JP5142807B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to an imaging apparatus and a control method thereof, and more particularly to an imaging apparatus that displays an image read from an imaging element on a display unit and a control method thereof.

  In general, in an imaging apparatus using a solid-state imaging device, it is necessary to increase the number of images of an individual imaging device in order to increase the definition of an image. However, when the number of images of the image sensor is increased, it takes time to read out images, and when all pixels are read out, the frame rate is lowered.

  For this reason, in Patent Document 1, all pixel readouts in which pixels are not thinned out from the focus adjustment pixel region and readouts in which pixels are thinned out from other pixel regions are performed within one readout. It is disclosed. Thus, by changing the reading method in one reading, high-resolution partial image information is obtained for focus adjustment, and the frame rate of the image is not lowered for captured image confirmation (live view). I am doing so.

  Japanese Patent Application Laid-Open No. 2004-228620 proposes a technique that makes it easy for a photographer to check the focused state of an image by enlarging and displaying an image in a focus adjustment frame before or after shooting.

JP 2000-032318 A JP-A-11-196301

  However, the method disclosed in Patent Document 1 requires a circuit for selecting image data for confirming a captured image and a circuit for selecting image data for focus adjustment, so that the selection circuit is complicated and large. turn into. Furthermore, since the image data for confirming the captured image and the image data for focus adjustment are stored in separate memory spaces, the data to be written to the memory increases when it is necessary to read out as fast as possible so that it can be recognized as a moving image. End up. For this reason, even if reading from the sensor can be performed, if writing to the memory is not completed in time, the frame rate needs to be lowered, and the quality of the moving image is deteriorated.

  Further, according to the method described in Patent Document 2, an image before photographing is an image that has been thinned and read to increase the frame rate so that it can be recognized as a moving image. Enough. However, even if the image in the focus adjustment frame is enlarged to confirm the in-focus state, the resolution of the enlarged image is not different from the resolution of the image when the entire image is displayed. turn into.

  FIG. 6 shows an example in which an image in the focus adjustment frame is enlarged and displayed as described in Patent Document 2. When the image in the dotted line frame is enlarged and displayed for the image as shown in FIG. 6A, the enlarged portion of the pixel becomes a coarse image as shown in FIG. 6B.

  The present invention has been made in view of the above problems, and an object of the present invention is to enable an imaging apparatus to display a high-definition image obtained by enlarging an image in a desired region while maintaining a frame rate.

In order to achieve the above object, an imaging device of the present invention includes an imaging device including a plurality of pixels arranged in a two-dimensional manner, and an image of a first pixel region that does not include an enlarged pixel region from the imaging device. reading a signal at a first between discount rate, the enlarged display image signal of the second pixel region including a pixel region, a reading means for reading at discount rate between lower second than the first between discount rate, the larger First means for displaying an entire image for one frame on a display unit from setting means for setting an enlargement ratio of a pixel area to be displayed and an image signal read from the pixels of the image sensor excluding the pixel area to be enlarged and displayed. An image having a second resolution higher than the first resolution for displaying in an area of the display unit from an image signal read out from a pixel in the pixel area to be enlarged and displayed is generated at an image resolution. Produces Serial superimposed image of the second resolution to the first resolution of the image, and generating means for generating an image to be displayed on the display unit, based on the set magnification by the setting unit, wherein The size of either the pixel area to be enlarged or the partial area, and the second thinning rate are determined, and the first frame is read so that an image for one frame is read within a predetermined time. Determining means for determining the first thinning-out rate for reading out the image signal of the pixel area .

