JP2010009057A - Camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera including an image processing means capable of performing appropriate image processing with respect to a display/tracking image signal, and accurately performing tracking-AF. <P>SOLUTION: The camera includes: imaging means (11, 12 and 13) for capturing an object image; image processing means (56, 57 and 58) for performing the image processing of the output image from the imaging means; a tracking means (53) for tracking the position of the object moving in the screen based on the image-processed image; and an AF means (59) for adjusting the focus of the imaging means by moving the focus area in accordance with the tracking by the tracking means. The image processing means performs the image processing for the tracking means during the operation of the AF means so that the tracking accuracy may be enhanced, and after finishing the focus adjustment by the AF means, the image processing means releases the image processing for enhancing the tracking accuracy with respect to the image to be recorded. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a camera equipped with a tracking AF device that tracks a moving subject within a screen for focusing.

  Continuous AF that always focuses the photographic lens on the subject is a convenient function not only for moving image shooting but also for still image shooting. Since the AF itself operates by detecting information at a certain position in the screen, if the subject moves within the screen in the above-described continuous AF in which the subject is always kept in focus, the target subject There is a problem that a focus error is caused by focusing on a different part.

  Accordingly, various proposals have been made regarding so-called tracking AF in which the contrast information of the subject is detected to track the moving subject and the AF detection area is moved in accordance with the movement.

  As one of them, in order to further improve the accuracy of tracking AF, the motion vector information detected in a plurality of motion detection areas on the screen is weighted differently depending on the position of each motion detection area in the screen. An invention has been proposed in which a region to be subjected to motion correction is set by performing calculation, representative motion vector information is calculated from a plurality of weighted motion vector information, and image motion is corrected (patent) Reference 1).

  In the present invention, because of the camera cost, the tracking signal is not an image signal from a tracking-dedicated imaging device, but a shooting image signal is used as the tracking signal. This is because the provision of an imaging circuit dedicated for tracking leads to an increase in the cost of the electric circuit and an increase in internal space.

The moving object tracking AF is realized by (contrast) pattern detection and tracking based on the output signal of the captured image, but when the signal is noisy, the contrast is low, or there is camera shake. May be erroneously detected by subject detection. Therefore, to improve accuracy, for example, it is necessary to obtain an image signal with little noise and high contrast. However, since the image signal for photographing is used, it cannot be optimized only for tracking.
Patent No. 2770957

  It is an object of the present invention to provide a camera including an image processing unit that can perform appropriate image processing on a display / tracking image signal and perform accurate tracking AF.

  A camera according to one aspect of the present invention moves in a screen based on an image processing unit that captures a subject image, an image processing unit that performs image processing on an image output of the imaging unit, and the image processed image Tracking means for tracking the position of the subject to be tracked, and AF means for adjusting the focus of the imaging means by moving the focusing area in accordance with tracking by the tracking means, the image processing means is an operation of the AF means The image processing for increasing the tracking accuracy is performed as the image processing for the tracking unit, and the image processing for increasing the tracking accuracy is performed on the image recording image after the focus adjustment by the AF unit is completed. It is characterized by being released.

  According to the present invention, it is possible to provide a camera including an image processing unit capable of performing appropriate image processing on a display / tracking image signal and performing accurate tracking AF.

1 is a block diagram showing a schematic configuration of a camera according to an embodiment of the present invention. The block diagram regarding the tracking function of the camera which concerns on this embodiment of this invention. The flowchart for demonstrating the operation | movement which concerns on 1st Embodiment. The flowchart for demonstrating the operation | movement which concerns on 2nd Embodiment. The flowchart regarding the application method of tracking mode in the case of still image photography. The flowchart regarding the application method of tracking mode in the case of video recording.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration of a camera according to an embodiment of the present invention. The operation of the camera according to the embodiment of the present invention will be described with reference to FIG.

  The subject image is converted into an electrical signal by the CCD 12 via the lens 11. The subject image converted into an electrical signal by the CCD 12 is amplified by the imaging circuit 13 and converted into a digital signal by the A / D converter 14. An image signal converted into a digital signal (hereinafter also referred to as “image information”. Note that the subject image includes not only a still image but also a moving image) is corrected by the correction circuit 15 for hue, noise, and the like. Done. The correction circuit 15 is connected to the FIFO memory 21, the frame memory 27, the recording buffer 31, and the second CPU 40 via the bus 16. The FIFO memory 21 outputs the input information to the on-screen circuit 22 in the input order. The on-screen circuit 22 converts the signal output from the FIFO memory 21 into a video signal and outputs the video signal to the video output circuit 23 and the TFT liquid crystal drive circuit 24. The video output circuit 23 is a circuit (interface) for outputting a video signal from the video output terminal 23a to an external display device (not shown). The TFT liquid crystal driving circuit 24 is a circuit for displaying an image or a moving image on the TFT panel 25 based on the video signal output from the on-screen circuit 22. On the TFT panel 25, an image processed by the correction circuit 15 for confirming the composition of the subject is displayed as a monitor image. The TFT panel 25 is irradiated with light from the back surface by a backlight unit 26 controlled by a first CPU, which will be described in detail later. The frame memory 27 is a working memory for processing image signals.

