JP2007267338A - Digital camera and focus position specifying method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera and a focus position specifying method, and a program with which photographed image can be easily confirmed, using a simple configuration. <P>SOLUTION: The digital camera comprises an image capturing means for capturing image, by converting the optical image of an object into an electric signal, and an image display means 25 for displaying the image and includes a storage means 28 for storing image in focusing and a focal position specifying means 41 for specifying a focus position during photographing, by comparing the image in focusing with an image at photographing, and the storage means 28 stores the focal position at photographing, specified by the focal position specifying means 41 at each photographing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a digital camera, a focus position specifying method, and a program, and more particularly, to a digital camera, a focus position specifying method, and a program for specifying a focus position on a captured image.

  2. Description of the Related Art Conventionally, a digital camera has a configuration capable of displaying stored photographed images one by one or as a list display on an LCD screen or a viewfinder. At that time, many models have a function of enlarging and displaying each captured image by a simple operation, and when enlarging the display, the image is always enlarged based on the center of the image at the time of shooting.

  In addition, in the case of a camera with an autofocus function, in general, by pressing the shutter button halfway to fix the focus distance, moving the camera in that state, then pressing the shutter button fully, It is equipped with a function that enables shooting with free composition. At this time, the position at which the focus distance is fixed is always adjusted to the center of the lens screen, or automatically determined by the camera adjustment function from a plurality of points on the lens screen or within a predetermined area. Although it exists, there is not much that actually takes a picture with the focus in the center of the screen.

  The enlarged display for confirming the captured image is always enlarged with reference to the center of the screen, and since the focus is rarely in the center of the screen as described above, the image is actually captured at the focused position. In order to confirm the image, after switching the display screen to the enlarged display screen, an operation of moving the position where the enlarged display is performed with the up / down / left / right keys to the focused position before photographing is required. In particular, when checking whether the shot image has failed due to camera shake immediately after shooting, the zoom display operation of the shot image is accompanied by the movement of the zoom display screen using the up / down / left / right keys. There was a problem that could not.

For example, in Patent Document 1, in order to confirm a captured image, in the viewfinder or LCD display, an enlarged display of an area centered on the screen center of the captured image, which is the focus position on the image plane at the time of shooting, is performed. A technique for enlarging and displaying a focus position preselected at the time of shooting from a plurality of focus positions is disclosed.
JP 2004-255057 A

  However, since the movement of the camera after the focus position is determined is not taken into consideration, the focus position at the time of shooting cannot be recognized. In addition, since the focus position is not stored for each shot, if you want to check the image at the time of shooting after shooting multiple shots, use the focus adjustment at a location different from the focus adjustment shooting. In order to confirm the enlarged image at the position where the focus is actually focused, the key operation as described above is required.

  Therefore, the present invention has been made in view of the above-described problems, and an object thereof is to provide a digital camera, a focus position specifying method, and a program capable of easily confirming an image after shooting with a simple configuration. To do.

The invention according to claim 1 is a digital camera,
Image acquisition means for acquiring an image by converting an optical image of a subject into an electrical signal, and image display means for displaying the image,
Storage means for storing an image at the time of focusing and a focus position;
A focus position specifying means for specifying a focus position at the time of shooting by comparing the image at the time of focusing and the image at the time of shooting;
The storage means stores a focus position at the time of shooting specified by the focus position specifying means for each shooting.

  According to the first aspect of the present invention, the digital camera stores the image at the time of focusing and the focus position, and identifies the focus position at the time of shooting by comparing the image at the time of focusing and the image at the time of shooting. The focus position at the time of shooting is stored for each shooting.

The invention described in claim 2 is the digital camera according to claim 1,
The focus position specifying means specifies the focus position at the time of shooting by comparing the image at the time of focusing and the image at the time of shooting.

  According to the second aspect of the present invention, the focus position specifying means specifies the focus position at the time of shooting by comparing the image at the time of focusing with the image at the time of shooting.

