JP2011044764A - Image capturing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image capturing apparatus capable of continuously tracking a subject with high accuracy when tracking the subject on a photographing screen. <P>SOLUTION: The image capturing apparatus includes: an imaging means of imaging subject images to sequentially generate image data; a storage means of storing location information, color information, and contrast information of a tracking area set to one portion of the image data; a discrimination means of setting a discrimination area based on the location information of the tracking area to discriminate whether the inside and outside of the discrimination area can be separated by color information; a first setting means of setting a tracking area to the image data, based on the color information stored in the storage means, when it is discriminated that the separation can be made by the discrimination means; and a second setting means of setting the tracking area to image data, based on the contrast information stored in the storage means, when it is discriminated that no separation can be made by the discrimination means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging apparatus such as a digital camera. More specifically, the present invention relates to an imaging apparatus that can continuously set a tracking area for a subject in a shooting screen.

  There exist some which are described in patent document 1 in the conventional imaging device. The imaging apparatus disclosed in Patent Literature 1 includes a first tracking unit that sets a focusing area in a part on a shooting screen based only on luminance information in the shooting screen, and a shooting screen based only on contrast information in the shooting screen. And a second tracking means for setting a focusing area in a part of the upper part. And in the imaging device of patent document 1, when the brightness | luminance difference of a to-be-photographed object and a background becomes small, switching from a 1st tracking means to a 2nd tracking means is described.

  On the other hand, there are other imaging devices that store the color characteristics (color information) of the subject and track the movement of the subject using the stored color information. In such an imaging apparatus, color information in a tracking area set in a part on the shooting screen is stored. Then, the imaging device sets a tracking area on the next generated shooting screen based on the stored color information. In this way, the tracking area can be set continuously on the shooting screen (image data) sequentially generated from the image sensor.

JP-A-1-231578

  By the way, in the other imaging devices described above, since the tracking area is set on the shooting screen (image data) using the color information of the subject, the tracking accuracy decreases when the subject color and the background color approach the same color. .

  Therefore, an object of the present invention is to provide an imaging apparatus capable of continuing tracking of a subject with higher accuracy when tracking a subject on a shooting screen.

  That is, the imaging apparatus of the present invention captures an image of a subject and sequentially generates image data, and a storage that stores position information, color information, and contrast information of a tracking area set in a part of the image data. A determination area based on the position information of the tracking area, a determination means for determining whether or not color information inside and outside the determination area is approximated, and A first setting unit that sets a tracking area in the image data generated by the imaging unit based on the color information stored in the storage unit and a case where the determination unit approximates the image data is stored in the storage unit. Second setting means for setting a tracking area in the image data generated by the imaging means based on the contrast information.

  In this way, when the subject is tracked with color information, tracking of the subject can be continued with higher accuracy even when the subject color and the background color are close to each other.

  Preferably, the second setting unit sets a tracking region in the image data based on the contrast information and temporarily sets the image data based on the color information when it is determined that the determination unit approximates. The tracking means searches for a tracking area, and the storage means uses the contrast information of the set tracking area and the color information of the searched temporary tracking area as information for setting a tracking area for new image data. Remember.

  In this way, the tracking operation based on the color information is continued even during the tracking operation based on the contrast information. Therefore, even when the color information of the subject and the background is not approximated after the color information of the subject and the background is approximated, the tracking of the subject can be continued with higher accuracy.

  According to the present invention, tracking of a subject can be continued with higher accuracy.

The perspective view of the digital camera which concerns on embodiment of this invention 1 is a configuration diagram of a digital camera according to an embodiment of the present invention. The figure which shows the example of a transition of the image data for display screens concerning embodiment of this invention The figure which shows the example of a transition of the image data for display screens concerning embodiment of this invention The figure for demonstrating the tracking function based on the color information which concerns on embodiment of this invention The figure for demonstrating the tracking function based on the contrast information which concerns on embodiment of this invention The figure for demonstrating the relationship between the color of a to-be-photographed object and the color of a background which concerns on embodiment of this invention The figure for demonstrating the histogram of the color information which concerns on embodiment of this invention The flowchart for demonstrating the operation example of the digital camera which concerns on embodiment of this invention. The flowchart for demonstrating the operation example of the digital camera which concerns on embodiment of this invention.

