JP4104336B2 - camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement in a camera with a digital image monitor that allows a photographed image to be viewed on a screen such as a liquid crystal display (LCD).
[0002]
[Prior art]
In recent years, digital cameras have been widely used. However, with regard to focusing, it is difficult to obtain a photograph of the focus as expected by the user. For example, in a scene in which subjects with various spatial frequencies and distances are mixed in the screen as in the shooting scene 10 of FIG. 1, a miscellaneous subject different from the main subject may be in focus. For this reason, further improvement is necessary so that focusing can be performed more correctly. Among such focusing techniques, a technique has been proposed that allows a user to check a focusing state by displaying a focusing state on a camera. As a technique for making it possible to confirm the state of focusing, there is a technique for superimposing and displaying a focusing point together with a distance measuring point in a finder screen like a camera disclosed in Japanese Patent Laid-Open No. 10-48733. is there.
[0003]
[Problems to be solved by the invention]
However, the camera disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 10-48733 is not sufficient for confirming the focus state, so that it can be understood more directly at which position and how the focus is achieved. The technology that can be displayed on is required. In addition, since the superimposed display is performed in the finder screen, other displays in the finder screen may be difficult to see. Furthermore, since frames and the like that are not actually photographed are also displayed on the finder screen, there is a possibility of causing confusion for the user.
[0004]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a camera that is easy to check whether a subject assumed by a user is correctly focused and has excellent operability.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a camera according to the present invention comprises: An imaging optical system that forms a subject image, an imaging unit that images a subject and outputs the image data, an operation unit that instructs a shooting preparation operation for the shooting, and an operation time interval of the operation unit are measured. In response to the operation of the time measuring means and the operation means, the distance to the subject corresponding to each of the plurality of distance measuring points is measured, and when the output of the time measuring means is longer than a predetermined time, the predetermined distance measuring point Distance information is output, and when the output of the time measuring means is shorter than a predetermined time, distance measuring means for outputting distance information of a distance measuring point different from the previously output distance measuring point, and the distance measuring means output A photographing drive unit that drives the photographing optical system so as to focus on a subject at a ranging point corresponding to the distance information, and the distance measurement in the entire image data output by the imaging unit after the photographing optical system is driven. Ranging point from which the means output distance information And a display means for displaying an enlarged image data of the sides It is characterized by that.
[0006]
In other words, the camera of the present invention displays the subject that has been focused during shooting so that the focus state can be confirmed during shooting, and it is easy to check the focus state through the enlarged display.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0008]
[First Embodiment]
FIG. 1 shows a block diagram of an electronic circuit inside the camera according to the first embodiment of the present invention.
[0009]
A person 11a as a main subject is small as in the shooting scene 10 of FIG. 1, and what occupies most of the screen is a long-distance landscape, and one having a high or low spatial frequency such as a tree 11b or a mountain. If they are mixed, the camera may inadvertently focus on something other than the person 11a as the main subject (for example, the tree 11b).
[0010]
The electronic circuit in the camera according to the first embodiment includes an image sensor 3 that forms an image signal of a subject via the photographing lens 2, and after image processing such as compression is performed on the image signal. In addition, an image processing circuit 6 or the like that is stored in the memory 6a or displayed on the display (LCD) 8 is provided. The CPU 1 is an arithmetic control unit composed of a one-chip microcomputer or the like, and controls the sequence of the entire camera according to the operation of each of the switches such as the release button 9a and the focus position change switch 9b, and focuses on the output of the image sensor 3. Perform alignment control. That is, the photographing lens 2 is driven and controlled via the photographing lens drive circuit (LD) 4 in accordance with the output of the focus determination circuit 5 that extracts a predetermined spatial frequency component from the image signal of the subject and determines its contrast. I do. The CPU 1 also controls the LCD driver 7 to display an image on the LCD 8. In particular, when the focusing state confirmation function that is a feature of the present embodiment is activated, only a specific portion of the image sensor 3 is selected via the image processing circuit 6, and an image of the specific portion is cut out to be displayed on the LCD 8. The LCD driver 7 is controlled so as to be enlarged and displayed. In addition, when the exposure is insufficient at the time of shooting, the CPU 1 also performs control to supplement the light by causing the strobe 12 to emit light.
