KR20100094201A - Apparatus and method for digital picturing image - Google Patents

Abstract

PURPOSE: A digital image processing device and a method controlling the same are provided to obtain normal AF estimation data after stabilizing AF area, thereby improving the quality of photographed image. CONSTITUTION: An image information extractor(129-1) extracts image information of AF(Auto Focus) area in current frame among inputted image data. An variation operation unit(129-2) calculates change amount between image information extracted from previous frame and image information extracted from current frame. An AF area position corrector(129-3) corrects location of the AF area as predetermined amount. If the size of the change amount is 0, a control unit(129-4) obtains AF evaluation data at current frame without correcting AF area.

Description

Digital image processing apparatus and control method thereof {Apparatus and method for digital picturing image}

The present invention relates to a digital image processing apparatus and a control method thereof, and more particularly, to a digital image processing apparatus for detecting whether a change in an image in an AF area occurs during AF, and correcting the change in an AF region to obtain AF evaluation data. And a control method thereof.

In general, a digital image processing apparatus includes any apparatus that processes an image such as a digital camera, a personal digital assistant (PDA), a phone camera, a PC camera, or uses a motion recognition sensor. The digital image processing apparatus receives a desired image through the image pickup device, displays the input image on the image display device, displays the image, saves the image as an image file according to the user's shooting selection, and prints the stored image file.

In order to perform auto focus (AF) in such a digital image processing apparatus, data necessary for AF is extracted from a predetermined area. However, when the AF is performed, AF may fail when the camera shake of the photographer occurs or the subject moves. That is, if the evaluation data for the AF are damaged due to the camera shake or the movement of the subject, the AF may fail if the AF algorithm cannot operate normally.

Various image stabilization techniques have been developed in the conventional digital image processing apparatus. However, the method using only image data among these image stabilization techniques is applied only to an image acquisition step, and thus, the function cannot be performed during AF. Was present. In addition, even when the image stabilization technique is applied, there is a problem that it is impossible to cope with the AF failure with the conventional image stabilization technique when a movement occurs in the subject.

An object of the present invention is to provide a digital image processing apparatus and a control method thereof, which detect whether a change of an image in an AF area occurs during AF, and correct AF when a change occurs to obtain AF evaluation data.

The present invention provides a digital image processing apparatus having an auto focus function, and detects whether or not a change of an image in the AF area occurs while performing the auto focus, and changes the AF area by the amount of change generated when the change occurs. A digital image processing apparatus including a digital image processing unit for correcting and obtaining AF evaluation data is provided.

In the present invention, the image information extraction unit for extracting the image information of the AF area of the image data input to the digital image processing apparatus; Change amount calculating section for calculating the amount of change (V) between the image information extracting unit preceding frame (t-1) image information (I _{t -1)} and the video information (I _t) extracted from the current frame (t) derived from; An AF area position corrector for correcting the position of the AF area by the amount of change (V); And a controller configured to control operations of the image information extractor, the change calculator, and the AF area position corrector.

Here, when the magnitude of the change amount V is 0, the controller may control to obtain the AF evaluation data in the current frame without correcting the position of the AF area.

The control unit controls to obtain the AF evaluation data by correcting the position of the AF area by the size of the change amount V when the size of the change amount V is greater than 0 and less than or equal to a predetermined reference value. can do.

Here, when the magnitude of the change amount V is greater than a predetermined threshold, and the change amount V exists only in a part of the image, the controller determines that another subject is interrupted, and the subject is the AF. After waiting to disappear in the area, it is possible to control to obtain the AF evaluation data.

In this case, the change amount calculator may extract a feature point in which the color of the image is independently distinguished in the AF area in order to calculate the change amount V.

According to another aspect of the present invention, there is provided a control method of a digital image processing apparatus having an auto focus function, comprising: extracting image information of an AF area from image data input to the digital image processing apparatus; Video information is extracted from the preceding frame _{(t-1) (I t} -1) , and a step of computing the variation (V) between the video information (I _t) extracted from the current frame (t); Determining the magnitude of the change amount (V); And acquiring AF evaluation data by correcting the position of the AF area by the amount of change (V).