(Embodiment 1)
The present embodiment will be described with reference to the drawings. Hereinafter, the digital camera 1 of the present embodiment will be specifically described.

<1. Overview of the present embodiment>
The digital camera 1 sets the tracking area based on the contrast information when the color information inside and outside the area tracking the subject is approximated based on the color information. Thus, the digital camera 1 can continue tracking of the subject with higher accuracy because the tracking can be continued based on the contrast information even when the subject color and the background color are approximate.

  That is, the digital camera 1 stores tracking area position information, color information, and contrast information set as part of the image data. When the digital camera 1 sets a tracking area for new image data, the digital camera 1 sets a determination area for the new image data based on position information of the tracking area in the previous image data. Then, the digital camera 1 determines whether or not the color information inside and outside the set determination area is approximate. When the color information inside and outside the discrimination area is not approximate, the digital camera 1 sets a tracking area in the image data based on the color information. On the other hand, when the color information inside and outside the discrimination area is approximate, the digital camera 1 sets a tracking area in the image data based on the contrast information.

  The digital camera 1 sets a tracking area in the image data based on the contrast information and sets a temporary tracking area in the image data based on the color information when the color information inside and outside the discrimination area is approximate. At this time, the digital camera 1 displays the image data and the tracking area as a display screen. That is, the digital camera 1 does not display the temporary tracking area.

  As described above, by continuing the tracking operation based on the color information even during the tracking operation based on the contrast information, the digital camera 1 can be used even when the subject color and the background color are changed from the approximate state to the non-existing state. It is possible to return to the tracking operation based on the color information with higher accuracy. The reason for configuring as described above is that the color information of the subject in the image data changes with time, so the stored color information must also be changed.

<2. Configuration example (FIGS. 1 and 2)>
The configuration of the digital camera 1 of the present embodiment will be described. 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. Hereinafter, a specific example of the configuration will be described.

  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.

  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. The CCD image sensor 12 is provided with a primary color filter, and an RGB signal is generated.

  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 by the AD converter 13. As the predetermined processing, gamma conversion, YC conversion, electronic zoom processing, compression processing, expansion processing, and the like can be considered, but are not limited thereto.

  The image processing unit 14 performs YC conversion after performing white balance gain multiplication processing and gamma conversion on the image data output from the AD converter 13. The image processing unit 14 generates image data including a Y signal, a Cb signal, and a Cr signal by YC conversion.

  Then, the image processing unit 14 acquires color information in a region set in a part using the image data subjected to YC conversion. Similarly, the image processing unit 14 acquires contrast information in a region set in a part using the image data subjected to YC conversion. Using these pieces of information, the image processing unit 14 realizes a tracking operation.

  The processing of the image processing unit 14 will be specifically described. First, a process for acquiring color information will be described. The image processing unit 14 acquires image data in the area. The image processing unit 14 obtains the hue of each pixel in the area. The hue can be represented by a phase angle of 0 to 359 degrees. In the present embodiment, red is associated with 0 degrees.

  In this embodiment, color information can be recorded using the phase thus obtained. In the present embodiment, the phase angle of 0 to 359 degrees is divided into 40, and each pixel is assigned to each divided unit. Therefore, the image processing unit 14 determines how many pixels corresponding to each divided unit (color units “0” to “39”, for example, color unit “0” corresponds to 0 to 8 degrees). And is recorded in the buffer memory 15 as color information. For example, the color information is information such that the color unit “0” is 100 pixels, the color unit “1” is 48 pixels, the color unit “2” is 23 pixels,. When the color information calculated in this way is represented by a histogram, for example, it is as shown in FIG. The horizontal axis of FIG. 8 indicates each divided unit (color unit), and the vertical axis indicates the number of pixels.

