JP2006128978A - Imaging apparatus and image processing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve visibility of a display image during focusing determination. <P>SOLUTION: An AF control unit 28 controls a driving circuit 46 to move an AF lens 47, calculates a focusing evaluation value on the basis of image data to be obtained from an A/D converter 58 while moving the AF lens 47 to perform focusing determination, and outputs a result of determination to a selection processing unit 32. Then, the selection processing unit 32 selects a signal to be outputted to a display 26 on the basis of a focusing signal (focusing determination result) to be output from the AF control unit 28. In particular, if the focusing determination result to be obtained from the AF control unit 28 shows non-focusing, display based on image data is performed on the display 26 by outputting the image data to be obtained from a signal processing unit 60 to the display 26 without any change, and if the focusing determination result to be obtained from the AF control unit 28 shows focusing, display based on image data is performed on the display 26 by outputting the image data subjected to contour enhancement processing by a contour enhancement processing unit 30 to the display 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging device and an image processing method of the imaging device, and more particularly to an imaging device having an autofocus function for automatically performing focus adjustment of an imaging device such as a digital camera and an image processing method of the imaging device.

  In recent years, a digital camera is generally used as an imaging device for photographing a subject. Conventional digital cameras (digital still cameras and digital video cameras) use digital image data acquired by an image sensor such as a CCD to a recording medium such as an internal memory, IC card, or magnetic tape provided in the digital camera. And based on the recorded digital image data, an image can be recorded on a recording sheet by a printer, or an image acquired by imaging can be displayed on a monitor. Further, as such a digital camera, there are generally many devices equipped with a liquid crystal monitor. Thus, in a digital camera equipped with a liquid crystal monitor, a captured image can be immediately displayed on the liquid crystal monitor, and the liquid crystal monitor can be used as a viewfinder.

  In addition, an imaging apparatus such as a digital camera as described above includes a lens for forming a subject image on an image sensor when photographing a subject. By adjusting the focal point of the lens, The focal length is adjusted. An imaging apparatus having an autofocus function for automatically adjusting the focal length with the subject has been proposed.

  By the way, if auto-focusing or manual focus adjustment is performed using a liquid crystal monitor as a viewfinder, it may be difficult to visually determine whether or not the subject is in focus. In addition, there are some devices that notify the in-focus by sound or display, but there are cases in which shooting is performed without noticing that the in-focus is not achieved.

  Therefore, various proposals have been made in order to improve the visibility when determining the focus of the image displayed on the liquid crystal monitor.

For example, in the technique described in Patent Document 1, when a captured image is displayed on an electronic viewfinder of a video camera, an edge enhancement process is performed to improve visibility of whether or not the subject is in focus. In addition, Patent Documents 2 to 5 include other techniques for improving the visibility of focus determination by performing contour emphasis processing and displaying on a display device such as a liquid crystal monitor.
JP 7-46453 A Japanese Patent Laid-Open No. 5-328172 JP-A-6-22323 JP-A-6-38096 JP-A-6-253200

  However, as in the technique described in Patent Document 1, when the contour enhancement processing is always performed and displayed on a display device such as a liquid crystal monitor, the visibility can be improved as compared with the case where the contour enhancement processing is not performed. Although it can be done, there is a problem that it is difficult to determine whether or not the focus has been achieved because the contour is always emphasized before and after the focus.

  The present invention has been made to solve the above problems, and an object thereof is to improve the visibility of a display image at the time of in-focus determination.

  In order to achieve the above object, an imaging apparatus according to claim 1, an imaging device that captures a subject image and outputs image data representing the subject image, and a display based on the image data output from the imaging device. A display device, a lens that forms a subject image on the image sensor, an adjustment unit that adjusts the focus of the lens, and a determination unit that determines a focus on the subject image when the focus of the lens of the adjustment unit is adjusted. Image processing for performing at least one of image enhancement processing for enhancing the contour of the image represented by the image data and blur processing for blurring the image represented by the image data on the image data output from the image sensor And a selection unit that selects a process to be performed by the image processing unit based on a determination result of the determination unit, and performs image processing according to the selection result of the selection unit It is characterized by performing display on the display device based on the image data subjected.

  According to the first aspect of the present invention, display based on the image data output from the image sensor is performed by the display device. Further, the focus adjustment of the lens is performed by the adjusting means. That is, the display device functions as a finder, and an image based on the image data output from the imaging unit when the focus of the lens is adjusted by the adjustment unit is displayed on the display device.

  In such an imaging apparatus, the lens focus adjustment by the adjusting means is completed, and it is determined by looking at the image displayed on the display device whether or not it is in focus. It is difficult to visually determine whether or not you are in focus.

