JP2008178031A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a photographer to confirm blurring of a main object by extracting the face of a person as the main object in personal photographing, and displaying a magnified image of the face on an image display unit. <P>SOLUTION: An imaging apparatus comprises a photographing optical system for photographing an object, a memory for recording a photographed image, a display panel capable of displaying the image thereon, an angular velocity sensor for detecting a camera shake during photographing, and a face detection circuit for extracting a face image from the photographed image. In a case where a detected blurring amount exceeds a threshold value, a message indicative of a caution on blurring of the photographed image is displayed on an LCD panel and a magnified image of the face image detected by the face detection circuit is then displayed on the display panel. In a case where storage is selected by the photographer who confirms a degree of blurring of the face image from the magnified image, the photographed image is stored on a memory card. If erasure is selected, temporarily stored image data are erased and a message as a notice of the erasure is displayed on the display panel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging apparatus including a display panel that displays a captured image, and more particularly to an imaging apparatus that allows a photographer to visually check the degree of blur when the captured image is a blurred image.

  In general, when imaging a dark subject, an imaging apparatus is prone to camera shake because it takes a long time to capture an image, such as a slow shutter speed. At this time, when a photographer performs so-called hand-held shooting in which the camera is held in his hand, camera shake often occurs in the captured image. Further, depending on the movement of the person in the subject, the person image may be blurred. When the shake of a photographed image due to camera shake or subject shake exceeds an allowable amount, it is disliked as an image unbearable for viewing. Therefore, various efforts are made on the camera side to prevent such a situation from occurring.

  In recent years, cameras with a camera shake correction function have been sold, which is one of the countermeasures. However, the camera shake correction function cannot cope with blur exceeding the correction range, and image blur due to movement of the subject itself cannot be corrected. Images with insufficient camera shake correction are also stored as captured images. It was. For this reason, the photographer is satisfied with the use of the camera shake correction function and finishes photographing, resulting in missed timing of re-taking of photographing.

  On the other hand, an imaging apparatus capable of performing imaging while confirming the presence or absence of camera shake when a still image is captured is known from Patent Document 1 below. In this imaging apparatus, after a shutter release operation is performed to capture a still image, when the confirmation button is operated, the captured image is enlarged and displayed on the LCD panel. Therefore, the user can proceed with imaging while confirming the presence or absence of camera shake by visually recognizing the recorded image displayed enlarged on the LCD panel.

  In the following Patent Document 2, an enlarged image obtained by enlarging a central portion of a photographed image is displayed on an image display unit only when a shake exceeding a correction range is detected by a camera shake sensor. A method of confirming is proposed.

In Patent Document 3 below, contour extraction is performed from captured image data temporarily stored in a memory, the blur amount of the extracted contour is detected, and the contour portion having the largest blur amount is enlarged and displayed on the image display unit. A method for confirming with the photographer whether the captured image is stored / not stored has been proposed.
JP 2001-177753 A JP 2004-080460 A JP 2006-020101 A

  However, none of the methods disclosed in the above-mentioned patent documents select and extract an important subject in the captured image, so only the degree of camera shake is confirmed on the image. Especially in the case of multiple person shooting, the main subject will be mistaken, and it will be inappropriate to recognize the blurring when judging the blurring from the enlarged image of the center part of the screen or any part of the shot image. .

  In order to solve such a problem, the present invention extracts the face of a person who is a main subject at the time of photographing a person and displays an enlarged image of the face on the image display unit so that the photographer can check the blur of the main subject. This is to provide a simplified camera. As a result, it is possible to appropriately perform re-shooting when hand-shake shooting is performed.

  An image pickup apparatus of the present invention has a shooting optical system for shooting a subject, a memory for recording a shot image, a display panel capable of displaying an image, a shake detection device for detecting a shake at the time of shooting, and a shot. A face detection circuit for extracting a face image from the image. When the shake detection device detects a shake, an enlarged image of the face image detected by the face detection circuit is displayed on the display panel. The motion detection device uses a motion vector detection circuit or a camera shake sensor. As the camera shake sensor, an angular velocity sensor such as a gyroscope is preferable.