  Next, processing of the image processing unit 14 that acquires contrast information will be described. The image processing unit 14 acquires image data in the area. The image processing unit 14 calculates a high frequency component in the region. Specifically, the image processing unit 14 performs DCT (discrete cosine transform) on the image data in the region. Thereby, the image processing unit 14 acquires contrast information obtained by quantifying the ratio of the high frequency component and the low frequency component for the image data in the region. The image processing unit 14 stores the acquired contrast information in the buffer memory 15.

  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 programs for controlling the controller 17 and setting values in addition to the image processed image data.

  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 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 the image data image-processed by the image processing unit 14.

  The liquid crystal monitor 20 displays image data and various settings of the digital camera 1.

  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. Example of operation (FIGS. 9 to 10)>
An operation example of the digital camera 1 according to the present embodiment will be described. 9 to 10 are flowcharts illustrating an operation example of the digital camera 1. This will be specifically described below.

<3.1 Tracking Area Setting Operation by User (FIG. 9)>
First, an operation (FIG. 9) for setting a tracking area in response to a user instruction for image data generated by the CCD image sensor 12 will be described. The controller 17 controls the timing generator 121 to cause the CCD image sensor 12 to generate image data. The image processing unit 14 acquires the image data generated by the CCD image sensor 12 (S1). The controller 17 determines whether or not the subject to be tracked has been determined by operating the operation unit 21 (a cross key and a determination button (not shown)) (S2). More specifically, the controller 17 displays a determination area for determining a subject in the center of the liquid crystal monitor 20. Then, the controller 17 moves the determination area in accordance with an operation on the cross key from the user. Then, the controller 17 determines the subject existing at the position of the determination region as the subject to be tracked in accordance with the operation on the determination key from the user. That is, the user moves the determination area by operating the cross key, and determines the subject existing in the determination area as the subject to be tracked by operating the determination key.

  If the subject to be tracked is not determined in step S2, the controller 17 repeats the operation in step S1. At this time, the image processing unit 14 displays the acquired image data on the liquid crystal monitor 20 as a display screen (S9). On the other hand, when the subject to be tracked is determined in step S2, the controller 17 controls the image processing unit 14 to set a tracking area for the subject (S3). For example, the image processing unit 14 sets a tracking area for the image data T1 as shown in FIG. At this time, the image processing unit 14 stores the position of the screen (first position information) in which the tracking area is set in the buffer memory 15 (S3). For example, the image processing unit 14 stores the position (m, n) of the upper left pixel in the tracking area in the buffer memory 15. Then, the controller 17 controls the image processing unit 14 to store the color information in the tracking area in the buffer memory 15 (S4). Further, the controller 17 controls the image processing unit 14 to store the contrast information in the tracking area in the buffer memory 15 (S5). The controller 17 controls the image processing unit 14 to display the image data in which the tracking area is set on the liquid crystal monitor 20 as a display screen (S6).

  Thereafter, the controller 17 performs a continuous AF operation on the image data in the tracking area (S7). Then, the controller 17 controls the image processing unit 14 to perform the tracking continuation operation of FIG. Note that the operation of the continuous AF is a general operation and will not be described.

<3.2 Tracking operation (Fig. 10)>
Next, the tracking continuation operation (FIG. 10) after the tracking area is set by the user operation will be described. Since the operation in FIG. 10 is the operation of the image processing unit 14 based on the control of the controller 17, the operation will be described with the image processing unit 14 as a main component.

  Hereinafter, the operation example of FIG. 10 will be described with reference to FIGS. 3 and 4. In FIG. 3, image data T <b> 1 to T <b> 5 indicate image data sequentially generated by the CCD image sensor 12. In FIG. 3, image data T1 indicates image data at the time of setting the tracking area, image data T2 indicates image data when the color in the captured area and the background color are not approximate, and image data T3 is The image data in the case where the color in the subject area approximates the color of the background is shown. In FIG. 4, image data T4 indicates image data when the color in the captured area approximates the background color, and image data T5 indicates an image when the color in the captured area does not approximate the background color. Data are shown. Each operation example in the transition of the image data from FIG. 3 to FIG. 4 will be described one by one.

<3.2.1 Example of Operation when Setting Tracking Area for Image Data T2>
In this operation example, the buffer memory 15 stores first position information, color information, and contrast information obtained from the image data T1. This will be specifically described below.