In the present invention, when the magnitude of the change amount V is determined by determining the magnitude of the change amount V, the AF evaluation data may be obtained in the current frame without correcting the position of the AF area.

In the present invention, when the magnitude of the change amount V is determined and the magnitude of the change amount V is greater than zero and less than or equal to a predetermined threshold, the position of the AF area is determined by the magnitude of the change amount V. By correcting as much as possible, the AF evaluation data can be obtained.

In the present invention, when the magnitude of the change amount V is determined and the magnitude of the change amount V is larger than a predetermined reference value, and the change amount V is present only in a part of the image, another subject is used. May be determined to have intervened, wait until the subject disappears in the AF area, and then obtain the AF evaluation data.

In the present invention, determining whether the subject disappears in the AF area includes: increasing a frame; Extracting image information of an AF area from image data input to the digital image processing apparatus; Video information is extracted from the preceding frame _{(t-1) (I t} -1) , and a step of computing the variation (V) between the video information (I _t) extracted from the current frame (t); And determining whether the subject has disappeared in the AF area based on the change amount V.

In the present invention, the step of calculating the amount of change (V), it is possible to extract a feature point that the color of the image is independently distinguished in the AF area in order to calculate the amount of change (V).

According to the present invention, it is possible to obtain an effect of improving user convenience and improving quality of the captured image.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

1 is a perspective view showing the front and the top of the digital image processing apparatus according to the present invention.

The shutter-release button 101 opens and closes to expose the CCD or film to light for a predetermined time, and records the image on the CCD by properly exposing the subject in conjunction with an aperture (not shown).

The shutter-release button 101 generates first and second image capturing signals by a photographer input. When the first shutter-release signal as the half-shutter signal is input, the digital image processing apparatus 100 focuses and adjusts the amount of light, and when the focus is achieved, the display unit (see 113 in FIG. 2) turns green. Will be turned on. When focus is achieved by the input of the first shutter-release signal and the amount of light is adjusted, the second shutter-release signal as a full-shutter signal is input to capture an image.

The power button 103 is input to supply power to and operate the digital image processing apparatus.

The flash 105 brightens the bright light instantly when shooting in a dark place. The flash mode includes auto flash, forced flash, flash off, red-eye reduction, and slow synchro.

The auxiliary light 107 supplies light to the subject so that the digital image processing apparatus automatically focuses quickly and accurately when the amount of light is insufficient or at night.

The lens unit 109 receives light from an external light source and processes an image.

FIG. 2 is a rear view of the rear surface of the digital image processing apparatus shown in FIG. 1, wherein the wide-angle zoom button 111w, the telephoto-zoom button 111t, the display unit 113, and a touch sensor or a contact switch are installed. The provided input buttons B1 to B14 (hereinafter referred to as buttons B1 to B14) are provided.

The wide-angle zoom button 111w or the tele-zoom button 111t increases the angle of view or narrows the angle of view according to an input, particularly when the size of the selected exposure area is to be changed. When the wide-zoom button 111w is input, the size of the selected exposure area is reduced, and when the tele-zoom button 111t is input, the size of the selected exposure area is increased.

The buttons B1 to B14 are provided in the horizontal column and the vertical column of the display unit 113. The buttons B1 to B14 provided in the horizontal and vertical columns of the display 113 are provided with a touch sensor (not shown) or a contact switch (not shown).

That is, the buttons B1 to B14 are provided with a touch sensor and move up / down / left / right in a state where the buttons B1 to B7 in the horizontal row or the buttons B8 to B14 in the vertical row are touched. Any value of the item (eg, color or brightness) may be selected or a submenu icon included in the main menu icon may be activated.

In addition, the buttons B1 to B14 are provided with contact switches so that the corresponding function can be executed by directly selecting the main menu icon and the submenu icon. Touch sensors require only weaker touches than contacted switch inputs, whereas contacted switch inputs require relatively strong touches compared to touch sensor inputs.