  When there are a plurality of face images in the photographed image, the face detection circuit detects only the face image facing the front and extracts the largest face image among them to obtain an enlarged image. . Alternatively, the motion vector detection circuit may detect a blur amount for a plurality of detected face images, and the face image with the largest detected blur amount may be used as an enlarged image. Further, there are provided a step of ranking according to the orientation of the face image, a step of ranking according to the size of the face image, and a step of ranking according to the amount of blurring of the face image. Prioritization may be performed, and the face image ranked first according to the ranked order may be used as an enlarged image. If the face detection circuit cannot detect a face image, the photographed image is displayed on the display panel.

  In the present invention, when a captured image is detected to be a blurred image, a person's face is detected from the captured image when saving the captured image, and the most appropriate face image among the detected face images is detected. By extracting and magnifying the image and displaying it on the LCD panel as the image display unit, the photographer can check the blur of the main subject. As a result, when hand-shake shooting is performed, it is possible to appropriately perform re-shooting, thereby eliminating the failure shooting.

  Hereinafter, a digital camera having a function of confirming an enlarged image of a blurred image according to an embodiment of the present invention will be described. A digital camera 10 shown in FIGS. 1 and 2 includes a collapsible lens barrel 13 having an imaging lens 12 and a strobe light emitting unit 14 on the front surface of a substantially rectangular parallelepiped camera body 11. A shutter button 15 and an operation dial 16 are provided on the upper surface of the digital camera 10. The operation dial 16 turns on / off the power switch and switches between the shooting mode / playback mode / setting mode.

  An LCD panel (display panel) 20 is provided on the back of the digital camera 10. In the shooting mode, the LCD panel 20 functions as an electronic viewfinder and displays a through image in real time. In the reproduction mode, the image data stored in the memory card 22 is read and displayed. Further, in the setting mode, various setting screens are displayed. A touch panel is provided on the surface of the LCD panel 20. An operation icon displayed on the LCD panel 20 can be operated by touching the touch panel using a user's finger or an attached operation pen (not shown).

  The memory card 22 is detachably loaded in a memory card slot 23 provided on the side of the digital camera 10. Image data obtained in the shooting mode is stored in the memory card 22. The cursor button 24 is used for switching various settings and for operations on various processing confirmation screens displayed on the LCD panel 20. The decision button 25 executes the process selected by the cursor button 24.

  In the electrical configuration of the digital camera 10 shown in FIG. 3, the control circuit 26 reads out the sequence program stored in the ROM 27 to the RAM 28 as a work memory and executes it. The control circuit 26 controls each part of the digital camera 10 according to operation signals generated by operating the shutter button 15, the operation dial 16, the cursor button 24, and the enter button 25. Further, a camera shake detection signal is input to the control circuit 26 from an angular velocity sensor 29 as a camera shake detection unit.

  In the lens barrel 12, a correction lens 30 for correcting camera shake is incorporated as one of the lenses constituting the photographing lens 13, and output from a hall element (not shown) provided in the vicinity of the correction lens 30. Is input to the position detector 31. An actuator that moves the correction lens 30 in a direction perpendicular to the photographing optical axis is incorporated in the lens barrel 12, and this actuator is driven by a drive circuit 32.

  The control circuit 26 drives the drive circuit 32 based on the camera shake detection signal from the angular velocity sensor 29 and the lens position signal from the position detection unit 31, and moves the correction lens 30 in the direction and speed for canceling camera shake. Moving.

  A CCD 33 is provided behind the taking lens 13. When displaying a through image, an imaging signal of a field image (even field or odd field) is read from the CCD 33 and this imaging signal is input to a correlated double sampling circuit (CDS) 34. The CDS 34 generates R, G, B analog image signals from the imaging signals output from the CCD 33. An amplifier (AMP) 35 amplifies the R, G, B analog image signals. The A / D converter 36 converts the analog image signal output from the AMP 35 into image data that is a digital image signal.