  The recording buffer 31 is a buffer memory when image information is stored in or read from the removable recording medium 33, and the image with the recording medium is recorded via the recording medium I / F 32. Input / output information. The second CPU 40 performs various processes in cooperation with the first CPU 50, but basically performs image processing and control of the recording medium. The second CPU 40 includes, for example, an image compression function 41, an image expansion function 42, a frame memory control function 43, and a recording medium access function 44. With these functions, for example, when an image is recorded on the recording medium 33, image information is controlled by the image compression function 31, for example, JPEG is controlled by the frame memory control function 43 using the frame memory 27 as a working memory. Compress. Then, the recording medium access function 44 accesses the recording medium 33 to record the compressed image information at a predetermined position on the recording medium 33. Further, when image information is read from the recording medium 33 and displayed on the TFT panel 25, for example, the recording medium 33 is accessed by the recording medium access function 44 and desired image information is read from the recording medium 33. The image information read from the recording medium 33 is decompressed by the image decompression function 42 using the frame memory 27 as a working memory, and output to the FIFO memory 21 as in the case of image compression. Subsequent operations are the same as those described above, and a description thereof will be omitted.

  The first CPU 50 controls the entire operation. The first CPU 50 includes, as a system control function 51, an ISO sensitivity control function 52, a subject tracking function 53, a CCD shutter control function 54, a lens frame aperture control function 55, a noise canceller function 56, and a contrast adjustment function 57. And a sharpness adjustment function 58. In addition to the system control function 51, the first CPU 50 also includes an AF control function 59 that performs AF (autofocus) control.

  The AF control function 59 continuously shoots while moving the lens 11, compares the contrast amounts of the image signals obtained by this shooting and corrected by the correction circuit 15, and the contrast amount The position of the lens 11 where the image showing the peak position is taken as the in-focus position, and the lens 11 is controlled to move to that position. Then, the AF control function 59 extracts and compares an image signal for a predetermined AF area in the screen from the frame memory 27 when comparing the contrast amount.

  The AF control function 59 sets the AF area to the center of the screen when normal AF is turned on, and when the tracking AF is turned on, the moving direction and amount of the subject as will be described later. Is set to the subject movement position in the screen in the AF setting area 515.

  Each function of the system control function 51 will be described. First, the ISO sensitivity control function 52 controls the ISO sensitivity of the CCD 12. The subject tracking function 53 tracks a moving subject. The CCD shutter control function 54 controls the exposure time of the CCD shutter. The lens frame diaphragm control function 55 controls the amount of the lens frame diaphragm. The noise canceller function 56 performs control for canceling noise in the image information. The noise canceller process is a process for removing an indefinite noise component by performing a filter process such as a median filter, for example. A contrast adjustment function 57 and a sharpness adjustment function 58 adjust contrast and sharpness, respectively. The contrast adjustment process is, for example, a process of changing the correction value of γ correction to adjust the sharpness between a dark place and a bright place, and the sharpness adjustment process is, for example, changing the level of the edge enhancement process, This is a process for sharpening the edge portion of an image. In the above function, noise cancellation, contrast, and sharpness adjustment are performed on the data in the frame memory via the frame memory control function 43.

  Various circuits are connected to the first CPU 50. For example, the actuator drive circuit 61 drives the actuator 62 to drive the lens 11. The lens barrier open / close detection means 63 detects the open / close state of the lens barrier. The EEPROM 64 stores camera setting conditions and the like, and retains the memory even after the camera is turned off. The connection detection means 65 detects the connection state between the camera and another device (not shown). The external data I / F (USB) is an interface for performing data connection with an external device (not shown) by USB connection. A key matrix 67 as an operation unit receives an operation from a user. The LCD panel 72 displays the camera state, setting conditions, and the like via the LCD display circuit 71. Further, the power source of the camera is normally a battery 75, and power from the battery 75 is supplied to each part of the camera via the power supply circuit 77. Further, the state of the battery 75 is detected by the battery state detection circuit 76, and necessary control is performed by the first CPU 50 in accordance with the remaining amount of the battery 75 and the like. Further, when the remaining amount of the battery 75 is remarkably lowered or when the battery is replaced, power is supplied from the backup power supply 78, and contents stored in a volatile memory (not shown) are retained.

  In the above configuration, the tracking function of the camera according to this embodiment of the present invention will be described with reference to FIG.