[0011]
FIG. 2 shows how a user handles a camera having such a configuration. The LCD 8 is provided on the rear surface of the camera 30 and is controlled by the CPU 1 so as to switch display images in accordance with operations of the release button 9a, the focus position change switch 9b, the focus position adjustment switch 9c, and the like. The release button 9a is a switch for storing an image captured by the image sensor 3 in the memory 6a. The focus position change switch 9b is a switch for changing a distance measuring point (focusing point). The focus position adjustment switch 9c is a switch for finely adjusting the focus position at the selected focusing point.
[0012]
The user can check whether the focus and composition are correct while viewing the screen displayed on the LCD 8. Here, the description will be continued assuming that the image pickup device 3 has three focus detection areas 3a, 3b, and 3c as shown in FIG. 3, but the number of areas is not limited to three and includes one central point. One or seven is acceptable. By using a plurality of focus detection areas in this way, the focus position can be detected not only when the subject is in the center but also in a scene where the subject is not at the center of the screen as shown in FIG. However, due to the side effects of such a configuration, a subject that was not originally intended to be focused will be brought into focus, and the main subject will be out of focus.
[0013]
The camera according to the present embodiment can display a main screen 8a and an enlarged screen 8b on the LCD 8, as shown in FIGS. 2 (B) and 2 (C). The screen switching between the main screen 8a and the enlarged screen 8b may be configured such that the CPU 1 switches when the ON operation of the display switching switch is determined by providing a dedicated display switching switch for a predetermined time. The display may be switched every time. Furthermore, the main screen 8a and the enlarged screen 8b may be divided and displayed so that they can be simultaneously displayed on one LCD 8.
[0014]
Here, the camera of the present embodiment examines the focus with respect to three points in the screen, for example, 10L, 10C, and 10R in FIG. 1 (on the image sensor 3, areas 3a and 3a shown in FIG. 3 respectively). 3b, 3c), assuming that a point can be focused on any point, and an image of the selected point is displayed as the enlarged screen 8b. The main screen 8a displays all the images to be photographed. For this reason, the user can easily check the overall composition or the focusing state of the point automatically selected by the camera. In addition, the camera according to the present embodiment enlarges and displays the next focus candidate point (for example, the tree 11b) by operating the focus position change switch 9b when the user does not like the result of automatic selection of the focus point. 2 (D) image 8c), and further, by operating the focus position adjustment switch 9c, the focus position within the selected point can be finely adjusted.
[0015]
FIG. 4 and FIG. 5 are flowcharts for explaining a camera operation control program of the present embodiment. In order to simplify the explanation, this flowchart is based on the idea that, after taking a picture once, if the picture is not taken correctly, it is sufficient to take another picture, but when the release button 9a is pressed halfway, A configuration may be adopted in which the focus state confirmation function is operated together with the determination of the focus position, and the photographing is finished when fully pressed.
[0016]
When the operation of this flowchart is started by half-pressing the release button 9a, first, an image captured by the image sensor 3 is displayed on the LCD 8 as the main screen 8a (step S1). At this time, the photographic lens 2 is placed at the pan focus position, and any subject can be seen on the LCD 8 with some focus. Thereafter, the position of the taking lens 2 is initialized to, for example, a position at infinity (∞) (step S2), and the contrast of the predetermined spatial frequency components in the three areas of FIG. 3 is checked at this initial position. That is, first, the contrast check of the area 3a is performed (step S3), then the contrast check of the area 3b is performed (step S4), and then the contrast check of the area 3c is performed (step S5). Needless to say, the contrast check order of these areas may be changed. Thereafter, it is determined whether or not the photographing lens 2 has reached the end (step S6). If it is determined that the end has not yet been reached, the position of the taking lens 2 at this time is stored in the memory 6a, and the taking lens 2 is extended (step S7). Then, the process returns to step S3 and the contrast check is performed again. The operation of checking the contrast while extending the photographing lens 2 is continued until the photographing lens 2 reaches the end.
