JP2010008620A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To focus on an object aimed by a user regardless of composition. <P>SOLUTION: A photographed image divided into a plurality of areas is displayed, an area including the object aimed by the user is designated by the user, and a focus lens is moved so as to focus on the basis of focusing information of the detected designated area, so that the user focuses on the aimed object. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging device having a focus function.

  In an imaging device such as a digital still camera or a video camera, there is an autofocus function as a function for controlling the focus. The autofocus function focuses on a subject by moving a focus lens based on focus detection information.

Conventional autofocus control methods include an active method that calculates the distance to the subject using infrared rays and sound waves, a phase difference detection method that determines whether the light is in focus through the lens, and contrast detection. There are methods. In particular, the contrast detection method can be focused by using an imaging sensor, so that the development cost is superior to other methods. Therefore, the contrast detection method is generally used as an autofocus control method for imaging devices.
In the contrast detection method, a high-frequency component of a captured image is detected while moving the focus lens, and the focus lens is moved to a position where the high-frequency component is maximized.
However, there is a limit to the depth of field of the lens when simultaneously photographing a plurality of subjects existing at least two types of distances from the photographing position. Therefore, it is impossible to focus on all subjects.
For example, when two types of subjects, a short-distance subject and a long-distance subject, are photographed simultaneously, only one of the subjects is in focus, and the other subject is out of focus.
In order to focus on the target subject in such a case, it is necessary to change the composition, change the zoom magnification, manually adjust the focus, or perform a combination thereof.
Therefore, the conventional autofocus function has a problem that it may take much time to focus on the subject intended by the user.

  In the present invention, in order to focus on the target subject, the captured image divided into a plurality of regions by the region dividing unit is displayed by the display unit, and the region including the target subject is designated by the divided region designating unit. The focus lens is moved by the lens driving means so as to focus based on the focus information of the designated area detected by the separate focus detection means.

  Since the imaging apparatus of the present invention can be focused by reflecting information on a specific divided area, it is possible to easily focus on a target subject by designating the area.

  The best mode for carrying out the invention is shown in the following examples.

  FIG. 1 is a diagram showing a basic configuration of the first embodiment of the present invention, and FIG. 2 is a diagram showing a basic processing flow. Details are described below.

As shown in FIG. 1, the basic configuration of an image pickup apparatus according to the present invention is a focus lens 101 for focusing, a lens driving means 103 for moving the position of the focus lens, and light passing through the lens as an electrical signal. An image sensor 102 for converting and outputting as a captured image, a signal processing circuit 109 for converting a signal output from the image sensor into a captured image, a recording unit 110 for recording the captured image, a captured image, a division pattern, and designation Display means 104 for displaying area information and the like, area dividing means 106 for dividing a photographed image according to a division pattern in order to detect the degree of focus for each divided area, and selecting a divided area according to the user's intention A divided area designating unit 105, a focus detection unit 107 for each area for detecting a focus evaluation value for each divided area from the photographed image, and a focus evaluation A focusing means for controlling the lens driving means for focusing based on the values, and a.
In the first embodiment, the imaging apparatus having such a configuration is used, and processing is performed according to a processing flow as shown in FIG. Detailed processing contents will be described below.

First, decide the composition you want to shoot and the target subject.
When there are two or more subjects with different distances in the composition to be photographed, it is necessary to focus on the target subject. FIG. 5 shows an example of a graph of the lens position and the high-frequency component detection amount when there are three subjects, a short-distance subject (A), a medium-distance subject (B), and a long-distance subject (C). Is shown. Broken lines represent high-frequency components detected from the entire captured image, and three solid lines represent high-frequency components for each subject. Thus, when the distance from the subject is different, the lens position at which the high-frequency component detected from the subject reaches a peak value is different. Therefore, when a high frequency component is detected from the entire captured image and a focus evaluation value is obtained as in a normal autofocus function, when the focus determination is started from the vicinity of the lens position (c), the high frequency component of the subject (C) is detected. Is determined to be in focus at the lens position (c) for detecting a large amount of light or the lens position (b) for detecting a high frequency component of the subject (B), and the subject (A) cannot be focused. Therefore, when the subject to be focused on most is the subject (A), the normal autofocus function may not be able to focus well.

