KR101495080B1 - Digital image processing apparatus, method for controlling the digital image processing apparatus, and recording medium storing program to implement the method - Google Patents

Abstract

The present invention relates to a digital image processing apparatus capable of effectively removing noise included in an image, a control method thereof, and a recording medium storing a program for executing the same, in which a minimum gray level is 0 and a maximum gray level is MGL (N, m) pixel by applying a first low-pass filter to a first image when data in a pixel of the first image is I _{n, m} , and a second image acquiring unit that acquires data in a second image of _{L1 n, m, (n,} m) in the pixel data of the _{H n, m = I n,} m -L1 n, m + (MGL + (N, m) pixels by applying a second low-pass filter to the third image to obtain a third image of H _{n, m} according to L _{n, m} of the data in the fourth image pickup unit, the reversal image of the fourth image (n, m) pixels for acquiring the image is 4 n _{n, m} fifth already And the fourth image obtaining portion for obtaining, I _{n, m} is (MGL + 1) / If is smaller than 2 (n, m) in the pixel data F _{n, m} is _{F n, m = N n,} m × I _n, it is given as _{m × 2 / (MGL + 1} ) I n, m is (MGL + 1) / 2 if greater than (n, m) of data F in the pixel _{n, m} is F _{n, m} = MGL And a final image obtaining unit for obtaining a final image given by the following _equation : MGL-N _{n, m} × MGL-I _{n, m} × 2 / (MGL + 1) A control method and a recording medium storing a program for executing the control method are provided.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital image processing apparatus, a control method thereof, and a recording medium storing a program for executing the digital image processing apparatus,

The present invention relates to a digital image processing apparatus, a control method thereof, and a recording medium storing a program for executing the same, and more particularly, to a digital image processing apparatus capable of effectively removing noise included in an image, And a recording medium storing a program for executing the program.

Generally, an image processing apparatus displays an image from image data stored in a storage medium on a display unit, adds various effects to an image from image data stored in a storage medium, stores the image data in a storage medium as new image data, And the like. Of course, the digital photographing apparatus, which is a kind of digital image processing apparatus, photographs a subject according to a signal from a user in the photographing mode and stores the image data on a storage medium.

When using such a digital image processing apparatus, it may be necessary to reduce the noise included in the image from the image data stored in the storage medium. In particular, in the case of a digital photographing apparatus, which is a kind of digital image processing apparatus, it is necessary to reduce noise included in an image from image data obtained by photographing and to store image data representing a clean image as a final product in a storage medium. However, in the case of a conventional digital image processing apparatus, a bi-lateral filter is typically used to reduce noise. For example, when noise included in an image of a face is removed (noise includes wrinkles, dullness, etc.) When the ratio of the noise in one region is larger than the ratio of the original skin color due to the characteristics of the bilateral filter, the luminance information of the noise is included in the final image and the original color information of the face is lost.

SUMMARY OF THE INVENTION The present invention provides a digital image processing apparatus capable of effectively removing noise included in an image, a control method thereof, and a recording medium storing a program for executing the digital image processing apparatus, .

The present invention relates to a digital image processing apparatus for processing an image in a range where the minimum gray level is 0 and the maximum gray level is MGL, wherein when data in (n, m) pixels of the first image is I _{n, m} , (N, m) pixel by applying a first low-pass filter to the first image and obtaining a second image in which the data in the (n, m) pixel is L1 _{n, m} ; data in equation by applying a second low-pass filter in the third image pickup unit, and a third image to obtain a third image of H _{n, m} according to 1 (n, m) pixel of L2 _{n, m} a fourth image obtaining unit and, the obtained fourth image to obtain a fifth image data is n _{n, m} in the (n, m) the inverted image of the fourth image display unit for obtaining a fourth image, I _{n , m} is (MGL + 1) / If is smaller than 2 (n, m) in the pixel data F _n, is given as in expression (2) to the _m I _{n, m} is (MGL + 1) / 2 than when the larger (n, m) pixels Stand F _n in the _data, and provides a digital image processing apparatus characterized by comprising a final image pickup for obtaining the final image is given by Equation 3 to yi _m.

