KR20090077491A - Apparatus and method for blurring an image background in digital image processing device - Google Patents

Abstract

An apparatus and a method for blurring an image background in a digital image processing device are provided to combine brightness data of the first image generated by flash emission with the second image generated by flash off, thereby realizing background blurring effects. A digital signal processor(129) comprises the following units. A brightness data extractor(129-1) extracts brightness data of the first image generated by flash emission. An out-of-focusing effect processor(129-2) combines brightness data of the first image with the second image. The third image to which a background blur effect is applied is generated through the combination. The digital signal processor blurs an area having relatively lower brightness in the second image.

Description

Apparatus and method for blurring an image background in digital image processing device}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital image processing apparatus and a method of controlling the same. Specifically, a background blur effect is realized by synthesizing luminance data of a first image generated by flash emission and a second image generated by flash off. The present invention relates to an apparatus and a method for processing a background blur effect of an image in a digital image processing apparatus.

Currently, digital image processing apparatuses, such as digital cameras, camera phones, and smart phones, which are becoming popular, have various digital elements and provide functions that are differentiated from analog photographing equipment by processing digitalized data.

For example, by having a large-capacity memory, it is possible to store a large amount of images that are difficult to compare with conventional films, and CCD (Charge Coupled Device) is a PC (Personal Computer) by replacing the film to form a high-pixel image ) And share image data and provide convenience in image processing.

In addition, it provides more functions than analog photographing equipment such as automatic control of shutter speed and aperture value, auto focus, image enhancement, and automatic light adjustment.

However, since analog imaging equipment is equipped with natural optical materials and is operated manually, it tends to be preferred to digital image processing apparatus when delicate work is performed by a professional.

In order to compensate for these disadvantages, recently released digital image processing apparatuses have tended to implement not only the advantages of digital apparatuses but also unique functions of conventional analog image processing apparatuses. In other words, beyond the limits of digital devices, the advantages of analog devices are gradually gathered and various and specialized functions are provided.

In addition, due to the widespread use of digital image processing devices, the population with a hobby of photography is gradually increasing, and thus, many users have acquired professional shooting techniques.

However, these digital image processing apparatuses still have a considerable part of the needs of specialized users.

For example, when taking portraits, most people use the Out of Focusing effect. When using a conventional digital image processing apparatus, the expression of the effect is almost impossible due to the limited size lens and CCD. It can be considered impossible.

In general, the background blur effect is formed as a circle having a predetermined diameter from the size of a confusion circle (a point where an image of a subject forms an image through a lens). In this case, the circular point having the diameter is called a confusion circle, and the size of the confusion circle is closely related to the depth (focal depth and depth of field). Therefore, the depth depends on factors such as the CCD size, aperture value, focal length of the lens, the distance between the subject and the camera, and the distance between the subject and the background of the digital image processing apparatus associated with the confusion source.

The focal lengths of the image sensor, aperture value, and lens except for the distance between the subject and the digital image processing device among the factors that determine the depth of field are changed according to the physical specifications of the digital image processing device. Due to its small image sensor and small aperture lens, it is possible to express deep depth at all times in structure, so that only the main subject can be clear and the background can not meet the needs of the shallow depth.

In addition, the use of a large size image sensor and lens for optical characteristics is also related to the yield of the semiconductor process for producing a relatively large image sensor, and also requires a large diameter lens, etc. The size of the image processing apparatus is also increased, which has the disadvantage of limitation of miniaturization.

According to the present invention, a background blur effect processing apparatus for a digital image processing apparatus is capable of realizing a background blur effect by combining luminance data of a first image generated by flash emission and a second image generated by flash off. And to provide a method.

The present invention provides a digital image processing apparatus, which extracts luminance data of a first image generated by flash emission, generates a second image generated by flash off, and generates the luminance data of the first image and the second image. An apparatus for processing a background blur effect of an image including digital signal processing means for synthesizing an image to generate a third image is provided.

In the present invention, the digital signal processing means, the brightness data extraction unit for extracting the brightness data of the first image generated by flash light emission; And a background blur effect processor configured to generate the third image to which the background blur effect is applied by synthesizing the luminance data of the first image and the second image.

In the present invention, the digital signal processing unit may clearly display a region having a relatively high luminance in the second image, and display a region where the luminance is relatively low in the second image.

In the present invention, the synthesis of the luminance data of the first image and the second image may be performed by an alpha blending process.

In the present invention, the synthesis of the luminance data of the first image and the second image may be performed by a low pass filter process.

In the present invention, luminance data of the first image generated by the flash emission may be stored in a look up table.