  Therefore, rather than obtaining the focus evaluation value from the entire captured image, the focus evaluation value is obtained by dividing the captured image into several regions and obtaining the focus evaluation value from the region including the target subject. The method to match is taken.

  In order to show the divided area to the user, the area dividing means 106 sends information on the area dividing pattern to the display means 104 (201), and the display means 104 divides and displays the captured image based on the information on the area dividing pattern. (202).

  The user inputs a divided area including the target subject from the displayed divided areas using the divided area specifying means 105.

  The divided area designating unit 105 sends designated area information, which is information about the designated divided area, to the focus detection means 107 for each area (203).

  In the region designated by the designated region information, the region-specific focus detection means 107 detects a high-frequency component by the detection circuit 802 (204), calculates the focus evaluation value by the evaluation value calculation unit 803, and sends it to the focus means 108. Send (205).

  The focusing unit 108 determines whether the current state is the in-focus state from the focus evaluation value (206). If the in-focus state is not the in-focus state, the lens moving amount is determined according to the focus evaluation value (207). The focus lens 101 is moved by controlling the lens driving means (208).

  The processing of (204) to (208) is repeated until the focus evaluation value reaches the peak value and is determined to be in focus.

  With the above procedure, it is possible to focus on the image area intended by the user.

  3 (301), (302), and (303) are diagrams showing types of area division patterns that can be set by the area division means 106 according to the second embodiment of the present invention. Among the constituent elements, the display means 104, the divided area specifying means 105, the area-specific focus detection means 107, and the focus means 108 have the same configuration, and the area division means 106 has a different configuration. Details are described below.

  In order to flexibly focus on the target subject, a plurality of types of area division patterns can be prepared and set in advance in the area division means 106 before photographing.

  As the area division pattern, by using an area division pattern having a fixed division area such as a 3 × 3 rectangular shape as shown in FIG. 3 (301), the division area can be easily shown to the user.

  Further, by using an area division pattern in which the position of the divided area in the image can be changed as shown in FIG. 3 (302), the area can be designated at an accurate position with respect to the target subject.

  Further, by using an area division pattern in which the size of the designated area as shown in FIG. 3 (303) can be changed, the area can be designated in an accurate size for the target subject.

  As described above, it is possible to flexibly select a region including a target subject.

  FIG. 4 is a diagram illustrating a display example of the focus evaluation value on the display unit 104 according to the third embodiment of the present invention. Among the components of the imaging apparatus described in the first embodiment, the region dividing unit 106 and the divided regions are illustrated. The designation unit 105, the area-specific focus detection unit 107, and the focus unit 108 have the same configuration, and the display unit 104 has a different configuration. Details are described below.

  When the user selects an area including the target subject from the divided areas, the focus evaluation value of the divided areas is detected using the focus detection means 107 for each area, and the divided areas are displayed on the displayed captured image. By displaying the degree of focus for each, the user can select a divided region while referring to the focus state in the current composition.

Further, when focusing with reference to the focused state, the focusing means 108 can also be operated by manual focus.
As shown in FIG. 4 (401), the display means 104 can display the current focus state in detail to the user by displaying the focus evaluation value of each area as a numerical value.

  Alternatively, as shown in FIG. 4 (402), the focus evaluation value of each area is displayed in a histogram or the like, so that the current focus state can be shown to the user in detail. As an example of the histogram, the horizontal axis is the frequency, and the vertical axis is each frequency component detection amount, so that it is possible to indicate the frequency-specific component detection amount included in each region. In this case, a bandpass filter is prepared for each frequency to be shown, frequency components are detected from one or more bandpass filters in each divided region, and the detection amount of the frequency component is displayed for each frequency detectable from the bandpass filter. To do. Further, it is possible to indicate the high-frequency component detection amount for each coordinate included in each region by using the horizontal axis as coordinates and the vertical axis as high-frequency component detection amount. In this case, the captured image is divided into regions that are smaller than the divided regions and are necessary for high-frequency component detection, high-frequency components are detected from one or more small regions included in each divided region, and according to the coordinates of the small regions Displays high frequency components.