  Therefore, the determination unit determines the focus on the subject image at the time of adjusting the focus of the lens of the adjustment unit. For example, as in the invention described in claim 6, the determination unit can determine the in-focus based on the image data output from the image sensor. In this case, it is determined that the in-focus state is obtained when the image data includes many high-frequency components, or the in-focus state is adjusted when the focus of the lens is adjusted where the contrast is maximized. Can be determined. In addition, the determination of the in-focus state by the determination unit is performed by measuring the distance to the subject image using a distance measuring sensor or the like, and determining whether or not the focus adjustment is completed at the lens position corresponding to the measured distance. However, other methods may be applied.

  Further, the image processing means performs at least one of image processing of image emphasis processing for emphasizing the contour of the image represented by the image data and blur processing for blurring the image on the image data output from the image sensor. In the means, processing to be performed by the image processing means is selected based on the determination result of the determination means. Note that selection of processing performed by the image processing unit in selection of the selection unit includes selection of whether or not to perform image processing.

  Then, an image is displayed on the display device based on the image data subjected to the image processing by the image processing means according to the selection result of the selection means.

  As described above, the image processing is selected based on the determination result of whether or not the determination unit has focused, and the image subjected to the selected image processing is displayed on the display device. It is possible to increase the difference between the displayed images at the time of focusing, and to improve the visibility of the displayed image at the time of focusing determination.

  For example, as in the second aspect of the invention, when the image processing unit performs the contour enhancement process, the selection unit performs the contour enhancement by the image processing unit only when the determination result of the determination unit is in focus. By selecting the processing, the image as it is obtained from the image sensor is displayed at the time of out-of-focus, and the contour-enhanced image is displayed on the display device at the time of focus. It is possible to make the determination easier, and the visibility of the display image at the time of focusing determination can be improved.

  When the image processing unit performs blurring processing as in the third aspect of the invention, the selection unit selects the blurring processing by the image processing unit only when the determination result of the determination unit is out of focus. Thus, a blurred image is displayed on the display device at the time of out-of-focus, and an image that has not been subjected to image processing is displayed from the image sensor at the time of focusing. In other words, the difference between the image displayed on the display device at the time of focusing and the image displayed on the display device at the time of out-of-focus can be emphasized, and as a result, it is easy to visually determine that the focus is achieved. It is possible to improve the visibility of the display image at the time of focusing determination.

  Further, when the image processing means performs the contour emphasis processing and the blurring processing as in the invention according to the fourth aspect, the selection means uses the image processing means when the determination result of the determination means is in focus. When contour enhancement processing is selected and the determination result of the determination means is out of focus, blurring processing by the image processing means is selected, and a blurred image is displayed on the display device when out of focus. Since the emphasized image is displayed on the display device, it can be easily determined visually that the in-focus state has been achieved, and the visibility of the display image at the time of in-focus determination can be improved.

  As the blurring process performed by the image processing means, the high-frequency component of the image data is cut by performing low-pass filter processing on the image data as in the invention described in claim 5, thereby blurring the image. It becomes possible.

  The image processing method of the imaging device according to claim 7, wherein an imaging device that captures a subject image and outputs image data representing the subject image, and a display device that performs display based on the image data output from the imaging device And an image processing method of an imaging apparatus comprising: a lens that forms a subject image on the image sensor; and an adjustment unit that performs focus adjustment of the lens, wherein the subject is adjusted when the lens is focused by the adjustment unit A determination step for determining focus on an image, contour enhancement processing for enhancing the contour of an image represented by the image data, and blur processing for blurring the image represented by the image data, on the image data output from the image sensor An image processing step for performing at least one of the image processing, and a selection step for selecting processing to be performed in the image processing step based on a determination result of the determination step It is characterized in that it comprises a display step of performing display on the display device based on the image data subjected to image processing in accordance with the selection result of said selection step.

  According to the seventh aspect of the present invention, display based on the image data output from the image sensor is performed by the display device. Further, the focus adjustment of the lens is performed by the adjusting means. That is, the display device functions as a finder, and an image based on the image data output from the imaging unit when the focus of the lens is adjusted by the adjustment unit is displayed on the display device.

  In such an imaging apparatus, as described above, the focus adjustment of the lens by the adjusting unit is finished, and it is determined by looking at the image displayed on the display device whether or not it is in focus. It is difficult to visually determine whether or not the image is in focus.

  Therefore, in the determination step, the focus on the subject image is determined during the focus adjustment of the lens of the adjusting means. For example, as in the invention described in claim 12, the determining means can determine the in-focus based on the image data output from the image sensor. In this case, it is determined that the in-focus state is obtained when the image data includes many high-frequency components, or the in-focus state is adjusted when the focus of the lens is adjusted where the contrast is maximized. Can be determined. In addition, the determination of in-focus in the determination step is performed by measuring the distance to the subject image using a distance measuring sensor or the like, and determining whether or not the focus adjustment is completed at the lens position corresponding to the measured distance. However, other methods may be applied.

