JP5100410B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to setting of a focus detection area in an imaging apparatus using an imaging element such as a CCD or a CMOS sensor.

  In a conventional imaging device, a live view image is displayed on the rear monitor before the actual shooting, which is a still image, so that the user can check the composition, and the camera is based on the image obtained at this time. Can automatically perform AF operation.

  One method for calculating the AF evaluation value for image data is, for example, as follows.

  In a conventional imaging apparatus, pixel data of a pixel in a focus detection area is read out from each pixel data of an image obtained by an imaging element, and an AF evaluation value Vn is obtained as follows.

When the pixel value of each pixel read from the focus detection area is represented by v (x, y) and the difference is represented by Δ (x, y) = v (x, y) −v (x + 1, y), AF evaluation is performed. The value Vn is expressed by the following equation. Here, x and y are indexes in the row and column directions for specifying each pixel, and each pixel in the focus detection area can be uniquely specified by being different from each other in x and y.
Vn = Σ | Δ (x, y) |
Here, Σ represents the sum of x and y indicating all the pixels read out when calculating the AF evaluation value Vn in the focus detection area. That is, the AF evaluation value Vn is a value representing the contrast of the focus detection area.

  FIG. 8 is a diagram illustrating a state of in-focus determination based on the AF evaluation value. The horizontal axis in FIG. 8 represents the position of the imaging lens, with the left on the near side and the right on the far side. The vertical axis in FIG. 8 represents the AF evaluation value Vn. When the lens position of the imaging lens is moved from the near side to the far side by a predetermined step, the AF evaluation value Vn gradually increases. As the lens is further moved, the AF evaluation value Vn is switched to decrease, and at this time, the imaging lens passes the in-focus position. Then, when switching to a decrease in the AF evaluation value Vn is detected, the driving direction of the imaging lens is reversed from the far side to the near side to detect a point where the AF evaluation value Vn is maximum, and the imaging lens is stopped there. The point where the AF evaluation value Vn is maximum is the in-focus position. The AF method for detecting the maximum AF evaluation value is generally called hill-climbing AF (or TVAF (contrast detection autofocus: see, for example, Patent Document 1)). The one that performs the hill-climbing AF is the mainstream. Moreover, in the conventional imaging device, this hill-climbing AF is generally performed using an image to be displayed on the image display unit.

Many imaging devices read all pixels of the image sensor when shooting still images, and thin or add horizontal and vertical pixels when shooting moving images necessary for framing and video recording. The necessary number of pixels and frame rate are maintained by reading out the data. Under such circumstances, it is unavoidable that the picture quality is deteriorated by thinning out or adding the pixels. This is particularly noticeable when the electronic zoom is used. Normally, when electronic zooming is performed, a method is adopted in which image data corresponding to a desired angle of view range is extracted from image data of the entire screen, and this is padded and displayed / recorded on the entire screen. For this reason, the image quality is deteriorated as compared with the image before the electronic zoom is performed. As a technique for suppressing this image quality degradation, it has been proposed to cut out and read out a partial area by reducing the thinning rate or performing non-addition / non-thinning when performing electronic zoom (for example, Patent Document 2). ).
JP-A-2005-300631 JP 2007-212273 A

  However, the number of image data obtained per imaging area changes between the case where pixels are thinned out or added and read, and the case where the thinning rate is reduced or read out by non-addition / non-decimation, The AF result sometimes became unstable.

  Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to prevent a decrease in AF accuracy even when reading methods for reading image data from an image sensor are mixed. I will. Another purpose is to notify the user of the in-focus area in an easy-to-understand manner.