Further, according to the control method of the present invention for an imaging apparatus having an imaging device including a plurality of pixels arranged in a two-dimensional manner, the setting means sets an enlargement ratio of a pixel region to be enlarged and displayed among the plurality of pixels of the imaging device. a setting step of setting, from the image sensor reads the image signal of the first pixel region not including a pixel region for the enlarged display in the first between discount rate, a second pixel region including the pixel region of the larger image 1 frame on the display unit from the readout step of reading out the image signal at the second thinning rate lower than the first thinning rate and the image signal read from the pixels of the image sensor excluding the pixel region to be enlarged and displayed. An image is generated at a first resolution for displaying the entire image, and an image having a second resolution higher than the first resolution is generated from an image signal read from the pixels in the pixel area to be enlarged and displayed. And before By superimposing an image of the second resolution to the first resolution of the image, said prior to the reading step and the generating step and generation step of generating an image to be displayed on the display unit, set by the setting step Based on the enlarged magnification, the size of either the pixel area to be enlarged or the partial area and the second thinning rate are determined, and one frame is determined within a predetermined time. A determination step of determining the first thinning rate for reading the image signal of the first pixel region so as to read an image .

  In the imaging apparatus, it is possible to display a high-definition image obtained by enlarging an image in a desired region while maintaining the frame rate.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a digital camera (imaging device) 100 according to an embodiment of the present invention.

  In FIG. 1, reference numeral 101 denotes an imaging lens including a diaphragm mechanism that forms an optical image of a subject on the imaging element 107. A lens driving unit 102 controls the imaging lens 101 such as a focus lens and a diaphragm based on control by the overall control / calculation unit 115.

  Reference numeral 103 denotes a mirror for guiding incident light that has passed through the imaging lens 101 to a finder unit (not shown), and is generally referred to as a quick return (QR) mirror. The QR mirror 103 guides incident light to an optical finder (not shown) except during photographing, but operates to jump up and guide incident light to the image sensor 107 during photographing. Further, when displaying an image before photographing on the display unit 117 as in live view display, the display unit 117 jumps up and operates to guide incident light to the image sensor 107. A mirror driving unit 104 drives the mirror 103 described above based on control by the overall control / calculation unit 115.

  Reference numeral 105 denotes a shutter having a shutter curtain corresponding to a focal plane type front curtain / rear curtain used in a so-called single-lens reflex camera, and performs blocking of incident light that has passed through the imaging lens 101 and controlling exposure time. . A shutter driving unit 106 drives the shutter described above based on control by the overall control / calculation unit 115.

  The focus adjustment control and the exposure amount control are performed by the lens driving unit 102 and the shutter driving unit 106 based on output signals of the focus measurement unit 114 that checks the focus state of the subject and the photometry unit 113 that measures the luminance of the subject. It is controlled by the control / arithmetic unit 115. However, it is arranged so as to guide the optical image to the focus measurement unit 114 and the photometry unit 113 only when the QR mirror 103 is at a position for guiding the incident light to the optical viewfinder. Therefore, the focus measurement unit 114 and the photometry unit 113 are not used when the QR mirror 103 is at the position where it jumps up. In that case, instead of the focus measurement unit 114 and the photometry unit 113, measurement of the focus state and photometry are performed based on the image signal of the image sensor 107.

  Reference numeral 107 denotes an image pickup element in which a plurality of pixels are two-dimensionally arrayed to convert and capture an optical image of a subject imaged by the image pickup lens 101 into an electrical image signal. The image sensor 107 of the present embodiment is formed by, for example, a CMOS sensor. Reference numeral 108 denotes an image signal processing unit that performs various processes on the image signal output from the image sensor 107. The imaging signal processing unit 108 performs various processing such as amplification processing of an image signal output from the imaging device 107, A / D conversion processing for converting from analog to digital, and defect correction for digital data after A / D conversion. Perform correction processing. Further, the imaging signal processing unit 108 performs development processing for converting digital data into image data, compression processing for compressing image data, or the like.

  Reference numeral 109 denotes a timing generation unit that outputs various timing signals to the imaging element 107 and the imaging signal processing unit 108. By timing control by the timing generation unit 109, when reading out an image signal for one frame from the image sensor 107, it is possible to perform thinning readout, readout of all pixels without thinning out, or readout combining these partially. Since this embodiment is characterized by this partially combined reading method, this reading will be described in detail later.