According to another aspect of the present invention, a method of operating a digital image processing apparatus includes: (a) generating a first image by emitting a flash; (b) extracting and storing luminance data from the first image; (c) generating a second image by flashing off; And (d) synthesizing the luminance data of the first image and the second image to generate a third image to which the background blur effect is applied.

In the present invention, step (b) is,

Luminance data may be extracted from the first image and stored in a look up table.

In the present invention, the step (d) may clearly display a region having a relatively high luminance in the second image, and display a region where the luminance is relatively low in the second image.

In the present invention, the step (d) may be performed by combining the luminance data of the first image and the second image to perform an alpha blending process.

In the present invention, the step (d) may perform a low pass filter process by combining the luminance data of the first image and the second image.

According to the present invention as described above, it is possible to obtain an effect of enabling the background blur effect in the digital image processing apparatus.

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 the 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 focuses and adjusts the amount of light, and when the focus is achieved, the green light is turned on in the display 113. When the 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 light emission, 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 button frame (B1 ~ B14) is provided with a contact switch, it is possible to directly select the main menu icon and sub-menu icon to execute the corresponding function. The touch sensor requires only a weak touch relative to the contact switch input, but the contact switch input requires a relatively strong touch compared to the touch sensor input.

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.

The user input unit 121 may open and close the shutter-release button 101 to expose the CCD or 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 incident (light quantity) according to 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 23 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 processor 129 extracts luminance data of the first image generated by flash emission, generates a second image generated by flash off, and generates the luminance data of the first image and the second image. Synthesis is controlled to generate a third image to which the background blur effect is applied.

In detail, most people take out-of-focusing effects when taking portraits. However, when using a conventional digital image processing device, it is almost impossible to express the effect due to a limited size lens and CCD. can see. In general, the background blurring effect depends on the size of the confusion circle, which is closely related to the depth. Therefore, the depth depends on factors such as the CCD size, aperture value, focal length of the lens, the distance between the subject and the camera, and the distance between the subject and the background of the digital image processing apparatus associated with the confusion source. Here, the CCD size, the aperture value, and the focal length of the lens are largely changed according to the physical specifications of the digital image processing apparatus. Only the expression can be made, so the main subject's sharpness and the background's blurred depth can't meet the needs of users.

In order to solve this problem, the digital image processing apparatus according to an embodiment of the present invention synthesizes the luminance data of the first image generated by flash emission and the second image generated by flash off, thereby causing a background. The third image may be generated by applying a blur effect.

The digital signal processor 129 includes a luminance data extractor 129-1, a background blur effect processor 129-2, and a controller 129-3.

The luminance data extractor 129-1 extracts and stores luminance data of the first image generated by flash emission under the control of the controller 129-3. Under the control of the controller 129-3, the background blur effect processor 129-2 synthesizes the luminance data of the first image generated by the flash emission and the second image generated by the flash off. A third image to which the effect is applied is generated. Here, the photographing in which the flash is emitted to generate the first image is performed as preliminary photographing, and the photographing in which the flash is turned off to generate the second image is performed as the main photographing.

4 is a diagram illustrating a state in which an image is captured by using the digital image processing apparatus illustrated in FIG. 1. Referring to FIG. 4, two spherical subjects are located at a short distance from a digital image processing apparatus as a main subject, and a columnar subject is relatively far from the digital image processing apparatus. And there will be backgrounds behind the columnar subject.

When the shutter-release signal is input in this state, the controller 129-3 first emits the flash 105 to generate the first image. 5 is a diagram illustrating a first image generated by flash emission.

The flash 105 serves to brighten the bright light momentarily when shooting in a dark place. When the image is taken by emitting the flash 105, since a large amount of light is instantaneously transmitted to the near subject as the main subject, the luminance value of the near subject becomes very high. On the other hand, the amount of light that is transmitted to the subject farther away is sharply reduced, the luminance value of the subject is sharply reduced, so that most of the background is almost black.

Therefore, the digital image processing apparatus of the present invention generates a first image by using such flash emission photographing, and extracts luminance data therefrom to distinguish a main subject to be displayed clearly and a background to be blurred. The main subject to be displayed clearly is displayed more clearly, and the background to be displayed more blurredly is displayed.

That is, as shown in FIG. 5, the luminance value of the near-spherical object as the main subject is very high, and the luminance value of the relatively long-distance columnar subject is slightly smaller than the luminance value of the spherical subject, and the background part at the rear thereof has the luminance. The value is detected very low.

As such, the luminance data of the first image extracted by the luminance data extractor 129-1 may be stored in a look up table. A look up table is an array or a set of memory for storing a result of pre-calculation in order to reduce the number of operations in an actual process and then processing the result using the look up table.

Next, the controller 129-3 performs the main shooting in a flash off state to generate a second image. FIG. 6 is a diagram illustrating a second image generated by flash off.