In order to solve such a problem, as a technical feature of the present invention, an imaging apparatus includes a plurality of pixels arranged in a first direction and a second direction perpendicular to the first direction. An image sensor that outputs the subject image photoelectrically converted by the pixels as image data, an electronic zoom unit that electrically enlarges and outputs a part of the image data obtained from the image sensor, and an image by the electronic zoom unit When the enlargement ratio is the first enlargement ratio, the image data for each of the plurality of pixels is thinned out and output, and when the second enlargement ratio is greater than the first enlargement ratio, the image data Based on the image data obtained from the pixels of the image sensor in the area corresponding to the focus detection area, out of the image data output from the control means , the control means for controlling to output without thinning Said The evaluation value for each direction, a detecting means for detecting the AF evaluation value integral calculation to the first direction of the array of pixels, by moving the imaging lens on the basis of the detected AF evaluation value focus of a focus adjustment means for performing adjustment, the image data output from said control means have a display means for displaying to overlap with information indicating a focus detection area, in the case of the first magnification, the first When the focus detection area is set so as to obtain a larger number of image data than the predetermined number in one direction and manual focus adjustment is performed, the display means does not display information indicating the focus detection area, further, in the case of the first magnification, in place of the information indicative of the focus detection area, expanding the information indicating the area to be enlarged so as to overlap with the image data, characterized in you to view when displaying.

  According to the present invention, it is possible to prevent the AF accuracy from being lowered even when read methods for reading image data from the image sensor coexist. In addition, the user can be notified of the in-focus area in an easy-to-understand manner.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[Embodiment]
<Configuration of imaging device>
FIG. 1 is a block diagram illustrating a configuration of an imaging apparatus having an image processing function according to an embodiment of the present invention. In the present embodiment, a single-lens reflex digital still camera with interchangeable lenses will be described as an example of an imaging apparatus.

  As shown in FIG. 1, the imaging apparatus of the present embodiment mainly includes a camera body 100 and an interchangeable lens type lens unit 300.

  In the lens unit 300, 310 is an imaging lens composed of a plurality of lenses, 312 is a diaphragm, and 306 is a lens mount that mechanically couples the lens unit 300 to the camera body 100. The lens mount 306 includes various functions for electrically connecting the lens unit 300 to the camera body 100. Reference numeral 320 denotes an interface for connecting the lens unit 300 to the camera body 100 in the lens mount 306, and 322 denotes a connector for electrically connecting the lens unit 300 to the camera body 100.

  The connector 322 has a function of transmitting control signals, status signals, data signals, and the like between the camera body 100 and the lens unit 300 and supplying currents of various voltages. The connector 322 may be configured to perform communication using not only electrical communication but also optical communication, voice communication, and the like. Reference numeral 340 denotes an aperture control unit that controls the aperture 312 in cooperation with a shutter control unit 40 that controls the sitter 12 of the camera body 100, which will be described later, based on photometric information. Reference numeral 342 denotes a focus control unit that controls focusing of the imaging lens 310, and 344 denotes a zoom control unit that controls zooming of the imaging lens 310.

  A lens system control circuit 350 controls the entire lens unit 300. The lens system control circuit 350 includes a memory for storing operation constants, variables, programs, and the like. Further, a non-volatile memory that holds identification information such as a unique number of the lens unit 300, management information, function information such as an open aperture value, a minimum aperture value, and a focal length, and current and past setting values is also provided.

  Next, the configuration of the camera body 100 will be described.

  A lens mount 106 mechanically couples the camera body 100 and the lens unit 300. Reference numerals 130 and 132 denote mirrors that guide light rays incident on the imaging lens 310 to the optical viewfinder 104 by a single-lens reflex system. Reference numeral 12 denotes a focal plane shutter, and reference numeral 14 denotes a CCD, a CMOS sensor, or the like, and an imaging device having a plurality of pixels that photoelectrically convert a subject image to obtain an electrical signal. The plurality of pixels are two-dimensionally arranged in the vertical direction and the horizontal direction. Further, the number of arranged pixels is larger in the horizontal direction than in the vertical direction. In front of the image sensor 14, an optical element 14a (not shown) such as an optical low-pass filter is disposed.

  The light beam incident on the imaging lens 310 is guided by the single-lens reflex system through the aperture 312, the lens mounts 306 and 106, the mirror 130, and the shutter 12, which are light amount limiting means, and is formed on the image sensor 14 as an optical image. .

  Reference numeral 16 denotes an A / D converter that converts an analog signal (output signal) output from the image sensor 14 into a digital signal. A timing generation circuit 18 supplies a clock signal and a control signal to the image sensor 14, the A / D converter 16, and the D / A converter 26, respectively, and is controlled by the memory control circuit 22 and the system control circuit 50.

