this state, the 1st release switch is ON
It is determined whether or not (step S71). If it is determined that the 1st release switch is not turned on, wait until the 1st release switch is turned on,
When it is determined that the 1st release switch is turned on, the image data I _{0 of the} subject with the matching target mark in the central area 24C in the photographing screen is acquired using the sensor arrays 21a and 21b (step S7).
2) Based on the subject image data I ₀ , subject distance data L ₀ in the central area 24C in the photographing screen is calculated (step S73).

With the above operation, the camera is set to the user's desire.
Detecting subject distance data and image data of the subject
become. Next, these subject distance data L₀And statue day
Ta I ₀Is stored in a RAM (not shown) (step S7).
4). After storing these data, the user
Change the direction of the camera to get the desired composition, and
Fully press the release button 9a (2nd release switch
ON) Operate.

Next, the CPU 1 determines whether or not the second release switch is turned on (step S75).
When it is determined that the second release switch is not turned on, it is determined whether or not the first release switch is still turned on (step S84). If it is determined that the 1st release switch remains ON, the process returns to step S75. If it is determined that the 1st release switch is turned off, the above step S7 is performed.
Return to 1.

If it is determined in the above step S75 that the second release switch is turned on, the entire photographing screen is imaged and the image data of the entire photographing screen is acquired (step S76). Then, based on the acquired image data, each distance measuring area 24L, 24C, 24R
Subject distances are measured at three points (step S7).
7). Next, it is determined whether or not there is a point that outputs data similar to I ₀ and L _{0 in the} distance measuring areas 24L, 24C, 24R (step S78).

When it is determined that a point for outputting similar data exists in the distance measuring areas 24L, 24C, 24R, the similar image data is selected as the image data of the focusing point (step S81). , And proceeds to step S82.

On the other hand, in the determination of step S78, the point at which similar data is output is the distance measuring area 24.
If it is determined that the data does not exist in L, 24C, and 24R, the image data I
_It is determined whether there is a point for outputting image data similar to ₀ (step S79). When it is determined that there is a point for outputting similar image data, the similar image data is selected as the image data of the focus point (step S81), and the process proceeds to step S82.

When it is determined in step S79 that there is no point for outputting similar image data, the image data in the central area 24C of the photographing screen is selected as the image data of the focusing point (step S8).
0), and proceeds to step S82.

After the image data of the selection point for focusing is found, hill-climbing AF is performed using the image data of the selection point (step S82).
After the processing is completed, the exposure operation is performed (step S8).
3) The photographed image is stored in the memory 6a.

As described above, according to the present embodiment, the user narrows down the subject to be focused by the user based on the subject image data (subject image signal) and the subject distance, so that more accurate focusing can be performed. .

Although the image display system is simplified in this embodiment, the distance measuring point selection mark follows when the composition is changed, as in the first embodiment. Alternatively, a function of confirming the focus state by enlarged display may be provided.

[Third Embodiment] A third embodiment of the present invention will be described with reference to FIGS. The present embodiment is an example in which a subject to be focused is enlarged and displayed on the LCD by using a technique of detecting similar image data. It is assumed that the configuration is the same as that of the first embodiment. Here, the focus position confirmation switch 9b and the focus position adjustment switch 9c will be supplemented with reference to FIG.

The focus position confirmation switch 9b and the focus position adjustment switch 9c are configured as one switch 31 as shown in FIG. 9 in the present embodiment. The switch 31 includes a push switch portion 51 and a dial switch portion 52, and a hole is provided at the center of the dial switch portion 52, and the push switch portion 51 is passed through the hole.

When the push switch section 51 is pushed down, the section 57 is also pushed to conduct with the electrode 58, and the signal output as a result is input to the CPU 1 to operate the function of confirming the focusing state. Let That is, it plays the role of the focus position confirmation switch 9b.

Further, by rotating the dial switch portion 52, the segment 53 also rotates in conjunction with the movement thereof. Depending on this rotating state, the electrode 54 and the electrode 55 or the electrode 56
And the electrode 55 become conductive, and the signal output as a result is the CPU
By inputting 1, the focus position is finely adjusted.
That is, it plays the role of the focus position adjusting switch 9c.

For example, when the electrode 54 and the electrode 55 are in conduction, the taking lens 2 can be moved in the extending direction to adjust to the front pin side, and when the electrode 56 and the electrode 55 are in conduction. The taking lens 2 is moved in the retracted direction so that the rearward pin can be adjusted.