  The image data output from the A / D converter 36 is input to an image signal processing circuit 37, where image processing such as gradation conversion, white balance correction, γ correction, and YC conversion processing is performed. The data is temporarily stored in the SDRAM 38 via the data bus 41 and sent to the LCD panel 20 via the LCD driver 39 to display a through image. The SDRAM 38 has a through-image memory area for storing two continuous field fractions, and writes to the other while reading from one.

  While the through image is displayed, AF control and AE control are performed at regular time intervals. In AF control, while moving the focus lens constituting the photographing lens 13, the focus position where the contrast (the value obtained by integrating the differences between adjacent pixels) is maximized is detected, and the focus lens is set at this focus position. To do. In the AE control, the diaphragm constituting the photographing lens 13 is changed. These controls are executed by the AF / AE processing circuit 40, and the information is sent to the control circuit 26 via the data bus 41.

  When the shutter button 15 is half-pressed (switch S1 is turned on), AF / AE is activated to set the exposure time, aperture value, and focus lens. When the subject brightness is lower than the predetermined value, the strobe circuit 42 Charges the built-in discharge capacitor. When photographing of the subject is executed by fully pressing the shutter button 15 (switch S2 is turned on), the frame image is read from the CCD 33 after the exposure is completed, and the image signal is passed through the CDS 34, the AMP 35, and the A / D converter 36. After the image processing is performed by the processing circuit 37, it is written in the SDRAM 38. Thereafter, the image data of the frame image is read out from the SDRAM 38, compressed in a predetermined compression format such as JPEG format by the compression / decompression processing circuit 43, and then recorded on the memory card 22 via the media controller 44. The

  The image data of the through image (field image) written in the SDRAM 38 is read into the face detection circuit 45, and the face portion of the subject is detected. The face detection circuit 45 extracts the face of the subject by extracting both eyes of the subject from the image data of the through image (hereinafter referred to as through image data). When extracting both eyes of the subject, the image of the through image data is divided into a grid pattern (for example, 16 × 16), and the skin level is determined from the signal levels of the R, G, and B color signals included in each divided region. A divided area including many estimated skin color pixels is selected.

  Furthermore, a region having white pixels of the eye part and a black pixel estimated to be a pupil is selected from a region containing many skin-colored pixels, and the position coordinates of both eyes of the subject on the image are obtained from the region, The face position is obtained using the midpoint of the position coordinates as a representative point. The face detection circuit 45 considers an area including many skin-colored pixels around it as a face area from the extracted position coordinates of both eyes of the subject. It is determined from the position coordinates of both eyes in the face area whether the face is facing front or side.

  The face image extracted by the face detection circuit 45 is sent to the LCD driver 39 and the enlarged image is displayed on the LCD panel 20. When a plurality of face images are detected, the face detection circuit 45 extracts the largest face image from them, but when there is a face facing forward, the face detection circuit 45 is largest among the faces facing forward. Extract face images.

  A procedure of still image shooting by the digital camera 10 configured as described above will be described. First, the operation dial 16 is operated to turn on the digital camera 10, and the still image shooting mode is selected. Thereby, acquisition of a through image is started. The through image written in the SDRAM 38 is read into the face detection circuit 45 to detect the face of the subject. When the shutter button 15 is half-pressed (S1 on), the AF / AE processing circuit 40 and the strobe circuit 42 prepare for shooting, and when the shutter button 15 is fully pressed (S2 on), shooting is performed.

  The blurred image confirmation operation after S2 is turned on will be described with reference to the flowchart shown in FIG. When S2 is turned on, the subject is photographed. At the same time, the amount of camera shake is detected by the angular velocity sensor 29, and the control circuit 26 moves the correction lens 30 to correct camera shake. The captured image (see FIG. 5) is temporarily stored in the SDRAM 38, and the amount of camera shake is also recorded.