  An image processing circuit 20 performs predetermined pixel interpolation processing and color conversion processing on the data from the A / D converter 16 or the data from the memory control circuit 22. Further, the image processing circuit 20 performs predetermined arithmetic processing using the image data output from the A / D converter 16 as necessary. The system control circuit 50 controls the shutter control unit 40 and the focus adjustment unit 42 on the basis of the obtained calculation result, so that contrast-type autofocus (AF) processing, automatic exposure (AE) processing, flash pre-emission (EF) ) Can be processed. Further, the image processing circuit 20 performs predetermined arithmetic processing using the image data output from the A / D converter 16, and also performs TTL auto white balance (AWB) processing based on the obtained arithmetic result. ing.

  A memory control circuit 22 controls the A / D converter 16, the timing generation circuit 18, the image processing circuit 20, the image display memory 24, the D / A converter 26, the memory 30, and the compression / decompression circuit 32. Image data output from the A / D converter 16 is written into the image display memory 24 or the memory 30 via the image processing circuit 20, the memory control circuit 22, or only through the memory control circuit 22.

  Reference numeral 24 denotes an image display memory, 26 denotes a D / A converter, and 28 denotes an image display unit made up of a TFT-type LCD or the like. Via the image display unit 28. An electronic viewfinder (EVF) function can be realized by sequentially displaying captured image data using the image display unit 28. Further, the image display unit 28 can arbitrarily turn on / off the display according to an instruction from the system control circuit 50, and when the display is turned off, the power consumption of the camera body 100 can be significantly reduced. it can.

  Reference numeral 30 denotes a memory for storing captured still images or moving images, and has a storage capacity sufficient to store a predetermined number of still images or a predetermined amount of moving images. This makes it possible to write a large amount of images to the memory 30 at high speed even in continuous shooting or panoramic shooting in which a plurality of still images are continuously shot. In moving image shooting, it is used as a frame buffer for images written continuously at a predetermined rate. Further, the memory 30 can be used as a work area for the system control circuit 50.

  A compression / decompression circuit 32 compresses / decompresses image data using a known compression method. The compression / decompression circuit 32 reads an image stored in the memory 30, performs a compression process or an expansion process, and writes the processed data to the memory 30 again. It also has a function of compressing and encoding moving image data into a predetermined format, or expanding a moving image signal from predetermined compression-encoded data.

  A shutter control unit 40 controls the shutter 12 in cooperation with the aperture control unit 340. A focus adjusting unit 42 performs AF (autofocus) processing. A light beam incident on the imaging lens 310 in the lens unit 300 is made incident as a single lens reflex system through a diaphragm 312, lens mounts 306 and 106, a mirror 130, and a focus adjustment submirror (not shown), thereby forming an optical image. The in-focus state of the captured image is measured.

  Further, the AF control is performed by selectively using the measurement result by the focus adjustment unit 42 and the calculation result of the AF evaluation value calculated by the image processing circuit 20 using the image data from the A / D converter 16 or both. May be performed. When AF control is performed using the calculation result obtained by calculating the AF evaluation value by the image processing circuit 20 using the image data, the image is picked up at the lens position where the AF evaluation value calculated by the image processing circuit 20 is maximized. The focus state is adjusted by moving the position of the lens 310. There are many types of AF evaluation values here, but an example is a value obtained by adding (integrating) the peak values for each horizontal line of the luminance signal obtained from the image data in the vertical direction. The greater this value, the higher the degree of focus. In the above example, the value added in the vertical direction is used. However, the AF evaluation value may be obtained by performing integral calculation in a predetermined direction. That is, a peak value in the vertical direction may be obtained and a value obtained by adding the peak values in the horizontal direction may be used as an AF evaluation value, or an AF evaluation value may be obtained by adding image data in the horizontal direction and the vertical direction.

  Reference numeral 50 denotes a system control circuit that controls the entire camera body 100, and incorporates a known CPU. A memory 52 stores constants, variables, programs, and the like for operating the system control circuit 50.

