JP2007074243A - Digital camera apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera apparatus having a function capable of simply and quickly segmenting only an object to be segmented. <P>SOLUTION: The digital camera apparatus comprising a focus lens driving means and a focusing means for automatically focusing an object comprises also a means for continuously inputting images on a focus position and positions defocused back and front and a means for dividing each inputted image into respective blocks, calculating an index value indicating a high frequency component of each block image, comparing respective index values, and extracting only a block in which an image having the highest index value is inputted on the focus position. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a digital camera having an image extraction function.

When it is desired to extract a specific subject from a photographed image, extraction is generally performed using a technique such as contour extraction. Further, according to the disclosure in Japanese Patent Laid-Open No. 9-312794, an example is shown in which the distance to the subject is measured in all blocks divided into blocks and divided into layer images for each distance.
JP 9-31794 A

  However, in the above-described conventional example, there are problems in that the former example takes time for contour extraction and the like and cannot be separated when the background of the object to be extracted is similar in color. In the latter example, it is necessary to calculate distances for all parts other than the target object to be cut out, and there is also a problem that a plurality of objects at the same distance are extracted simultaneously.

  The present invention has been made in view of the above technical problem, and an object thereof is to provide a digital camera device having a function of easily cutting out only an object to be cut out in a short time.

  To achieve the above object, a digital camera apparatus according to claim 1 of the present invention is a digital camera apparatus having a focus lens driving means and a focusing means for automatically focusing on a subject. Means for continuously capturing the image at the position and the position before and after the defocus, and dividing the captured image into blocks, and comparing the index value indicating the high-frequency component for each block image, the index value is the most It is characterized by having means for extracting only the block whose image is the image captured at the in-focus position.

  According to a second aspect of the present invention, the digital camera device includes means for excluding an image block discontinuous with the subject from the extracted image from the extracted image block.

  According to a third aspect of the present invention, the digital camera device has means for re-dividing the periphery of the extracted image into finer blocks and performing extraction by comparing the high-frequency components again.

  According to a fourth aspect of the present invention, the image captured by the continuous capturing means captures not all pixel data but an image with thinned pixels.

  The digital camera device according to claim 5, wherein the amount of defocus by the means for continuously capturing images at positions defocused before and after is determined according to the depth of field. .

  As described above, according to the present invention, since the object near the focal length is extracted in continuous blocks, it is possible to realize a digital camera device that can easily cut out only the object to be cut out in a short time. is there.

  Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[Embodiment 1]
FIG. 1 is a block diagram showing a schematic configuration of a digital camera apparatus according to the first embodiment of the present invention.

  In FIG. 1, a camera unit 100 includes a lens group 101, a CCD 102, a CDS 103, an ADC 104, a digital image processing unit 105, and a TG 106.

  An image input from the lens group 101 is converted into an electrical signal by the CCD 102, noise removal processing by correlated double sampling is performed by the CDS 103, converted from an analog signal to a digital signal by the ADC 104, and digitally processed by the digital image processing unit 105. Image processing is applied. The TG 106 is a timing generator that generates a signal for controlling the processing timing of the CCD 102, the CDS 103, and the ADC 104.

  A CPU 110 controls the device based on an input from the key SW 112 to control the camera unit 100 and display data on the TFT liquid crystal display unit 114. In addition to the so-called microprocessor, this CPU is called a so-called SOC (system-on-chip) that contains logic such as a memory controller that controls an external memory such as the program memory 116 and the work memory 115.

  Reference numeral 115 denotes a work memory made of SRAM, SDRAM, or the like that is connected by a memory bus and is used as a work area of the CPU 110. Reference numeral 116 denotes a program memory, such as a flash memory or a mask ROM, which is connected by a memory bus and stores a control program for controlling the device and font data. Reference numeral 117 denotes a CF card which is a storage means connected via a memory bus with a dedicated connector.

  Reference numeral 120 denotes a buffer memory made of SDRAM capable of storing four frames of images sent from the camera unit 100.

Reference numeral 113 denotes a display control circuit that receives RGB signals and synchronization signals from the CPU 110 and generates and outputs signals for displaying an image on the TFT liquid crystal display unit 114.
Reference numeral 114 denotes a VGA-size TFT liquid crystal display.

  A key SW 112 detects various control keys such as a shutter key and a mode key.

  FIG. 2 and FIG. 3 are flowcharts showing processing at the time of image extraction in the present embodiment.

  FIG. 2 is a diagram showing processing related to the operation of the shutter key. In step S100, the state of the shutter key is determined. Depending on whether the shutter key is half-pressed, fully pressed, or released, step S120 and step S140 are performed. Branches to step S110.

  When half-pressed, autofocus processing is performed in step S120. In step S130, 1 is assigned to a flag F indicating whether autofocusing is performed, and the key processing ends.

  When the key is released, the flag F in step S110 is cleared.

  When the key is fully pressed, image capture and object cut-out processing are performed in steps S140 and subsequent steps.

  In step S140, the flag F is checked. If F is 0, it indicates that the autofocus process has not been performed, that is, it has been pressed all at once without going through the half-pressed state, so autofocus is performed in step S150.

  In step S160 to step S180, images are taken in three states before the focal position, just before the focal position, and deeper than the focal position with respect to the focal position determined by the autofocus, and sequentially from 121 to 123 in FIG. Are stored in the image buffers 1 to 3. The shift amount before and behind the focal position is determined in proportion to the depth of field. An example of capturing an image here is shown in the upper part 121a, 122a, 123a of FIG.

  In step S190, a process of cutting out the object at the focal position from the captured image is performed. Details of this processing will be described with reference to the flowchart of FIG.