H _{n, m} = I _{n, m} -L 1 _{n, m} + (MGL + 1) / 2

F _{n, m} = N _{n, m} x I _{n, m} x 2 / (MGL + 1)

F _{n, m} = MGL- (MGL-N _{n, m} ) × (MGL-I _{n, m} ) × 2 /

The present invention also provides a digital image processing apparatus for processing an image in a range where the minimum gray level is 0 and the maximum gray level is MGL, wherein when data in the (n, m) pixel of the first image is I _{n, m} A second image acquiring section for acquiring a second image whose data in the (n, m) pixel which is an inverted image of the first image is I ' _{n, m} , and a second low- n, m) the third image data of the pixel is obtain a third image of L1 _{n, m} obtaining unit and, (n, m) _n data of the pixel is H according to equation _{1, m} in the fourth (N, m) pixels by applying a second low-pass filter to the fourth image to obtain a fifth image with data of N _{n, m} ; and a fourth image acquiring unit , I _{n, m} is (MGL + 1) / If is smaller than 2 (n, m) the data F _{n, m} of the pixel is given as shown in equation 2 I _{n, m} is (MGL + 1) / 2 (N, m) And a final image acquiring unit for acquiring a final image given data F _{n, m} in the pixel as shown in Equation (3).

The present invention also provides a digital image processing apparatus for processing an image in a range where the minimum gray level is 0 and the maximum gray level is MGL, wherein when data in the (n, m) pixel of the first image is I _{n, m} (N, m) pixel by applying a first low-pass filter to the first image to obtain a second image with data of L1 _{n, m} in the (n, m) wherein the third image pickup unit for obtaining a third image of H _{n, m} according to the equation (1), first of the data in the pixel (n, m) the inverted image of the third image H _{'n, m} 4 (N, m) pixels by applying a second low-pass filter to the fourth image to obtain a fifth image with data of N _{n, m} ; and a fourth image acquiring unit , I _{n, m} is (MGL + 1) / If is smaller than 2 (n, m) the data F _{n, m} of the pixel is given as shown in equation _2, I _{n, m} is (MGL + 1) / When (n, m) is greater than 2, And a final image obtaining unit for obtaining a final image given by the data F _{n, m} in the pixel as shown in Equation (3).

The present invention also provides a control method of a digital image processing apparatus for processing an image in a range where the minimum gray level is 0 and the maximum gray level is MGL, wherein the data in the (n, m) pixel of the first image is I _{n, m} (N, m) pixel by obtaining a second image with data of L1 _{n, m} by applying a first low-pass filter to the first image, (N, m) pixel data is L2 _{n, m} , which is obtained by applying a second low-pass filter to the third image by obtaining a third image of H _{n, m} according to Equation (1) the method comprising the steps of obtaining an image, and inverting the data in the image with the (n, m) pixel of the fourth image is acquired of a fifth image of n _{n, m,} and I _{n, m} is (MGL + 1) / 2 (N, m) pixel data F _{n, m} in the (n, m) pixel is given as in the above-mentioned equation (2) and I _{n, m} is larger than (MGL + _{n, m} is the number of Provides a control method for a digital image processing apparatus characterized in that it comprises the step of obtaining the final image is given as Equation 3.

The present invention also provides a control method of a digital image processing apparatus for processing an image in a range where the minimum gray level is 0 and the maximum gray level is MGL, wherein the data in the (n, m) pixel of the first image is I _{n, m} when be called, inverted image data of the pixel (n, m) of the first image I _'n, by applying a first low pass filter for obtaining a second image with the _m, a second image (n , m) obtaining a third image in which the data in the pixel is L1 _{n, m} , and obtaining a fourth image in which the data in the (n, m) pixel is H _{n, m} according to Equation and, applying a second low-pass filter in the fourth image (n, m) with the data in the pixel obtaining a fifth image of n _{n, m,} I _{n, m} is (MGL + 1) / 2 (N, m) pixel data F _{n, m} in the (n, m) pixel is given as in the above-mentioned equation (2) and I _{n, m} is larger than (MGL + _{n, and m} are math And a step of acquiring a final image given by Equation (3).