  The image processing unit 14 acquires the image data generated by the CCD image sensor 12 (V1). Next, the image processing unit 14 sets a discrimination area in the image data acquired in step V1 based on the position information stored in the buffer memory 15 (V2). At this time, since the first position information is stored in the buffer memory 15, the image processing unit 14 sets a determination area based on the first position information.

Next, the image processing unit 14 determines whether the color information inside and outside the determination region is approximate (V3).
The specific operation of step V3 will be described below. First, the image processing unit 14 acquires color information in the discrimination area. In addition, the image processing unit 14 acquires color information in the background area provided outside the determination area. In the present embodiment, the image processing unit 14 sets a background area at a position as shown in FIG. 7 and acquires color information from the two background areas provided on the left and right sides of the determination area. The image processing unit 14 compares the color information in the acquired determination area and the color information in the background area, and determines whether at least one is approximate. In other words, in the present embodiment, the image processing unit 14 determines that the inside and outside of the determination region are approximated when at least one or more approximates.

  Here, in the present embodiment, the fact that the color information of the discrimination area and the background area is approximate means that the unit having the largest number of pixels included in each unit of the color information matches among the color information. For example, when the number of pixels of the color unit “1” is the largest in the color information of the discrimination area and the number of pixels of the color unit “1” is the largest in the color information of the background area, the discrimination area and the background area Can be determined to be approximate. On the other hand, when the number of pixels of the color unit “1” is the largest in the color information of the discrimination area and the number of pixels of the color unit “5” is the largest in the color information of the background area, the discrimination area and the background area Can be determined not to approximate. This is an example, but the image processing unit 14 can determine the approximation of the color information in the determination area and the background area in this way. For example, FIG. 7 shows an example when the left diagram is not approximated, and shows an example when the right diagram is approximated.

  Returning to the description of FIG. 10, when it is determined in step V3 that the color information inside and outside the determination area is not approximate (for example, in the case of an image like the image data T2 in FIG. 3), the color information Based on the above, a tracking area is set in the image data (V4). Specifically, the image processing unit 14 sets a search area at a position as shown in FIG. 5 based on the position information stored in the buffer memory 15. At this time, since the first position information is stored in the buffer memory 15 in the image processing unit 14, a search area is set based on the first position information.

  Then, based on the color information stored in the buffer memory 15, the image processing unit 14 searches for an area having the closest color information in the search area. The image processing unit 14 sets the searched closest area as the tracking area in the image data. For example, a tracking area is set like the image data T2 in FIG.

  In step V <b> 4, the image processing unit 14 stores the position (first position information) of the screen where the tracking area is set in the buffer memory 15. That is, the first position information stored in the buffer memory 15 is updated.

  Then, the image processing unit 14 stores the color information in the set tracking area in the buffer memory 15 (V5). Further, the image processing unit 14 stores the contrast information in the set tracking area in the buffer memory 15 (V6). The color information and contrast information are also updated in the buffer memory 15 as described above. Note that since the second position information is not stored in the buffer memory 15, the operation of Step V13 is not performed.

  The image processing unit 14 displays the image data including the tracking area on the liquid crystal monitor 20 as a display screen (V11). Thereafter, the controller 17 executes a continuous AF operation on the image data in the tracking area (V12).

<3.2.2 Example of Operation when Setting Tracking Area for Image Data T3>
In this operation example, the buffer memory 15 stores first position information, color information, and contrast information obtained from the image data T2. This will be specifically described below.

  The image processing unit 14 acquires the image data generated by the CCD image sensor 12 (V1). Next, the image processing unit 14 sets a discrimination area in the image data acquired in step V1 based on the position information stored in the buffer memory 15 (V2). At this time, since the first position information is stored in the buffer memory 15, the image processing unit 14 sets a determination area based on the first position information.

