JP4504158B2 - Camera, tracking device, tracking method, and tracking program - Google Patents

Description

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

  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.
Moving body tracking AF is realized by (contrast) pattern detection and tracking based on a captured image output signal, but if the signal is noisy or there is camera shake, an error may occur in subject detection. There is a possibility of detection. Therefore, to improve accuracy, it is necessary to obtain an image signal with less noise and blur, but since an image signal for photographing is used, it cannot be optimized only for tracking.

In addition, moving body tracking AF (tracking by contrast pattern detection) is realized by contrast pattern detection and tracking thereof. However, in order to reduce the false detection as much as possible and improve the accuracy, the outline of the subject can be used. It is preferable that the moving direction is known.
Patent No. 2770957

  An object of the present invention is to provide a camera that realizes tracking AF with higher accuracy, a tracking device and a tracking method applied to the camera.

  Depending on the shooting scene, there are many cases where the moving direction of the subject is known in advance. In one aspect of the present invention, the user can easily set the information in the camera. Thereby, it is possible to realize tracking AF with higher accuracy.

Specifically, the invention according to the aspect of the present invention includes an imaging unit that captures a subject image, and a tracking unit that tracks the position of a subject that moves within a shooting screen based on an image output of the imaging unit. The tracking means sets a tracking detection area including a detection area for detecting a feature point of the subject and a monitoring area arranged in the vicinity of the detection area for detecting movement of the subject in the photographing screen. And when the movement direction of the subject is not predicted , the setting unit arranges the monitoring area evenly around the detection area and can predict the movement direction of the subject. Is characterized in that the monitoring area is biased and arranged on the predicted movement direction side of the subject.

  Note that the present invention is not limited to the above-described camera only, and is also established as an invention of a tracking device and a tracking method applied to a camera having the above functions.

  According to the present invention, tracking AF with higher accuracy can be realized.

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. It is a block diagram regarding the tracking function of the camera which concerns on this embodiment of this invention. FIG. 3 is an overview of the back of the camera. 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 the removable recording medium 33 or read from the recording medium 33, and an 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 41. 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 automatically 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 control function performs control for canceling noise in the image information. A contrast adjustment function 57 and a sharpness adjustment function 58 adjust contrast and sharpness, respectively. 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 671 and the like. 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 periphery of 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. Details will be described below.

In the camera configured as described above, as shown in FIG. 3, the TFT panel 25, the key matrix 67, and the viewfinder 80 are arranged on the back surface. In the embodiment of the present invention, in the case where the moving direction of the subject can be predicted (for example, a train running on a track), the moving direction (to be precise, the “predicted moving direction”) is simply “moving direction”. Or may be referred to as “direction”) in advance, the tracking accuracy is improved. Therefore, as shown in FIG. 3, a cross button 671, a tracking AF on / off button 672, and an OK / menu button 673 are prepared as the key matrix 67. On the TFT panel 25, the moving direction 251 of the subject input by the user is displayed.
In the above configuration, the operation will be briefly described with reference to FIGS. FIG. 4 is a diagram for explaining the state of the tracking AF, and FIG. 5 is a diagram for explaining a difference in the tracking operation when the moving direction of the subject is known and not.
Consider the case where the subject 92 is ring-shaped as shown in FIG. When the power is turned on, the focusing center 91 is set at the center of the screen as a default. Here, when the tracking AF is on, the detection area 93 detects a subject 92 (around: a feature point). Here, when the subject 92 moves from the initial position A to the moving position B, the focusing center 91 follows the movement of the subject 92 and moves to the center of the subject 92, and the detection area 93 also moves the subject 92. Move accordingly.

At this time, in normal tracking AF, since the moving direction of the subject is unknown, as shown in FIG. 5A, the movement of the subject 92 is set with one area outside the detection region 93 as the monitoring region 94. The direction and speed are detected and tracked. In this case, for example, consider a case where the subject 92 has moved from the initial position A to the moving position B and the moving position C.
First, when the subject 92 moves to the movement position B, since the subject 92 is detected in the peripheral region 94 (the peripheral region 94 on the left side in the figure), it is detected that the subject 92 has moved to the left side in the drawing. Is done. However, if the subject 92 quickly moves to the movement position C, the subject 92 cannot be detected in the peripheral area 94, and the subject 92 cannot be tracked. Therefore, if the area of the peripheral area 94 is increased, it can cope with a large movement in a short time, but the processing load by the CPU increases and the calculation is not in time.
Therefore, in the embodiment of the present invention, when the tracking AF is turned on by the tracking AF on / off button 672, the predicted movement direction 251 of the subject is displayed on the TFT panel 25. When the user instructs the predicted moving direction 251 using the cross button 671 (leftward in FIG. 5) and sets the moving direction in a desired direction, the OK / menu button 673 is used for determination. As a result, as shown in FIG. 5B, the monitoring region 94 is set on the set moving direction side (left side in the figure), so that even when the subject 92 moves more than one area, Tracking is possible even when the amount of movement of the subject 92 is large. In addition to the above functions, the cross button 671 is used for menu selection and frame advance, and the OK / menu button 673 is used for displaying a menu. Of course, when the moving direction of the subject cannot be specified, the peripheral region 94 remains equal.