  Reference numeral 54 denotes a notification unit for notifying the outside of an operation state, a message, and the like using characters, images, sounds, and the like in accordance with execution of a program in the system control circuit 50.

  Reference numeral 56 denotes an electrically erasable / recordable non-volatile memory in which programs and the like to be described later are stored. For example, an EEPROM or the like is used.

  Reference numerals 60, 62, 64, 66, 68, and 70 denote operation means for inputting various operation instructions of the system control circuit 50. A single unit such as a switch, a dial, a touch panel, pointing by line-of-sight detection, a voice recognition device, or the like Consists of multiple combinations.

  Here, a specific description of these operating means will be given.

  Reference numeral 60 denotes a mode dial switch which can be used to switch and set each function shooting mode such as an automatic shooting mode, a program shooting mode, a shutter speed priority shooting mode, an aperture priority shooting mode, a manual shooting mode, and a depth of focus priority (depth) shooting mode. it can. In addition, each function shooting mode such as portrait shooting mode, landscape shooting mode, close-up shooting mode, sports shooting mode, night view shooting mode, panoramic shooting mode, and the like can be switched and set.

  Reference numeral 62 denotes a shutter switch SW1, which is turned on while a shutter button (not shown) is being operated (for example, half-pressed), and instructs to start operations such as AF processing, AE processing, AWB processing, and EF processing.

  A shutter switch SW2 64 is turned on when a shutter button (not shown) is completed (for example, fully pressed), and instructs the start of a series of processes including exposure processing, development processing, and recording processing. First, in the exposure process, a signal read from the image sensor 14 is written to the memory 30 via the A / D converter 16 and the memory control circuit 22, and further, an operation in the image processing circuit 20 and the memory control circuit 22 is used. Development processing is performed. Further, in the recording process, the image data is read from the memory 30, compressed by the compression / decompression circuit 32, and written or transmitted to the recording medium 200 or an external device such as a PC.

  Reference numeral 66 denotes a playback switch, which instructs to start a playback operation in which an image shot in the shooting mode is read from the memory 30, the recording medium 200, or an external device such as a PC and displayed on the image display unit 28. In addition, the playback switch 66 can set various function modes such as a playback mode, a multi-screen playback / erase mode, and a PC connection mode.

  68 is a single-shot / continuous-shot switch. When the shutter switch SW2 (64) is pressed, a single-shot mode is set in which one frame is shot and the camera is in a standby state. The continuous shooting mode can be set.

  An operation unit 70 includes various buttons and a touch panel.

  As an example of the operation unit 70, there is an image display ON / OFF switch for setting ON / OFF of the image display unit 28, and a quick review ON / OFF switch for setting a quick review function for automatically reproducing image data taken immediately after shooting. . In addition, there is an AF mode setting switch that can set a one-shot AF mode and a servo AF mode. In the one-shot AF mode, an autofocus operation is started when the shutter switch SW1 (62) is pressed, and once focused, the focused state is maintained. In the servo AF mode, the autofocus operation is continued while the shutter switch SW1 (62) is being pressed.

  Reference numeral 90 denotes an interface with a recording medium such as a memory card or hard disk, and reference numeral 92 denotes a connector for connecting to a recording medium such as a memory card or hard disk.

  Reference numeral 120 denotes an interface for connecting the camera body 100 to the lens unit 300 in the lens mount 106.

  A connector 122 electrically connects the camera body 100 to the lens unit 300. The connector 122 transmits a control signal, a status signal, a data signal, and the like between the camera body 100 and the lens unit 300, and has a function of supplying currents of various voltages.

  Various optical information (aperture, zoom position, pupil distance, focal length, etc.) of the lens unit 300 communicated via the connector 122 is stored in the optical information storage memory 58 of the camera body 100. The communication request may be made from the camera side, or may be communicated from the lens side every time information is updated.

  Further, the connector 122 may be configured to perform communication by optical communication and voice communication as well as electrical communication.

  Reference numeral 200 denotes a recording medium such as a memory card or a hard disk. The recording medium 200 includes a recording unit 202 composed of a semiconductor memory, a magnetic disk, and the like, an interface 204 with the camera body 100, and a connector 206 for connecting with the camera body 100.