  When the image processing unit 14 determines in step V3 that the color information inside and outside the determination region is approximate based on the information from the image processing unit 14 (for example, in the case of an image such as the image data T3 in FIG. 3), the contrast information Based on the above, a tracking area is set in the image data (V7). For example, the image processing unit 14 sets auxiliary areas (A to E) at positions as shown in FIG. 6 based on the position information stored in the buffer memory 15. At this time, since the first position information is stored in the buffer memory 15 in the image processing unit 14, an auxiliary area is set based on the first position information. The area set at the same position as the past tracking area is the auxiliary area E.

  Then, the image processing unit 14 selects an area having the closest contrast in the auxiliary area based on the contrast information stored in the buffer memory 15. The image processing unit 14 sets the searched closest area as the tracking area in the image data. For example, the tracking area is set as shown in the upper diagram of the image data T3 in FIG.

  In step V <b> 7, the image processing unit 14 stores the position of the screen (first position information) where the tracking area is set in the buffer memory 15. That is, the first position information stored in the buffer memory 15 is updated.

  Then, the image processing unit 14 stores the contrast information in the set tracking area in the buffer memory 15 (V8). That is, the contrast information stored in the buffer memory 15 is updated.

  Next, the image processing unit 14 searches for a temporary tracking area from the image data based on the color information stored in the buffer memory 15 (V9). For example, the temporary tracking area is searched as shown in the lower diagram of the image data T3 in FIG. In this case, since the first position information is stored in the buffer memory 15, the first position information stored in the buffer memory 15 is used as the search area for searching for the temporary tracking area.

  In step V <b> 9, the image processing unit 14 stores the position of the screen (second position information) where the temporary tracking area is searched for in the buffer memory 15. That is, the second position information is newly stored in the buffer memory 15.

  Then, the image processing unit 14 stores the color information in the set temporary tracking area in the buffer memory 15 (V10). That is, the color information stored in the buffer memory 15 is updated.

  The image processing unit 14 displays the image data including the tracking area on the liquid crystal monitor 20 as a display screen (V11). Thereafter, the controller 17 executes a continuous AF operation on the image data in the tracking area (V12).

<3.2.3 Example of Operation when Setting Tracking Area for Image Data T4>
In this operation example, the buffer memory 15 stores first position information, second position information, color information, and contrast information obtained from the image data T3. This will be specifically described below.

  The image processing unit 14 acquires the image data generated by the CCD image sensor 12 (V1). Next, the image processing unit 14 sets a discrimination area in the image data acquired in step V1 based on the position information stored in the buffer memory 15 (V2). At this time, since the first position information and the second position information are stored in the buffer memory 15, the image processing unit 14 sets the determination area using the second position information. The reason for configuring in this way is to perform tracking based on color information even when tracking based on contrast information is performed. That is, the tracking of the color information from the image data T2 is continued.

  If the image processing unit 14 determines in step V3 that the color information inside and outside the determination region is approximate based on the information from the image processing unit 14 (for example, an image such as the image data T4 in FIG. 4), the contrast information Based on the above, a tracking area is set in the image data (V7). Specifically, the image processing unit 14 sets an auxiliary area based on the position information stored in the buffer memory 15. At this time, since the first position information and the second position information are stored in the buffer memory 15 in the image processing unit 14, the auxiliary area is set using the first position information. This is to continue tracking based on the contrast information of the image data T3.

  Then, the image processing unit 14 selects an area having the closest contrast in the auxiliary area based on the contrast information stored in the buffer memory 15. The image processing unit 14 sets the searched closest area as the tracking area in the image data. For example, the tracking area is set as shown in the upper diagram of the image data T4 in FIG.

  In step V <b> 7, the image processing unit 14 stores the position of the screen (first position information) where the tracking area is set in the buffer memory 15. That is, the first position information stored in the buffer memory 15 is updated.

  Then, the image processing unit 14 stores the contrast information in the set tracking area in the buffer memory 15 (V8). That is, the contrast information stored in the buffer memory 15 is updated.

  Next, the image processing unit 14 searches for a temporary tracking area from the image data based on the color information stored in the buffer memory 15 (V9). For example, the temporary tracking area is searched as shown in the lower diagram of the image data T4 in FIG. In this case, since the first position information and the second position information are stored in the buffer memory 15, the second position information is used as the search area for searching the temporary tracking area. This is to continue tracking based on the color information of the image data T3.