  In the image processing step, image data output from the image sensor is subjected to at least one of image processing of contour enhancement processing for enhancing the contour of the image represented by the image data and blur processing for blurring the image. Then, based on the determination result of the determination step, the process to be performed in the image processing step is selected. Note that the selection of processing performed by the image processing means in the selection step includes selection of whether or not to perform image processing.

  Then, an image is displayed on the display device based on the image data subjected to the image processing in the image processing step according to the selection result of the selection step.

  In this way, based on the determination result of whether or not the determination step is in focus, image processing is selected, and the image subjected to the selected image processing is displayed on the display device. It is possible to increase the difference between the displayed images at the time of focusing, and to improve the visibility of the displayed image at the time of focusing determination.

  For example, in the case of performing the contour emphasis processing in the image processing step as in the invention described in claim 8, the selection step performs contour emphasis by the image processing step only when the determination result of the determination step is in focus. By selecting the processing, the image as it is obtained from the image sensor is displayed at the time of out-of-focus, and the contour-enhanced image is displayed on the display device at the time of focus. It is possible to make the determination easier, and the visibility of the display image at the time of focusing determination can be improved.

  Further, as in the ninth aspect of the invention, when performing the blurring process in the image processing step, the blurring process in the image processing step is performed only in the selection step when the determination result in the determination step is out of focus. By selecting, when the image is out of focus, a blurred image is displayed on the display device, and when the image is in focus, an image not subjected to image processing is displayed from the image sensor. In other words, the difference between the image displayed on the display device at the time of focusing and the image displayed on the display device at the time of out-of-focus can be emphasized, and as a result, it is easy to visually determine that the focus is achieved. It is possible to improve the visibility of the display image at the time of focusing determination.

  Further, as in the invention described in claim 10, when performing the contour emphasis process and the blurring process in the image processing step, the selection step depends on the image processing step when the determination result of the determination step is in focus. By selecting the contour enhancement processing and selecting the blurring processing by the image processing step when the determination result of the determination step is out of focus, a blurred image is displayed on the display device at the time of out of focus, and at the time of focusing, the contour is displayed. Since the emphasized image is displayed on the display device, it can be easily determined visually that the in-focus state has been achieved, and the visibility of the display image at the time of in-focus determination can be improved.

  As the blurring process performed in the image processing step, the high frequency component of the image data is cut by performing the low pass filter process on the image data as in the invention described in claim 11, thereby blurring the image. It becomes possible.

  As described above, according to the present invention, image processing for image data obtained from the image sensor is selected based on the result of focusing determination, and an image is displayed based on the selected image data. Thus, there is an effect that the visibility of the display image at the time of in-focus determination can be improved.

Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is a perspective view showing an appearance of a digital camera according to the first embodiment of the present invention.

  As shown in FIGS. 1A and 1B, the main body 12 of the digital camera 10 is substantially box-shaped, and a lens barrel 16 to which a lens 14 is attached is provided at the center of the front side of the main body 12.

  Above the lens 14 of the main body 12, a strobe 18 for emitting auxiliary light in the case of shooting at low illuminance or the like is provided.

  On the upper surface of the main body 12, a power switch 20 is provided on the right side when viewed from the front, and a release switch 22 is provided on the left side. A memory card (not shown) is loaded on the right side when viewed from the front of the main body 12. A possible slot 24 is provided.

  The release switch 22 can be operated in two positions, half-pressed and fully-pressed. When the release switch 22 is half-pressed, autofocus (hereinafter referred to as AF) is performed. Is supposed to do.

  A display 26 such as a liquid crystal is provided at the center of the back side of the main body, and displays a photographed image and functions as a finder.

  FIG. 2 is a block diagram showing the configuration of the electrical system of the digital camera 10 according to the first embodiment of the present invention.

  Specifically, the lens 14 is a zoom lens (focal length variable lens), and the zoom mechanism is driven by a drive circuit 46. An autofocus (AF) lens 47 is also provided, and the AF lens 47 is similarly driven by the drive circuit 46. Instead of the zoom lens, a variable focal length lens having only the AF lens 47 may be used.

  An image sensor 50 composed of a CCD sensor or the like is disposed at a position corresponding to the focal position of the lens 14 inside the main body 12, and light incident on the lens 14 reflecting the subject is reflected by the image sensor 50. An image is formed on the light receiving surface. The imaging device 50 outputs an analog signal representing the amount of received light in each of a large number of photoelectric conversion cells arranged in a matrix on the light receiving surface as an image signal. The image sensor 50 is driven at a timing synchronized with a timing signal generated by a timing signal generator connected to the drive circuit 46 and outputs an image signal.

  A diaphragm 48 is disposed between the lens 14 and the image sensor 50. The aperture may be configured as a single aperture that can be changed continuously, or may be configured to switch a plurality of apertures with different aperture amounts.

