JP2011059977A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To track a subject image by adjusting a tracking domain to have a more suitable size, even when a subject is moved in the far-and-near direction to an imaging device. <P>SOLUTION: This imaging device is equipped with: an imaging means imaging the subject image and generating image data successively; a tracking domain setting means setting a tracking domain to image data generated successively by the imaging means based on tracking information for tracking the subject image; and a relational information acquisition means acquiring relational information between determination domains from a first determination domain set on a part of the image data and a second determination domain having a different size from the first determination domain. When setting a tracking domain to the image data, the tracking domain setting means adjusts the size of the tracking domain corresponding to the size of change of second relational information acquired by the relational information acquisition means in the image data and first relational information acquired by the relational information acquisition means in the image data acquired beforehand. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging apparatus capable of setting a tracking area for a captured image and tracking a subject image in the tracking area. More specifically, the present invention relates to an imaging apparatus capable of automatically adjusting the size of a tracking area for tracking a subject image.

  As a conventional imaging device, there is one as described in Patent Document 1.

  The imaging device disclosed in Patent Document 1 is intended to set a tracking area having an optimum size for a moving subject. In this imaging apparatus, the size of the tracking area is adjusted based on the focal length of the imaging lens in order to achieve the object.

Japanese Patent Laid-Open No. 7-30801

  Some imaging apparatuses track a subject image in a captured image in a tracking area of a certain size based on subject characteristic information.

  In such an imaging apparatus, when the subject approaches or moves away, the tracking accuracy is deteriorated because the tracking area has a certain size. For example, as shown in FIG. 17, when the subject approaches the imaging device, the proportion of the subject image in the captured image increases. For this reason, when the tracking area is set in the captured image, the imaging apparatus increases information similar to the feature information in the captured image, and the tracking area having a certain size cannot be set at a more appropriate position. Further, when the subject moves away from the imaging device, the proportion of the subject image in the captured image decreases. For this reason, when the tracking device sets a tracking area in a captured image, information similar to feature information is reduced in the captured image, and a tracking region having a certain size cannot be set at a more appropriate position.

  Therefore, in order to solve the above-described problem, the present invention provides an imaging apparatus capable of tracking a subject image by adjusting a tracking area to a more optimal size even when the subject moves in a perspective direction with respect to the imaging apparatus. The purpose is to provide.

  That is, the imaging apparatus of the present invention captures subject images and sequentially generates image data, and based on tracking information for tracking the subject image, the image data sequentially generated by the imaging unit. A tracking area setting means for setting a tracking area, a relationship for acquiring relation information between determination areas from a first determination area set in a part of the image data and a second determination area having a different size from the first determination area Information acquisition means. When the tracking area setting means sets a tracking area for certain image data, the relation information is acquired with the second relation information acquired by the relation information acquisition means with the image data, and the image data acquired previously. The size of the tracking area is adjusted based on the change in the first relation information acquired by the information acquisition means.

  In this way, the imaging apparatus can adjust the size of the tracking area based on the change in the relationship information of certain image data and the relationship information of previous image data. Therefore, even when the subject moves in the perspective direction with respect to the imaging apparatus, the subject image can be tracked by adjusting the tracking area to a more optimal size.

  According to the present invention, the imaging device can track the subject image by adjusting the tracking area to a more optimal size even when the subject moves in the perspective direction with respect to the imaging device.

The perspective view of the digital camera which concerns on this Embodiment Configuration diagram of a digital camera according to the present embodiment The figure for demonstrating the example of a transition of the display screen of the digital camera which concerns on this Embodiment The figure for demonstrating operation | movement when a tracking area | region is set to the image data A which concerns on this Embodiment. The figure for demonstrating the specific operation | movement when a tracking area | region is set to the image data A which concerns on this Embodiment. The figure for demonstrating BM information of the image data which concerns on this Embodiment The figure for demonstrating the acquisition method of the color ratio which concerns on this Embodiment. The figure for demonstrating the acquisition method of the tracking information which concerns on this Embodiment The figure for demonstrating the setting operation | movement of a determination area | region based on the tracking area | region which concerns on this Embodiment. The figure for demonstrating operation | movement when the tracking area | region is set in the image data B which concerns on this Embodiment. The figure for demonstrating the operation | movement which adjusts the size of a tracking area | region in the image data B which concerns on this Embodiment. The figure for demonstrating the operation | movement which adjusts the size of a tracking area | region in the image data which concerns on this Embodiment. The figure for demonstrating the relationship of the tracking area | region and determination area | region which concerns on other embodiment. A flowchart showing an operation example of the digital camera according to the present embodiment A flowchart showing an operation example of the digital camera according to the present embodiment The figure for demonstrating the adjustment operation | movement of the magnitude | size of the tracking area at the time of the tracking area setting operation | movement which concerns on this Embodiment. Illustration for explaining the problem

(Embodiment 1)
An embodiment of the present invention will be described with reference to the drawings. This will be specifically described below. In the present embodiment, the digital camera 1 will be described as an example.