  Reference numeral 115 denotes an overall control / arithmetic unit that comprehensively controls various arithmetic processes and the entire camera 100. 116 is a memory for temporarily storing image data and the like, and a memory for permanently storing various adjustment values and programs for executing various controls by the overall control / arithmetic unit 115. A memory unit having both functions.

  Reference numeral 110 denotes a recording medium control interface (I / F) unit for performing recording processing of image data or the like on the recording medium 111 or reading processing of image data or the like from the recording medium 111. Reference numeral 111 denotes a detachable recording medium including a semiconductor memory or the like for recording various data such as image data.

  Reference numeral 112 denotes an external interface (I / F) unit for communicating with an external device 500 such as a computer. Reference numeral 117 denotes a display unit that displays captured still images, moving images, and the like. Reference numeral 118 denotes a switch (SW) detection unit that detects operations such as shooting start and mode change performed by the photographer on the camera 100.

  FIG. 2 is a view of the camera 100 having the above configuration as viewed from the back. A display unit 117 is disposed on the rear surface, and an image before photographing can be displayed on the display unit 117. In addition to the display unit 117, a direction switch (SW) 202 (changing unit) for the photographer to indicate a direction to the camera is disposed on the back surface, and is connected to the SW detection unit 118. Further, an enlargement switch (SW) 200 and a reduction switch (SW) 201 for the photographer to instruct an enlargement ratio are disposed on the back surface of the camera 100 (setting means), and are connected to the SW detection unit 118.

  Next, with reference to FIG. 3, a reading method of the image sensor 107 in the present embodiment will be described. FIG. 3A shows an area d to be enlarged, an area to be thinned out (area with thinning, first pixel area), and an area without thinning out (area without thinning, second pixel area) in the image sensor 107. FIG. The position and size of the enlarged region d can be changed by the direction SW202 and the enlargement / reduction SWs 200, 201.

  As shown in FIG. 3A, when a part of the screen (enlarged area d) is enlarged and displayed, first, the thinned area a is read out from the image sensor 107, and then the decimation including the enlarged area d is not performed. The area b is read without thinning out. Finally, the thinned area c is thinned and read. FIG. 3B shows the concept of the size of the read image data. This reading is performed continuously so that one screen is obtained in three areas.

  The image signal read out in this way is A / D converted into digital data and stored in this state in the memory unit 116. As shown in FIG. 3B, the thinned-out areas a and c are read at an image size suitable for display, that is, with a thinning rate at which the number of pixels in the vertical direction substantially matches the number of pixels in the display unit. On the other hand, an image read from the non-thinning region b without thinning (that is, with a thinning rate of 0%) becomes a large image composed of more image data than image data necessary for display. The digital data stored in the memory unit 116 is developed to generate image data for display. However, the thinned-out areas a and c on the memory unit 116 are not subjected to magnification conversion as they are (the first one). A display image is generated by performing development (at a resolution).

  Next, the display image of the region b ′ where the enlarged display is not performed in the non-decimated region b is a display image having the same magnification (first resolution) as the upper and lower thinned regions a and c by development and reduction. Convert to Then, in the non-thinning-out area b, the enlarged area d for enlarged display is developed with almost the same size, or development and enlargement are performed, or reduction and development are performed at a rate smaller than that of the area b. (Second resolution). The image of the enlarged area d developed in this way is displayed superimposed on the images of the displayed areas a, b ', and c. At this time, the display image of the enlarged region d is displayed as a display region e larger than the display images of the regions a, b ′, and c.

  Next, the movement of the enlarged region d will be described with reference to FIG.

  For example, when displaying an image before imaging such as live view display, the user can move the enlarged region d by the direction SW 202 to enlarge and display an image of a desired region.

  FIG. 4A shows the relationship between the enlarged area d and the display area e when the center of the screen is enlarged. At this time, the enlarged area d without thinning is displayed in the size of the display area e, so that only the display area is enlarged. Except for this display area e, the entire screen is displayed.

  From this state, as shown in FIG. 4B, when the photographer presses the left button of the direction SW202, the enlarged area d moves to the left. At the same time, the display area e moves to the left in accordance with the left movement. By moving the display area e in this way, it is possible to show the photographer what is enlarged on the screen. However, as shown in FIG. 4C, when the display area e reaches the left end, the display area e moves to the left and does not go out of the screen, stops at the left end of the screen, and expands. Move only d.