Finally, under the control of the controller 129-3, the background blur effect processor 129-2 synthesizes the luminance data of the first image generated by the flash emission and the second image generated by the flash off. A third image to which the effect is applied is generated. FIG. 7 is a diagram illustrating a third image generated by synthesizing the luminance data of the first image and the second image.

Here, the background blur effect processor 129-2 may synthesize the luminance data of the first image and the second image through an alpha blending process.

An alpha blending process is a general method used to blend two images. The blending process involves mixing two images at an appropriate ratio so that the images overlap. That is, the background blur effect processor 129-2 alpha-blending the luminance data of the first image generated by the flash emission to the second image generated by the flash off, thereby processing the third image. Create Then, since the luminance value of the near spherical subject which is the main subject in the luminance data of the first image is very high, the spherical subject of the third image is more clearly generated. On the other hand, since the luminance value of the columnar subject that is relatively far from the luminance data of the first image is considerably smaller than the luminance value of the spherical subject, the columnar subject of the third image is generated to be somewhat blurred. Since the background part behind the back of the luminance data of the first image has a very low luminance value, the background part of the third image is generated to be very blurry.

Alternatively, the background blur effect processor 129-2 may synthesize the luminance data of the first image and the second image through a low pass filter process.

The low pass filter refers to a filter of an electronic device that passes only a frequency below a cutoff point and weakens a higher frequency. In the digital image photographing apparatus, low pass filter processing means blurring an image by killing an edge of a specific region. That is, the background blur effect processor 129-2 filters a low pass portion of luminance data of the first image generated by flash emission on the second image generated by flash off. ) To generate a third image. That is, since the luminance value of the near spherical subject which is the main subject in the luminance data of the first image is very high, no separate processing is applied to the spherical subject of the third image. On the other hand, since the luminance value of the columnar subject that is relatively far from the luminance data of the first image is considerably smaller than the luminance value of the spherical subject, the columnar subject of the third image is slightly blurred by performing some low pass filter processing. Is generated. Since the background part behind the back of the luminance data of the first image has a very low luminance value, the background part of the third image is processed to be very blurry by performing a low pass filter process.

According to the present invention, a portion having a higher luminance in the first image, that is, a main subject portion to be highlighted, becomes sharper, and a portion having a lower luminance in the first image, that is, a portion to be blurred, is further blurred, thereby digitally An effect of implementing an out of focusing effect in the image processing apparatus may be obtained.

Next, a digital image processing method according to the present invention will be described in detail with reference to FIG. 8. The image processing method according to the present invention may be performed inside the image processing apparatus as shown in FIG. 3. Can be performed internally.

Referring to FIG. 8, in the control method of the digital image processing apparatus according to the present invention, a shutter-release signal is input (step S110), a flash is emitted to generate a first image (step S120), and the generated Extracting and storing the luminance data from the first image (step S130), generating a second image by flashing off (step S140), and combining the luminance data of the first image and the second image to blur the background image; And generating and storing the third image file to which the effect is applied (step S150).

First, when the shutter-release signal is input (step S110), the flash is emitted to generate a first image (step S120), and luminance data is extracted from the generated first image and stored (step S130). That is, the luminance data extractor 129-1 extracts and stores luminance data of the first image generated by flash emission under the control of the controller 129-3.

The flash 105 serves to brighten the bright light momentarily when shooting in a dark place. When the image is taken by emitting the flash 105, since a large amount of light is instantaneously transmitted to the near subject as the main subject, the luminance value of the near subject becomes very high. On the other hand, the amount of light that is transmitted to the far-away subject is sharply reduced, the luminance value of the subject is sharply reduced, so that most of the background is almost black.

Therefore, the digital image processing apparatus of the present invention generates a first image by using such flash emission photographing, and extracts luminance data therefrom to distinguish a main subject to be displayed clearly and a background to be blurred. The main subject to be displayed clearly is displayed more clearly, and the background to be displayed more blurredly is displayed.

That is, as shown in FIG. 5, the luminance value of the near-spherical object as the main subject is very high, and the luminance value of the relatively long-distance columnar subject is slightly smaller than the luminance value of the spherical subject, and the background part at the rear thereof has the luminance. The value is detected very low.

As such, the luminance data of the first image extracted by the luminance data extractor 129-1 may be stored in a look up table. A look up table is an array or a set of memory for storing a result of pre-calculation in order to reduce the number of operations in an actual process and then processing the result using the look up table.

Next, a second image is generated by flashing off (step S140), and the third image file to which the background blur effect is applied is synthesized by combining the luminance data of the first image and the second image (step S150). do. That is, the background blur effect processor 129-2 synthesizes the luminance data of the first image generated by flash emission and the second image generated by flash off under the control of the controller 129-3. A third image to which the effect is applied is generated.