  Also, as shown in FIG. 4 (403), by setting a threshold value for the focus evaluation value and displaying the pattern image in two or more stages, the current focus state can be easily understood by the user. Can show. The pattern image is, for example, a color or a mark displayed on the image.

  As described above, it is possible to assist the user in selecting a divided region.

  FIG. 6 is a diagram showing the divided area designating unit 105 using the touch panel 602 according to the fourth embodiment of the present invention. Among the components of the imaging apparatus described in the first embodiment, the area dividing unit 106 and the area classification are shown. The focus detection unit 107 and the focusing unit 108 have the same configuration, and a configuration in which a touch panel 602 and a position coordinate comparator 603 are added as input units to the divided region designating unit 105 and the display unit 104 having configurations different from those in the first embodiment. To do. Details are described below.

  When the divided area designating unit 105 is combined with the display unit 104 using the touch panel 602 capable of performing an input operation simply by touching the display on the screen as the input unit 601, the user can designate the region including the subject. Can be specified easily. A touch panel is a device that detects the position of the screen touched by the user by arranging matrix switches and the like so as not to obstruct the screen display. By comparing the position information on the touch panel 602 touched by the user with the coordinate position on the display means 104 by the position coordinate comparator 603, the divided area specifying means 105 refers to the divided pattern information and the divided area that the user wants to specify. Can be specified.

  As described above, an area intended by the user can be designated.

  FIG. 7 is a diagram showing the divided area designating unit 105 using the speech recognition technology according to the fourth embodiment of the present invention. Among the components of the image pickup apparatus described in the first embodiment, the area dividing means 106 and the area classification are shown. The focus detection unit 107 and the focusing unit 108 have the same configuration, and a configuration in which a microphone 701 and a voice recognition unit 702 are added as input units to the divided region designation unit 105 having a configuration different from that of the first embodiment. Details are described below.

  By using a microphone 701 capable of inputting by voice as the input means 601 and using a voice recognition technology, an area indicated by the input voice can be designated. The speech recognition technology is a technology that compares the input speech signal with the speech feature model 704 and outputs the most probable language system as a recognition result. For example, for a word indicating a direction with respect to the display screen such as “right” and “down” input by the user, the divided area designating unit 105 designates a divided area corresponding to each direction. In the feature model of speech, the recognition rate is increased by placing specific gravity on words that are frequently used when selecting divided regions such as “right” and “bottom”, thereby enabling accurate region designation.

  As described above, an area intended by the user can be designated.

  FIG. 8 is a diagram showing an example of the configuration of the region-by-region focus detection unit 107 according to the sixth embodiment of the present invention. Among the components of the imaging apparatus described in the first embodiment, the display unit 104 and the divided region designation are shown. The means 105, the area dividing means 106, and the focusing means 108 have the same configuration, and the area-specific focusing detection means 107 have different configurations. Details are described below.

  The focus detection unit 107 for each region does not create a focus evaluation value only from the high-frequency component detected from the region specified by the user, but considers the high-frequency component detected from the surrounding region and focuses evaluation value. Can be created.

  The area selection unit 801 also selects the peripheral area of the specified area from the division pattern information and the specified area information, the high frequency component is detected by the detection circuit 802, the evaluation value calculation unit 803 performs weighting with a coefficient, and the like. The focus evaluation value is created by changing. As in the configuration shown in FIG. 8, the detection circuit can reduce the difference in the time at which the high frequency component is detected for each divided region by adopting a configuration in which the focusing degree for each region can be processed in parallel. In addition, even in a detection circuit that cannot process the in-focus level for each region in parallel, the captured images for detection are temporarily stored and detected one by one, so that the time at which the high-frequency component for each divided region is detected is detected. The difference can be reduced.

  In addition, in the case where there are a plurality of designated areas, a focus evaluation value can be similarly created.

  As described above, it is possible to prevent the focus on only the designated area.