  From the state shown in FIG. 4C, as shown in FIG. 4D, when the photographer presses the direction SW 202 downward, the enlarged area d moves downward. For the movement of the enlarged region d, the thinned-out region a above the enlarged region d is increased, and the thinned-out region c below the enlarged region d is decreased. And control to move.

  As shown in FIG. 4 (e), when the display area e reaches the lower end, the display area e moves below it and does not go out of the screen, stops at the lower end of the screen, and only the enlarged area d. Try to move. As a result, the entire enlarged area d can always be displayed.

  Next, a reading method of the image sensor 107 in this embodiment is described with reference to FIG. In FIG. 5, the horizontal direction indicates time, and the vertical direction indicates the vertical direction of the image sensor 107 (from the top to the bottom of the screen). The example shown in FIG. 5 shows a reading method in the case where the image of the enlarged region d is displayed 10 times, 5 times, or 3 times when the size of the display region e described in FIG. 4 is constant. . The enlargement ratio can be changed by operating the enlargement / reduction SWs 200 and 201. In the example shown in FIG. 5, when the display is performed at a magnification of 3 times, the size of the image of the enlarged area d read without thinning is developed with the size as it is, and the size of the display area e on the screen is almost the same. It shall match. The size of the display area e on the screen is not changed regardless of the enlargement ratio of the image of the enlarged area d.

  FIG. 5A shows the readout timing when the image of the entire screen is normally displayed on the display unit 117, and the whole is readout with thinning. By reading the image signal once from the top row to the bottom row of the image sensor 107, one image can be read. Prior to this reading, the charge period of the pixels is sequentially reset before a predetermined accumulation time period, whereby the accumulation period can be made constant at the top and bottom of the screen.

  FIG. 5D shows a case where the image of the enlarged area d is displayed at a magnification of 3 times. Reading with thinning is performed at the top and bottom of the screen, and the number of rows corresponding to the non-decimation area b necessary for triple display. Is read without thinning out. Here, since readout with thinning is performed at the upper and lower portions of the screen, readout is performed quickly with respect to the vertical rows of the image sensor 107. Since this row is read out, reading is slow. For this reason, the inclination of the reset line and the readout line in the readout without thinning out becomes gentle. In the case of 3 times display, the read image data is displayed with almost the same size.

  FIG. 5B shows a case where the image of the enlarged region d is displayed at 10 times, and FIG. 5C shows a case where the image is displayed at 5 times. Each row of charges corresponding to the necessary enlargement area d is read without thinning out, and the read image data is enlarged according to the enlargement ratio, so that the display area e can be enlarged and displayed.

FIG. 5 shows an example of a full screen (FIG. 5A), 10 times (FIG. 5B), 5 times (FIG. 5C), and 3 times (FIG. 5C). , its Rezorede, by changing the thinning rate at the time of reading of thinning there, one screen reading time of the control is performed so as to be constant. Thus, it is possible to prevent a problem that the frame rate changes every time the enlargement ratio is changed.

  As described above, according to the present embodiment, it is possible to display a high-definition image obtained by enlarging an image in a desired region while maintaining the frame rate in the imaging apparatus.

  In the present embodiment, the description has been given with respect to the two areas, ie, the area with thinning and the area without thinning. However, when the enlargement ratio is not high (for example, double display in the case described in FIG. 5) or when the number of pixels of the display unit 117 is significantly smaller than the total number of pixels of the image sensor, thinning is performed. It does not have to be. Accordingly, as read-out, there are two areas: a region with a high thinning rate (first pixel region read with a first thinning rate) and a region with a low thinning rate (second pixel region read with a second thinning rate). Also good.

  Further, in the example of the enlargement process described with reference to FIG. 5, the size of the display area e is assumed to be constant. However, the present invention is not limited to this, and the size of the enlarged area d may be fixed, and the ratio of the display area e to the screen may be increased as the enlargement rate increases.