According to a third aspect of the present invention, in the digital camera according to the first aspect,
The focus position specifying means includes a direction sensor, and the focus position at the time of shooting is specified by comparing the change in posture of the digital camera at the time of focusing and at the time of shooting.

  According to the third aspect of the present invention, the focus position specifying means includes the direction sensor, and the focus position at the time of shooting is specified by comparing the posture change between the time when the digital camera is focused and the time of shooting. ing.

According to a fourth aspect of the present invention, in the digital camera according to the first aspect,
The storage means stores the image at the time of focusing and the focus position in association with the image at the time of shooting,
The focus position specifying means specifies a focus position at the time of shooting from an image at the time of shooting stored by the storage means at the time of non-shooting.

  According to the fourth aspect of the present invention, the image at the time of focusing and the focus position are stored in association with the image at the time of shooting, and the focus position at the time of shooting is specified from the image at the time of shooting stored at the time of non-shooting. The specified focus position at the time of shooting is stored in association with the image at the time of shooting.

According to a fifth aspect of the present invention, in the digital camera according to the first or fourth aspect,
The focus position specifying unit detects a feature point and a focus position with respect to the image at the time of focusing, and detects a focus position of the image at the time of shooting by detecting a corresponding feature point with respect to the image at the time of shooting. It is characterized by that.

  According to the fifth aspect of the present invention, the focus position specifying unit detects the feature point and the focus position with respect to the image at the time of focusing, and detects the corresponding feature point with respect to the image at the time of shooting. The focus position of the image at the time can be detected.

The invention according to claim 6 is the digital camera according to claim 1 or 4,
The focus position specifying means detects a focus position at the time of photographing based on a rotation angle detected by an angular velocity sensor.

  According to the sixth aspect of the present invention, the focus position specifying unit can detect the angular velocity of the digital camera by detecting the focus position of the image at the time of photographing based on the rotation angle detected by the angular velocity sensor. It can be done.

The invention according to claim 7 is the digital camera according to any one of claims 1 to 6,
Key input means,
The image display means is characterized in that an enlarged image centered on a focused position is selected and displayed based on an operation of the key input means.

  According to the invention of claim 7, when confirming an image at the time of shooting such as after shooting, an enlarged image centered on a focused position is selected from the image at the time of shooting or the image at the time of shooting. Since it can be displayed, an image to be displayed can be selected according to the application.

The invention according to claim 8 is the digital camera according to claim 7,
The key input means has an enlarged display key,
The image display means displays an enlarged image centered on a focused position in the image at the time of shooting by inputting the enlarged display key.

  According to the eighth aspect of the present invention, when confirming an image at the time of photographing such as after photographing, an enlarged image centered on a focused position is displayed among the images at the time of photographing by inputting an enlargement display key. Therefore, it is possible to easily confirm the suitability of the photographed image without the trouble of performing the key operation from the focus position at the time of photographing to the focused position, and to improve user convenience. .

The invention according to claim 9 is the digital camera according to any one of claims 1 to 8,
The storage means stores the focus position of the image at the time of focusing as property information for each shooting.

  According to the ninth aspect of the present invention, not only general photographing information but also a focus position at the time of focusing can be stored in the property information.

The invention according to claim 10 is:
A focus position specifying method for specifying a focus position on a captured image using the digital camera according to claim 1,
A storage process for storing an in-focus image by the storage unit and a focus position in the image plane;
A focus position specifying process for specifying the focus position at the time of shooting by comparing the image at the time of focusing and the image at the time of shooting by the focus position specifying means;
In the storing process, a process of storing a focus position at the time of shooting specified by the focus position specifying process for each shooting is performed.

  According to the tenth aspect of the present invention, the same effect as in the first aspect can be obtained, and the digital camera stores the image at the time of focusing and the focus position, and the image at the time of focusing and the image at the time of photographing. And the focus position at the time of shooting is specified, and the focus position at the time of shooting is stored for each shooting.