<1. Overview of the present embodiment>
The digital camera 1 sets a tracking area for the image data generated by the CCD image sensor 12. On the other hand, the digital camera 1 determines the size of the tracking area based on the change in the relationship information (approximation in FIGS. 11 and 12) in the first and second determination areas set in a part of the past and current image data. Adjust. That is, when the subject approaches the digital camera 1, the difference in the relationship information between the first determination area and the second determination area is smaller than in the past (FIG. 11). On the other hand, when the subject moves away from the digital camera 1, the difference in the relationship information between the first determination area and the second determination area becomes larger than in the past (FIG. 12). In this embodiment, the size of the tracking area is adjusted using this relationship.

  The digital camera 1 displays the image data and the tracking area whose size has been adjusted on the liquid crystal monitor 20 as a display screen. For example, image data and tracking areas 71 to 74 are displayed on the liquid crystal monitor 20 of the imaging apparatus as a display screen, for example, as shown in FIG.

  As a result, the digital camera 1 can track the subject image by adjusting the tracking area to a more optimal size even when the subject moves in the perspective direction.

<2. Configuration Example (FIGS. 1 and 2)>
FIG. 1 is a perspective view of a digital camera 1 according to the present embodiment. FIG. 2 is a block diagram showing a configuration of the digital camera 1 according to the present embodiment. A specific configuration will be described below.

  The optical system 11 collects optical signals from the subject and forms a subject image on the CCD image sensor 12. The optical system 11 includes an objective lens 111, a zoom lens 112, a focus lens 113, and an aperture / shutter 114.

  The zoom lens 112 is driven by the zoom driving unit 115 and adjusts the range (view angle) in which the subject image is captured. That is, the zoom lens 112 can adjust the focal length. The focus lens 113 is driven by the focus drive unit 116 to adjust the focus. The zoom drive unit 115 includes a cam mechanism for moving the zoom lens 112 and an actuator for driving the cam mechanism, and drives the zoom lens 112 in accordance with control from the controller 17. The focus driving unit 116 includes a cam mechanism for moving the focus lens 113, an actuator for driving the cam mechanism, and the like. The focus driving unit 116 drives the focus lens 113 in accordance with control from the controller 17.

  The diaphragm / shutter 114 is a member that serves as both a diaphragm and a shutter. The aperture / shutter 114 is driven by an aperture / shutter driver 117. The stop is composed of five blades and adjusts the amount of light passing through the optical system 11. The shutter is opened and closed to adjust the amount of light hitting the CCD image sensor 12 with time. The aperture / shutter drive unit 117 includes a cam mechanism and an actuator for driving the cam mechanism, and drives the aperture / shutter in accordance with control from the controller 17.

  In the present embodiment, the diaphragm / shutter 114 that serves both as a diaphragm and a shutter is provided. However, the present invention is not limited to this, and the diaphragm and the shutter may be provided separately. In this case, for example, the shutter is not provided in the optical system, and only the diaphragm is provided in the optical system. At this time, the shutter may be provided between the optical system and the CCD image sensor. In this way, since the shutter is provided by a member different from the optical system, it can be applied to a lens exchange type digital camera.

  The CCD image sensor 12 captures a subject image formed by the optical system 11 and generates image data. The CCD image sensor 12 captures a subject image based on the pulse signal supplied from the timing generator 121 and generates image data. The timing generator 121 is configured by an integrated circuit such as an LSI and supplies a pulse signal to the CCD image sensor 12. Here, the pulse signal that the timing generator 121 supplies to the CCD image sensor 12 supplies, for example, 30 frame readout pulse signals per second. As a result, the CCD image sensor 12 can acquire image data of a frame every 1/30 second. A primary color filter is used as the color filter.

  The AD converter 13 converts the image data generated by the CCD image sensor 12 into digital data.

  The image processing unit 14 performs predetermined processing on the image data converted into digital data. Examples of the predetermined process include an interpolation process, a gamma conversion, a YC conversion, an electronic zoom process, a compression process, and an expansion process, but are not limited thereto. Here, in the present embodiment, the image processing unit 14 converts the image data converted into digital data into BM data and YC data. That is, the image processing unit 14 generates BM data and YC data. The BM data is information indicating the color ratio in the image data. Details of the BM data will be described in Chapter 3. The image processing unit 14 can be realized by an LSI, for example.

  The buffer memory 15 functions as a work memory when the image processing unit 14 performs image processing and when the controller 17 performs control processing. The buffer memory 15 can be realized by, for example, a DRAM.