3 is a block diagram showing the configuration of the digital image processing apparatus illustrated in FIGS. 1 and 2, wherein the display unit 113, the user input unit 121, the imaging unit 123, the image processing unit 125, and the storage unit ( 127 and a digital signal processor 129. 4 is a detailed block diagram of the digital signal processor of FIG. 3.

The user input unit 121 may open and close the shutter-release button 101 to expose the CCD or the film to light for a predetermined time, the power button 103 to input power, and widen the angle of view according to the input, Wide-Zoom button (111w) and Tele-Zoom button (111t) for narrowing the angle of view, and a touch sensor or contact switch provided in the horizontal and vertical columns around the display unit 113 for text or menu settings There are buttons B1 to B14.

The imaging unit 123 includes a shutter, a lens unit, an aperture, a charge coupled device (CCD), and an analog-to-digital converter (ADC), which are not shown in the figure. The shutter is a mechanism for adjusting the amount of light exposed together with the aperture. The lens unit receives light from an external light source and processes an image. At this time, the iris adjusts the amount of light (light quantity) incident on the degree of opening and closing. The opening and closing degree of the iris is controlled by the digital signal processing unit 129.

The CCD accumulates the amount of light input through the lens unit and outputs an image captured by the lens unit in accordance with the accumulated light amount in accordance with the vertical synchronization signal. Image acquisition of the digital image processing apparatus is performed by a CCD that converts light reflected from a subject into an electrical signal. In order to obtain a color image using a CCD, a color filter is required, and most of them employ a filter (not shown) called a color filter array (CFA). CFA has a structure arranged regularly by passing only one color light per pixel, and has various shapes according to the arrangement structure. The ADC converts an analog video signal output from the CCD into a digital signal.

The image processor 125 performs signal processing to display the digitally converted RAW data. The image processor 125 removes the black level due to the dark current generated by the CCD and the CFA filter that are sensitive to the temperature change. The image processor 125 performs gamma correction for encoding information according to nonlinearity of human vision. The image processor 125 performs CFA interpolation to interpolate the Bayer pattern implemented by the RGRG line and the GBGB line of the gamma corrected predetermined data into the RGB line. The image processing unit 125 converts the interpolated RGB signal into a YUV signal, sharpens the image by filtering the Y signal by a high band filter, and uses the standard color coordinate system to adjust the color values of the U and V signals. Perform color correction to correct and remove their noise. The image processor 125 compresses and signals the Y, U, and V signals from which the noise is removed to generate a JPEG file, and the generated JPEG file is displayed on the display unit 113 and stored in the storage unit 127. . All of the operations of the image processor 125 operate under the control of the digital signal processor 129.

The digital signal processing unit 129 includes an image information extracting unit 129-1, a change amount calculating unit 129-2, an AF area position correcting unit 129-3, and a control unit 129-4, and the AF area during AF. It detects whether a change in the image occurs in the inside, and corrects it when a change occurs to obtain AF evaluation data.

In detail, in order to perform auto focus (AF) in a conventional digital image processing apparatus, data necessary for AF is extracted from a predetermined area. However, when the AF is performed, AF may fail when the camera shake of the photographer occurs or the subject moves. That is, when the evaluation data for the AF are damaged due to the camera shake or the movement of the subject, the AF may fail when the AF algorithm cannot operate normally.

In order to solve such a problem, the digital image processing apparatus 100 according to an exemplary embodiment of the present invention detects whether a change of an image in the AF area occurs during AF, and corrects the change when the change occurs, thereby correcting the AF evaluation data. Characterized by performing the role of obtaining.

The image information extracting unit 129-1 extracts the image information I _t of the AF area in the current frame t among the image data input to the CCD through the lens unit under the control of the controller 129-4. Play a role.