The invention according to claim 11 is a program,
The digital camera according to claim 1,
Storage means for storing the image at the time of focusing in association with the captured image;
Let the computer function as transfer means for transferring the captured image,
The computer,
A focus position specifying means for specifying a focus position at the time of shooting from the transferred shot image;
It functions as image display means for displaying the image at the time of shooting.

  According to the eleventh aspect of the present invention, the same effect as in the first aspect can be obtained, and the digital camera stores the image at the time of focusing and the focus position, and the image at the time of focusing and the image at the time of photographing. And the focus position at the time of shooting is specified, and the focus position at the time of shooting is stored for each shooting.

  According to the present invention, since the movement of the focus position can be detected by comparing the images at the time of focusing and at the time of shooting, the focus position at the time of shooting is determined even when the camera is moved after shooting after determining the focus position. Can be detected.

A digital camera according to an embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a block diagram showing the internal configuration of this digital camera.

  The digital camera has a lens block 1, and a plurality of optical elements including a shutter 3, an aperture 4, a zoom lens 5, and a focus lens 6 provided in a lens barrel 2 of the camera body. A retractable optical system comprising a lens is provided. The aperture of the diaphragm 4 can be controlled in two stages, an “open” state and an “aperture” state (predetermined opening), and the zoom lens 5 and the focus lens 6 are not shown in FIG. Therefore, it can be moved mechanically in the optical axis direction.

  The lens block 1 includes a shutter actuator 7 for opening and closing the shutter 3, a diaphragm actuator 8 for driving the diaphragm 4, a zoom motor 9 and a focus motor 10 for driving the zoom lens 5 and the focus lens 6 by the driving mechanism, A zoom lens position detection sensor 11 and a focus lens position detection sensor 12 for detecting the movement positions of both lenses 5 and 6, respectively, are provided separately from the optical system, and detect the phase difference of incident light and output it as a distance measurement signal. A distance measuring sensor 31 is provided. The actuators 7 and 8 and the motors 9 and 10 are provided on the driver block 13 with a driver (Iris), a shutter (Shutter), a zoom (ZOOM), and a focus (Focus). 17 is driven.

  The digital camera has a CCD imaging system block 18 comprising a CCD 19, which is an imaging means arranged behind the optical axis of the optical system, a CDS (Correlated Double Sampling) / AD block 20, and a TG (Timing Generator) 21. have. When the digital camera is set to the recording mode, the CCD 19 photoelectrically converts the light image of the subject imaged by the optical system, and scan-driven by the TG 21 to output a photoelectric conversion output for one screen at a certain period. It is like that. The CDS / AD block 20 performs noise removal by correlated double sampling and conversion to a digital signal with respect to an analog output signal that has been appropriately gain-adjusted for each RGB color component after being output from the CCD 19, and is a color process circuit 22 is output.

  The color process circuit 22 performs color process processing including pixel interpolation processing on the input image pickup signal, generates a digital luminance signal (Y) and color difference signals (Cb, Cr), and controls the entire digital camera. It is configured to output to. The CPU 23 is actually a microprocessor having an internal memory, various arithmetic processing circuits, a data input / output interface, and the like.

  The digital signal (image signal) sent to the CPU 23 is temporarily stored in the DRAM 24 and sent to the image display means 25. The image display means 25 is composed of a video encoder, a VRAM, a liquid crystal monitor and a drive circuit thereof, and constitutes the display means of the present invention. In the image display means 25, a video signal is generated by the video encoder based on the digital signal sent from the CPU 23, and a display image based thereon, that is, an image of the subject after being picked up by the CCD 19 and thinned to a predetermined number of pixels. An image is configured to be displayed on the liquid crystal monitor.