  The photographed image temporarily stored in the SDRAM 38 is sent to the face detection circuit 45 and face detection in the image is executed, and all faces in the photographed image are detected. (See FIG. 6). Here, when no face image is detected, the captured image is displayed on the LCD panel 20. When the detected face image is one, the face image is a face image to be enlarged and displayed. When there are a plurality of face images, the face image to be enlarged and extracted is extracted by the face image extraction flow.

  Here, the face image extraction flow will be described with reference to a flow (1) shown in FIG. When a plurality of face images are detected, the face detection circuit 45 selects a face facing the front from the photographed images (see FIG. 8). The largest face (FIG. 9B) is extracted from the selected plurality of face images (see FIG. 9). If the face image facing the front cannot be extracted, the largest face is extracted from the plurality of face images.

  Next, the amount of camera shake is confirmed, and if the value does not exceed the threshold value, the image data temporarily stored in the SDRAM 38 is stored in the memory card 22 and the captured image is displayed on the LCD panel 20.

  If the amount of camera shake exceeds the threshold value, a warning message (see FIG. 10) is displayed on the LCD panel 20 to notify the photographer that the image is blurred. Thereafter, an enlarged image of the face image extracted by the face detection circuit 45 is displayed on the LCD panel 20. In addition to the enlarged face image, a touch panel for selecting save / delete is displayed on the LCD panel 20 (see FIG. 11).

  When saving is selected here, the image data temporarily saved in the SDRAM 38 is saved in the memory card 22, and the photographed image is displayed on the LCD panel 20 together with a save message (see FIG. 12). When erasure is selected, the image data temporarily stored in the SDRAM 38 is erased, and a message is displayed on the LCD panel (see FIG. 13) to notify the photographer that the image data has been erased.

  In the above embodiment, when extracting the face image to be enlarged, the face image facing the front is extracted. However, the size is simply selected from all the face images (see FIG. 14) regardless of the face direction. You can just choose. In this case, the face image extraction flow is as shown in FIG.

  Also, as shown in the flow of FIG. 16, the motion vector detection circuit 46 detects the blur amount for all of the detected face images (see FIG. 17), and extracts the face image with the largest detected blur amount. The image may be displayed on the LCD panel 20 as an enlarged image, and a save / delete selection button may be displayed beside the enlarged face image (see FIG. 18).

  Further, as in the flow shown in FIG. 19, priority is given to the above-mentioned three patterns, the face image facing the front, giving priority to the largest face image, giving priority to the face image with the largest amount of blurring, and giving priority to enlargement. The photographer may be able to rank the face image to be displayed.

  Further, instead of automatically determining an image to be enlarged and displayed by ranking, for example, as shown in FIG. 14, only the face image is temporarily displayed, and the face image selected by the photographer is enlarged and displayed. You may make it do. In this case, instead of the display as shown in FIG. 14, all face images are displayed side by side as small images as shown in FIG. 20, and can be selected sequentially by scrolling. The enlarged image may be confirmed.

  Further, when the angular velocity sensor detects a camera shake, an enlarged image confirmation inquiry message as shown in FIG. 21 may be displayed instead of the message shown in FIG.

  In the above-described embodiment, camera shake detection is performed using the angular velocity sensor 29, but it may be obtained from the blur amount of the entire image by the motion vector detection circuit 46. In this case, the motion vector detection circuit 46 detects a motion vector α which is a blur amount of the entire image from the image data of the through image (field image) written in the SDRAM 38, and the control circuit 26 determines the motion vector α. The correction lens 30 is moved so as to cancel, and camera shake is corrected.

  In the above-described embodiment, the image pickup apparatus having the camera shake correction function has been described. However, the camera shake correction function is not necessarily required, and an image pickup apparatus without the camera shake correction function may be used. In this case, a blur threshold value for determining a blur image is set.