  The key matrix 67 includes detection area instruction means 671 including a cross key and a jog dial. The detection area designated by the detection area instruction means 671 is sent to the subject contrast detection area setting function 531 of the subject tracking function 53 to set the detection area of the feature point (that is, contrast) of the subject. Next, the subject contrast detection function 532 detects the contrast of the subject in the detection area set by the subject contrast detection area setting function 531. The subject movement direction determination function 533 sets a region surrounding the subject contrast detection region as a monitoring region, monitors the set contrast change every predetermined time, and detects the detected subject contrast in the monitoring region. When a contrast pattern similar to all or a part of the image appears, it is determined that the subject has moved in that direction. The subject movement amount determination function 534 similarly determines the movement amount from the coordinates of the monitoring area where the same contrast pattern as the whole or part of the subject contrast appears. Finally, the AF area determination unit 535 determines the AF area based on the moving direction and movement amount of the subject.

In such a tracking function, the embodiment of the present invention is characterized in that the accuracy of the tracking function is improved by preventing noise from increasing when the subject is dark and suppressing the noise. For this,
(1) Emphasize contrast and sharpness.
(2) Strengthen noise canceller processing.
Is the main focus. Each embodiment will be described below.

(First embodiment)
FIG. 3 is a flowchart for explaining the operation according to the first embodiment. In the first embodiment, when automatic tracking AF is turned on (that is, during automatic tracking), processing for enhancing contrast and sharpness by the contrast adjustment function 57 and sharpness adjustment function 58 is performed during AF operation. .

  As shown in FIG. 3, when performing automatic tracking, the camera power supply is turned on (step S31), and automatic tracking AF is turned on (step S32). Then, it is determined whether or not automatic tracking is on (step S33). If automatic tracking is on, at least one of contrast enhancement processing and sharpness enhancement processing is turned on (step S34). Thereby, at the time of the tracking operation, at least one of the contrast enhancement processing and the sharpness enhancement processing is turned on. Then, a shooting standby state is entered (step S35). In step S33, if the auto tracking AF is off, the contrast enhancement process and the sharpness enhancement process are not performed, and the camera enters a shooting standby state. In the shooting standby state, the monitor image is displayed by the set contrast enhancement processing and sharpness enhancement processing while the AF is continuously operated. However, the contrast enhancement process and the sharpness enhancement process at the time of actual photographing are not affected by on / off of the automatic tracking.

  In this embodiment, by performing at least one of contrast enhancement processing and sharpness enhancement processing during automatic tracking, the influence of noise can be reduced, so that tracking accuracy can be increased.

(Second Embodiment)
FIG. 4 is a flowchart for explaining the operation according to the second embodiment. In the second embodiment, the noise canceller processing by the noise canceller function 56 during the tracking operation is strengthened.

  As shown in FIG. 4, when automatic tracking is performed, the camera power is turned on (step S41), and automatic tracking AF is turned on (step S42). Then, it is determined whether or not automatic tracking is turned on (step S43). If automatic tracking is turned on, the noise canceller processing is strengthened (step S44). Then, a shooting standby state is entered (step S45). In step S43, if the automatic tracking AF is off, the setting of the noise canceller process is not changed and the photographing standby state is set as it is.

  Also in the present embodiment, as in the first embodiment, the tracking accuracy can be improved by strengthening the noise canceller process and suppressing the influence of noise.

  Next, with reference to FIGS. 5 and 6, application of the tracking mode in the case of still image shooting and moving image shooting in the present invention will be described. First, the application of the tracking mode in the case of still image shooting will be described with reference to FIG.

  In the still image shooting processing mode (step S51), the subject is displayed on the monitor while the AF operation is continued, and the standby state is maintained until the shutter is turned on (No in step S52 and step S53). When the shutter is turned on (Yes in step S53), it is determined whether or not the automatic tracking AF is turned on (step S54). In step S54, if the AF operation is stopped and the automatic tracking AF is on, the contrast and sharpness enhancement processing is turned off or the noise canceller processing is weakened (step S55), and the photographing processing is performed (step S55). S56). If the automatic tracking AF is off in step S54, the photographing process is performed as it is (step S56). The above enhancement processing contributes to the improvement of the tracking accuracy of automatic tracking AF. However, when actual shooting is performed with this enhancement processing performed, the optimum image quality may not be obtained. If it has been done, it is desirable to release it at that time. Further, since the monitor image is used for confirming the angle of view or the like, some image quality deterioration is allowed.

  Then, after the shooting process, it is determined whether or not the automatic tracking AF setting is on (step S57). If the auto tracking AF setting is on, the contrast or sharpness enhancement process is turned on again or the noise canceller process is strengthened (step S58). ), And starts automatic tracking AF. Then, the photographing standby state is entered (step S59).