The present invention also provides a control method of a digital image processing apparatus for processing an image in a range where the minimum gray level is 0 and the maximum gray level is MGL, wherein the data in the (n, m) pixel of the first image is I _{n, m} (N, m) pixel by obtaining a second image with data of L1 _{n, m} by applying a first low-pass filter to the first image, Obtaining a third image of H _{n, m} according to Equation (1) above _, and obtaining a fourth image in which the data in the (n, m) pixel which is an inverted image of the third image is H ' _{n, m} and, applying a second low-pass filter in the fourth image (n, m) with the data in the pixel obtaining a fifth image of n _{n, m,} I _{n, m} is (MGL + 1) / 2 (N, m) pixel data F _{n, m} in the (n, m) pixel is given as in the above-mentioned equation (2) and I _{n, m} is larger than (MGL + _{n, and m} are math And a step of acquiring a final image given by Equation (3).

The present invention also provides a recording medium storing a program for executing the above method.

According to the digital image processing apparatus of the present invention, the control method thereof, and the recording medium storing the program for executing the same, the digital image processing apparatus capable of effectively removing the noise included in the image, the control method thereof, And a recording medium storing a program for executing the program.

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

FIG. 1 is a block diagram schematically showing a digital photographing apparatus which is a kind of digital image processing apparatus according to a first embodiment of the present invention, and FIG. 2 is a conceptual diagram schematically showing a part of FIG.

The overall operation of the digital photographing apparatus is governed by the CPU 100. [ The digital photographing apparatus is provided with an operation unit 200 including a key for generating an electrical signal from the user. An electrical signal from the operation unit 200 is transmitted to the CPU 100 so that the CPU 100 can control the digital photographing apparatus in accordance with an electrical signal.

The CPU 100 controls the lens driving unit 11, the diaphragm driving unit 21 and the imaging device control unit 31 so that the position of the lens 10, the opening degree of the diaphragm 20, The sensitivity and the like of the image pickup device 30 are controlled. This may be done as an electrical signal from the user is applied to the CPU 100 and may be made by the CPU 100 automatically. Of course, it is needless to say that it is possible to control not only the position of the lens 10, the opening degree of the diaphragm 20, and the sensitivity of the image sensing device 30, but a part of them.

The image pickup element 30 generates data from the input light, and the analog / digital conversion section 40 converts the analog data output from the image pickup element 30 into digital data. Of course, the analog-to-digital conversion section 40 may not be required depending on the characteristics of the imaging element 30. [

The data from the image pickup device 30 may be input to the digital signal processing unit 50 via the memory 60 or may be input to the digital signal processing unit 50 without going through the memory 60, (Not shown). Here, the memory 60 is a concept including ROM, RAM, and the like. The digital signal processing unit 50 can perform digital signal processing such as gamma correction and white balance adjustment as necessary.

2, the digital signal processing unit 50 includes a second image acquiring unit 52, a third image acquiring unit 53, a fourth image acquiring unit 54, a fifth image acquiring unit 55, And a final image acquiring unit 56. [ Of course, the digital signal processing unit 50 may include a second image acquiring unit 52, a third image acquiring unit 53, a fourth image acquiring unit 54, a fifth image acquiring unit 55, and a final image acquiring unit 56 And the remainder may be included in another component other than the digital signal processor 50, or may be a separate component. In addition, the second image acquiring unit 52, the third image acquiring unit 53, the fourth image acquiring unit 54, the fifth image acquiring unit 55, and the final image acquiring unit 56 are all different components Or may be a separate component, and the like. On the other hand, some of the second image acquiring unit 52, the third image acquiring unit 53, the fourth image acquiring unit 54, the fifth image acquiring unit 55 and the final image acquiring unit 56 may be one May be integrated into the component. The second image acquiring unit 52, the third image acquiring unit 53, the fourth image acquiring unit 54, the fifth image acquiring unit 55 and the final image acquiring unit 56 acquire the first image The second image, the third image, the fourth image, the fifth image, and the final image, thereby effectively reducing the noise included in the image (including the unevenness of wrinkles, The function of the bar will be described later.