It is a block diagram which shows schematic structure of the digital camera in embodiment of this invention. It is a rear view of the digital camera in the embodiment of the present invention. It is a figure for demonstrating the reading method of the image pick-up element in embodiment of this invention. It is a figure which shows the movement of the expansion area | region in embodiment of this invention. It is a figure for demonstrating the reading method of the image pick-up element in embodiment of this invention. It is a figure which shows an example of the image at the time of carrying out enlarged display of a part of conventional display image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Imaging lens 102 Lens drive part 103 Quick return mirror 104 Mirror drive part 105 Shutter 106 Shutter drive part 107 Image pick-up element 108 Imaging signal processing part 109 Timing generation part 110 Recording medium control interface (I / F) part 111 Recording medium 112 External interface (I / F) unit 113 photometry unit 114 focusing measurement unit 115 overall control / calculation unit 116 memory unit 117 display unit 118 switch (SW) detection unit 200 enlargement switch (SW)
201 Reduction switch (SW)
500 External device

Claims (7)

An imaging device including a plurality of pixels arranged two-dimensionally;
An image signal of a first pixel area that does not include a pixel area to be enlarged and displayed is read from the image sensor at a first thinning rate, and an image signal of a second pixel area that includes the pixel area to be enlarged and displayed is Reading means for reading at a second thinning rate lower than the thinning rate of 1,
Setting means for setting an enlargement ratio of the pixel area to be enlarged and displayed;
A pixel area that generates an image at a first resolution for displaying an entire image of one frame on a display unit from an image signal read from the pixels of the image sensor excluding the pixel area to be enlarged and displayed, Generating an image having a second resolution higher than the first resolution to be displayed in a partial area of the display unit from the image signal read from the pixel, and adding the first resolution image to the first resolution image. Generating means for superimposing an image having a resolution of 2 and generating an image for display on the display unit ;
Based on the enlargement rate set by the setting means, the size of either the pixel region to be enlarged or the partial region and the second thinning rate are determined, and within a predetermined time And an deciding means for deciding the first decimation rate for reading out the image signal of the first pixel area so as to read out an image for one frame .   The imaging apparatus according to claim 1, further comprising changing means for changing a position of the pixel area to be enlarged and displayed.   3. The partial area has a predetermined size, and the determination unit determines the pixel area to be enlarged and displayed according to the set enlargement ratio. The imaging device described in 1.   The pixel area to be enlarged and displayed has a predetermined size, and the determining means determines the size of the partial area according to the set enlargement ratio. The imaging apparatus according to 1 or 2.   5. The imaging apparatus according to claim 1, wherein the second thinning-out rate is 0%. When the enlargement factor is changed by the setting unit, the reading unit further sets the second thinning rate so that the time taken to read the image sensor before and after changing the enlargement factor is constant. the imaging apparatus according to claim 3, characterized in that to change as. A method for controlling an image pickup apparatus having an image pickup element including a plurality of pixels arranged two-dimensionally,
A setting step in which a setting unit sets an enlargement ratio of a pixel region to be enlarged and displayed among the plurality of pixels of the image sensor;
From the image sensor reads the image signal of the first pixel region not including a pixel region for the enlarged display in the first between discount rate, an image signal of the second pixel region including the pixel region to the enlarged display, the A reading step of reading at a second decimation rate lower than the first decimation rate;
A pixel area that generates an image at a first resolution for displaying an entire image of one frame on a display unit from an image signal read from the pixels of the image sensor excluding the pixel area to be enlarged and displayed, Generating an image having a second resolution higher than the first resolution from an image signal read from the pixel, superimposing the image having the second resolution on the image having the first resolution, and the display unit A generating step for generating an image to be displayed on
Prior to the readout step and the generation step, based on the enlargement rate set in the setting step, the size of either the pixel region to be enlarged or the partial region, and the second thinning rate And determining the first thinning rate for reading the image signal of the first pixel region so as to read the image for one frame within a predetermined time. A control method characterized by the above.

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