  The key input means 26 includes various keys such as a power key, a recording / playback mode switch, a shutter key, a zoom key, an enlarged display key, and a menu key, and sends an operation signal to the CPU 23 in accordance with the key operation by the user. It is configured. For example, in the recording mode, when a shooting operation is performed when the shutter key is half-pressed (during focusing), a trigger signal indicating that is output to the CPU 23, and when a shooting operation is performed when the shutter key is fully pressed, a trigger signal indicating it is output. Is output to the CPU 23. In addition, the menu key has a mode (image mode at focus / image mode at shooting) for selecting whether to display an image at the time of focusing or at the time of shooting when displaying an enlarged image on the image display means 25 described later. Has been.

  When the CPU 23 receives a trigger signal when the shutter key is half-pressed or fully pressed, the image data for one screen taken in from the CCD 19 in accordance with the trigger signal corresponding to the Y, Cb, and Cr components is basically 8 pixels × 8 pixels. Each basic unit called a block is read from the DRAM 24, sent to the JPEG circuit 27, and the JPEG circuit 27 stores the compressed data for one image compressed by DCT (discrete diffusion transform) and encoding in the image recording means 28. It has become.

  Specifically, the image recording means 28 includes a card interface and various nonvolatile memory cards that are connected to the CPU 23 via the card interface and are detachably attached to the camera body. The image data recorded in the image recording means 28 is read by the CPU 23 in the reproduction mode, expanded by the JPEG circuit 27, and then displayed on the liquid crystal display monitor of the image display means 25.

  The image display means 25 normally displays the image data recorded in the image recording means 28 in the reproduction mode. When the enlargement display key is input in the reproduction mode, the image data is enlarged and displayed. It has become so. In addition, when an enlarged display key is input in the in-focus image mode by operating the menu key, the in-focus image is displayed in an enlarged manner, and the enlarged display key is input in the shooting image mode. Then, the image at the time of shooting is enlarged and displayed.

  The flash memory 30 is a rewritable non-volatile memory. The flash memory 30 causes the CPU 23 to control the above-described units and stores various programs and data.

  Further, the lens control block 29 is connected to the CPU 23, and the CPU 23 causes the lens control block 29 to generate drive signals to be sent to the drivers 14 to 17 of the driver block 13 described above, thereby opening the aperture 4. The zoom lens 5 and the position of the focus lens 6 and the opening / closing operation of the shutter 3 are controlled.

  The CPU 23 periodically detects the subject distance by the phase detection method based on the distance measurement signal sent from the distance sensor 31 via the lens control block 29, and controls the position of the focus lens 6 based on the detection result. Is configured to do.

  Further, the CPU 23 is configured such that the position detection information of the lenses 5 and 6 detected by the zoom lens position detection sensor 11 and the focus lens position detection sensor 12 is sequentially input via the lens control block 29. Has been.

  Further, the CPU 23 is provided with a focus position specifying means 41. When the autofocus mode is set as the focus mode, the focus at the time of shooting is compared by comparing the image at the time of focusing with the image at the time of shooting. It is comprised so that a position may be specified.

  Here, first, the situation in which the autofocus mode is used will be described, and then a specific method by which the focus position specifying unit 41 specifies the focus position at the time of shooting will be described.

  The shooting situation in which the autofocus mode is used is basically the purpose of shooting a person, but it is a case where the whole building is also captured, and the person as shown in FIG. An example of the composition is as shown in FIG.

  In this case, when the focus area is fixed on the extension of the lens optical axis, prior to the shooting operation, as shown in FIG. Align with the center of the lens, that is, the center of the shooting frame, and press the shutter key halfway in this state. Then, the focus position of the digital camera is fixed to the “person's face” reflected in the center of the monitor corresponding to the lens, that is, focus adjustment (focusing) is performed on the “person's face”.

  Next, the desired composition of the camera with the shutter key pressed halfway, that is, here, the camera is moved in the upper left direction to match the composition of FIG. In this state, the focus is fixed to the state at the time of previous focusing, and the focus of the camera remains on the person's face. In this state, if the shutter key is further pressed (fully pressed), a photograph as shown in FIG. 3B can be taken. When the shutter key is fully pressed in the composition of FIG. 3B from the beginning, the center of the background building will be in focus, and the person's face will not be in focus, resulting in out of focus on the person's face. Become a photo.