  In step S300, as shown in the lower part of FIG. 4, first, images taken at three kinds of focal lengths are decomposed into blocks. In this example, an image of 1600 × 1200 pixels is divided into 16 × 12 blocks with one block of 100 × 100 pixels (121b, 122b, 123b at the bottom of FIG. 4). The following processing is executed for each decomposed block.

  In step S310, the high frequency component of each block image is calculated. This calculation is performed, for example, by a cumulative addition of the absolute value of the difference between the luminance values of the pixels at positions separated by two pixels.

  In step S320, the high-frequency component calculated in step S310 is compared with images at three types of focal lengths. If the high-frequency component of the image having the focal length at the center is the maximum, step S320 is performed to extract the image. In S330, the corresponding block is copied from the central data to the extraction area. If the high frequency component of the image at the front or back of the focal length is the maximum, the corresponding block is masked so that the corresponding portion of the extraction area is cleared in step S340.

  The processing so far is repeated from the upper left block to the lower right block (step S350).

  An example of the extracted image at this time is shown by 124a in FIG.

  In the example of 124a, in addition to the butterfly image which is the image to be cut out, the lower left grass portion is also extracted because it is equidistant.

  In step S360, in order to delete a non-target extracted image, only the blocks that are continuous from the center of the screen are left, and the discontinuous blocks are deleted. As a result, as shown in the example of 124b in FIG. 5, only the target object is extracted.

[Embodiment 2]
In the present embodiment, processing for improving the image extraction accuracy of the first embodiment is added.

  FIG. 6 illustrates an example of processing in the present embodiment after image extraction according to the first embodiment.

  122c of FIG. 6 shows a state in which the image of 122 in the image buffer 2 corresponding to the block at the position along the outer periphery of the extracted image 124b is divided into finer blocks. In this figure, for the convenience of the original explanation, it is divided into 50 × 50 pixels, which is a quarter of the original area, but in actuality, it can be divided into about 10 × 10 pixels. The same division is also applied to the images 121 and 123, and the same processing as the image cutout processing of FIG. 3 of the first embodiment is applied to the blocks divided in this embodiment, so that the example of 124c in FIG. As shown in FIG. 5, an image extraction result with higher accuracy than the image extraction result in the first embodiment can be obtained.

[Embodiment 3]
In the first embodiment, the image area that is automatically extracted is not known until the shutter key is fully pressed and actual shooting is performed.

  In this embodiment, image extraction is performed using an image used in the finder with autofocus when half-pressed, and a frame in which the extraction is performed is displayed on the finder.

  FIG. 7 is a flowchart of shutter key processing in the present embodiment. In the figure, the description of the same processing as in FIG. 2 of the first embodiment will be omitted.

  After step S130 in the process after half-pressing the shutter, in steps S500 to S520, the image is captured into the image buffers 121 to 123 while changing the focal position in the same manner as in steps S160 to S180. The image captured here is an image to be displayed in real time in the finder display, and is an image that is thinned out from the image at the time of shooting because of the transfer speed. In this example, an image of 1600 × 300 pixels is captured using a CCD in which the number of vertical lines is ¼.

  In step S530, the object is cut out by the same process as in step S190, but the block division is 100 × 25 pixels per block. In step S540, a frame that traces the outer periphery of the image cut out is displayed on the finder image displayed on the TFT liquid crystal display unit (FIG. 8). For this composite display, a function called OSD (on-screen display) is used.

  When the shutter key is released, the display of the cutout frame that has been compositely displayed on the viewfinder is erased in step S600.

It is a block diagram which shows the structure of the digital camera apparatus which concerns on Embodiment 1 of this invention. It is a flowchart figure which shows the shutter key process which concerns on this Embodiment 1. FIG. It is a flowchart figure which shows the image cut-out process which concerns on this Embodiment 1. FIG. It is a figure which shows the example of the image capture concerning this Embodiment 1. FIG. It is a figure which shows the example of the image cut-out which concerns on this Embodiment 1. FIG. It is a figure which shows the example of extraction of the digital camera apparatus which concerns on Embodiment 2 of this invention. It is a flowchart figure which shows the shutter key process of the digital camera apparatus which concerns on Embodiment 3 of this invention. It is a figure which shows the example of the frame display of the image extraction result which concerns on this Embodiment 3. FIG.

Explanation of symbols

100 Camera Unit 105 Digital Image Processing Unit 110 CPU
114 TFT liquid crystal display 120 Image buffer

Claims (6)

  In a digital camera device having a focusing lens driving unit and a focusing unit that automatically focuses on a subject, a unit that continuously captures an image at an in-focus position and a position defocused before and after the focusing position; Means to divide each captured image into blocks, compare after calculating index values indicating high-frequency components for each block image, and extract only the block whose index value is the image captured at the in-focus position A digital camera device characterized by the above.   The digital camera device according to claim 1, wherein the amount of defocus in the means for continuously capturing images at positions defocused before and after is determined according to the depth of field.   The digital camera device according to claim 1, further comprising means for excluding an image block discontinuous with a subject from the extracted image among the extracted image blocks.   4. The digital camera device according to claim 3, further comprising means for re-dividing the periphery of the extracted image into finer blocks and performing extraction by comparing the high-frequency components again.   2. The digital camera device according to claim 1, wherein the image captured by the continuous capturing unit captures not a whole-pixel data but a finder image in which pixels are thinned out.   6. The digital camera apparatus according to claim 5, further comprising means for combining and displaying an outer frame of an extraction area obtained as a result of image extraction using capture of the finder image with a finder image.

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