  FIG. 9 is a diagram showing the basic configuration of the seventh embodiment of the present invention. Among the components of the image pickup apparatus described in the first embodiment, the display means 104, the divided area designation means 105, and the focus detection means for each area. 107 and the focusing unit 108 have the same configuration, and a configuration in which an object recognition unit 901 is added to an area dividing unit 106 different from the configuration described in the first embodiment. Details are described below.

  By using the object recognition unit 901 to use the object recognition technique for the region dividing unit 106 and creating a region dividing pattern from the recognition information of the subject, it is possible to divide the region in a range close to the subject. The object recognition technology is a technology for extracting a portion having a strong correlation by performing pattern matching between a model such as a contour of a prepared object and a reference image. Traffic models such as cars and signs, and human face and body models are used as object models.

  For example, by using “face recognition technology” using a human face model, it is possible to set a human face extracted from the image as a divided region.

  As a result, when a plurality of human faces are present in the image, it is possible to designate a divided area in which the target human face is recognized.

  The object extractor 903 performs pattern matching using an object model 902 having information such as the captured image and the contour of the subject, extracts a subject existing in the captured image, and creates recognition information.

  Based on the recognition information of the subject, the region dividing means 106 sets a divided region in a range as close as possible to the subject.

  As described above, it is possible to set a divided area in which a subject in a captured image is recognized.

  FIG. 3 (304) is a diagram showing an area division pattern according to the eighth embodiment of the present invention. Among the components of the image pickup apparatus described in the seventh embodiment, the display means 104, the divided area designation means 105, and the area classification are shown. The focus detection unit 107 and the focusing unit 108 have the same configuration, and the area division unit 106 and the object recognition unit 901 have different configurations. Details are described below.

  In the area dividing means 106, in order to realize an optimum divided area including an object as shown in FIG. 3 (304), first, the top, bottom, left, and right of the coordinates of the area including the object are recognized from the recognition information. Calculate the coordinates. The upper left coordinate is determined from the calculated upper end coordinate and left end coordinate, and this is used as the reference point. Next, the upper left position of the divided area is aligned with the reference point using a divided pattern in which the position of the area can be changed as shown in FIG. 3 (302). Then, using a division pattern that can change the size of the region as shown in FIG. 3 (303), the size of the divided region is adjusted so as to include the right end and the lower end. Further, depending on the shape of the subject, it is possible to set the divided region in a more accurate region by combining a plurality of divided regions used for one subject. The reference point is not limited to the upper left, and for example, the center point of the subject may be calculated from the object model 902 to be compared with the subject and used as the reference point.

  As described above, it is possible to set an accurate position and size divided region for each subject in the captured image.

  In the configuration of the ninth embodiment of the present invention, the divided area designation means 105, the area-specific focus detection means 107, and the focus means 108 are the same among the components of the image pickup apparatus described in the seventh embodiment. The area dividing unit 106 and the object recognizing unit 901 have different configurations.

  When setting the divided area where the subject is recognized, the object recognition means 901 recognizes the subject in the captured image, the area dividing means 106 detects the divided area where the subject is recognized during shooting, and the display means 104 sets the divided area. A series of processing to display is required.

  By repeating this series of processing at regular intervals, even if the composition changes during shooting due to movement of the subject or the imaging device, it is possible to set a divided region that follows the subject.

  Before the user specifies a subject, the time required for a series of processes is set as the shortest update period, and the update period is set based on the power consumption and the performance of the imaging apparatus.

  When shooting a still image after specifying the subject by the user, the range is accurately divided into the target subject by updating at the timing just before shooting by half-pressing the shutter button as in the normal autofocus function. The focus evaluation value can be detected by the area.

  Even when a moving image is shot after the user specifies a subject, the time required for a series of processing is the shortest update period. However, the shooting is performed in accordance with the timing of taking captured image data from the image sensor 102 separately from the update period before shooting. By setting the middle update period, it is possible to detect the focus evaluation value by the divided area that smoothly follows the subject within an accurate range.

  As described above, it is possible to detect the focus evaluation value by the divided area following the subject.