  As the recording medium 200, a memory card such as a PCMCIA card or compact flash (registered trademark), a hard disk, or the like can be used. Of course, it may be composed of a micro DAT, a magneto-optical disk, an optical disk such as a CD-R or CD-RW, a phase change optical disk such as a DVD.

  The camera body 100 can also be connected to an external device such as a PC.

<Setting the focus detection area>
The focus detection area designates a range of a plurality of pixels in the image sensor when the image processing circuit 20 calculates an AF evaluation value using image data. As described above, an AF evaluation value is calculated using image data output from the focus detection area, and AF control is performed.

  At this time, if the focus detection area is set to be small, the number of image data to be used is reduced, and it is easy to be affected by noise. In addition, the frequency at which the subject goes out of the small focus detection area due to the camera shake of the photographer or the slight movement of the subject is high, and malfunctions are likely to occur. Therefore, when the focus detection area is small, the accuracy of AF may decrease. Conversely, if the focus detection area is increased, the number of image data used increases, noise is leveled, the influence is reduced, and AF accuracy is improved.

  On the other hand, in order to notify the user on which position the focus is on the screen, the focus detection area should be small. Also, if the focus detection area is set large, it is uncertain which subject to focus on when shooting subjects with different distances on the same screen or when the background of the subject is high contrast. It may be difficult to always focus on the desired subject.

  Therefore, there are advantages and disadvantages depending on the size and shape of the focus detection area. Therefore, a method for appropriately setting the focus detection area in the non-enlarged display and the enlarged display will be described below.

(1) Area setting for non-enlarged display In the imaging apparatus having the above configuration, setting of a focus detection area in the case of non-enlarged display (that is, when the electronic zoom enlargement ratio is 1) will be described.

  In the case of non-enlarged display, information indicating an area corresponding to the focus detection area is superimposed and displayed on the image display unit 28 so as to overlap the image. FIG. 2 is a diagram showing the image display unit 28 in non-enlarged display. A portion (area A) displayed in the center gray rectangle is an area for acquiring image data for focus detection. The focus detection area has a vertically long shape on the screen on which a signal from the image sensor is displayed. As will be described later, when image data is displayed on the image display unit 28 as needed, the image data is in the horizontal direction (horizontal direction). This is because many thinnings are performed in the vertical direction (vertical direction). Since the evaluation value is integrated in the vertical direction and the contrast of the image is determined by determining the calculation result, it is necessary to increase the amount of data in the vertical direction so that the influence of noise on the AF evaluation value is reduced. Because there is. On the other hand, if the focus detection area is set wide in the horizontal direction, the area becomes wide, and as described above, it is impossible to easily notify the user of the position on the screen where the focus is suitable. In addition, there is a high possibility that the area includes a subject at a short distance or a long distance. This is because the contrast AF determines only the image data in the focus detection area. At this time, when focusing on a subject at a short distance or focusing on a subject at a long distance, AF becomes unstable. Therefore, in order to reduce the possibility of such distance conflict, the area in the horizontal direction is set as narrow as possible within the range where AF determination can be performed.

  This will be described in detail below. During non-enlarged display, the image data of the entire imaging area of the image sensor is read out, but in order to maintain the determined frame rate, the amount of image data read out from the image sensor 14 is reduced and the readout time is shortened. The image pickup device is driven as described above.

  A method for reducing the image data read from the image sensor will be described with reference to FIG. FIG. 3 is an enlarged view of a part of the image sensor, and the numbers X1 to X6 representing the column direction are given to the pixels for easy explanation. Similarly, numbers from Y1 to Y5 are also given in the row direction. First, when reading out image data from the image sensor, image data is read out for each row, so reading is performed to reduce image data when reading out image data for one row. FIG. 3 shows thinning readout for reading out only one pixel of image data for three pixels. Therefore, the read pixels are X1, X4. Similarly, reading is performed to reduce image data in the column direction. FIG. 3 shows thinning-out reading in which only one row is read out of three rows. Therefore, the read rows are Y1, Y3,. Therefore, the pixels actually read out are (X1, Y1), (X4, Y1), (X1, Y4), and (X4, Y4) painted in gray in the drawing in FIG. As a result, 1/9 pixels are read out from the original number of pixels of the image sensor, so that the reading time is shortened.