The data outputted from the digital signal processing section 50 is transmitted to the display control section 81 through the memory 60 or directly. The display control unit 81 controls the display unit 80 to display an image from the data on the display unit 80. [ When the image sensing element 30 generates still image data by a photographing signal from the user, the data output from the digital signal processing section 50 is input to the memory 60 or directly to the storage / In this case, the storage / read control unit 71 stores the data in the storage medium 70 in accordance with a signal from the user or automatically. Of course, in the case of a playback mode or the like, the storage / reading control unit 71 reads data relating to a still image from a file stored in the storage medium 70 and transmits it to the display control unit 81 So that the still image is displayed on the display unit 80. The storage medium 70 may be removable or permanently attached to the digital photographing apparatus.

Such a digital photographing apparatus according to the present embodiment can effectively reduce the noise contained in the image from the image data stored in the storage medium 70 or from the image data obtained by photographing, 8 to FIG. 8. FIG.

3 is a photograph schematically showing a first image which is an original image. Referring to FIG. 3, it can be seen that the face included in the first image has many wrinkles such as wrinkles and stains. The first image, which is the original image, appears as a preset gray range, that is, an image that appears in a range where the minimum gray level is 0 and the maximum gray level is MGL. For example, for an 8 bit image, the minimum gray level is 0 and the maximum gray level MGL is 255 (255 = 2 ⁸ -1).

The second image acquiring unit 52 applies a first low-pass filter to the first image as shown in Fig. 3 so that the data in the (n, m) pixel is expressed as L1 _{n, m} To obtain a second image. When a low-pass filter is applied to an image, a low-frequency component remains. As shown in FIG. 4, the second image due to the low-frequency component is an image having information on color, brightness, etc. rather than information on the edge of the subject . That is, no noise (including unevenness such as wrinkles and stains) appearing as a high frequency component appears in the second image.

The third image acquiring section 53 acquires a third image as shown in Fig. 5 from the first image as shown in Fig. 3 and the second image as shown in Fig. The data in the (n, m) pixels of the third image is H _{n, m} according to the following equation (1).

[Equation 1]

H _{n, m} = I _{n, m} -L 1 _{n, m} + (MGL + 1) / 2

Since the second image is obtained by applying the first low-pass filter to the first image, it can be understood that I _{n, m} -L 1 _{n, m} is a high-pass filter applied to the first image. However, the (n, m) pixel of the second image to which the first low-pass filter is applied is darker than the original if it is brighter than the surrounding area and becomes brighter than the original if it is darker than the surrounding area. That is, the second image (n, m) pixel data at the L1 _{n, m} of the data from the first image of the (n, m) pixel I _n, I number greater than _{m, n I, n m -L1, m} may be negative. Therefore, if the brightness of the first image is brighter than that of the surrounding area, it is darker than the half gray level and the brightness of the first image is greater than the surrounding gray level If it is dark, it acquires a third image that appears brighter than the half gray level. The third image shown in Fig. 5 includes noise (including unevenness such as wrinkles and stains) and a contour (an image of a subject) corresponding to a high frequency component in a first image which is an original image as shown in Fig. Edge). Specifically, in the third image as shown in Fig. 5, darker than the half gray level, the part near black is darker than the surrounding part, such as hairs, eyebrows, dullness and wrinkles, contours, The near portion corresponds to the brighter hair, eyebrows, dullness and wrinkles, contours, etc., which are brighter than the surrounding areas.

The fourth image acquiring unit 54 applies a second low-pass filter to the third image as shown in Fig. 5 so that the data in the (n, m) pixel is expressed by L2 _{n, m} To obtain a fourth image. This reduces noise (including unevenness such as wrinkles and stains) existing in the third image. At this time, since the data on the contour may also be partially lost, the second low-pass filter may be weaker than the first low-pass filter.