  The timing signal generator 52 is further connected to a strobe control circuit 54 that controls the light emission of the strobe 18. When the strobe 18 is detected to have low illuminance or when the user instructs to emit light. Light emission is controlled at a timing synchronized with the timing signal generated by the timing signal generator 52.

  A sampling unit 56, an A / D converter 58, a signal processing unit 60, a memory 62, and a compression / decompression unit 64 are connected in order to the signal output terminal of the image sensor 50, and each is connected to a system bus 68. The system control unit 70 connected to the system bus 68 controls the entire system.

  The sampling unit 56 samples the image signal output from the image sensor 50 at a timing synchronized with the timing signal generated by the timing signal generation unit 52, amplifies it, and outputs it to the A / D converter 58. The sampling unit 56 includes a CDS (Correlated Double Sampling: hereinafter referred to as CDS) unit (not shown). The CDS unit uses, for example, a CCD type imaging device, and basically holds a clamp circuit that clamps various noises generated by the device with a timing signal from the timing signal generation unit, and an analog voltage signal with the timing signal. It has a sample hold circuit. The CDS unit removes the noise component and sends the image signal to the A / D converter 58 as an analog output signal. The image signal output from the sampling unit 56 is converted into digital image data by the A / D converter 58 and input to the signal processing unit 60. The signal processing unit 60 performs various processes such as gain adjustment, color correction, γ correction, and Y / C conversion on the input image data. The image data output from the signal processing unit 60 is temporarily recorded in a memory 62 composed of a RAM or the like. When the release switch 22 is operated, it is compressed by the compression / expansion unit 64 and then stored in the built-in memory 84 or the memory card 80 loaded in the slot 24.

  A display 26 is also connected to the system bus 68 so that an image can be displayed based on image data obtained by photographing.

  Furthermore, a release switch 22 and an operation switch (not shown) are connected to the system bus 68, and control according to the operation of the switch is performed.

  That is, when an instruction to store image data in the internal memory 84 or the memory card 80 loaded in the slot 24 is given, for example, by operating an operation switch, the system control unit 70 is temporarily recorded in the memory 62 by photographing. The read image data is read out and transferred to the compression / decompression unit 64. As a result, the image data is compressed by the compression / decompression unit 64 and then stored in the built-in memory 84 or the memory card 80. The image data may be stored in the built-in memory 84 or the memory card 80 without being compressed depending on the shooting mode.

  When an instruction to reproduce (display) an image represented by image data stored in the internal memory 84 or the memory card 80 loaded in the slot 24 is given, the memory card loaded in the internal memory 84 or the slot 24. Image data is read from 80, and the read image data is decompressed (decompressed) by the compression / decompression unit 64 and then temporarily recorded in the memory 62. Then, using the image data temporarily recorded in the memory 62, the image is displayed (reproduced) on the display 26.

  Incidentally, as described above, the digital camera 10 according to the present embodiment has an AF function, but the AF function of the present embodiment performs AF control based on image data obtained from the image sensor 50. Yes. Here, the part which extracted the structure which performs AF control among the structures of the electric system of the digital camera 10 mentioned above is demonstrated.

  FIG. 3 is a block diagram showing a configuration of a control system for performing AF control in the digital camera 10 according to the first embodiment of the present invention.

  As described above, the image data sampled from the image sensor 50 by the sampling unit 56 is input to the system control unit 70 via the A / D converter 58 and the signal processing unit 60.

  The system control unit 70 includes an edge emphasis processing unit 30, a selection processing unit 32, and an AF control unit 28. Image data output from the signal processing unit 60 includes an edge emphasis processing unit 30 and a selection process. Input to the unit 32.

  In addition to outputting the A / D converted image data to the signal processing unit 60, the A / D converter 58 also outputs the A / D converted image data to the AF control unit 28.

  The AF control unit 28 controls the drive circuit 46 to move the AF lens 47 and calculates a focus evaluation value based on image data obtained from the A / D converter 58 while moving the AF lens 47. To determine focus. In-focus determination can be determined as in-focus, for example, where there are many high-frequency components in the image data. In addition, a so-called contrast method or the like in which focusing is determined at a position where the contrast is maximum can be applied.

  The contour enhancement processing unit 30 performs contour enhancement processing on the image data obtained from the signal processing unit 60 and outputs the image data to the selection processing unit 32.

  The selection processing unit 32 selects a signal to be output to the display 26 based on the focus signal (focus determination result) output from the AF control unit 28. Specifically, when the in-focus determination result obtained from the AF control unit 28 is out of focus, the image data obtained from the signal processing unit 60 is output to the display 26 as it is, so that the display 26 is based on the image data. When the focus determination result obtained from the AF control unit 28 is in focus, the image data subjected to the contour emphasis processing by the contour emphasis processing unit 30 is output to the display 26 so that the image is displayed on the display 26. Display based on data.