  The flash memory 16 is used as a built-in memory. The flash memory 16 can store a program for controlling the controller 17, a set value, and the like in addition to image data subjected to image processing (data after interpolation processing). In the present embodiment, face information is stored. The face information is used to detect a person's face from the image data. That is, the face information is used when determining whether face information exists in the image data. As the face information, for example, template information corresponding to the contour of the entire face and facial components (eyes, nose, ears, etc.) can be considered.

  The controller 17 controls each part of the digital camera 1. The controller 17 may be realized by a microcomputer or a hard-wired circuit. The various controls of the controller 17 will be described in detail later.

  The shake detector 30 is composed of a gyro sensor or the like, and detects vibration of the own device. The shake detector 30 detects a first gyro sensor that detects rotational vibration in the vertical direction around the horizontal axis of the digital camera 1 and a first gyro sensor that detects rotational vibration in the horizontal direction around the vertical axis of the digital camera 1. 2 gyro sensors. That is, the shake detector 30 detects the motion angular velocity of the digital camera 1. The controller 17 obtains the motion angular velocity from the shake detector 30 and integrates this angular velocity to calculate the angular velocity of the digital camera 1. This angular velocity is the shake amount of the digital camera 1. The shake amount is calculated by a value such as −300 to 300 deg / sec, for example.

  The card slot 18 is a slot for inserting and removing the memory card 19. The card slot 18 may have a function of controlling the memory card 19. The memory card 19 includes a flash memory or the like. The memory card 19 can store image data (data after interpolation processing) that has been subjected to image processing by the image processing unit 14.

  The liquid crystal monitor 20 displays image data and various settings of the digital camera 1. Note that an organic EL display or the like can be used instead of the liquid crystal monitor 20.

  The operation unit 21 is a general term for operation members attached to the exterior of the digital camera 1. The operation unit 21 may be a cross key or a push button.

  In the present embodiment, there is a shutter switch 211 as one push button of the operation unit. The shutter switch 211 is provided on the upper surface of the digital camera 1 and can detect half-press and full-press from the user. When a half-press or full-press operation is performed by the user, the shutter switch 211 outputs an operation signal corresponding to the operation to the controller 17.

  In the present embodiment, a zoom lever 212 is provided as one member of the operation unit 21. The zoom lever 212 changes the focal length of the digital camera 1 in accordance with an operation from the user. The zoom lever 212 outputs an operation signal to the controller 17 when operated by the user. As a result, the controller 17 can send a control signal for changing the focal length to the zoom lens 112.

<3. BM data and YC data generated by image processing unit>
The image processing unit 14 can generate BM data and YC data from the image data generated by the CCD image sensor 12. The BM data is used for obtaining relationship information, adjusting WB, adjusting exposure, and the like. The YC data is used to set a tracking area based on the tracking information, to generate a display screen of the liquid crystal monitor 20, and to generate image data to be recorded on the memory card 19.

<3.1 Image Data Input from AD Converter 13 (Before Image Processing)>
Image data input from the AD converter 13 is charge data of each pixel. When the CCD image sensor 12 is provided with a primary color filter, each pixel corresponds to red, green, or blue. Therefore, the image processing unit 14 can determine which color each pixel corresponds to in the image data if the arrangement of the primary color filters is stored in advance.

<3.2 BM data>
The BM data is information indicating the color ratio of each divided area (hereinafter, divided area) when the image data is divided into a plurality of parts. The image processing unit divides the image data into 16 × 16 areas. The image processing unit acquires the color ratio from each divided region. Hereinafter, the BM data acquisition method of the image processing unit 14 will be described with reference to FIG.

  The image processing unit 14 divides the information input from the AD converter 13 for each region. For example, charge data for each pixel in a certain divided area A is acquired. Since the image processing unit 14 can determine which pixel corresponds to which color, the information is accumulated for each of red, green, and blue based on the information obtained for each region (FIG. 6). As a result, the image processing unit can acquire the size of each color of red, green, and blue in each region. The image processing unit 14 is configured to express each BM size in each region with 12 bits, for example. Therefore, each value of R, G, B takes a value of 0-4095.

<3.3 YC data>
The YC data is obtained by performing YC (YCbCr) conversion after performing interpolation processing on image data. The image processing unit 14 converts the brightness “Y (luminance information)”, color information “Cb (luminance signal and blue color difference), and Cr (luminance signal and red color difference) into each pixel by YC (YCbCr) conversion. Can be obtained.

  The YC data acquisition method of the image processing unit 14 will be described with reference to FIG. The image processing unit 14 performs gamma processing and white balance gain on the input image data, and then performs interpolation processing. The interpolation processing can be realized by, for example, Bayer-RGB conversion from R / Gr / Gb / B to R / G / B. As a result, each pixel includes all the information of RGB. Then, the image processing unit 14 converts the RGB information of each pixel into YCbCr. Thus, the image processing unit 14 can obtain YC data. Note that YC conversion is a general technique, and thus description thereof is omitted.