In the case of a contour line that can be understood as a boundary between a bright image area and a dark image area, the area of the bright image on one side of the contour line and the dark image on the other side The size of the area is considerably large, so that even if a part of the data on the outline is lost, the outline of the overall image is not noticeably blurred. In the case of noise (including unevenness such as wrinkles and stains), it can be understood as a boundary between a bright image area and a dark image area like a contour line. In the case of noise, unlike a contour line, The size of the image area is small. Therefore, when acquiring the fourth image, since the size of the area occupied by each noise is small, the noise is removed so as not to be conspicuous in the overall image. Especially, when noise (including unevenness such as wrinkles and stains) is large in the original image, such noise remains in the fourth image but the degree of appearance thereof is alleviated.

The fifth image acquiring unit 55 acquires the fifth image whose data in the (n, m) pixel as shown in Fig. 7, which is the inverted image of the fourth image as shown in Fig. 6, is N _{n, m} . That is, in the high-frequency component in which the noise is reduced, the fifth image in which the high-frequency components darker than the surroundings are brighter than the half-gray level and the higher-frequency components brighter than the surroundings appear darker than the half-gray level.

The final image acquiring unit 56 acquires the final image as shown in Fig. 8 from the original image and the fifth image. Specifically, when the data I _{n, m} in the (n, m) pixels of the first image is smaller than (MGL + 1) / 2, the data F _{n, m} in the (n, m) And the data F _{n, m} in the (n, m) pixel is determined as shown in the following equation (3) when I _{n, m} is larger than (MGL + 1) / 2.

&Quot; (2) "

F _{n, m} = I _{n, m} x N _{n, m} x 2 / (MGL + 1)

&Quot; (3) "

F _{n, m} = MGL- (MGL-I _{n, m} ) MGL-N _{n, m} 2 /

As a result, the (n, m) pixel data of the final image is obtained by applying a weight to the data of the (n, m) pixels of the original image.

Referring to Equation (2), it can be understood that the weight of N _{n, m} x 2 / (MGL + 1) is applied to the data of the (n, m) pixel of the original image. (N, m) pixels of the original image are the values adjacent to (MGL + 1) / 2 when the data N _{n, m} of the (n, m) pixels of the fifth image are data adjacent to the half gray level 1 " or a weight close thereto.

When the data N _{n, m} of the (n, m) pixel of the fifth image is data adjacent to the half gray level, the data I _{n, m} of the (n, m) pixel of the first image has a low frequency component rather than a high frequency component The data on the hue and color of the first image is not lost but included in the data of the final image.

If the data N _{n, m} of the (n, m) pixel of the fifth image is data not adjacent to the half gray level, the data of the (n, m) pixel of the original image is significantly It becomes to apply a considerably large weight in the vicinity. As a result, the outline of the original image is much smaller than 1 or greater than 1 and weighs a fairly large weight close to 2, so that the outline, which is the boundary between the dark and bright parts of the original image, (A weight less than 1 is applied) and a bright portion (weight greater than 1 is applied), so that the contour lines can be clearly displayed.

On the other hand, as described above, the data N _{n, m} of the (n, m) pixel of the fifth image is data in which the outline is clear but noise (including unevenness such as wrinkles and stains) is removed. That is, in the data of the (n, m) pixel of the fifth image, the noise (including the unevenness of wrinkles, stains, etc.) appears at a half gray level to apply a weight of about 1 to the noise of the original image, It is possible to prevent the noise from becoming clearer. Furthermore, if noise (including unevenness such as wrinkles and stains) is large in the original image, such noise remains in the fourth image, but the degree of appearance thereof is alleviated. Since the fifth image is the image inverted from the fourth image, the noise that appears bright in the original image appears dark in the fifth image, and the noise that appears dark in the original image appears bright in the fifth image. Therefore, when the weight according to Equation 2 is applied to the noise portion of the original image, the noise that appears bright in the original image becomes slightly darker in the final image, and the noise that appears darker in the original image becomes slightly brighter in the final image. As a result, noise in the final image becomes less noticeable.