Under the control of the controller 129-4, the change amount calculating unit 129-2 extracts the image information I _{t -1} extracted from the previous frame t-1 and the image information I _t extracted from the current frame _t . It calculates the amount of change (V) between.

The AF area position correction unit 129-3 serves to correct the position of the AF area by a predetermined amount under the control of the controller 129-4.

The controller 129-4 determines the magnitude of the change amount V calculated by the change amount calculation unit 129-2, and when the change amount V is 0, the AF evaluation data is corrected in the current frame without correction of the AF area. It plays a role of controlling to acquire.

On the other hand, when the magnitude of the change amount V is greater than zero and less than or equal to a predetermined threshold, the controller 129-4 corrects the AF evaluation data by the amount of the change amount V calculated by calculating the position of the AF area. It plays a role of controlling to acquire.

On the other hand, when the magnitude of the change amount V is larger than a predetermined threshold, the controller 129-4 determines that another subject has suddenly entered, and waits until the suddenly interrupted subject disappears in the AF area. After that, it controls to obtain AF evaluation data.

5A and 5B are views illustrating a state in which an image is captured by using the digital image processing apparatus according to the present invention.

The digital signal processor 129 according to an embodiment of the present invention may use a feature point extraction method to calculate the amount of change in the image information. Here, the feature point means a place where colors of an image are independently distinguished in the AF area. That is, as shown in the characteristic point CP _{t -1} indicated by '+' in the AF area AF _{t- 1 of} FIG. Independently distinguishable regions may be indicated by feature points.

FIG. 5A is a diagram illustrating image information I _{t -1} extracted from a previous frame t-1, and FIG. 5B is a diagram illustrating image information I _t extracted from a current frame t. Under the control of the controller 129-4, the change amount calculating unit 129-2 extracts the image information I _{t -1} extracted from the previous frame t-1 and the image information I _t extracted from the current frame _t . The amount of change (V) is calculated. 5A and 5B, it can be seen that the feature points are moved to the opposite direction of the arrow of FIG. 5B to a certain extent in the current frame compared to the previous frame. That is, since the magnitude of the change V is greater than zero and less than or equal to a predetermined threshold, it is determined that the camera shake or the movement of the subject occurs to some extent, and the AF area position correction unit 129-3 determines the AF. The position of the region is corrected in the direction of the arrow of FIG. 5B by the amount of the change amount V, and the controller 129-4 obtains the AF evaluation data in the corrected region. That is, by correcting the AF area present in the AF position _t in Figure 5b to the AF position _{t -1,} to obtain the AF evaluation data from the corrected area.

According to the present invention as described above, when camera shake or subject movement occurs, lossless AF data can be obtained by shifting the AF area to obtain AF data.

6A, 6B, and 6C are diagrams illustrating another exemplary embodiment of photographing an image using a digital image processing apparatus according to the present invention. 6A, 6B, and 6C illustrate a shooting method when another subject suddenly interrupts during AF.

Comparing FIGS. 6A and 6B, it can be seen that another subject has suddenly entered the AF area in FIG. 6B during AF. In this case, the magnitude of the change amount V calculated by the change amount calculating unit 129-2 is larger than a predetermined reference value, and the change amount V is present only in a part of the AF area. As described above, when another subject is suddenly interrupted during shooting, the controller 129-4 waits until the suddenly interrupted subject disappears in the AF area, and controls to acquire AF evaluation data.

In detail, when another subject is suddenly interrupted during shooting, the controller 129-4 controls the image information extraction unit 129-1 to extract image information I _t of the AF area in the current frame t. do. Then, the controller 129-4 controls the change amount calculating unit 129-2 to extract the image information I _{t -1} extracted from the previous frame t-1 and the image information I extracted from the current frame t. Calculate the amount of change (V) between _t ). As a result of determining the change amount V, if the interrupted subject still exists, the determination process is repeated until the subject disappears. Thus, if the interposed subject disappears, the normal AF evaluation data acquisition process is performed again.