  Therefore, the focus position specifying means 41 is configured to specify the focus position on the image plane at the time of shooting by the method described below.

  When the shutter key is half-pressed in the auto focus mode, the trigger signal and distance information when the shutter key is half-pressed are sent to the CPU 23 and are output from the color process circuit via the CPU 23 based on the signal. An image signal (FIG. 3A) with a fixed focus position on the image plane is temporarily stored in the DRAM 24 based on the input image signal. It has become so. Next, when the direction of the digital camera is changed and the shutter key is fully pressed, an image signal based on a trigger signal when the shutter key is fully pressed is sent to the CPU 23 and the color process is performed based on the signal via the CPU 23. An image signal output from the circuit is input to the DRAM 24. In the DRAM 24, an image (FIG. 3B) when the shutter key is fully pressed is temporarily based on the input image signal. To be saved.

  Then, when the image (FIG. 3A) in which the focus position is fixed in the DRAM 24 and the image when the shutter key is fully pressed by changing the direction of the digital camera (FIG. 3B) are stored, the focus position is saved. The specifying unit 41 extracts feature points between an image with a fixed focus position as an image at the time of focusing and an image when the shutter key is fully pressed as an image at the time of shooting, and the position of the feature point in both images is determined. The movement of the feature points is detected by comparison. FIG. 3 shows an example in which the corner (a1) of the building, the window (a2), the entrance, the roof boundary (a3), and the like are detected as feature points in the in-focus and shooting images. When the images at the time of focusing and at the time of shooting are arranged adjacent to each other, the trajectory drawn when each feature point (a1 to a3) moves from the time of focusing to the time of shooting is indicated by dotted arrows A1 to A1, respectively. This is indicated by A3. In the figure, since the feature points (a1 to a3) are moving in parallel, the focus position specifying means 41 detects that the feature points (a1 to a3) are moving in parallel. It has become.

  In addition, after detecting the parallel movement, the focus position specifying unit 41 moves the arrow B parallel to the arrows A1 to A3 and equal in length to the focus position (focused) of the focused image (FIG. 3A). When a person's face, b) is drawn with respect to the image at the time of shooting (FIG. 3B), the end point (b ′) of the arrow becomes the focus position at the time of shooting, and the focus position on the image plane at the time of shooting is changed. It has come to identify. Note that depending on the amount of movement of the camera, it may be assumed that the correspondence between the feature points cannot be obtained well. However, if the image comparison is performed sequentially on the reduced image of the camera-through image, for example, at the time of focusing and at the time of shooting The movement detection of the focus target is relatively easy. In addition, the amount of calculation can be reduced by using a reduced image.

  Next, the operation at the time of still image shooting in the recording mode in the digital camera having the above configuration will be described.

  First, a case where an autofocus mode for automatically controlling a focus position is set in advance as a focus mode for a digital camera will be described. FIG. 4 is a flowchart showing the processing contents according to the present invention executed by the CPU 23 in that case.

  The direction of the camera is determined so that the “person's face” to be focused is located in the focus area set in the center of the frame, and when the shutter key is pressed halfway in this state (step S1), the key input means 26 and After the trigger signal when the shutter key is half-pressed from the distance sensor 31 and the distance information to the portion corresponding to the focus area of the subject are sent to the CPU 23, the TG 21, CCD 19, CDS / AD 20, and color process circuit 22 are sent. The image signal obtained through the process is input to the DRAM 24, and the focused image (FIG. 3A) is temporarily stored (step S2).