<4. Relation Information and Color Information Obtained by Image Processing Unit (FIGS. 4, 5, 7, and 8)>
In the present embodiment, as shown in FIG. 4, the image processing unit 14 is configured to be able to acquire the degree of approximation (an example of relationship information) and color information (an example of tracking information) from image data. Specifically, as shown in FIG. 5, the image processing unit 14 can obtain the degree of approximation between the first determination area 81 and the second determination area 91 based on the BM data. Further, as shown in FIG. 5, the image processing unit 14 can obtain the color information of a certain tracking area 71 based on the YC data. Details will be described below.

<4.1. Approximation between judgment areas (related information)>
A method of obtaining the degree of approximation between the determination areas will be described with reference to FIG. FIG. 4 shows the color ratio of the first determination area 81 and the color ratio of the second determination area 91 obtained based on the BM data.

  The first determination area 81 and the second determination area 91 are set for YC data (not shown) of the image data A. That is, the first determination area 81 and the second determination area 91 are set in the image data A so as to correspond to the pixels of the image data (FIG. 7). For example, when the image data A is assumed to be 1600 × 1600 pixels, the first determination area 81 is set at the positions of the upper left end (750, 720) and the lower right end (900, 880). The second determination area 91 is set at the positions of the upper left end (650, 690) and the lower right end (950, 910). In this way, the first determination area and the second determination area are set as part of the YC data.

  The image processing unit 14 acquires the color ratio of the first determination region 81 from the BM data using the first determination region 81 set in this way. At this time, the image processing unit 14 extracts a divided region that includes at least part of the pixels in the first determination region 81. For example, in the upper right diagram in FIG. Then, the image processing unit 14 acquires and integrates the color ratios (red, green, and blue) of each region in the extracted divided regions. In this way, the image processing unit 14 can obtain the color ratio of the first determination area 81. In a similar manner, the image processing unit 14 can obtain the color ratio of the second determination area 91.

  Next, the image processing unit 14 calculates the degree of approximation using the color ratio of the first determination area 81 and the color ratio of the second determination area 91. Here, the first determination area 81 and the second determination area 91 have different area sizes. For this reason, calculating the approximation degree in this state complicates the calculation. Therefore, in the present embodiment, the respective color ratios when the first determination region 81 and the second determination region 91 are converted to the same area are obtained. Then, the degree of approximation is obtained by subtracting the obtained color ratio.

  For example, when the area ratio between the first determination region 81 and the second determination region 91 is 1: 4 as shown in FIG. 7, the color ratio of each of the second determination regions (R / G / B) is divided by 4. . Then, the color ratio of the first determination area 81 and the color ratio of the second determination area 91 are subtracted. In this way, the image processing unit 14 can obtain the degree of approximation between the first determination area 81 and the second determination area 91.

<4.2. Color information in the tracking area>
A method for obtaining the color information in the tracking area will be described with reference to FIG. FIG. 8 is a diagram showing color information obtained based on YC data. In FIG. 8, a tracking area 71 is set in the image data after YC conversion. Similar to the determination area, the tracking area 71 is set in the image data in a form corresponding to the pixels of the image data.

  The image processing unit 14 acquires color information from the YC data using the tracking area 71 set in this way. More specifically, the image processing unit 14 converts each pixel of YC data in the tracking area into a hue angle (0 to 359 degrees). That is, the image processing unit 14 acquires how many times each pixel corresponds to the hue angle. For example, a certain pixel has a hue angle of 5 degrees. Then, the image processing unit 14 distributes each pixel converted into the hue angle into a color region obtained by dividing the entire hue angle by 40. Since the entire color angle is divided into 40, the color area is divided such that the first color area is 0 to 8 degrees, the second color area is 9 to 17 degrees, and so on. Therefore, for example, when a certain pixel is converted to a hue angle of 5 degrees, the image processing unit 14 distributes the pixel to the first color region (0 to 8 degrees). The image processing unit 14 calculates the number of pixels distributed as described above for each color region.

  In this way, the image processing unit 14 can acquire color information of a certain tracking area from the YC data.

  In addition, the method of converting each pixel of YC data into a hue angle converts, for example, YCbCr into RGB. This can be done by converting RGB into hue angle. For example, YCbCr may be directly converted into a hue angle based on table information.

<4. Example of Operation (FIGS. 14, 15, and 4 to 12)>
Next, an operation example of the digital camera 1 according to the present embodiment will be described. Hereinafter, an operation for setting a tracking area in image data by a user operation and an operation for continuously setting a tracking area set in a part of the image data in sequentially generated image data will be described.