  As described above, in the still image shooting mode, tracking of a subject (that is, a moving object) is a process performed during framing before shooting, and tracking of the subject is not necessary during shooting. There is no need to perform sharpness enhancement processing or to increase noise canceller processing. Therefore, as described above, these processes are turned off at the time of shooting, and when the shooting is finished, when the tracking mode is set, the contrast and sharpness enhancement processing is turned on, or the noise canceller processing is strengthened. I am doing so.

  Next, application of the tracking mode in the case of moving image shooting will be described with reference to FIG. In the moving image shooting processing mode (step S61), the standby state is maintained until the shutter is turned on (No in step S62 and step S63). When the shutter is turned on (Yes in step S63), the photographing process is performed (step S64), the photographing standby state is again entered, and the process is terminated (step S65).

  In this way, in the video shooting mode, unlike in the case of still image shooting, it is conceivable to shoot a video while tracking the subject. For example, when the video tracking AF is on, the subject (Movie) Shooting is performed with tracking AF turned on. Even when moving image tracking AF is off, moving image shooting is performed without turning on moving image tracking AF during shooting.

As mentioned above, according to embodiments of the present invention,
1. Since image processing suitable for tracking is performed, tracking accuracy is improved.
2. 2. Control is performed so that different image processing is performed at the time of still image shooting and at the end of still image shooting (or at the time of tracking AF), so that stable tracking accuracy and good shooting image quality can be compatible. By performing contrast and sharpness enhancement processing at the time of tracking, the contrast of the image becomes stronger, so that tracking accuracy is improved (that is, determination of the subject position is increased).
4). Since noise is reduced by performing strong noise canceller processing at the time of tracking, tracking accuracy is improved.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation.

  In the above-described embodiment, the description has been given of performing control so that a similar image is displayed even in a state where the AF is continuously operated in the standby state, but the present invention is not necessarily limited thereto. For example, the AF operation may be started when the first stage of the shutter is pressed. In addition, display of the monitor image is not necessarily required, and for example, control may be performed so that the monitor image is not displayed before shooting.

  Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  Further, each of the above embodiments is realized by the control process of the CPU 50 according to the program. That is, this means that the above program itself realizes the above-described embodiment, and this program itself constitutes the present invention. .

  In the above embodiments, the present invention has been described as an example in which the present invention is mounted on a camera product. However, the present invention can naturally be applied to a camera part of a mobile phone or a PDA other than a single camera product. It is included in the category of “camera” described above.

  In addition, for example, even if some structural requirements are deleted from all the structural requirements shown in each embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the effect of the invention Can be obtained as an invention.

  DESCRIPTION OF SYMBOLS 11 ... Lens, 12 ... CCD, 13 ... Imaging circuit, 14 ... A / D converter, 15 ... Correction circuit, 16 ... Bus, 21 ... FIFO memory, 22 ... On-screen circuit, 23 ... Video output circuit, 23a ... Video output Terminals 24 ... TFT liquid crystal drive circuit 25 ... TFT panel 26 ... Backlight unit 27 ... Frame memory 31 ... Recording buffer 32 ... Recording medium I / F 33 ... Recording medium 40 ... Second CPU DESCRIPTION OF SYMBOLS 41 ... Image compression function, 42 ... Image expansion function, 43 ... Frame memory control function, 44 ... Recording medium access function, 50 ... First CPU, 51 ... System control function, 52 ... ISO sensitivity control function, 53 ... Subject tracking 54: CCD shutter control function, 55: Lens frame aperture control function, 56: Noise canceller function, 57: Control Strike adjustment function, 58 ... sharpness adjustment function, 59 ... AF control function, 61 ... actuator drive circuit, 62 ... actuator, 63 ... lens barrier open / close detection means, 64 ... EEPROM, 65 ... connection detection means, 67 ... key matrix, 71 ... LCD display circuit, 72 ... LCD panel, 75 ... battery, 76 ... battery state detection circuit, 77 ... power supply circuit, 78 ... backup power supply, 531 ... subject contrast detection area setting function, 532 ... subject contrast detection function, 533 ... subject Movement direction determination function, 534... Subject movement amount determination function, 535... AF area determination unit, 671.

Claims (3)

Imaging means for capturing a subject image;
Image processing means for performing image processing on the image output of the imaging means;
Tracking means for tracking the position of the subject moving within the screen based on the image processed image;
AF means for adjusting the focus of the imaging means by moving a focusing area in accordance with tracking by the tracking means, and the image processing means as image processing for the tracking means during the operation of the AF means. A camera which performs image processing for increasing tracking accuracy and cancels image processing for increasing the tracking accuracy for an image recording image after completion of focus adjustment by the AF means.   The camera according to claim 1, wherein the image processing means includes at least one of contrast processing, sharpness processing, and noise canceller processing. The camera according to claim 1, further comprising an image display unit configured to display, as a monitor image, an image subjected to image processing so as to increase tracking accuracy for the tracking unit during the operation of the AF unit.

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