  Next, an example of a processing flow when performing autofocus in the digital camera 10 according to the first embodiment of the present invention configured as described above will be described.

  FIG. 4 is a flowchart illustrating an example of a flow of processing performed by the system control unit 70 during autofocus in the digital camera 10 according to the first embodiment of the present invention.

  In step 100, AF search processing is performed. The AF search process is performed by the AF control unit 28. Specifically, the AF lens 47 is moved by controlling the drive circuit 46. Then, image data obtained from the image sensor 50 is sampled at a predetermined timing in accordance with the movement of the AF lens 47, and a focus evaluation value is calculated.

  Next, in step 102, it is determined whether or not the AF search is finished. This determination is made by determining whether or not the calculation of the focus evaluation value has been completed in the entire movement range of the AF lens 47. If the determination is negative, the process returns to step 100 and the AF search process is performed. When the determination is affirmed, the routine proceeds to step 104.

  In step 104, the AF lens is moved to the in-focus position. That is, the AF lens 47 is moved to the in-focus position determined based on the in-focus evaluation value by the AF control unit 28.

  In step 106, it is determined whether or not the subject is in focus. The determination is made by the AF control unit 28 determining whether or not the movement of the AF lens 47 to the in-focus position under the control of the AF control unit 28 is completed. 108. That is, when the determination in step 106 is affirmed, the AF control unit 28 outputs an in-focus signal indicating the in-focus state as the in-focus determination result to the selection processing unit 32.

  In step 108, the contour-enhanced image is displayed on the display 26, and the process proceeds to step 112. That is, when the selection processing unit 32 acquires a focus signal representing the focus obtained from the AF control unit 28, the image data on which the contour enhancement processing is performed by the contour enhancement processing unit 30 is output to the display 26. As a result, the contour-enhanced image is displayed on the display 26.

  On the other hand, if the determination in step 106 is negative, the process proceeds to step 110, and the display 26 displays an image that is not contour-enhanced, and the process proceeds to step 112. That is, when the selection processing unit 32 obtains a focus signal representing in-focus obtained from the AF control unit 28, the image data obtained from the signal processing unit 60 is output to the display 26. As a result, an image whose contour is not emphasized is displayed on the display 26.

  In step 112, it is determined whether or not the release switch 22 has been operated. The determination is made by determining whether or not the system control unit 70 has detected the operation of the release switch 22. If the determination is negative, the process returns to step 100 and the above processing is repeated. When the determination is affirmed, the series of processes is terminated, and the process proceeds to a photographing process (not shown).

That is, in the present embodiment, when focus is not achieved during AF, display based on image data obtained from the image sensor 50 is performed on the display 26 as in the case of a conventional digital camera, and when the focus is achieved, contour enhancement is performed. Since the display based on the image data is performed on the display 26, it is easy to visually determine that the in-focus state has been achieved when the in-focus state is achieved. Therefore, the visibility at the time of in-focus determination can be improved, and photographing errors can be reduced.
[Second Embodiment]
Next, a digital camera according to the second embodiment of the present invention will be described. In the digital camera according to the first embodiment, it is easy to visually determine that the image is focused by enhancing the outline of the display image on the display 26 at the time of focusing. 26 display images are blurred to make it easier to visually determine that they are not in focus.

  In the digital camera according to the second embodiment, only the configuration of the system control unit 70 is different from that of the first embodiment, and the other configuration is the same as that of the first embodiment, and thus the description thereof is omitted.

  FIG. 5 is a block diagram showing a configuration of a control system for performing AF control in the digital camera according to the second embodiment of the present invention. The same parts as those in the first embodiment will be described with the same reference numerals.

  The image data sampled from the image sensor 50 by the sampling unit 56 is input to the system control unit 71 via the A / D converter 58 and the signal processing unit 60 as in the first embodiment.

  The system control unit 71 includes a low-pass filter processing unit 34, a selection processing unit 32, and an AF control unit 28. The image data output from the signal processing unit 60 is the low-pass filter processing unit 34 and the selection processing. Input to the unit 32.

  In addition to outputting the A / D converted image data to the signal processing unit 60, the A / D converter 58 also outputs the A / D converted image data to the AF control unit 28.

  The AF control unit 28 controls the drive circuit 46 to move the AF lens 47 and calculates a focus evaluation value based on image data obtained from the A / D converter 58 while moving the AF lens 47. To determine focus. In-focus determination can be determined as in-focus, for example, where there are many high-frequency components in the image data. In addition, a so-called contrast method or the like in which focusing is determined at a position where the contrast is maximum can be applied.

  The low-pass filter processing unit 34 performs low-pass filter processing on the image data obtained from the signal processing unit 60 and cuts high-frequency components of the image data, thereby blurring the image and outputting it to the selection processing unit 32. .