On the other hand, when the data I _{n, m} in the (n, m) pixel of the original image is larger than (MGL + 1) / 2, the value may be larger than MGL according to Equation (2). To prevent this _, when Equation (3) as described above is applied when I _{n, m} is larger than (MGL + 1) / 2, errors that may occur in the final image can be prevented. Specifically, when I _{n, m} is larger than (MGL + 1) / 2, the data I _{n, m} in the (n, m) pixels of the original image are inverted and the data (2) is transformed as shown in Equation (3) when N _{n, m} are also inverted and Equation (2) is applied. Therefore, when I _{n, m} is greater than (MGL + 1) / 2, Equation (3) as described above is applied.

Comparing FIG. 8, which is the final image obtained by the digital photographing apparatus according to the present embodiment through the above-described process, with FIG. 3 showing the original image, noise (including unevenness such as wrinkles and stains) , But it can be confirmed that the sharpness is not lowered. In particular, it is noticeable that in the case of the pupil, the sharpness in the nose or the ball is drastically reduced.

Although the digital photographing apparatus has been described as an embodiment of the present invention, the present invention is not limited thereto. That is, the present invention can be applied to a digital image processing apparatus such as a PDA (personal digital assistants), a PMP (personal multimedia player), and the like, rather than a digital photographing apparatus. This also applies to the following embodiments and modifications thereof. In the case of the digital photographing apparatus, when the still image data is obtained by photographing, noise may be removed from the still image from the still image data and stored in the storage medium 70 as new still image data through the process as described above Further, when acquiring still image data, noise may be removed from the still image from the still image data through the above-described process, and the resultant still image data may be stored in the storage medium 70 as final still image data.

9 is a flow chart schematically showing a control method of a digital image processing apparatus according to a second embodiment of the present invention. Specifically, the control method of the digital image processing apparatus according to the present embodiment is a control method of a digital image processing apparatus that processes an image in a range where the minimum gray level is 0 and the maximum gray level is MGL. According to the control method of the digital image processing apparatus according to the present embodiment, when data in (n, m) pixels of the first image is I _{n, m} , a first low pass filter is applied to the first image (step S110) of obtaining a second image in which the data in the n, m pixels is L1 _{n, m} . Thereafter, a third image similar to that obtained by applying the high pass filter to the first image using the second image is obtained (S120). This is because the data in the (n, m) Lt; RTI ID _{= 0.0} > _{Hn, m} , _{< / RTI} > The meaning of the following equation (1) is as described above.

[Equation 1]

H _{n, m} = I _{n, m} -L 1 _{n, m} + (MGL + 1) / 2

Thereafter, a second low-pass filter is applied to the third image to obtain a fourth image (L2, m) in which the data at (n, m) pixels is L2 _n, , a step (S140) of acquiring a fifth image in which the data in the (n, m) pixel is N _{n, m} . Then go through the steps (S150) to obtain the final image, specifically, I _{n, m} is (MGL + 1) / 2 When less than in the pixel data (n, m) F _n, to the _m Formula 2, and the data F _{n, m} in the (n, m) pixel is given as the following equation (3) when I _{n, m} is larger than (MGL + 1) / 2. The meanings of the following expressions (2) and (3) are as described above.

&Quot; (2) "

F _{n, m} = N _{n, m} x I _{n, m} x 2 / (MGL + 1)

&Quot; (3) "

F _{n, m} = MGL- (MGL-N _{n, m} ) × (MGL-I _{n, m} ) × 2 /

According to the control method of the digital image processing apparatus according to this embodiment, the noise contained in the image can be effectively reduced.

Meanwhile, in the control method of the digital image processing apparatus according to the present embodiment, it is also possible to modify the step of obtaining the inverted image after acquiring the fourth image and acquiring the inverted image of the fifth image.