  A specific operation will be described below. FIG. 6 is a flowchart showing an operation example in the tracking mode, and FIG. 7 is a flowchart showing an input flow in the moving direction of the subject.

  In FIG. 6, first, the camera is turned on (step S51). Next, the automatic tracking AF is turned on (step S52). Then, it is determined whether or not the automatic tracking AF is on (step S53). If the automatic tracking AF is on, the moving direction of the subject is input as will be described in detail later (step S54). If the moving direction of the subject is input or if the automatic tracking AF is off in step S53, it is determined whether or not the photographing operation of the subject is on (that is, whether the shutter is on) (step S55). If is off, the process returns to step S53. If the shooting operation is on in step S55, the shooting operation is performed (step S56), and the operation ends.

Next, the flow of setting input for the moving direction of the subject will be described with reference to FIG.
When the automatic tracking AF is turned on in step S52 of FIG. 6, the display 251 indicating the moving direction of the subject is displayed on the TFT panel 25 as described above. This display 251 can be changed with the cross button 671.
First, when the cross button 671 is operated (step S61), it is determined whether or not the cross button 671 is operated (step S62). If the cross button 671 is pressed, it is determined whether the direction of the cross button 671 is more than 90 degrees away from the moving direction of the currently displayed subject (that is, the predicted movement direction) (step). S63). In step S63, when the currently set direction and the input direction are 90 degrees or less, the moving direction is set between the currently set direction and the input direction (step S64). . If the currently set direction and the input direction exceed 90 degrees in step S63, the moving direction is set in the input direction (step S65).
Then, the operations from step S61 to step S65 are repeated until the direction input is completed (step S66). If it is determined in step S62 that the cross button 671 has not been operated, the process proceeds to step S66.

An example of the operation when the cross button 671 is pressed in the above operation will be described with reference to FIG. In the following description, it is assumed that the upward direction is 0 degree and the angle increases in the clockwise direction.
First, when the automatic tracking AF is turned on, as shown in FIG. 8A, it is assumed that the direction of the arrow of the display 251 (hereinafter referred to as “arrow” for convenience of explanation) is upward. At this time, if the right button is pressed, the current arrow is upward (0 degrees) and the cross button operation is right (90 degrees), so the angle between the two arrows is 90 degrees. As shown in FIG. 8B, the arrow points in the 45-degree direction. If the right button is further pressed in this state, the current arrow is in the 45 degree direction and the cross button operation is in the right direction (90 degrees), so that (90−45) /2+45=67.5 is obtained. As shown in (c), the arrow points in the direction of 67.5 degrees.
Next, when the down button is pressed in the state of FIG. 8A, the current arrow direction is 0 degrees and the downward direction is 180 degrees, so the angle formed by the two arrows is 180 degrees. Thus, as shown in FIG. 8D, the arrow points in the direction in which the cross button 671 is pressed (that is, downward in FIG. 8D). The same applies when the down button is pressed in the state of FIG. In addition, when the right button is pressed in this state, the angle formed by the two arrows is 90 degrees, and the arrow is directed in the direction of 135 degrees by the same operation as described above. When only the left and right keys are used instead of the cross button 671, the forward direction is changed by a predetermined angle by pressing the pointing direction counterclockwise with the left key and clockwise with the right key. Also good.

As mentioned above, according to embodiments of the present invention,
1. Since the arrangement of the peripheral area is changed according to the state of the subject (particularly the moving direction), an appropriate detection area can be set. In addition, since it can be determined efficiently with a small detection area, tracking can be performed in a short time.
2. Since focus adjustment is performed based on the position of the subject to be tracked, it is possible to reliably perform in-focus shooting.