  The selection processing unit 32 selects a signal to be output to the display 26 based on the focus signal (focus determination result) output from the AF control unit 28. Specifically, when the in-focus determination result obtained from the AF control unit 28 is in focus, the image data obtained from the signal processing unit 60 is output to the display 26 as it is, so that the display 26 displays based on the image data. When the in-focus determination result obtained from the AF control unit 28 is out of focus, the image data subjected to the low-pass filter processing by the low-pass filter processing unit 34 is output to the display 26, whereby the image is displayed on the display 26. Display based on data.

  Next, an example of a processing flow when performing autofocus in the digital camera according to the second embodiment of the present invention will be described.

  FIG. 6 is a flowchart showing an example of the flow of processing performed by the system control unit 71 during autofocus in the digital camera according to the second embodiment of the present invention. The same processes as those in the first embodiment will be described with the same reference numerals.

  In step 100, AF search processing is performed. The AF search process is performed by the AF control unit 28. Specifically, the AF lens 47 is moved by controlling the drive circuit 46. Then, image data obtained from the image sensor 50 is sampled at a predetermined timing in accordance with the movement of the AF lens 47, and a focus evaluation value is calculated.

  Next, in step 102, it is determined whether or not the AF search is finished. This determination is made by determining whether or not the calculation of the focus evaluation value has been completed in the entire movement range of the AF lens 47. If the determination is negative, the process returns to step 100 and the AF search process is performed. When the determination is affirmed, the routine proceeds to step 104.

  In step 104, the AF lens is moved to the in-focus position. That is, the AF lens 47 is moved to the in-focus position determined based on the in-focus evaluation value by the AF control unit 28.

  In step 106, it is determined whether or not the subject is in focus. The determination is made by the AF control unit 28 determining whether or not the movement of the AF lens 47 to the in-focus position under the control of the AF control unit 28 is completed. Move to 107. That is, when the determination in step 106 is affirmed, the AF control unit 28 outputs an in-focus signal indicating the in-focus state as the in-focus determination result to the selection processing unit 32.

  In step 107, an image not subjected to low-pass filter processing is displayed on the display 26, and the process proceeds to step 112. That is, when the selection processing unit 32 acquires a focus signal representing the focus obtained from the AF control unit 28, the image data acquired from the signal processing unit 60 is output to the display 26. As a result, an image that has not been subjected to the low-pass filter process is displayed on the display 26.

  If the determination in step 106 is negative, the process proceeds to step 109, and the display of the low-pass filtered image is performed on the display 26, and the process proceeds to step 112. In other words, when the selection processing unit 32 obtains a focus signal representing out-of-focus obtained from the AF control unit 28, the image data subjected to the low-pass filter processing by the low-pass filter processing unit 34 is output to the display 26. As a result, a low-pass filter process and a blurred image are displayed on the display 26.

  In step 112, it is determined whether or not the release switch 22 has been operated. The determination is made by determining whether or not the system control unit 71 has detected the operation of the release switch 22. If the determination is negative, the process returns to step 100 and the above processing is repeated. When the determination is affirmed, the series of processes is terminated, and the process proceeds to a photographing process (not shown).

That is, in the present embodiment, when focusing is performed during AF, display based on the image data obtained from the image sensor 50 is performed on the display 26 as in the case of a conventional digital camera. Since the display based on the image data is performed on the display 26, the display image at the time when it is not in focus becomes a blurred image. As a result, the outline is emphasized as in the first embodiment. This makes it easier to visually determine that the subject is in focus. Therefore, the visibility at the time of in-focus determination can be improved, and photographing errors can be reduced.
[Third Embodiment]
Next, a digital camera according to the third embodiment of the present invention will be described. The third embodiment is a combination of the first embodiment and the second embodiment. The image displayed on the display 26 is contour-enhanced at the time of focusing, and the image is blurred by performing a low-pass filter process at the time of non-focusing. Is displayed to make it easier to visually determine the in-focus determination.

  Note that the digital camera according to the third embodiment is different from the first and second embodiments only in the configuration of the system control units 70 and 71, and the other configurations are the same as those in the first embodiment. Is omitted.

  FIG. 7 is a block diagram showing a configuration of a control system for performing AF control in the digital camera according to the third embodiment of the present invention.

  The image data sampled from the image sensor 50 by the sampling unit 56 is input to the system control unit 72 via the A / D converter 58 and the signal processing unit 60 as in the first embodiment.

  The system control unit 72 includes a contour enhancement processing unit 30, a low-pass filter processing unit 34, a selection processing unit 32, and an AF control unit 28. Image data output from the signal processing unit 60 is contour enhancement. The data is input to the processing unit 30 and the low-pass filter processing unit 34.