According to the present invention, if another subject suddenly interrupts the process of acquiring AF evaluation data, it ignores this and resumes normal AF evaluation data acquisition process after the AF area is stabilized, thereby improving user convenience and improving the quality of the captured image. The effect can be improved.

Next, a digital image processing method according to the present invention will be described in detail with reference to FIG. 7. The image processing method according to the present invention may be performed inside the image processing apparatus as shown in FIG. 3. It can be done internally.

Referring to FIG. 7, the control method of the digital image processing apparatus according to the present invention may include extracting image information of an AF area from image data input to the digital image processing apparatus, extracted from a previous frame t-1. Calculating a change amount V between the image information I _{t -1} and the image information I _t extracted from the current frame t, determining a magnitude of the change amount V, and Correcting the position by the amount of change (V) to obtain AF evaluation data.

This will be described in more detail as follows.

First, under the control of the controller, the image information extracting unit extracts the image information I _t of the AF area in the current frame t from the image data input to the CCD through the lens unit (step S110).

Next, the change amount calculation unit is the amount of change (V) between under the control of the control unit, before the frame (t-1) image information (I _{t -1)} and the video information (I _t) extracted from the current frame (t) derived from the In operation S120, the feature point extraction method may be used to calculate the change amount V of the image information. Here, the feature point means a place where colors of an image are independently distinguished in the AF area. In other words, areas distinguishable from the surrounding colors such as the eyes, eyebrows, nose, mouth, neck, and ears of the person may be displayed as feature points.

Next, the controller determines whether the magnitude of the change amount V of the image information is 0 (step S130).

As a result of the determination, when the change amount V of the image information is 0, the AF evaluation data is acquired in the current frame without correcting the position of the AF area (step S170), and the captured image is generated as a JPEG image file. It is displayed on the display unit and stored in the storage unit (step S180).

On the other hand, as a result of the determination, if the magnitude of the change amount V of the image information is not 0, it is determined whether the magnitude of the change amount V of the image information is greater than 0 and less than or equal to a predetermined threshold value (S140). step)

As a result of the determination, when the magnitude of the change amount V of the image information is greater than 0 and less than or equal to a predetermined reference value, after correcting the position of the AF area by the amount of the change amount V (step S141), AF evaluation is performed. Data is acquired (step S170), and the captured image is generated as a JPEG image file and displayed on the display unit and stored in the storage unit (step S180).

Meanwhile, as a result of the determination, when the amount of change V of the image information is larger than a predetermined reference value, it is determined whether the amount of change V of the image information exists only in a part of the image.

As a result of the determination, when the change amount V of the image information does not exist only in a part of the image, it is determined that the AF has failed (step S160), and the process returns to step S110.

On the other hand, if the amount of change (V) of the image information exists only in a part of the image as a result of the determination, it is determined that another subject is suddenly interrupted, waits until the subject disappears in the AF area, and then controls to obtain AF evaluation data. (Steps S151 to S159)

This will be described in more detail as follows.

As a result of the determination, if the change amount V of the image information exists only in a part of the image, the controller determines that another subject is suddenly interrupted during shooting (step S151), and increases the frame to the next frame (step S153). The image information extracting unit extracts the image information I _t of the AF area in the current frame t from the input image data. (Step S155) Next, the change amount calculating unit extracts the previous frame t-1. The amount of change V between the image information I _{t -1} and the image information I _t extracted from the current frame t is calculated (step S157). It is determined whether the subject has disappeared in the AF area (step S159). As a result of the determination, if the interrupted subject still exists, step S151 is repeated to wait until the subject disappears in the AF area. On the other hand, when the determined subject disappears, repeating step S130 to obtain the AF evaluation data again.

According to the present invention as described above, when camera shake or subject movement occurs, lossless AF data can be obtained by shifting the AF area to obtain AF data. In addition, if another subject is suddenly interrupted during the AF evaluation data acquisition process, it is ignored and resumes the normal AF evaluation data acquisition process after the AF area is stabilized, thereby improving user convenience and improving the quality of the captured image. Can be.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

1 is a perspective view showing the front and the top of the digital image processing apparatus according to the present invention.