Basic configuration diagram of the present invention Basic processing flow of the present invention Example of area division by area dividing means Display example of focus evaluation value by display means Example of focus level detection when there are multiple subjects Configuration example using a touch panel as the division area designation means Configuration example using speech recognition technology as a segmentation area designation means Configuration example of focus detection means by area Configuration example using object recognition technology

Claims (16)

A focus lens that focuses light on the imaging surface, lens driving means for driving the focus lens, an imaging device that converts light on the imaging surface into an electrical signal, and the electrical signal output from the imaging device A signal processing circuit for converting to an image;
Area dividing means for generating information specifying a plurality of arbitrary areas on the captured image;
A focus detection means for each area for detecting the degree of focus of the subject for each area specified by the information generated by the area dividing means;
Display means for displaying information indicating the degree of focus detected by the focus detection means for each region;
A divided area designating means for selecting an arbitrary area from a plurality of areas indicated by the area dividing means;
Focusing means for controlling the lens driving means to focus on the area selected by the divided area designating means;
An imaging device comprising:
An imaging device controlled to focus a captured image on the selected region. 2. The imaging apparatus according to claim 1, wherein the area dividing means is an area dividing means capable of selecting only some areas from a plurality of area information on a photographed image before starting photographing. There is,
An imaging apparatus characterized by the above.   2. The imaging apparatus according to claim 1, wherein the area dividing unit can divide a captured image into rectangular areas.   2. The imaging apparatus according to claim 1, wherein the position indicated by the area information generated by the area dividing unit is arbitrarily changed.   2. The imaging apparatus according to claim 1, wherein the size of the area indicated by the area information generated by the area dividing unit is changed to an arbitrary size. The display means according to claim 1 comprises:
A numerical display that indicates the degree of focus is possible along with the captured images of each divided area.
An imaging apparatus characterized by the above. The display means according to claim 1 comprises:
It is possible to display a histogram showing the degree of focus along with the captured images of each divided area,
An imaging apparatus characterized by the above. The display means according to claim 1,
A pattern image showing the degree of focus can be displayed along with the captured images of each divided area.
An imaging apparatus characterized by the above. The imaging apparatus according to claim 1, wherein
An image pickup apparatus, wherein a touch panel that senses which part of display content is selected by touching a display on a screen is used as a command input interface of a divided area designation unit. The imaging apparatus according to claim 1,
A voice comparator that extracts a feature parameter of a voice input microphone and a voice signal that has been input, performs pattern matching processing with the voice feature model using the extraction result, and generates a command for selecting a region;
An imaging apparatus to which a voice feature model used for pattern matching processing performed by the voice comparator is added,
An imaging apparatus, wherein an area indicated by a divided area designating unit is selected by voice input. The imaging apparatus according to claim 1, wherein
The focus detection means for each area is
Evaluation value for calculating a focus evaluation value so that the first high-frequency component detected from the designated area indicated by the divided area designating means and the second high-frequency component detected from the surrounding area are weighted and added. Has an arithmetic unit,
An imaging apparatus characterized in that the focus evaluation value is used as an evaluation reference for focusing a lens on a focal position by a focusing means, or used for indicating a degree of focusing of a designated area to a user by a display means. The imaging apparatus according to claim 1, wherein
The focus detection means and display means for each area are as follows:
An imaging apparatus characterized in that a focus level of a plurality of divided areas is displayed on a display unit by detecting a plurality of frequency components within a predetermined period in a focus detection unit for each region. The imaging apparatus according to claim 1, wherein
The focus detection means for each area is
A focus detection means for each region that can arbitrarily set the range of the region for detecting the focus degree;
An imaging apparatus characterized by the above. The imaging apparatus according to claim 1,
An imaging apparatus comprising: an object recognizing unit for recognizing a subject in a captured image; and an area dividing unit for setting a divided region based on information on the subject recognized by the object recognizing unit. The object recognition means according to claim 14,
Object recognition means capable of detecting subject contour information or center position coordinates as subject recognition information for setting a divided region in the region dividing means;
An imaging apparatus characterized by the above. The object recognition means, area dividing means and display means according to claim 14,
Object recognition that can automatically repeat a series of three processes: object recognition by object recognition means, setting of divided areas based on recognition information, and display of divided areas by display means within a certain period of time Means, area dividing means and display means,
An imaging apparatus characterized by the above.

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