<4.1. Tracking region setting operation by user operation (FIG. 14)>
First, an operation in which the imaging apparatus sets a tracking area in image data by a user operation will be described. FIG. 14 is a flowchart for explaining the tracking region setting operation.

  The image processing unit 14 acquires image data (S1). At this time, the image processing unit 14 generates YC data and BM data from the image data. The image processing unit 14 detects whether a tracking area is set by a user operation (S2). When the image processing unit 14 detects that a predetermined button has been operated by the user, the image processing unit 14 determines that a tracking region has been set for the subject located at the center of the image data (YC data). In the present embodiment, the predetermined button is a lower button of the cross key. That is, when the user tracks the subject in the tracking area, the user moves the angle of the digital camera 1 to move the subject to be tracked to the center of the image data (YC data). Then, the user presses the down button when the subject to be tracked moves to the center of the image data. Thus, the user can set a tracking area for the subject to be tracked.

  Returning to the description of FIG. 14, the image processing unit 14 adjusts the size of the tracking region (S3). Specifically, it can be realized by the following method.

  In the image data (YC data), the image processing unit 14 provides a temporary area and an auxiliary area such as the pattern 1 in FIG. 16 at a position corresponding to the set tracking area. The image processing unit 14 acquires color information from the temporary area, the first auxiliary area, and the second auxiliary area set in this way. The image processing unit 14 determines whether the color information of the temporary area and the auxiliary area can be separated. Here, the color information of the temporary area and the auxiliary area can be separated means that the color area having the largest number of pixels in the color information does not match. Therefore, for example, the image processing unit 14 has the largest number of pixels in the first color area (0 to 8 degrees) in the color information of the temporary area, and the second color area (9 to 17 degrees in the color information of the first auxiliary area). ) Is the largest in number, it is determined that the color information of the temporary area and the first auxiliary area can be separated. Note that the color information in the temporary area and the auxiliary area can be acquired by the same method as the color information in the tracking area.

  In the present embodiment, the image processing unit 14 determines whether or not the color information of the temporary area can be separated from the color information of both the first auxiliary area and the second auxiliary area. Therefore, when the color information of the temporary area can be separated from the color information of both the first auxiliary area and the second auxiliary area, the image processing unit 14 determines the size of the current temporary area as the size of the tracking area. To do. On the other hand, when the color information of the temporary area cannot be separated from the color information of both the first auxiliary area and the second auxiliary area, the image processing unit 14 has a temporary area larger than the temporary area, such as the pattern 2 in FIG. And an auxiliary area. In this way, the image processing unit 14 increases the size of the temporary area until the temporary area and the auxiliary area can be separated. Thus, the image processing unit 14 can adjust the size of the tracking area to a more optimal size when setting the tracking area. In this way, the image processing unit 14 adjusts the size of the tracking area set in step S2 (S3).

  Thereafter, the image processing unit 14 acquires color information in the tracking area and stores it in the buffer memory 15 (S4). The color information in this tracking area is an example of tracking information. The image processing unit 14 stores information indicating the set position / size of the tracking area in the image data (YC data). For example, the information indicating the set position / size of the tracking area is information such as the upper left end (750, 720) and the lower right end (900, 880).

  Next, the image processing unit 14 sets a first determination area at the same position as the tracking area in the image data (YC data). In addition, the image processing unit 14 sets a second determination area in the image data (YC data) that is twice as long as the first determination area. For example, the image processing unit 14 sets the first determination region 81 and the second determination region 91 at the position of the image data A (YC data) as shown in FIG.

  Then, as shown in FIG. 7, the image processing unit 14 starts from a position corresponding to the first determination area 81 and the second determination area 91 set in the image data A (YC data) in the image data A (BM data). The color ratio is acquired (S5). Further, as shown in FIG. 7, the image processing unit 14 calculates the degree of approximation of the first determination area 81 and the second determination area 82 based on the acquired color ratio, and stores it in the buffer memory 15 (S6). Here, the degree of approximation calculated and stored by the image processing unit 14 is referred to as a first degree of approximation.

  Here, the image processing unit 14 stores information indicating the set positions and sizes of the set first and second determination areas (S7). For example, the information indicating the set position / size of the first determination area is information such as the upper left end (750, 720) and the lower right end (900, 880), as in the tracking area. Information indicating the set position / size of the second determination area is information such as the upper left end (650, 690) and the lower right end (950, 910).

  The image processing unit 14 displays the image data and the tracking area on the liquid crystal monitor 20 as a display screen (S8). For example, the image data A in FIG. 3 is displayed as a display screen. Thereafter, the image processing unit 14 repeats the tracking operation for the image data (S9).

<4.2. Tracking operation for image data (repetition) (FIG. 15)>
A tracking operation for image data in the image processing unit 14 will be described. FIG. 15 is a flowchart for explaining the tracking operation.