  In addition to outputting the A / D converted image data to the signal processing unit 60, the A / D converter 58 also outputs the A / D converted image data to the AF control unit 28.

  The AF control unit 28 controls the drive circuit 46 to move the AF lens 47 and calculates a focus evaluation value based on image data obtained from the A / D converter 58 while moving the AF lens 47. To determine focus. In-focus determination can be determined as in-focus, for example, where there are many high-frequency components in the image data. In addition, a so-called contrast method or the like in which focusing is determined at a position where the contrast is maximum can be applied.

  The contour enhancement processing unit 30 performs contour enhancement processing on the image data obtained from the signal processing unit 60 and outputs the image data to the selection processing unit 32.

  The low-pass filter processing unit 34 performs low-pass filter processing on the image data obtained from the signal processing unit 60 and cuts high-frequency components of the image data, thereby blurring the image and outputting it to the selection processing unit 32. .

  The selection processing unit 32 selects a signal to be output to the display 26 based on the focus signal (focus determination result) output from the AF control unit 28. Specifically, when the in-focus determination result obtained from the AF control unit 28 is in-focus, the image data subjected to the contour emphasis processing by the contour emphasis processing unit 30 is output to the display 26, so By performing display based on the data and when the focus determination result obtained from the AF control unit 28 is out of focus, by outputting the image data subjected to the low-pass filter processing by the low-pass filter processing unit 34 to the display 26, The display 26 performs display based on the image data.

  Next, an example of the flow of processing when performing autofocus in the digital camera according to the third embodiment of the present invention configured as described above will be described.

  FIG. 8 is a flowchart showing an example of the flow of processing performed by the system control unit 72 during autofocus in a digital camera according to the third embodiment of the present invention. The same processes as those in the first embodiment and the second embodiment will be described with the same reference numerals.

  In step 100, AF search processing is performed. The AF search process is performed by the AF control unit 28. Specifically, the AF lens 47 is moved by controlling the drive circuit 46. Then, image data obtained from the image sensor 50 is sampled at a predetermined timing in accordance with the movement of the AF lens 47, and a focus evaluation value is calculated.

  Next, in step 102, it is determined whether or not the AF search is finished. This determination is made by determining whether or not the calculation of the focus evaluation value has been completed in the entire movement range of the AF lens 47. If the determination is negative, the process returns to step 100 and the AF search process is performed. When the determination is affirmed, the routine proceeds to step 104.

  In step 104, the AF lens is moved to the in-focus position. That is, the AF lens 47 is moved to the in-focus position determined based on the in-focus evaluation value by the AF control unit 28.

  In step 106, it is determined whether or not the subject is in focus. The determination is made by the AF control unit 28 determining whether or not the movement of the AF lens 47 to the in-focus position under the control of the AF control unit 28 is completed. 108. That is, when the determination in step 106 is affirmed, the AF control unit 28 outputs an in-focus signal indicating the in-focus state as the in-focus determination result to the selection processing unit 32.

  In step 108, the contour-enhanced image is displayed on the display 26, and the process proceeds to step 112. That is, when the selection processing unit 32 acquires a focus signal representing the focus obtained from the AF control unit 28, the image data on which the contour enhancement processing is performed by the contour enhancement processing unit 30 is output to the display 26. As a result, the contour-enhanced image is displayed on the display 26.

  If the determination in step 106 is negative, the process proceeds to step 109, and the display of the low-pass filtered image is performed on the display 26, and the process proceeds to step 112. In other words, when the selection processing unit 32 obtains a focus signal representing out-of-focus obtained from the AF control unit 28, the image data subjected to the low-pass filter processing by the low-pass filter processing unit 34 is output to the display 26. As a result, a low-pass filter process and a blurred image are displayed on the display 26.

  In step 112, it is determined whether or not the release switch 22 has been operated. The determination is made by determining whether or not the system control unit 72 has detected the operation of the release switch 22. If the determination is negative, the process returns to step 100 and the above processing is repeated. When the determination is affirmed, the series of processes is terminated, and the process proceeds to a photographing process (not shown).

  That is, in the present embodiment, when focus is not achieved during AF, display based on the low-pass filtered image data is displayed on the display 26, and when focus is achieved, display based on the image data with enhanced outline is displayed on the display 26. Therefore, the difference between the display at the time of focusing and the non-focusing can be emphasized, and it becomes easy to visually determine that the focus is achieved when the focus is achieved. Therefore, the visibility at the time of in-focus determination can be improved, and photographing errors can be reduced.

  In each of the embodiments described above, the A / D converted image data is input to the AF control unit 28. However, the image data subjected to various corrections by the signal processing unit 60 is input to the AF control unit 28. Alternatively, a processing unit different from the signal processing unit 60 may be provided, and image data may be input to the AF control unit 28 after performing correction necessary for performing AF control.