The present invention is not limited to the above embodiments.
For example, in the above embodiment, the moving direction of the subject is set with the cross button. However, when the camera has a jog dial, the moving direction of the subject is set by rotating the jog dial. Also good. In this case, for example, the arrow may rotate in the same direction as the jog dial rotates. Further, in addition to the cross button and the jog dial, for example, a touch pad or other pointing device may be used.
In the above embodiment, the direction of the arrow is determined according to the current direction of the arrow and the operation direction of the cross button. However, the present invention is not limited to this. Any method can be used.
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, in the implementation stage, various modifications can be implemented without departing from the scope of the invention. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  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.

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. Overview of the back of the camera. The figure for demonstrating the mode of tracking AF. The figure for demonstrating the difference of a tracking operation | movement in the case where the moving direction of a to-be-known object is not known. The flowchart which shows the operation example in tracking mode. The flowchart which shows the flow of input of a to-be-photographed object's moving direction. The figure which shows the operation example when the cross button is pushed.

Explanation of symbols

  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 (10)

In a camera including an imaging unit that captures a subject image, and a tracking unit that tracks the position of a subject that moves within a shooting screen based on an image output of the imaging unit.
The tracking means is configured to set a tracking detection area including a detection area for detecting a feature point of a subject and a monitoring area arranged in the vicinity of the detection area for detecting movement of the subject in the photographing screen. Having means,
The setting means, when the movement direction of the subject is not expected, the monitoring area evenly disposed around the detection area, if the moving direction of the subject is predictable, predicted movement of the object A camera characterized in that the monitoring area is arranged to be biased toward a direction side.   The operation unit for the photographer to set the predicted moving direction of the subject is further provided, and the setting unit arranges the peripheral region in a biased manner based on the setting of the operation unit. 1. The camera according to 1. A recording medium on which a photographed image photographed by the imaging means is recorded;
A control unit that reads a captured image from the recording medium and displays the image on a display unit;
The operation means is used for at least an operation of feeding a photographed image displayed on the display unit, and includes at least four directions indicating units arranged on the back side of the camera. Item 3. The camera according to item 2. The camera according to any one of claims 1 to 3 , further comprising a focusing unit that adjusts a focus of the imaging unit based on a position of the subject tracked by the tracking unit. . The camera according to any one of claims 1 to 4, characterized in that it comprises an image display means for displaying an image and the predicted moving direction based on the image output of the imaging means. A tracking device that is applied to a camera having an imaging unit that captures a subject image, the tracking device tracking a position of a subject that moves within a shooting screen based on an image output of the imaging unit.
Setting means for setting within the shooting screen a detection area for detecting a feature point of the subject and a tracking detection area that is arranged in the vicinity of the detection area and that includes a monitoring area for detecting movement of the subject;
The setting means, when the movement direction of the subject is not expected, the monitoring area evenly disposed around the detection area, if the moving direction of the subject is predictable, predicted movement of the object A tracking device characterized in that the monitoring area is biased toward the direction side.   The tracking device according to claim 6, further comprising an operation unit configured to set a predicted movement direction of the subject, wherein the setting unit is arranged to bias the peripheral area based on the setting of the operation unit.   The tracking device according to claim 6 or 7, wherein the tracking device tracks the position of a subject for designating a focusing area of a focusing unit that performs focus adjustment of the imaging unit. A tracking method applied to a camera having an imaging unit that captures a subject image, the tracking method tracking a position of a subject moving within a shooting screen based on an image output of the imaging unit.
A tracking detection area consisting of a detection area for detecting a feature point of the subject and a monitoring area for detecting movement of the subject arranged in the vicinity of the detection area is set in the shooting screen,
When the moving direction of the subject is not expected, the monitoring area evenly disposed around the detection area, if the moving direction of the subject is predictable, the monitoring predicted movement direction of the subject A tracking method characterized in that the regions are arranged in a biased manner. A program for causing a computer of a camera to execute a tracking method applied to a camera having an imaging unit that captures a subject image, the position of the subject moving in a shooting screen based on an image output of the imaging unit In the program that realizes the tracking method to track,
A function for setting a tracking detection area, which is composed of a detection area for detecting feature points of a subject and a monitoring area for detecting movement of the subject arranged in the vicinity of the detection area, in the shooting screen;
When the moving direction of the subject is not expected, the monitoring area evenly disposed around the detection area, if the moving direction of the subject is predictable, the monitoring predicted movement direction of the subject A tracking program for causing a camera computer to execute a function of arranging areas in a biased manner.

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