[0017]
When the photographic lens 2 reaches the end, the peaks in the respective contrast waveforms checked in the areas 3a, 3b, and 3c are detected (step S8). By detecting the contrast peak, the position of the photographing lens 2 corresponding to the peak becomes the optimum focus position in the area. However, since the optimum focus positions are different in the areas 3a, 3b, and 3c, the closest object is selected from the peaks detected in the areas 3a, 3b, and 3c, and this is selected as the first focus candidate. Points are set (step S9). Thus, an image in the vicinity of a point (corresponding to any of the areas 3a, 3b, and 3c) selected from 10L, 10C, and 10R in FIG. 1 is displayed on the enlarged screen 8b when necessary. In the next step S10 and subsequent steps, a sequence in which either a photo opportunity (when the captured image is immediately stored in the memory) or a focus position (when the image is stored after being adjusted to the correct focus position) is prioritized. .
[0018]
When giving priority to the photo opportunity over the focus position, the user fully presses the release button 9a without stopping the release button 9a. Therefore, the CPU 1 determines whether or not to store the captured image in the memory 6a depending on whether or not the release button 9a is fully pressed (step S21). If it is determined not to store the image, it is determined whether or not the image display is performed as it is (step S22). This determination may be made, for example, by determining that there is no button operation by the user for a predetermined time, or by determining the state of a switch for switching ON / OFF of image display. If it is determined in step S22 that the image display is not finished, the process returns to step S20. If it is determined in step S22 that the image display is to be terminated, the display on the LCD 8 is turned off, and the process is immediately exited. On the other hand, if it is determined in step S21 that the image is to be stored, the currently selected point is focused (step S23). Then, after image processing such as compression is performed on the captured image, the image is stored in the memory 6a (step S24), and this flow is exited.
[0019]
On the other hand, the focus position is prioritized in a scene where the focus position is important, such as a portrait. In such a case, the user operates the focus position change switch 9b. The CPU 1 determines whether or not to check the focus state of the camera mode based on the state of the focus position change switch 9b (step S20). If it is determined that the focus state is to be confirmed, first, the photographing lens 2 is adjusted to the currently selected focus position (step S30). Then, the enlarged image 8b around the selected focus position is displayed on the LCD 8 (step S31). The user looks at the enlarged image 8b and confirms whether or not the subject he / she wants to shoot is displayed and whether or not the focus state is favorable to him / her. When the subject to be photographed is displayed but not in focus, the user operates the focus position adjustment switch 9c. Further, when the subject to be photographed is not displayed, the user operates the focus position change switch 9b again.
[0020]
Thus, the CPU 1 first determines the state of the focus position adjustment switch 9c, and determines whether or not to adjust the focus position (step S32). If it is determined that the focus position adjustment switch 9c has not been operated, the process proceeds to step S40. Then, it is determined whether or not to change the focus point according to the state of the focus position change switch 9b (step S40). If it is determined that the focus position change switch 9b is ON, that is, the focus point is to be changed, a point with the best focus at the next closest distance is selected and the process returns to step S20, and the next focus point is displayed on the LCD 8. To do. If the focus point is not changed, the process returns to step S20 as it is.
[0021]
If it is determined in step S32 that the focus position adjustment switch 9c has been operated, that is, if the user performs fine focus adjustment at a desired position, it is better to check the focus conditions other than the selection unit. Since the adjustment is easy, in this embodiment, as shown in FIG. 2E, other than the main subject is displayed, that is, the two enlarged images 8b and 8d are divided and displayed on the LCD 8. Thereby, the user can confirm whether the main subject is in focus or what other points are.