  In step V <b> 9, the image processing unit 14 stores the position of the screen (second position information) where the temporary tracking area is searched for in the buffer memory 15. That is, the second position information stored in the buffer memory 15 is updated.

  Then, the image processing unit 14 stores the color information in the set temporary tracking area in the buffer memory 15 (V10). That is, the color information stored in the buffer memory 15 is updated.

  The image processing unit 14 displays the image data including the tracking area on the liquid crystal monitor 20 as a display screen (V11). Thereafter, the controller 17 executes a continuous AF operation on the image data in the tracking area (V12).

<3.2.4 Operation Example when Setting Tracking Area for Image Data T5>
In this operation example, the buffer memory 15 stores first position information, second position information, color information, and contrast information obtained from the image data T4. This will be specifically described below.

  The image processing unit 14 acquires the image data generated by the CCD image sensor 12 (V1). Next, the image processing unit 14 sets a discrimination area in the image data acquired in step V1 based on the position information stored in the buffer memory 15 (V2). At this time, since the first position information and the second position information are stored in the buffer memory 15, the image processing unit 14 sets the determination area using the second position information. The reason for configuring in this way is to perform tracking based on color information even when tracking based on contrast information is performed. That is, the tracking of the color information from the image data T2 is continued.

  Next, the image processing unit 14 determines whether the color information inside and outside the determination region is approximate (V3).

  When it is determined in step V3 that the color information inside and outside the determination area is not approximate (for example, in the case of an image such as the image data T5 in FIG. 4), the image processing unit 14 adds the tracking area to the image data based on the color information. Is set (V4). Specifically, the image processing unit 14 sets a search area based on position information stored in the buffer memory 15 as shown in FIG. At this time, since the first position information and the second position information are stored in the buffer memory 15 in the image processing unit 14, the search area is set using the second position information. The reason for configuring in this way is to continue the tracking operation based on the color information from the image data T2 with higher accuracy.

  In step V <b> 4, the image processing unit 14 stores the position of the screen (first position information) where the tracking area is set in the buffer memory 15. That is, the first position information stored in the buffer memory 15 is updated.

  Then, the image processing unit 14 stores the color information in the set tracking area in the buffer memory 15 (V5). Further, the image processing unit 14 stores the contrast information in the set tracking area in the buffer memory 15 (V6). That is, the color information and contrast information stored in the buffer memory 15 are updated. Then, the image processing unit 14 discards the second position information stored in the buffer memory 15 (V13).

  The image processing unit 14 displays the image data including the tracking area on the liquid crystal monitor 20 as a display screen (V11). Thereafter, the controller 17 executes a continuous AF operation on the image data in the tracking area (V12).

  In this embodiment, the tracking operation can be continued with higher accuracy by performing any one of the above four operations.

<4. Summary>
In the present embodiment, a CCD image sensor 12 that captures a subject image and sequentially generates image data, and first position information, color information, and contrast information of a tracking area set in a part of the image data are stored. A determination area is set based on the buffer memory 15 and the first position information of the tracking area, and the image processing section 14 that determines whether or not the color information inside and outside the determination area approximates, and the image processing section 14 does not approximate. Is determined based on the color information stored in the buffer memory 15, the image processing unit 14 that sets the tracking area in the image data generated by the CCD image sensor 12, and the image processing unit 14 determine that the approximation is performed. In this case, the image processing for setting the tracking area in the image data generated by the CCD image sensor 12 based on the contrast information stored in the buffer memory 15. Comprises a section 14, the.

  In this way, tracking can be continued with higher accuracy for the subject.

  Preferably, when it is determined that the image processing unit 14 approximates, the image processing unit 14 sets a tracking area in the image data based on the contrast information, searches for the temporary tracking area from the image data based on the color information, and the buffer memory 15 The contrast information of the set tracking area and the color information of the searched temporary tracking area are stored as information for setting the tracking area for new image data.

In this way, tracking can be continued with higher accuracy for the subject.
(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 CCD image sensor 12 is used as the imaging device. However, the present invention is not limited to this, and a CMOS image sensor may be used. If comprised in this way, it will become possible to suppress the power consumption of the whole apparatus.