  First, the image processing unit 14 acquires new image data from the AD converter 13 (T1). At this time, the image processing unit 14 generates YC data and BM data from the image data. The image processing unit 14 sets a new tracking area in the image data (YC data) acquired in step T1 based on the color information in the tracking area stored in the buffer memory 15 (T2).

  A method for setting a new tracking area based on color information will be described. The image processing unit 14 sets a search area larger than the past tracking area in the image data (YC data) acquired in step T <b> 1 based on information indicating the set position / size of the past tracking area. The image processing unit 14 searches the image data (YC data) in the search area for an area that most closely matches the color information of the tracking area. The image processing unit 14 sets a new tracking area in the area searched in this way. At this time, the tracking area set by the image processing unit 14 has the same size as the past tracking area.

  Returning to the description of FIG. 15, the image processing unit 14 determines whether or not the tracking accuracy has deteriorated when the tracking area is set in step S4 (T3). Here, the determination of the deterioration of the tracking accuracy can be realized by the following method, for example.

  The deterioration of the tracking area can be determined, for example, by comparing the color information of the tracking area stored in the buffer memory 15 with the color information in the tracking area set in step T2. For example, in the present embodiment, the image processing unit 14 has the largest number of pixels in the color area that is included most in the color information stored in the buffer memory 15 and the color information in the tracking area set in step T2. The number of pixels in the included color area is compared. The image processing unit 14 determines that the tracking accuracy has deteriorated when the difference in the number of pixels in the color region is equal to or greater than a certain threshold value. On the other hand, the image processing unit 14 determines that the tracking accuracy has not deteriorated when the difference in the number of pixels in the color region is less than a certain threshold. Accordingly, the image processing unit 14 can determine whether or not the tracking accuracy has deteriorated.

  If the tracking accuracy has not deteriorated, the image processing unit 14 proceeds to Step T9. On the other hand, when the tracking accuracy is deteriorated, the image processing unit 14 determines whether or not the setting position / size information of the first and second determination areas stored in the buffer memory 15 as shown in FIG. A first determination area 82 and a second determination area 92 are set in the acquired image data (BM data). Then, the image processing unit 14 acquires the respective color ratios from the positions corresponding to the first determination area 82 and the second determination area 92 (T4). Thereafter, the image processing unit 14 calculates the degree of approximation of the first and second determination areas based on the color ratio of the first determination area 82 and the color ratio of the second determination area 92 (T5). In the present embodiment, the degree of approximation calculated in step T5 is referred to as a second degree of approximation.

  The image processing unit 14 compares the approximation degree (first approximation degree) stored in the buffer memory 15 with the approximation degree (second approximation degree) calculated in step T5. Specifically, the image processing unit 14 determines whether or not the difference between the first approximation degree and the second approximation degree is equal to or greater than a predetermined value (T61). If the difference between the first approximation degree and the second approximation degree is less than the predetermined value, the image processing unit 14 proceeds to Step T9. That is, the image processing unit 14 does not change the size of the tracking area, assuming that the size of the subject has not changed significantly.

On the other hand, when the difference between the first approximation degree and the second approximation degree is greater than or equal to a predetermined value, the image processing unit 14 determines whether or not the second approximation degree is smaller than the first approximation degree (T62).
If the second degree of approximation is smaller than the first degree of approximation, the image processing unit 14 adjusts the size of the tracking area to be enlarged (T7). In this case, as illustrated in FIG. 11, the image processing unit 14 determines that the subject has approached the imaging apparatus. On the other hand, when the second approximation is not smaller than the first approximation, the image processing unit 14 adjusts the size of the tracking area to be reduced. In this case, as illustrated in FIG. 12, the image processing unit 14 determines that the subject has moved away from the imaging device.

  Here, the tracking region adjustment method can be realized by the following method, for example. Although two methods are illustrated, it is not restricted to this. In this embodiment, it is assumed that the first method is used.

  The first method is a method of increasing or decreasing the size of the tracking area defined in advance by one step.

  The tracking area is defined in advance with a plurality of sizes. For example, when the entire screen is QVA 160 × 120 pixels, the image processing unit can define 16 × 16 pixels, 20 × 20 pixels, 24 × 24 pixels,... 48 × 48 pixels as the size of the tracking area. An explanation will be given taking as an example a case where tracking is performed in a tracking area of 20 × 20 pixels. When the second approximation is smaller than the first approximation, the image processing unit 14 increases the size of the tracking area by one step. That is, the image processing unit 14 changes the tracking area to 24 × 24 pixels. On the other hand, if the second approximation is not smaller than the first approximation, the image processing unit 14 reduces the size of the tracking area by one step. For example, the image processing unit 14 changes the tracking area to 16 × 16 pixels. In this way, the size of the tracking area is adjusted. In this way, the size of the tracking area is changed stepwise. For this reason, the change of the tracking area can be smoothed.