[0022]
That is, if it is determined in step S32 that the focus position adjustment switch 9c has been operated, it is determined whether or not the currently selected point is the center point (area 3b) (step S33). If the area 3b is determined, an enlarged image of the center point is displayed, and an enlarged image of the next focus candidate point (the point with the next highest contrast) is divided and displayed on the LCD 8 (step S34). . If the area is not the area 3b, the enlarged image of the selected point is displayed, and the enlarged image of the center point (area 3b) is divided and displayed on the LCD 8 (step S35). Thereafter, the CPU 1 determines whether or not the focus position adjustment switch 9c has been operated to the front pin side according to the state of the focus position adjustment switch 9c (step S36). When it is determined that the focus position adjustment switch 9c has been operated to the front pin side, drive control is performed in a direction in which the photographing lens 2 is extended according to the amount of operation of the focus position adjustment switch 9c (step S37). On the other hand, when it is determined that the focus position adjustment switch 9c has been operated to the rear pin side, the driving control is performed in the direction in which the photographing lens 2 is retracted according to the amount of operation of the focus position adjustment switch 9c (step S38). After the photographing lens 2 is driven and controlled and the focus position is changed, the currently displayed image is changed accordingly (step S39), and the process returns to step S32.
[0023]
If the release button 9a is operated during the confirmation and adjustment of the focus state, the release sequence is immediately executed and the image in the current focus state is stored in the memory 6a.
[0024]
As described above, according to the present embodiment, the user can easily take a picture while confirming the focus of the main subject aimed at. Further, there is no unnecessary display other than the image on the LCD, and the subtle focus can be confirmed by the enlarged image, and the user can determine whether or not the camera is correctly focused. In this way, it is possible to provide a camera that can shoot while correctly checking the focus, composition, facial expression of the subject, and the like.
[0025]
A second embodiment of the present invention will be described with reference to FIG. Camera according to this embodiment Is two So-called external light triangulation, 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 the sensor arrays 21a and 21b via the light receiving lenses 20a and 20b. Focusing by distance method I do Is. Image signals obtained by the sensor arrays 21 a and 21 b are converted into digital signals by an A / D converter (A / D) 22 and input to the CPU 1. The CPU 1 calculates the subject distance L from L = Bf / x, which is the principle formula of triangulation, by obtaining the aforementioned x by comparing these two digital image data. Here, B is the distance between the two light receiving lenses, and f is the distance between the light receiving lens 20a and the sensor array 21a or the distance between the light receiving lens 20b and the sensor array 21b. In this way, based on the obtained subject distance L, the CPU 1 focuses the photographing lens 2 via the LD 4. Thereafter, when actually capturing an image, the CPU 1 also performs light amount control of the strobe light emitting unit 12 based on the amount of light received by the photographing lens 2 and the amount of light received by the image sensor 3. The distance measuring device based on the principle of triangulation is a well-known technique and will not be described in detail. Further, the display drive control operations of the LCD 8 and the LCD driver 7 are the same as those in the first embodiment, and the description thereof will be omitted.
[0026]
Note that the range 23 monitored by the above-described triangulation sensor array in the photographing scene 10 is as shown in FIG. Therefore, it is possible to measure three points in the screen depending on which of 24L, 24C, and 24R of the sensor array 21a is used as a distance measuring point. Here, FIG. 6B shows only one of the sensor arrays 21a and 21b (for example, the sensor array 21a), and actually there is another same one. Thereafter, the description will be continued for the sensor array 21a, but the same description can be made for the sensor array 21b. In addition, the distance measurement area is not limited to the number of three areas as in the first embodiment, and can be five or seven points depending on how the area is divided.
[0027]
FIG. 7 is a front view of the camera having such a configuration. Although the basic appearance is the same as that of the first embodiment, a photometric window 25 that is a window for the light receiving lenses 20a and 20b is provided above the photographing lens 2, Focus check switch And the point which comprised the said focus position adjustment switch 9c as one switch 31 differs. The configuration of the switch 31 will be described with reference to FIG.