  At this time, the shutter key is in a half-pressed state, and when this state is maintained and the camera orientation is changed to a desired composition and the shutter key is fully pressed (step S3), key input is performed. After the trigger signal when the shutter key is fully pressed from the means 26 is sent to the CPU 23, the image signal obtained through the TG 21, CCD 19, CDS / AD 20, and color process circuit 22 is inputted to the DRAM 24. The image when the shutter key is fully pressed (FIG. 3B) is temporarily saved (step S4).

  Next, the focus position specifying means 41 extracts the feature points of the image at the time of focusing and the image at the time of shooting, compares the positions of the feature points in both images, and detects that the feature points are moving in parallel. To do.

  Thereafter, the focus position specifying means 41 uses the arrow A1 for the image (FIG. 3B) taken from the focus position (the face of the person in focus) of the focused image (FIG. 3A). An arrow parallel to .about.A3 and having the same length is drawn, and the position that becomes the end point of the arrow is specified as the focused position on the subject at the time of shooting (step S5).

  Thereafter, the focus position specifying unit 41 associates the specified focus position with the image at the time of photographing (FIG. 3B) (step S6), and the information (image information at the time of photographing associated with the focus position). Is sent to the image storage unit 28. The image storage unit 28 stores image information at the time of shooting associated with the focus position (step S7).

  Then, when confirming whether the person's face is in focus in the photographed image, the recording mode is switched to the reproduction mode (step S8).

  When the reproduction mode is switched based on the operation of the key input means 26, an image at the time of shooting is displayed on the image display means 25 (step S9). At this time, the image display means 25 displays the image shown in FIG. When the enlargement display key is operated to check whether or not the face of the person at the edge of the screen is in focus, the image shown in FIG. 5C is displayed on the image display means 25, and the target image is obtained. It can be confirmed whether or not.

  As described above, this digital camera stores the in-focus image and the focus position on the image plane when shooting a still image in the autofocus mode. The focus position at the time of shooting can be specified by comparing. In addition, when detecting the focus position at the time of shooting, it is not necessary to add a special circuit, and the focus position at the time of shooting can be specified with an easy configuration.

  Further, since the focus position at the time of shooting is stored for each shooting, the focus position at the time of shooting can be specified for each shooting even when the images at the time of shooting are checked together after shooting a plurality of images.

  Further, when the captured image is confirmed by displaying the enlarged display image (FIG. 5C) at the focused position on the image display means 25, the focus position at the time of shooting is once used as in the prior art. It is possible to eliminate the trouble of performing the key operation to the position where the focused image is displayed after displaying the enlarged image (FIG. 5B). Therefore, it is possible to easily confirm the suitability of the captured image. And user convenience can be improved.

  In the present embodiment, the focus position specifying means 41 detects the movement of the camera by comparing the images at the time of focusing and at the time of shooting, but the focus positions at the time of focusing and at the time of shooting are as shown in FIG. It is good also as a structure represented by a coordinate (X, Y). In order to facilitate the correspondence with the original image before the enlarged display, the focus position may be stored as a ratio to the number of vertical and horizontal pixels.

  In the present embodiment, the focus position specifying unit 41 detects the operation of the camera by extracting and comparing the feature points of the focused image and the captured image. In order to perform extraction and processing for specifying corresponding points, it is necessary to increase the processing capacity of the CPU. In general, image processing such as noise removal and color correction is required at the time of shooting, and continuous shooting performance is often required in recent years, and it may be difficult to perform the process of specifying the focus position as described above.

  In order to solve this problem, when the focus position and image at the time of focusing and the image at the time of shooting are input to the DRAM 24, the focus position and image at the time of focusing are associated with the image at the time of shooting. In addition to storing the image, the focus position specifying unit may be configured to specify the focus position at the time of shooting in the same manner as described above and associate the specified focus position with the image at the time of shooting at the time of non-shooting. Thereafter, as described above, the image information at the time of photographing associated with the focus position is sent to the image storage unit 28, and the image storage unit 28 stores the image information at the time of photographing associated with the focus position. do it. Alternatively, the focus position information may be rewritten by deleting the focused image in the DRAM 24 after associating the identified focus position with the image at the time of shooting. In this case, it is possible to determine whether the focus position information is at the time of focusing or at the time of shooting by confirming whether or not the image at the time of focusing exists in the DRAM 24. It can be.