  When thinning readout is performed to reduce the image data from the image sensor in this way, the AF evaluation value is also generated from the thinned image, so the number of pixels is smaller than the number of pixels included in the set focus detection area (see FIG. 3 is an AF evaluation value based on image data obtained from 1/9). Therefore, in order to maintain the AF accuracy, in order to secure the amount of image data used for the calculation of the AF evaluation value, the vertical size of the focus detection area is increased according to the thinning rate. At this time, with respect to the horizontal direction, the size of the focus detection area in the horizontal direction may be increased according to the thinning rate. However, in the calculation of the AF evaluation value, the horizontal direction is used to obtain a peak value. Even if there is little, it is not so affected by noise. Therefore, it is conceivable to set the area in the horizontal direction so that the area is not enlarged from the idea of notifying the user of the position on the screen where the above-mentioned focus is in an easy-to-understand manner. Although the case of reading out 1/9 pixels has been described here, the thinning rate is not limited to this.

  When the shutter switch SW1 (62) is pressed, contrast AF is started. The system control circuit 50 reads the image data from the image sensor 14 by controlling the timing generation circuit 18 and the image processing circuit 20. The system control circuit 50 controls the image processing circuit 20 to perform signal processing on the image data acquired from the image sensor 14 to generate an AF evaluation image. Then, an AF evaluation value related to the distance to the subject is acquired based on the image data of the AF evaluation image, and the focus control unit 342 is driven by determining the lens driving direction based on the AF evaluation value. By repeating the above operation, the imaging lens driving position where the AF evaluation value is maximized is detected and set as the in-focus point. At this time, in order to notify the digital camera user that the focus point has been reached, the color of the rectangle indicating the focus detection area is changed to green. Moreover, you may notify simultaneously by an electronic sound. In addition, when the focus point cannot be found, the color of the rectangle indicating the focus detection area is changed to red to notify the user.

  Further, when the camera AF setting is turned off and the manual focus mode is set in the non-enlarged display state, AF is not performed, so that the focus detection area displayed on the image display unit 28 changes to indicate the enlarged display position area. FIG. 4 is a diagram showing the image display unit 28 in a non-enlarged display state during manual focus. Area B indicates the position of the enlarged display area in the screen. In FIG. 2, the focus detection area is narrowed as in area A to suppress the occurrence of perspective conflict, but in FIG. 4, the area is changed to a rectangle indicating the enlarged display position area as in area B. Area B is a rectangle having the same ratio as the aspect ratio of the screen. When the area B is enlarged, it becomes as shown in FIG.

(2) Area setting for enlarged display Next, setting of a focus detection area for enlarged display will be described.

  When enlarging display, it is conceivable to use an enlarging function for focus confirmation or the like, and therefore detailed image display is required. Therefore, it is necessary to acquire image data without obtaining image data by greatly thinning out the output from the image sensor in the vertical and horizontal directions as in the case of non-enlarged display.

  However, when all the image data is acquired without thinning out the image data, it takes time to acquire the image data and the frame rate cannot be maintained. Therefore, the image data read time can be shortened by reading all pixels of the image data required for display from the image sensor and not reading the other portions. As a result, the frame rate can be maintained and the displayed image can be a detailed image.

  When the enlarged display is performed from the non-enlarged display state in FIG. 2, the area centered on the focus detection area is enlarged. If the range to be enlarged is an area represented by a rectangle in the manual focus shown in FIG. 4, the enlarged image is as shown in FIG.

  As described above, in the case of enlarged display, the output from the image sensor 14 is not thinned out, and information on all pixels can be used. Therefore, even if the size of the entire focus detection area with respect to the entire image (the entire screen in FIG. 2) is set narrower than in the case of non-enlarged display, a large number of pixels from which AF evaluation values can be acquired can be secured.