[0028]
The switch 31 includes a push switch unit 51 and a dial switch unit 52. A hole is opened at the center of the dial switch portion 52, and the push switch portion 51 is passed through the hole. When the push switch unit 51 is pushed down, the section 57 is also pushed, passes through the electrode 58, and a signal output as a result is input to the CPU 1 to operate the focusing state confirmation function. The Further, by rotating the dial switch unit 52, the segment 53 is also rotated in conjunction with the movement. The electrode 54 and the electrode 55 or the electrode 56 and the electrode 55 pass through the rotation state, and a signal output as a result is input to the CPU 1 to finely adjust the focus position (that is, the focus position adjustment switch). 9c role). For example, when the electrode 54 and the electrode 55 are electrically connected, the photographing lens 2 is moved in the extending direction and adjustment to the front pin side can be performed, and when the electrode 56 and the electrode 55 are electrically connected, the photographing lens 2 is provided. Can move in the direction in which it is retracted and can be adjusted to the rear pin side.
[0029]
Next, a camera operation control program according to the present embodiment having the above-described configuration will be described with reference to the flowchart of FIG. In the present embodiment, the release button 9a is configured in a two-step push-down type, the first release switch is turned on when the first step is pushed down, and the operation of the focus state confirmation function is started. It is assumed that an operation is performed in which an image captured with the release switch turned on is stored in the memory 6a.
[0030]
The CPU 1 determines whether or not the release button 9a has been depressed by one step by the user, that is, whether or not the 1st release switch has been turned on (step S50). 1st release switch is turned on Not If it is determined, the system waits until the first release is turned on. If it is determined that the 1st release switch has been turned on, it is determined whether or not the 1st release switch has been turned on within a predetermined time since the previous 1st release switch was turned on (step S51). If it is determined that the 1st release switch has not been turned on within the predetermined time, the subject distance is measured by the above-mentioned triangulation (step S53). This subject distance is measured for the distance measuring areas 24L, 24C, and 24R in FIG. _L , L _C , L _R And After calculating the subject distance, the calculated L _L , L _C , L _R The closest distance is selected as the main subject distance, and the area that outputs this distance is selected as the main subject focus point (step S54). This is because, in general, the subject present at the closest distance is often the main subject, and it is not always necessary to select the main subject by this short distance selection method. Needless to say, the selection can be made with higher accuracy by detecting the image signal and the contour, but here, in order to simplify the description, the short distance selection method is used. After selecting the focusing point in step S54, the process proceeds to step S55. If it is determined in step S51 that the first release switch has been turned on within a predetermined time, the next point at which the subject distance is output is selected as the focus point (step S52). Proceed to step S55.
[0031]
When the user wants to check whether the selected focus point (subject) is correct and the focus position is correct, the push switch unit 5 1 Turn on. Then, the CPU 1 determines whether or not the push switch unit 51 is turned on according to the state of the push switch unit 51 (step S55). If it is determined that the push switch unit 51 is OFF, the process directly proceeds to step S61. On the other hand, when it is determined that the push switch unit 51 is ON, the photographing lens 2 is driven and controlled to the currently selected focus position, and the subject is imaged by the image sensor 3 at that position (step S56). . Then, the image around the subject in the currently selected area is enlarged and displayed on the LCD 8 (step S57). Of course, the image display at this time may be divided display as shown in FIG. 2E described in the first embodiment. The user who sees this operates the dial switch unit 52 (that is, the focus position adjustment switch 9c) to finely adjust the focus. The CPU 1 determines whether or not fine adjustment of the focus has been performed according to the state of the dial switch unit 52 (step S58). When it is determined that the dial switch unit 52 has been operated, the photographing lens 2 is driven and controlled according to the adjustment amount of the dial switch unit 52. Then, the adjusted image is displayed on the LCD 8 (step S59), and the process proceeds to step S61.