  Alternatively, as another solution to the case where it is difficult to perform the process of specifying the focus position, information relating the focus position at the time of focusing and the image and the image at the time of shooting is transferred from the digital camera to the personal computer (PC). When the image capturing is performed, the PC is determined based on the focus position specifying means for specifying the focus position at the time of shooting by the same method as described above based on the transferred information, and the PC based on the specified focus position at the time of shooting. What is necessary is just to comprise the program for functioning as an image display means for carrying out enlarged display of the picked-up image in a focus position in the image display part of the side. In this case, the digital camera alone cannot detect the focus position of the photographed image, but this program allows the PC to specify the focus position in the image at the time of focusing and at the time of photographing. For example, when the image display system breaks down or when it is desired to check the image on the slide show screen of the PC, the captured image can be enlarged and displayed at the focused position on the PC side to check the image. Further, when a slide show is performed on a PC, a plurality of captured images can be displayed with the focus position of each image as the center, and the effect of the slide show can be enhanced.

  In the present embodiment, the focus position specifying unit 41 detects the movement of the camera by comparing the in-focus image and the image at the time of shooting, and specifies the focus position on the image plane at the time of shooting. As shown in FIG. 4, an angular velocity sensor 43 (direction sensor) for detecting the movement (posture change) of the digital camera may be provided as the focus position specifying means 41.

  In this case, the user focuses on the object to be focused on (focus target) in the state of FIG. 7A, and then rotates the camera as shown in FIG. 7B to obtain the desired composition. think of. By using the angular velocity sensor 43 in the digital camera, the rotation angle θ (°) of the camera can be measured. How much the focus target moves with respect to the actual captured image when the camera is rotated by θ (°) depends on the distance D between the focus target and the image sensor and the size of the image sensor. Even if the rotation angles are the same, the object close to the camera moves greatly, but converges to a certain value depending on the amount of rotation of the camera as the object is farther from the camera. In the camera, since the distance D between the image pickup element and the focus target after adjusting the focus by the lens design is uniquely determined, the lens is incorporated into the image pickup element from the focus distance and distance D of the lens and the size of the image pickup element. The moving distance in the image can be calculated. If this process is performed with respect to the elevation angle and depression angle of the camera and the optical axis, the focus position in the captured image can be specified.

  Strictly speaking, the focus position is affected by where the center of rotation is, but since the image sensor is sufficiently small relative to the subject, the camera's translational component can be almost ignored. In photographing, only the rotational movement of the camera needs to be detected. When the camera itself is rotated in the same plane as the surface of the image sensor (the captured image itself rotates), it is necessary to detect the angle in three dimensions, but when using the camera in the normal usage method The camera itself is rarely rotated in the same plane as the surface of the image sensor, and the movement is not accompanied by a rotation component. Therefore, it is only necessary to detect the depression angle and elevation angle of the camera.

  In this way, by specifying the focus position using the angular velocity sensor 43, it is possible to directly detect the rotation angle, so that a configuration that does not require calculation capability for performing image processing can be achieved. Even in a digital camera equipped with a CPU with low processing power, the focus position after shooting can be specified.

In the present embodiment, the focus position at the time of shooting is configured to be stored in association with the shot image, and the image storage unit 28 stores various shooting information as property information. Further, it may be configured to include focus position information at the time of shooting. In this case, the shooting information included in the property information generally includes a shutter speed, an aperture, and the like such as the number of shooting pixels, a focus distance, and film sensitivity applied to a digital camera. With this configuration, it is possible to realize an additional function using the focus position in the image at the time of focusing, as described above.
Finally, in the present embodiment, autofocus is performed using the distance measuring sensor 31, but based on the contrast value of a predetermined focus area of the image acquired by the image acquisition means when the lens is moved. A method of detecting focus and performing autofocus may be used.