  In the case of the image pickup device of FIG. 3, since the vertical and horizontal thinning is performed by three pixels, the same area on the image is set as the focus detection area in the case of non-enlarged display and in the case of enlarged display. Thus, the number of pixels that can be used as the AF evaluation value can be secured three times in the vertical and horizontal directions. Therefore, as shown in FIG. 5, even if the focus detection area is reduced to 1/3 of the entire image compared to FIG. 2, the AF evaluation value is secured from the same number of pixels as in non-enlarged display. And the accuracy of the AF evaluation value can be maintained. In addition, since the focus detection area can be narrowed, it is difficult for near- and long-distance subjects to enter the area, making it difficult for perspective conflicts to occur, and stable focus results can be obtained when the focus detection area is not changed. Can be obtained.

  As described above, FIG. 5 is a diagram showing the image display unit 28 when the focus detection area is １ ／ in the vertical and horizontal directions and the area is narrowest. An area C displayed by a gray rectangle at the center indicates a focus detection area, and a narrower area becomes a focus detection area, and indicates an area for capturing a subject to be focused on the user. Although the focus detection area is narrower than the focus detection area in the case of non-enlarged display in FIG. 2, the number of pixels for acquiring the AF evaluation value is the same as the number of pixels. To do.

  Further, even if the focus detection area is not narrowed down to 1/3 in the vertical and horizontal directions, the area for all images can be set narrower than the focus detection area in the case of non-enlarged display, so it is difficult to cause perspective conflict. Further, the number of pixels used for acquiring the AF evaluation value can be increased as compared with the case of non-enlarged display. Therefore, the AF evaluation value becomes stronger against noise, and the S / N of the AF evaluation value can be improved. Therefore, FIG. 6 is a diagram showing the image display unit 28 when the focus detection area is narrowed to 1/2 in the vertical direction and 1/1 in the horizontal direction. An area D displayed as a central gray rectangle indicates a focus detection area. By narrowing the vertical direction, the focus detection area is narrowed to reduce perspective conflict, and the number of vertical pixels for integrating the AF evaluation value is secured more than in the case of non-enlarged display. The S / N is improved and the AF accuracy can be improved. In this way, stable AF operation is achieved by setting the focus detection area so that the number of image data in the vertical direction at a certain enlargement ratio is the same as or substantially the same as the number of image data at a larger enlargement ratio. realizable. Also, stable AF operation is achieved by setting the focus detection area so that the field of view of the subject image in the focus detection area is the same or substantially the same for a certain magnification ratio and for a larger magnification ratio. realizable.

  In addition, when the camera AF setting is turned off and the manual focus mode is set in the enlarged display state, since the AF is not performed, there is no need to display the focus detection area displayed on the image display unit 28, and the rectangle indicating the area is not displayed. To change. FIG. 7 is a diagram showing the image display unit 28 in an enlarged display state when the manual focus is set. The focus detection area shown in FIGS. 5 and 6 is no longer displayed, indicating that the camera is set so that AF cannot be performed.

  As described above, by changing the display method of the focus detection area between non-enlarged display and enlarged display, it is possible to notify the user of the in-focus position in an easy-to-understand manner.

  In the above embodiment, the case where the image is enlarged (enlarged display) and the case where the image is not enlarged (non-enlarged display, that is, the enlargement ratio is 1 time) are described as examples. However, the present invention is not limited to this. For example, the thinning rate of image data output from the image sensor when the magnification rate is 2 or 4 may be changed, and the shape, size, or position of the focus detection area may be changed.

  In the above embodiment, the case where the focus detection area and the information indicating the area corresponding to the focus detection area match is described. However, the position, the size, and the shape do not have to be exactly the same. It suffices to be able to notify the in-focus area.