  The second method is to adjust the size of the tracking area according to the magnitude of the second approximation. This will be specifically described.

  In the present embodiment, the image processing unit selects one pixel from the R pixel, the G pixel, and the B pixel having the second approximation degree. For example, the image processing unit selects a pixel having the largest value among the color ratios of the first determination area 82. That is, the image processing unit selects the R pixel if the value of the R pixel is larger than the G and B pixels in the color ratio of the first determination region 82.

  Then, the image processing unit adjusts the size of the tracking area based on the value of the R pixel having the second degree of approximation. Here, in the present embodiment, the area ratio of the first discrimination region 82 and the second discrimination region 92 is 1: 4. Therefore, when the value of the R pixel of the second degree of approximation (the difference in color ratio between the first discrimination region and the second discrimination region) is 0, it can be assumed that the area of the tracking region should be quadrupled. On the contrary, when the value of the R pixel of the second approximation degree is a predetermined value (Z), it can be assumed that the area of the tracking region should be ¼ times. Therefore, the image processing unit uses the information that the value of the R pixel of the second approximation degree is 4 times if the value is 0, and the information that the value of the R pixel of the second approximation degree is 1/4 times if the value is the predetermined value (Z), Using linear interpolation, the enlargement magnification based on the value of the R pixel of the second degree of approximation is calculated. The image processing unit adjusts the size of the tracking area according to the enlargement magnification.

  Note that, when adjusting the size of the tracking area, the image processing unit 14 enlarges or reduces the area based on the approximate center of the area set in step T2. In this way, the image processing unit 14 can adjust the size of the tracking area as shown in FIG.

  The image processing unit 14 acquires color information from the image data (YC data) in the tracking area after the size adjustment, and stores it in the buffer memory 15 (T9). Then, the image processing unit 14 sets a first determination region and a second determination region corresponding to the tracking region after the size adjustment in the image data (YC data). Specifically, the image processing unit 14 sets a first determination area having the same position and the same size as the tracking area after the size adjustment in the image data (YC data). In addition, the image processing unit 14 sets a second determination area in the image data (YC data) that is twice as long as the first determination area.

  Thereafter, the image processing unit 14 acquires the color ratio from the positions corresponding to the first determination region and the second determination region set in the image data (YC data) in the image data (BM data). Further, the image processing unit 14 calculates the degree of approximation of the first determination region and the second determination region based on the acquired color ratio, and stores it in the buffer memory 15 (T10). That is, the image processing unit 14 updates the first approximation stored in the buffer memory 15.

  Next, the image processing unit 14 stores information indicating the setting positions and sizes of the first and second determination areas set in step T10 (T11). After that, the image processing unit 14 displays the image data and the tracking area after the size adjustment on the liquid crystal monitor 20 as a display screen as in the image data B of FIG. 3 (T12).

  In this way, the image processing unit 14 can realize a tracking operation for certain image data. The image processing unit 14 repeats the above operation to repeat the tracking region setting operation for the image data sequentially generated from the CCD image sensor 12. For example, as shown in FIG. 3, tracking areas 73 and 74 are set for sequentially generated image data.

<5. Summary>
The digital camera 1 captures a subject image and sequentially generates image data, and the image data sequentially generated by the CCD image sensor 12 is traced based on tracking information for tracking the subject image. An image processing unit 14 that sets an area, and an image processing unit 14 that acquires a degree of approximation from a first determination area and a second determination area set in a part of the image data. When the image processing unit 14 sets a tracking area for certain image data, the second approximation obtained with the image data and the change in the first approximation obtained with the previously acquired image data. The size of the tracking area is adjusted according to the size of.

In this way, the digital camera can adjust the size of the tracking area in accordance with the degree of change in the degree of approximation of certain image data and the degree of approximation of previous image data. Therefore, even when the subject moves in the perspective direction with respect to the digital camera, the subject image can be tracked by adjusting the tracking area to a more appropriate size.
(Other embodiments)
The above embodiment has been exemplified as an embodiment of the present invention. However, the present invention is not limited to the above embodiment, and can be implemented in other embodiments. Therefore, other embodiments of the present invention will be described collectively below.

  In the present embodiment, the first determination area is set at the same position as the tracking area. However, the present invention is not limited to this, and the first determination area may be set at a position different from the tracking area. For example, as shown in FIG. 13, as in other embodiment A, determination areas may be set at different locations of the subject. Further, as in the other embodiment B, the determination area may be set for an object held by the subject.