  In the present embodiment, the operation example of step V3 has been described when determining whether the inside and outside of the determination area are approximate. However, the present invention is not limited to this, and any configuration may be used as long as it can determine whether or not the color information of the subject and the background is approximate.

  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.

  In the present embodiment, the liquid crystal monitor 20 is used as the display unit. However, the present invention is not limited to this, and an organic EL display can also be used.

  In the present embodiment, the operation using the search area has been described as the tracking operation based on the color information. However, the present invention is not limited to this, and any operation is possible as long as the tracking operation can be realized based on the color information.

  In the present embodiment, the operation using the auxiliary region has been described as the tracking operation based on the contrast information. However, the present invention is not limited to this, and any operation may be used as long as the tracking operation can be realized based on the contrast information.

  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, color information may be separated only by saturation.

  Also, in the present embodiment, whether the color information of the discrimination area and the background area is approximate or not is determined based on whether or not the unit with the largest number of pixels included in each decomposed unit of the color information matches. I decided to judge. However, the present invention is not limited to this, and the image processing unit may make the determination by using the total degree of coincidence of pixels of each unit (color region) between the discrimination region and the background region. For example, the image processing unit determines how much the number of pixels in each unit (color region) matches between the discrimination region and the background region. Then, the image processing unit may determine that the determination area and the background area are approximate when the total number of matched pixels is equal to or greater than a predetermined threshold.

  Further, in the present embodiment, as shown in FIG. 6, the auxiliary areas A to E are set so as to overlap the image data. However, the present invention is not limited to this, and a plurality of auxiliary areas may be set so as not to overlap with the image data. In this embodiment, five auxiliary areas are set for image data. In other embodiments, the present invention is not limited to this, and any number of auxiliary regions may be set. For example, nine or thirteen auxiliary regions can be provided. If nine auxiliary regions are provided, contrast tracking can be realized with higher accuracy than five. Further, if 13 auxiliary areas are provided, the auxiliary area can be set in a wider range, so that it is possible to cope with high-speed subject movement.

  That is, the present invention is not limited to the above embodiment, and can be implemented 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 111 Objective lens 112 Zoom lens 113 Focus lens 114 Aperture / shutter 115 Zoom drive part 116 Focus drive part 117 Aperture / shutter drive part 12 CCD image sensor 121 Timing generator 13 AD converter 14 Image processing part 15 Buffer memory 16 Flash memory 17 Controller 20 LCD monitor 21 Operation unit

Claims (3)

Imaging means for capturing a subject image and sequentially generating image data;
Storage means for storing position information, color information and contrast information of a tracking area set in a part of the image data;
A determination unit that sets a determination region based on position information of the tracking region, and determines whether or not the color information inside and outside the determination region approximates;
A first setting unit configured to set a tracking area in the image data generated by the imaging unit based on the color information stored in the storage unit when the determination unit determines that the approximation is not performed;
A second setting unit that sets a tracking area in the image data generated by the imaging unit based on contrast information stored in the storage unit when it is determined that the determination unit approximates;
An imaging apparatus comprising: The second setting means includes
When it is determined that the determination means approximates, a tracking area is set in the image data based on the contrast information, and a temporary tracking area is searched for in the image data based on the color information.
The storage means stores contrast information of the set tracking area and color information of the searched temporary tracking area as information for setting a tracking area for new image data.
The imaging device according to claim 1. Imaging means for capturing a subject image and sequentially generating image data;
Storage means for storing position information, first feature information, and second feature information of a tracking area set in a part of the image data;
A determination unit that sets a determination region based on position information of the tracking region and determines whether or not the first feature information inside and outside the determination region approximates;
A first setting unit configured to set a tracking area in the image data generated by the imaging unit based on the first feature information stored in the storage unit when the determination unit determines that the approximation is not performed;
A second setting unit that sets a tracking region in the image data generated by the imaging unit based on the second feature information stored in the storage unit when it is determined that the determination unit approximates;
An imaging apparatus comprising:

Images