FIG. 2 is a rear view illustrating a rear shape of the digital image processing apparatus illustrated in FIG. 1.

3 is a block diagram illustrating a configuration of the digital image processing apparatus illustrated in FIGS. 1 and 2.

4 is a detailed block diagram of the digital signal processor of FIG. 3.

4 is a graph sequentially showing high frequency components extracted from a plurality of images photographed during continuous shooting.

7 is a flowchart illustrating a control method of a digital image processing apparatus according to the present invention.

<Explanation of symbols for the main parts of the drawings>

100: digital image processing apparatus 121: user input unit

123: imaging unit 125: image processing unit

127: storage unit 129: digital signal processing unit

129a: high frequency component extraction unit 129b: control unit

Claims (12)

Digital image processing device with an auto focus function, And a digital image processor which detects whether a change of an image in the AF area occurs during the auto focus, and corrects the AF area by the amount of change generated when the change occurs to obtain AF evaluation data. The method of claim 1, An image information extracting unit which extracts image information of the AF area from among image data input to the digital image processing apparatus; Change amount calculating section for calculating the amount of change (V) between the image information extracting unit preceding frame (t-1) image information (I _{t -1)} and the video information (I _t) extracted from the current frame (t) derived from; An AF area position corrector for correcting the position of the AF area by the amount of change (V); And And a controller configured to control operations of the image information extracting unit, the change amount calculating unit, and the AF area position correcting unit. The method of claim 2, And the control unit controls to obtain the AF evaluation data in the current frame without correcting the position of the AF area when the change amount V is zero. The method of claim 2, The control unit controls to acquire the AF evaluation data by correcting the position of the AF area by the size of the change amount V when the size of the change amount V is greater than 0 and is less than or equal to a predetermined threshold. Digital image processing device characterized in that. The method of claim 2, If the magnitude of the change amount V is greater than a predetermined threshold, and the change amount V exists only in a part of the image, the controller determines that another subject is interrupted and the subject is in the AF area. Wait until disappears, and controls to obtain the AF evaluation data. The method of claim 2, And the change amount calculating unit extracts a feature point in which the color of the image is independently distinguished in the AF area in order to calculate the change amount (V). A control method of a digital image processing apparatus having an auto focus function, Extracting image information of an AF area from image data input to the digital image processing apparatus; Video information is extracted from the preceding frame _{(t-1) (I t} -1) , and a step of computing the variation (V) between the video information (I _t) extracted from the current frame (t); Determining the magnitude of the change amount (V); And And acquiring AF evaluation data by correcting the position of the AF area by the variation amount (V). The method of claim 7, wherein Determining the magnitude of the change amount V, and when the magnitude of the change amount V is 0, controlling the digital image processing apparatus, wherein the AF evaluation data is obtained from the current frame without correcting the position of the AF area. Way. The method of claim 7, wherein When the magnitude of the change amount V is determined to be greater than zero and less than a predetermined reference value, the position of the AF area is corrected by the magnitude of the change amount V. A method of controlling a digital image processing apparatus, characterized by acquiring AF evaluation data. The method of claim 7, wherein When the magnitude of the change amount V is greater than a predetermined threshold, and the change amount V is present only in a part of the image, it is determined that another subject is interrupted. And waiting until the subject disappears in the AF area, and then acquiring the AF evaluation data. The method of claim 10, The determining of whether the subject disappears in the AF area may include: Increasing the frame; Extracting image information of an AF area from image data input to the digital image processing apparatus; Video information is extracted from the preceding frame _{(t-1) (I t} -1) , and a step of computing the variation (V) between the video information (I _t) extracted from the current frame (t); And And determining whether the subject has disappeared in the AF area based on the change amount (V). The method of claim 7, wherein Computing the amount of change (V), And extracting feature points that are independently distinguished from each other in the AF area in order to calculate the amount of change (V).

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