  In the present embodiment, when the image processing unit 14 calculates the second approximation degree in steps T4 and T5, the first determination area and the second determination area are set with past image data. Set to the same position as the position. However, the present invention is not limited to this, and the image processing unit may not perform the operations in steps T4 to T8 when the angle of view shift occurs in the captured image due to panning. Here, whether or not the angle-of-view deviation has occurred in the captured image due to panning may be determined by whether or not the output of the shake detector 30 has exceeded a predetermined threshold value between the image data. Further, the image processing unit may shift the position of the determination region set in step T4 in accordance with the output of the shake detector when the angle of view shift occurs in the captured image due to panning. In this way, the size of the tracking area can be adjusted to a more appropriate size even when the angle of view is shifted by panning the imaging device.

  In the present embodiment, the color information is separated using the hue angle. However, the present invention is not limited to this, and color information may be separated using the hue angle and saturation. In this case, in the present embodiment, the entire phase angle is divided into 40, but in the other embodiments, for example, the entire phase angle may be divided into 20 and the saturation may be divided into 2. Further, separation of color information may be realized only by saturation.

  Furthermore, in this embodiment, when determining whether or not the color information in the temporary area and the color information in the auxiliary area can be separated, it is determined by whether or not the color area having the largest number of pixels matches in the color information. I tried to do it. However, the present invention is not limited to this, and the image processing unit may make the determination using the total degree of coincidence of each color region (unit). For example, the image processing unit determines how much the number of pixels in each color region (unit) matches. Then, the image processing unit may determine that the temporary area and the auxiliary area cannot be separated by the color information when the total number of matched pixels is equal to or greater than a predetermined threshold.

  That is, the present invention is not limited to the above embodiment, and can be realized in various forms.

  The present invention can be applied to a digital still camera, a digital video camera, a camera-equipped mobile phone, and the like.

DESCRIPTION OF SYMBOLS 1 Digital camera 11 Optical system 12 CCD image sensor 121 Timing generator 13 AD converter 14 Image processing part 15 Buffer memory 16 Flash memory 17 Controller 20 Liquid crystal monitor 21 Operation part 71, 72, 73, 74 Tracking area | region 81, 82 1st determination area | region 91, 92 Second determination area

Claims (10)

Imaging means for capturing a subject image and sequentially generating image data;
Based on tracking information for tracking a subject image, tracking area setting means for setting a tracking area in image data sequentially generated by the imaging means;
Relationship information acquisition means for acquiring relationship information between determination regions from a first determination region related to a tracking region set in a part of the image data and a second determination region having a size different from that of the first determination region. When,
From the first relationship information acquired from the first image data generated by the imaging unit by the previous period relationship information acquisition unit, and from the second image data acquired after the first image data by the relationship information acquisition unit Tracking area adjusting means for adjusting the size of the tracking area of the second image data set by the tracking area setting means based on the acquired second relationship information;
An imaging apparatus comprising: Tracking information acquisition means for acquiring tracking information for tracking the subject image based on a tracking area set in a part of the image data generated by the imaging means;
The tracking area setting means sets a tracking area based on the tracking information acquired by the tracking information acquisition means;
The imaging device according to claim 1. The imaging apparatus according to claim 1, further comprising: a display unit configured to display a display screen indicating image data generated by the imaging unit and a tracking area set in the image data. The imaging apparatus according to claim 1, wherein the tracking area and the first determination area are the same area. Color ratio acquisition means for acquiring color ratio information indicating a color ratio from the image data generated by the imaging means,
The relationship information acquisition means acquires the relationship information using the color ratio information acquired by the color ratio acquisition means.
The imaging device according to claim 1. The imaging apparatus according to claim 1, wherein the tracking information and the relationship information are information of the same index. The imaging apparatus according to claim 1, wherein color information is used for the tracking information and the relationship information. The imaging apparatus according to claim 1, wherein information regarding contrast is used for the tracking information and the relationship information. The imaging device according to claim 1, wherein the tracking information and the relationship information are information of different indexes. Imaging means for capturing a subject image and sequentially generating image data;
Provided at the same position as the first feature information of the tracking area provided in a part of the generated image data, the second feature information of the first determination area related to the tracking area, and the first determination area Feature information acquisition means for acquiring second feature information of a second determination region having a size different from that of the first determination region;
Relation information acquisition means for acquiring relation information between the determination areas based on the second characteristic information of the first determination area and the second characteristic information of the second determination area acquired by the acquisition means;
Tracking that sets the tracking region in the second image data generated after the first image data based on the first feature information of the tracking region set in a part of the first image data generated by the imaging unit Region setting means;
Set by the tracking area setting unit based on the first relationship information acquired by the relationship acquisition unit in the first image data and the second relationship information acquired by the relationship acquisition unit in the second image data. Adjusting means for adjusting the size of the tracking area of the second image data that has been obtained;
An imaging apparatus comprising:

Images