  In the above embodiment, an example in which the present invention is applied to a digital camera has been described. However, the present invention is not limited to this. For example, the present invention may be applied to a video camera with an AF function.

  Further, in each of the above embodiments, the focus determination is performed based on the image data obtained from the image sensor 50. However, the present invention is not limited to this. It is also possible to measure the distance to the subject image and determine whether or not the focus adjustment is finished at the lens position corresponding to the measured distance, and other methods may be applied.

1 is a perspective view showing an appearance of a digital camera according to a first embodiment of the present invention. It is a block diagram which shows the structure of the electric system of the digital camera concerning 1st Embodiment of this invention. FIG. 2 is a block diagram illustrating a configuration of a control system for performing AF control in the digital camera according to the first embodiment of the present invention. 3 is a flowchart illustrating an example of a flow of processing performed by a system control unit during autofocus in the digital camera according to the first embodiment of the present invention. It is a block diagram which shows the structure of the control system for performing AF control in the digital camera concerning 2nd Embodiment of this invention. It is a flowchart which shows an example of the flow of the process performed in a system control part at the time of autofocus in the digital camera concerning 2nd Embodiment of this invention. It is a block diagram which shows the structure of the control system for performing AF control in the digital camera concerning 3rd Embodiment of this invention. It is a flowchart which shows an example of the flow of the process performed in a system control part at the time of autofocus in the digital camera concerning 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Digital camera 26 Display 28 AF control part 30 Outline emphasis process part 32 Selection process part 34 Low pass filter process part 50 Image pick-up element 56 Sampling part 58 A / D converter 60 Signal processing part 70, 71, 72 System control part

Claims (12)

An image sensor that captures a subject image and outputs image data representing the subject image;
A display device for performing display based on image data output from the image sensor;
A lens that forms a subject image on the image sensor, and an adjustment unit that adjusts the focus of the lens;
Determination means for determining a focus on a subject image at the time of focus adjustment of the lens of the adjustment means;
Image processing means for performing at least one of image enhancement processing for enhancing the contour of the image represented by the image data and blur processing for blurring the image represented by the image data on the image data output from the image sensor When,
A selection unit that selects processing to be performed by the image processing unit based on a determination result of the determination unit;
With
An image pickup apparatus that performs display on the display device based on the image data that has been subjected to image processing in accordance with a selection result of the selection means.   When the image processing means performs the edge enhancement process, the selection means selects the edge enhancement process by the image processing means only when the determination result of the determination means is in focus. The imaging device according to claim 1.   When the image processing unit performs the blurring process, the selection unit selects the blurring process by the image processing unit only when the determination result of the determination unit is out of focus. The imaging apparatus according to 1.   When the image processing means performs the edge enhancement process and the blurring process, the selection means selects the edge enhancement process by the image processing means when the determination result of the determination means is in focus. The imaging apparatus according to claim 1, wherein the blurring process by the image processing unit is selected when a determination result of the determination unit is out of focus.   The imaging apparatus according to claim 3, wherein the image processing unit performs a low-pass filter process on the image data as the blurring process.   The imaging apparatus according to claim 1, wherein the determination unit determines in-focus on a subject image based on image data output from the imaging element. An image sensor that captures a subject image and outputs image data representing the subject image, a display device that performs display based on image data output from the image sensor, and a lens that forms a subject image on the image sensor An image processing method of an imaging apparatus comprising: an adjustment unit that performs focus adjustment of the lens,
A determination step of determining focusing on a subject image when the focus of the lens of the adjustment unit is adjusted;
An image processing step of performing at least one of image enhancement processing for emphasizing the contour of the image represented by the image data and blur processing for blurring the image represented by the image data on the image data output from the image sensor When,
A selection step of selecting a process to be performed in the image processing step based on a determination result of the determination step;
A display step for displaying on the display device based on the image data subjected to image processing according to a selection result of the selection step;
An image processing method for an imaging apparatus, comprising:   When performing the edge enhancement process in the image processing step, the selection step selects the edge enhancement process by the image processing step only when the determination result of the determination step is in focus. The image processing method of the imaging device according to claim 7.   The blur processing by the image processing step is selected only when the determination result of the determination step is out of focus when the blur processing is performed in the image processing step. The image processing method of the imaging device according to claim 7.   When performing the contour enhancement processing and the blurring processing in the image processing step, the selection step selects the contour enhancement processing by the image processing step when the determination result of the determination step is in focus. The image processing method of the imaging apparatus according to claim 7, wherein when the determination result of the determination step is out of focus, the blurring process by the image processing step is selected.   The image processing method for an imaging apparatus according to claim 9 or 10, wherein the image processing step performs low-pass filter processing on the image data as the blurring processing.   The image of the imaging apparatus according to any one of claims 7 to 11, wherein the determination step determines a focus on a subject image based on image data output from the imaging element. Processing method.

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