When a photograph having the composition as shown in FIG. 10B is taken by using the camera having such a structure,
In FIG. 11, first, the composition of 10a shown by the alternate long and short dash line in FIG. 11 is set so that the target mark 90 displayed in the center of the shooting screen is aligned with the main subject 11a. Next, the camera is repositioned to the composition of 10b indicated by the broken line in FIG. 11 so that the target mark 90 is aligned with the tree 11b which is the sub subject. The operation of the user aiming at the subject with the target mark 90 in this way is hereinafter referred to as a SPOT operation. After this SPOT operation, the image data of the subject selected by the user is transferred to the image sensor 3
Obtained by.

Operation control of the camera according to the present embodiment will be described with reference to FIG. Note that, also in this embodiment, the user preliminarily sets the subject to be focused on in the center of the shooting screen as shown in FIG. Further, the flow of FIG. 12 shows a part related to the enlarged display of the camera,
Although the control of the exposure operation and the like is omitted, the control of the first or second embodiment can be applied to these controls.

First, the CPU 1 determines whether or not a SPOT operation has been performed (step S90). If it is determined that the SPOT operation has not been performed, the process waits until the SPOT operation is performed, and if it is determined that the SPOT operation has been performed, the image data I _{1 of the} subject with which the target mark 90 is aligned is acquired. (Step S91), the image data I ₁ is stored in a RAM (not shown) (step S91).
92).

Here, the user aims at another subject with the target mark 90, that is, a subject other than the subject whose focus state is to be confirmed. The CPU 1 determines again whether the SPOT operation has been performed (step S93). SPOT
If it is determined that the operation has not been performed, it waits until the SPOT operation is performed, and if it is determined that the SPOT operation has been performed, the image data I _{2 of the} subject with which the target mark 90 is aligned is acquired ( In step S94, the image data I ₂ is stored in an area (not shown) other than the area in which the image data I ₁ is stored (step S94).
95).

Next, the CPU 1 determines whether or not to display on the LCD 8 according to the operating state of a monitor button (not shown) (step S96). When it is determined that the display on the LCD 8 is not performed, it is determined whether to clear the image data stored in the RAM (step S97).

Note that this determination may be performed, for example, by determining the elapse of a predetermined time so that the image data is cleared after the elapse of the predetermined time. This step S
If it is determined in 97 that the image data is not cleared, the process returns to step S96. If it is determined to clear the image data, the image data stored in the RAM is cleared (step S98), and the process returns to step S90.

The LCD 8 is determined by the determination in step S96.
If it is determined that the image is to be displayed, all image data in the shooting screen is acquired (step S99). Next, image data similar to the image data I ₁ and I ₂ is extracted from the acquired image data (step S100). Next, it is determined whether or not the push switch unit 51 is turned on, that is, whether or not enlarged display is performed to confirm the focus state (step S101). When it is determined that the enlarged display is not performed, the flow directly ends.

On the other hand, when it is determined that enlarged display is to be performed, the images corresponding to the extracted image data I ₁ and I ₂ are displayed in FIG.
An enlarged display is displayed on the LCD 8 as in (F) (step S
102). Next, the CPU 1 operates the push switch unit 51.
Is turned off, that is, whether or not the enlarged display is canceled is determined (step S103). When it is determined that the enlarged display is to be canceled, the enlarged display is canceled (step S104), and this flow ends.

On the other hand, when it is determined that the enlarged display is not canceled, it is determined whether the dial switch unit 52 has been operated.
That is, it is determined whether or not the focus position is finely adjusted (step S105). When it is determined that the dial switch unit 52 has been operated, the photographing lens 2 is extended or retracted according to the operation amount of the dial switch unit 52 (step S106), and then the process returns to step S99 to change the image. To do. When it is determined that the dial switch unit 52 is not operated, the above step S1 is performed.
Return to 02.

As described above, according to the present embodiment, by using the similar image data detection technique which is a feature of the present invention, it is possible to determine at which point in the photographing screen the subject desired by the user exists. By specifying and enlarging and displaying it, it becomes possible to perform high-speed focusing and confirm the accurate focus state. In the present embodiment, the relationship between the two points of focus is made visible in the form of an LCD display, but the focus is adjusted to a focus position where the contrast between the two images is the best. Such applications are also possible.

Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and various modifications and applications are possible within the scope of the gist of the present invention. Of course.

Here, the summary of the present invention includes the following in addition to those described in the claims.

(1) If the image data obtained during the focusing does not include a portion similar to the image data stored in the storage means, after issuing a warning, the subject in the central portion of the photographing screen is displayed. The camera according to claim 1 or 2, wherein the taking lens is focused on.

(2) It further comprises a selecting means for arbitrarily selecting a focusing point for focusing, and when the focusing point is selected by the selecting means, the image data of the object at the selected focusing point is displayed. The camera according to claim 1, wherein acquisition is performed.

[0088]

As described in detail above, according to the present invention,
To provide a camera capable of accurately focusing on a main subject exactly as intended by a user even on a screen in which various spatial frequencies are mixed and a subject in which various distances are mixed are mixed. You can

Further, it is possible to provide a camera which allows the user to easily recognize what is to be focused and to correctly recognize the focusing state of the subject in the enlarged display.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electric circuit configuration of a camera according to a first embodiment of the present invention.

FIG. 2A is a diagram showing how the camera according to the first embodiment of the present invention is used, and FIG.
2B to 2F are diagrams showing display examples on the LCD of the camera.

FIG. 3 is a diagram showing a detection area of an image sensor.

FIG. 4 is a diagram showing a flowchart for explaining a program for operation control of the camera of the first embodiment of the present invention.

FIG. 5 is a diagram showing a state in which the direction of the camera is changed and the target subject is changed with the distance measurement point selection mark.

FIG. 6A is a block diagram showing an electric circuit configuration of a camera according to a second embodiment of the present invention.
(B) is a diagram showing a detection area of the sensor array.

FIG. 7 is an external configuration diagram of a camera according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a flowchart for explaining a program for operation control of a camera according to a second embodiment of the present invention.

FIG. 9 is a diagram for explaining switches related to an enlarged display function of a camera of a third embodiment of the invention.

FIG. 10 is a diagram showing a display example of target marks.

FIG. 11 is a diagram for explaining a SPOT operation according to the third embodiment of this invention.

FIG. 12 is a diagram showing a flowchart for explaining a program for operation control of a camera of a third embodiment of the invention.

[Explanation of symbols]

1 CPU 2 Shooting lens 3 image sensor 4 Photography lens drive circuit (LD) 5 Focus judgment circuit 6 Image processing circuit 6a memory 7 LCD driver 8 Liquid crystal display (LCD) 9a Release switch 9b Focus position change switch 9c Focus position adjustment switch 51 Push switch section 52 Dial switch section

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Claims (4)

[Claims] 1. A camera comprising: an image sensor for obtaining subject image data; and a storage unit for storing the subject image data obtained by the image sensor. A portion similar to the central object image data stored in the storage means, the object image data is acquired again when the photographing lens is focused, and the object image data acquired again is stored in the storage means. And a focus signal is detected by using a contrast signal in the image data of the similar portion. 2. An image sensor for obtaining subject image data, a storage unit for storing subject image data obtained by the image sensor, and a display unit for displaying an image based on the subject image data obtained by the image sensor. In the camera provided with, the image data of the central portion of the image sensor is stored in the storage unit in advance, the subject image data is acquired again at the time of focusing of the photographing lens, and the object image data obtained again is acquired. A camera which detects a portion similar to the image data stored in the storage means from inside and displays a subject image of the portion on the display means. 3. A camera having an image pickup means for obtaining a subject image signal, wherein a subject image signal at a central portion of a photographing screen is obtained in response to a first operation prior to a photographing operation, and the first operation is continued. In accordance with the second operation, the subject image signal is acquired again by the image pickup means, a portion similar to the subject image signal in the central portion is extracted from the again obtained subject image signal, and the extracted similar portion of the subject is extracted. A camera characterized by performing focus control during shooting based on an image signal. 4. A camera comprising: an image pickup means for picking up a subject image signal; and a distance measuring means for measuring a subject distance in an optical path different from that of the image pickup means. A subject image signal and a subject distance signal in the central portion of the shooting screen are acquired by the distance measuring means, and at the time of shooting, focusing control of the taking lens is performed according to the subject image signal and the subject distance signal in the central portion. And the camera.