[0032]
In step S61, in order to determine whether or not to store the captured image in the memory 6a, it is determined whether or not the user has pressed the release button 9a in the second stage, that is, whether or not the 2nd release switch has been turned on. If it is determined that the 2nd release switch is OFF, it is determined whether or not the 1st release switch remains ON (step S69). If it is determined in step S69 that the 1st release switch is still ON, the process returns to step S55. If it is determined that the 1st release switch is OFF, the process returns to step S50.
[0033]
On the other hand, if it is determined in step S61 that the 2nd release switch is turned on, the captured image is subjected to image processing such as compression, and the processed image is stored in the memory 6a (step S66). ), Exit this flow.
[0034]
As described above, according to the present embodiment, since the focusing point is selected at a high speed according to the result of the triangulation without lens scan, the selected position is imaged, and the enlarged image is displayed on the LCD 8. Focus determination is possible, and quicker shooting is possible. In addition, the user can see the state of the selected point on the enlarged screen while checking the overall composition clearly on the main screen, and can perform more advanced shooting.
[0035]
Although the present invention has been described based on the above embodiments, the present invention is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the gist of the present invention. is there.
[0036]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a camera that can correctly focus on a main subject even on a screen in which subjects of various distances are mixed. In addition, it is possible to provide a camera that allows the user to easily recognize the subject to be focused and correctly check the focus of the subject on the enlarged display screen.
[Brief description of the 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 a state in which the camera according to the first embodiment of the present invention is used, and FIGS. 2B to 2E are views of the camera. It is a figure which shows the example of a display of LCD.
FIG. 3 is a diagram illustrating a detection area of an image sensor.
FIG. 4 is a diagram showing a first half of a flowchart for explaining a camera operation control program according to the first embodiment of the present invention;
FIG. 5 is a diagram showing a latter half of a flowchart for explaining a camera operation control program according to the first embodiment of the present invention;
FIG. 6A is a block diagram showing an electric circuit configuration of a camera according to a second embodiment of the present invention, and FIG. 6B is a diagram showing a detection area of a sensor array. is there.
FIG. 7 is an external configuration diagram of a camera according to a second embodiment of the present invention.
FIG. 8 is a configuration diagram of a switch related to a focus state confirmation function of a camera according to a second embodiment of the present invention.
FIG. 9 is a flowchart for explaining a camera operation control program according to the second embodiment of the present invention.
[Explanation of symbols]
1 CPU
2 Photo lens
3 Image sensor
4 Shooting 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
52 Dial switch

Claims (5)

A shooting optical system for forming a subject image;
Imaging means for photographing a subject and outputting it as image data;
Operation means for instructing a shooting preparation operation for the shooting,
Time measuring means for measuring an operation time interval of the operation means;
In response to the operation of the operation means, the distance to the subject corresponding to each of the plurality of distance measuring points is measured, and when the output of the time measuring means is longer than a predetermined time, the distance information of the predetermined distance measuring point is output. And, when the output of the time measuring means is shorter than a predetermined time, distance measuring means for outputting distance information of a distance measuring point different from the distance measuring point output last time,
Photographing driving means for driving the photographing optical system so as to focus on a subject at a distance measuring point corresponding to the distance information output by the distance measuring means;
Display means for enlarging and displaying the image data around the distance measuring point from which the distance measuring means output distance information in the entire image data output by the imaging means after driving the imaging optical system;
A camera comprising: The predetermined distance measuring point is a distance measuring point having the closest distance to the subject among the distance information of the plurality of distance measuring points, and a distance measuring point different from the previously output distance measuring point is: The camera according to claim 1, wherein the distance measuring point closest to the subject next to the previously output distance measuring point is a distance measuring point . The camera according to claim 1, wherein the display unit further displays the entire image data output from the imaging unit after the focusing operation. The display means displays on the same screen the entire image data output by the imaging means and image data around the distance measuring point from which the distance measuring means outputs distance information in the image data. The camera according to claim 3. It further comprises display switching means for switching the display between the entire image data output by the imaging means and the image data around the distance measuring point from which the distance measuring means outputs distance information in the image data. The camera according to claim 3.

Images