That is, as shown in Fig. 10 showing a control method of the digital image processing apparatus according to the third embodiment of the present invention, the inverted image of the first image in which the data in the (n, m) pixel is I _{n, m} (N, m) pixel by applying a first low-pass filter to the second image through a step S210 of obtaining a second image with data of I ' _{n, m} at (n, m) (S230) of acquiring a fourth image similar to applying the high pass filter to the second image using the third image through the step S220 of obtaining the third image with the data of L1 _{n, m} . Here, Equation (1) described in the digital image processing apparatus according to the first embodiment and the control method of the digital image processing apparatus according to the second embodiment may be used as is in step S230. That is, in the fourth image, the data in the (n, m) pixel becomes H _{n, m} according to the equation (1). Thereafter, a second low-pass filter is applied to the fourth image to obtain a final image (S240) by obtaining a fifth image with data at (n, m) pixels _{Nn, m} S250). In step S250, if I _{n, m} is smaller than (MGL + 1) / 2 on the same principle as described in the above embodiments _, data F _{n, m} in (n, m) , The data F _{n, m} in the (n, m) pixel can be given as shown in Equation (3) when I _{n, m} is larger than (MGL + 1) / 2.

The digital image processing apparatus according to the fourth embodiment of the present invention employing the control method of the digital image processing apparatus according to the third embodiment has a structure as shown in Figs. 1 and 2 . However, the second image acquiring unit 52, the third image acquiring unit 53, the fourth image acquiring unit 54, the fifth image acquiring unit 55 and the final image acquiring unit 56 shown in Fig. The function may be different from that of the digital image processing apparatus according to the first embodiment.

That is, the second image acquiring unit 52 acquires a second image whose data at (n, m) pixels is I ' _{n, m} , which is an inverted image of the first image. The third image acquiring unit 53 applies a first low pass filter to the second image to obtain a third image in which the data at (n, m) pixels is L1 _{n, m} . The fourth image obtaining unit 54 obtains the fourth image in which the data in the (n, m) pixel is H _{n, m} according to Equation (1). The fifth image acquiring unit 55 applies a second low pass filter to the fourth image to obtain a fifth image with the data at (n, m) pixels N _{n, m} . The final image obtaining unit 56 is I _{n, m} is (MGL + 1) / 2 When less than the (n, m) the data F _{n, m} of the pixel is given by Equation _2, I _{n, m} is (MGL + 1) / 2, the data F _{n, m} in the (n, m) pixel is obtained as shown in Equation (3).

On the other hand, unlike the control method of the digital image processing apparatus according to the second embodiment and the third embodiment, the step of acquiring the inverted image may be changed differently. That is, as shown in Fig. 11 showing a control method of the digital image processing apparatus according to the fifth embodiment of the present invention, a first low-pass filter is applied to the first image so that data (n, m) (S310) of obtaining a second image of L1 _{n, m} and obtaining a third image in which the data in the (n, m) pixel is H _{n, m} according to equation (1) After the step S330 of obtaining the fourth image with the data in the (n, m) pixel, which is the inverted image of the third image, is H ' _{n, m} through step S320 _, by applying a second low-pass filters (n, m) the data in the pixel are n _n, through the steps (S340) to obtain a fifth image of _m, I _{n, m} is (MGL + 1) / 2 when less than (n, m) to the data F _{n, m} of the pixel is given by equation _2, I _{n, m} is (MGL + 1) / 2 if greater than (n, m) the data in the pixel F _n, Choi to two _m given by equation 3 It may be subjected to a step (S350) for acquiring the image.

The digital image processing apparatus according to the sixth embodiment of the present invention employing the control method of the digital image processing apparatus according to the fifth embodiment has a structure as shown in Figs. 1 and 2 . However, the second image acquiring unit 52, the third image acquiring unit 53, the fourth image acquiring unit 54, the fifth image acquiring unit 55 and the final image acquiring unit 56 shown in Fig. Functions of the digital image processing apparatus according to the first embodiment or the digital image processing apparatus according to the fourth embodiment described above may be different.