It is the perspective appearance figure which looked at the digital camera which is an embodiment of the present invention from the front. It is the perspective appearance figure which looked at the digital camera which is an embodiment of the present invention from the back. It is a block diagram which shows the structure of the digital camera which is embodiment of this invention. It is a flowchart of the detection method of the face image which is embodiment of this invention. It is the picked-up image by the digital camera which is embodiment of this invention. It is a figure which shows having detected the face from the picked-up image. It is a flowchart of the method of extracting the face image enlargedly displayed on an LCD panel. It is a figure which shows having detected only the face which faced the front. It is a figure which shows only the face which faced the detected front. It is a display image of the LCD panel which warns of a blurred image. It is a figure which shows the enlarged image displayed on the LCD panel. It is an image displayed on the LCD panel when image data is stored. It is a figure which shows the warning message displayed on the LCD panel when the image | photographed image was erase | eliminated. It is a figure which shows the detected face image in another embodiment. It is a flowchart of the method of extracting the face image enlargedly displayed on the LCD panel in another embodiment. It is a flowchart of the method of detecting the face image with the largest blur amount and extracting the face image to be enlarged and displayed on the LCD panel. It is a figure which shows the detected face image in the method of detecting the blurring amount of a face image. It is a figure which shows the enlarged image displayed on the LCD panel in another embodiment. 10 is a flowchart of a method of extracting face images that are ranked and enlarged on an LCD panel according to another embodiment. It is a figure which shows another display method of the detected face image. It is the figure which displayed on the LCD panel the inquiry message whether to confirm whether the blurring image was enlarged and displayed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Digital camera 12 Shooting lens 13 Lens barrel 15 Shutter button 20 LCD panel 22 Memory card 26 Control circuit 29 Angular velocity sensor 45 Face detection circuit 46 Motion vector detection circuit

Claims (11)

In an imaging apparatus having a photographing optical system for photographing a subject, a memory for recording a photographed image, and a display panel capable of displaying an image or the like,
A blur detection unit that detects a blur at the time of shooting; and a face image detection unit that detects a face image from the captured image. When the blur detection unit detects a blur exceeding a threshold value, the face image detection unit An image pickup apparatus, wherein an enlarged image of the face image detected by the method is displayed on the display panel.   The imaging apparatus according to claim 1, wherein the blur detection unit is a motion vector detection unit that detects a blur amount of a captured image.   The imaging apparatus according to claim 1, wherein the blur detection unit is a camera shake sensor that detects that the imaging apparatus vibrates during shooting.   The imaging apparatus according to claim 3, wherein the camera shake sensor is an angular velocity sensor.   5. The imaging apparatus according to claim 1, wherein the face image detecting unit detects only a face image facing the front when there are a plurality of face images in the photographed image. .   6. The face image detecting means according to claim 1, wherein when there are a plurality of face images in the photographed image, the face image detecting means extracts the largest face image and makes it an enlarged image. Imaging device. When a plurality of face images are detected in the image captured by the face image detecting means,
The motion vector detection means detects a blur amount of the plurality of face images;
The imaging apparatus according to claim 1, wherein the face image detection unit extracts a face image having the largest amount of blurring to obtain an enlarged image. The face image detecting means includes
A first step for ranking a plurality of face images in the captured image according to the orientation of the face image, a second step for ranking according to the size of the face image, and a blur amount of the face image A third step of ranking according to the size of the three, and a priority setting step of prioritizing the three steps,
When there are a plurality of face images in the photographed image, the face image ranked first in the order determined by the three steps according to the order set in the priority order setting step is extracted and used as an enlarged image. The imaging apparatus according to claim 1, wherein   9. The image pickup apparatus according to claim 1, wherein when a face image cannot be detected from images taken by the face image detection means, the taken image is displayed on the display panel.   10. The imaging according to claim 1, wherein the display panel displays a message notifying that the photographed image is a blurred image when the blur detecting unit detects a blur exceeding a threshold value. apparatus. 11. The imaging apparatus according to claim 1, wherein the imaging apparatus has a camera shake correction function, and a threshold value for detecting the blur image is a correction limit value of the camera shake correction function.

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