It is a figure which shows the internal structure of the digital camera which concerns on this invention. It is a figure explaining the imaging | photography operation | movement which moves a camera after deciding a focus position and image | photographs. It is a figure for demonstrating a mode which shows the motion of the camera at the time of obtaining the photograph of the composition of FIG. It is a flowchart which shows the flow of operation | movement of the digital camera of FIG. It is a figure for demonstrating a mode that the preserve | saved image is enlargedly displayed according to the size of a display image part. It is a figure of the display screen which represented the focus position by the coordinate. It is a figure for demonstrating a mode that a focus position is detected when a focus position specific | specification means is an angular velocity sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens block 2 Lens barrel 3 Shutter 4 Aperture 5 Zoom lens 6 Focus lens 9 Zoom motor 10 Focus motor 11 Zoom lens position detection sensor 12 Focus lens position detection sensor 19 CCD
23 CPU
24 DRAM
26 Key input means 25 Image display means 28 Storage means 29 Lens control block 30 Flash memory 31 Distance sensor 32 Color process circuit 41 Focus position means 43 Angular velocity sensor

Claims (11)

In a digital camera including an image acquisition unit that acquires an image by converting an optical image of an object into an electrical signal, and an image display unit that displays the image.
Storage means for storing an image at the time of focusing and a focus position in the image plane;
A focus position specifying means for specifying a focus position at the time of shooting by comparing the image at the time of focusing and the image at the time of shooting;
The digital camera according to claim 1, wherein the storage unit stores a focus position at the time of shooting specified by the focus position specifying unit for each shooting.   The digital camera according to claim 1, wherein the focus position specifying unit specifies a focus position at the time of shooting by comparing the image at the time of focusing with an image at the time of shooting.   2. The focus position specifying unit includes a direction sensor, and specifies a focus position at the time of shooting by comparing a change in posture of the digital camera at the time of focusing and at the time of shooting. Digital camera. The storage means stores the image at the time of focusing and the focus position in association with the image at the time of shooting,
The digital camera according to claim 1, wherein the focus position specifying unit specifies a focus position at the time of shooting from an image at the time of shooting stored by the storage unit at the time of non-shooting.   The focus position specifying unit detects a feature point and a focus position with respect to the image at the time of focusing, and detects a focus position of the image at the time of shooting by detecting a corresponding feature point with respect to the image at the time of shooting. The digital camera according to claim 1, wherein the digital camera is a digital camera.   5. The digital camera according to claim 1, wherein the focus position specifying unit detects a focus position of an image at the time of photographing based on a rotation angle detected by an angular velocity sensor. Key input means,
The image display means, based on an operation of the key input means, selects and displays an enlarged image centered on a focused position from an image at the time of shooting or an image at the time of shooting. The digital camera as described in any one of Claims 1-6. The key input means has an enlarged display key,
8. The digital camera according to claim 7, wherein the image display means displays an enlarged image centered on a focused position among images at the time of photographing by inputting the enlarged display key.   The digital camera according to claim 1, wherein the storage unit stores, as property information, a focus position of an image at the time of focusing for each photographing. A focus position specifying method for specifying a focus position on a captured image using the digital camera according to claim 1,
A storage process for storing an in-focus image by the storage unit and a focus position in the image plane;
A focus position specifying process for specifying the focus position at the time of shooting by comparing the image at the time of focusing and the image at the time of shooting by the focus position specifying means;
In the storage process, a process for storing a focus position at the time of shooting specified by the focus position specifying process for each shooting is performed. The digital camera according to claim 1,
Storage means for storing the image at the time of focusing in association with the captured image;
Let the computer function as transfer means for transferring the captured image,
The computer,
A focus position specifying means for specifying a focus position at the time of shooting from the transferred shot image;
A program for functioning as image display means for displaying an image at the time of shooting.

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