1 is a block diagram illustrating a configuration of an imaging apparatus having an image processing function according to an embodiment of the present invention. It is the figure which showed the image display state which displayed the focus detection area in the non-expanded display state. It is a figure which shows an outline | summary about the drive method of an image pick-up element. FIG. 6 is a diagram illustrating an image display state when a manual focus focus state is set in a non-enlarged display state. It is the figure which showed the image display state at the time of narrowing a focus detection area to the minimum in an enlarged display state. It is the figure which showed the image display state at the time of setting a focus detection area so that many AF evaluation value acquisition pixel numbers may be acquired in an enlarged display state. FIG. 6 is a diagram illustrating an image display state when a manual focus focus state is set in an enlarged display state. It is a figure which shows the mode of the focusing determination by AF evaluation value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 Shutter 14 Image pick-up element 16 A / D converter 18 Timing generation circuit 20 Image processing circuit 22 Memory control circuit 24 Image display memory 26 D / A converter 28 Image display part 30 Memory 32 Image compression / decompression circuit 40 Shutter control part 42 Focus adjustment unit 50 System control circuit 52 Memory 54 Notification unit 56 Non-volatile memory 60 Mode dial switch 62 Shutter switch SW1
64 Shutter switch SW2
66 Image display ON / OFF switch 68 Quick review ON / OFF switch 70 Operation unit 90 Interface 92 Connector 100 Camera body 104 Optical viewfinder 200 Recording medium 202 Recording unit 204 Interface 206 Connector 300 Lens unit 306 Lens mount 310 Imaging lens 312 Aperture 320 Interface 322 Connector 340 Aperture control unit 342 Focus control unit 344 Zoom control unit 350 Lens system control circuit

Claims (4)

A plurality of pixels arranged in a second direction perpendicular to the first direction and the first direction, and an imaging device for outputting the converted image data photoelectrically object image by the person the arrayed pixels,
Electronic zoom means for electrically enlarging and outputting a part of image data obtained from the image sensor;
When the enlargement ratio of the image by the electronic zoom means is the first enlargement ratio, the image data for each of the plurality of pixels is thinned out and output, and the second enlargement ratio is larger than the first enlargement ratio Control means for controlling to output without thinning out the image data,
Among the image data output from said control means, the evaluation value for each of the second direction based on the image data obtained from the pixels of the imaging element in a region corresponding to the focus detection area, the sequence of the pixel Detecting means for detecting an AF evaluation value by performing an integral operation in the first direction of
Focus adjusting means for adjusting the focus by moving the imaging lens based on the detected AF evaluation value ;
Display means for displaying the image data output from the control means superimposed on information indicating a focus detection area ;
Wherein when the first magnification, focus detection areas as a predetermined large number image data than the number obtained in said first direction is set,
When manual focus adjustment is performed, the display means does not display information indicating the focus detection area, and in the case of the first enlargement ratio, the display means displays an enlarged display instead of the information indicating the focus detection area. imaging device according to claim you to view the information indicating the area to be enlarged so as to overlap with the image data when. The shape of the focus detection area is characterized in that the ratio of the first direction to the second direction is larger in the case of the first magnification ratio than in the case of the second magnification ratio. the image pickup apparatus according to. The imaging apparatus according to claim 1 or 2, wherein the first magnification is 1x. An imaging element in which a plurality of pixels are arranged in a second direction perpendicular to the first direction and the first direction, and outputs the object image photoelectrically converted by the person the arrayed pixels as image data, the imaging A method of controlling an imaging apparatus having electronic zoom means for electrically enlarging and outputting a part of image data obtained from an element ,
When the enlargement ratio of the image by the electronic zoom means is the first enlargement ratio, the image data for each of the plurality of pixels is thinned out and output, and the second enlargement ratio is larger than the first enlargement ratio A control process for controlling to output without thinning the image data;
Among the image data output in said control step, the evaluation value for each of the second direction based on the image data obtained from the pixels of the imaging element in a region corresponding to the focus detection area, the sequence of the pixel A detection step of detecting an AF evaluation value by performing an integral operation in the first direction of
A focus adjustment step of adjusting the focus by moving the imaging lens based on the detected AF evaluation value ;
Have a display step of displaying superimposed information indicating a focus detection area of image data output in said control step,
Wherein when the first magnification, set the focus detection area such that the predetermined large number image data than the number obtained in said first direction,
When manual focus adjustment is performed, information indicating the focus detection area is not displayed in the display step, and in the case of the first enlargement ratio, an enlarged display is used instead of the information indicating the focus detection area. the method according to claim you to view the information indicating the area to be enlarged so as to overlap with the image data when.

Images