Here, the background blur effect processor 129-2 may synthesize the luminance data of the first image and the second image through an alpha blending process.

An alpha blending process is a general method used to blend two images. The blending process involves mixing two images at an appropriate ratio so that the images overlap. That is, the background blur effect processor 129-2 alpha-blending the luminance data of the first image generated by the flash emission to the second image generated by the flash off, thereby processing the third image. Create As shown in FIG. 7, since the luminance value of the near-spherical subject that is the main subject in the luminance data of the first image is very high, the spherical subject of the third image is more clearly generated. On the other hand, since the luminance value of the columnar subject that is relatively far from the luminance data of the first image is considerably smaller than the luminance value of the spherical subject, the columnar subject of the third image is generated to be somewhat blurred. Since the background part behind the back of the luminance data of the first image has a very low luminance value, the background part of the third image is generated to be very blurry.

Alternatively, the background blur effect processor 129-2 may synthesize the luminance data of the first image and the second image through a low pass filter process.

The low pass filter refers to a filter of an electronic device that passes only a frequency below a cutoff point and weakens a higher frequency. In the digital image photographing apparatus, low pass filter processing means blurring an image by killing an edge of a specific region. That is, the background blur effect processor 129-2 filters a low pass portion of luminance data of the first image generated by flash emission on the second image generated by the flash off. Processing to generate a third image. That is, since the luminance value of the near spherical subject which is the main subject in the luminance data of the first image is very high, no separate processing is applied to the spherical subject of the third image. On the other hand, since the luminance value of the columnar subject that is relatively far from the luminance data of the first image is considerably smaller than the luminance value of the spherical subject, the columnar subject of the third image is slightly blurred by performing some low pass filter processing. Is generated. Since the background part behind the back of the luminance data of the first image has a very low luminance value, the background part of the third image is processed to be very blurry by performing a low pass filter process.

According to the present invention, a portion having a higher luminance in the first image, that is, a main subject portion to be highlighted, becomes sharper, and a portion having a lower luminance in the first image, that is, a portion to be blurred, is further blurred, thereby digitally An effect of implementing an out of focusing effect in the image processing apparatus may be obtained.

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 diagram illustrating a state in which an image is captured by using the digital image processing apparatus illustrated in FIG. 1.

5 is a diagram illustrating a first image generated by flash emission.

FIG. 6 is a diagram illustrating a second image generated by flash off.

FIG. 7 is a diagram illustrating a third image generated by synthesizing the luminance data of the first image and the second image.

8 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 101: shutter-release button

105: flash 107: auxiliary light

113: display unit 121: user input unit

123: imaging unit 125: image processing unit

127: storage unit 129: digital signal processing unit

129-1: Luminance data extraction unit 129-2: Background blur effect processing unit

129-3: control unit

Claims (11)

As a digital image processing device, Extract luminance data of the first image generated by flash emission, generate a second image generated by flash off, and generate a third image by combining the luminance data of the first image and the second image. Background image blur effect processing apparatus comprising a digital signal processing means. The method of claim 1, The digital signal processing means, A luminance data extractor configured to extract luminance data of the first image generated by flash emission; And And a background blur effect processor configured to generate a third image to which a background blur effect is applied by synthesizing the luminance data of the first image and the second image. The method of claim 1, The digital signal processing means, An apparatus for processing a background blur effect of an image, wherein an area having a relatively high luminance is displayed clearly in the second image, and an area having a relatively low luminance is displayed blurry in the second image. The method of claim 1, And the brightness data of the first image and the synthesis of the second image are performed by alpha blending. The method of claim 1, And the luminance data of the first image and the second image are synthesized by a low pass filter process. The method of claim 1, And the luminance data of the first image generated by the flash emission is stored in a look up table. As an operation method of a digital image processing apparatus, (a) generating a first image by emitting a flash; (b) extracting and storing luminance data from the first image; (c) generating a second image by flashing off; And and (d) synthesizing the luminance data of the first image and the second image to generate a third image to which a background blur effect is applied. The method of claim 7, wherein In step (b), And extracting luminance data from the first image and storing the luminance data in a look up table. The method of claim 7, wherein In step (d), The region of the second image is displayed with a relatively high brightness is displayed clearly, the region of the relatively low brightness is displayed in the second image is blurred, the image blur effect processing method. The method of claim 7, wherein In step (d), And combining the luminance data of the first image and the second image to perform an alpha blending process. The method of claim 7, wherein In step (d), And combining the luminance data of the first image and the second image to perform a low pass filter process.

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