That is, the second image acquiring unit 52 applies a first low-pass filter to the first image to acquire a second image in which the data at (n, m) pixels is L1 _{n, m} . The third image obtaining unit 53 obtains the third image in which the data in the (n, m) pixel is H _{n, m} according to Equation (1). The fourth image acquiring unit 54 acquires a fourth image in which the data in the (n, m) pixel, which is the inverted image of the third image, is H ' _{n, m} . The fifth image acquiring unit 55 applies a second low pass filter to the fourth image to obtain a fifth image with the data at (n, m) pixels N _{n, m} . The final image obtaining unit 56 is I _{n, m} is (MGL + 1) / 2 When less than the (n, m) the data F _{n, m} of the pixel is given by Equation _2, I _{n, m} is (MGL + 1) / 2, the data F _{n, m} in the (n, m) pixel is obtained as shown in Equation (3).

On the other hand, the data I _{n, m} in the (n, m) pixels of the first image, which is the original image, may be in the form of YCbCr having Y data, Cb data and Cr data, It may be in HSI form. In this case, in the above-described embodiments, not all the data of the data I _{n, m} in the (n, m) pixel of the first image as the original image is processed _, but only the data of a part of I _{n, m} It is possible. That is, when the data I _{n, m} in the (n, m) pixel of the first image, which is the original image, is YCbCr having Y data, Cb data, and Cr data, only Y data, which is luminance data, , And other filtering processes may be performed such that Cb data and Cr data are not subjected to such processing, or processing using a bi-lateral filter is performed. This is because the noise mainly appears in the luminance data. Even when the data I _{n, m} in the (n, m) pixels of the first image, which is the original image, is, for example, the HSI form having the H data, the S data and the I data, only the H data And other filtering processes may be performed such that the same process is not performed for the S data and the I data, or the process using the bi-lateral filter is performed.

Meanwhile, a program for executing the control methods of the digital image processing apparatus and the control methods of the digital image processing apparatus according to the modification examples described above in the digital image processing apparatus can be stored in the recording medium. Here, the recording medium may be a storage medium 80 as shown in FIG. 1, a memory 60 as shown in FIG. 1, or a separate recording medium. The storage medium may be a storage medium such as a magnetic storage medium (e.g., ROM, floppy disk, hard disk, etc.) and an optical reading medium (e.g., CD-ROM, DVD (Digital Versatile Disc) .

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

1 is a block diagram schematically showing a digital photographing apparatus according to an embodiment of the present invention.

Fig. 2 is a conceptual diagram schematically showing a part of Fig.

3 is a photograph schematically showing a first image which is an original image.

FIG. 4 is a photograph schematically showing a second image obtained by applying a low-pass filter to the first image of FIG. 3. FIG.

5 is a photograph schematically showing a third image obtained by applying Equation (1) to each pixel of the second image.

6 is a photograph schematically showing a fourth image obtained by applying a second low-pass filter to a third image.

7 is a photograph schematically showing a fifth image which is an inverted image of the fourth image.

8 is a photograph schematically showing a final image obtained by applying equations (2) and (3) to each pixel of the first image and the fifth image.

9 is a flow chart schematically showing a control method of a digital image processing apparatus according to another embodiment of the present invention.

10 is a flow chart schematically showing a control method of a digital image processing apparatus according to another embodiment of the present invention.

11 is a flow chart schematically showing a control method of a digital image processing apparatus according to another embodiment of the present invention.

Description of the Related Art

10: lens 11:

20: Aperture 21: Aperture drive unit

30: Imaging element 31: Imaging element controller

40: A / D converter 50: digital signal processor

60: Memory 71: Storage /

70: Storage medium 81: Display control unit

80: display unit 100: CPU

200:

Claims (7)

A digital image processing apparatus for processing an image in a range where the minimum gray level is 0 and the maximum gray level is MGL, characterized in that when data in (n, m) pixels of the first image is I _{n, m} , A second image acquiring unit applying a first low pass filter to the first image to obtain a second image with data at (n, m) pixels being L1 _{n, m} ; a third image acquiring unit for acquiring a third image whose data in (n, m) pixels is H _{n, m} according to the following equation (1); A fourth image acquiring unit for acquiring a fourth image whose data in (n, m) pixels is L2 _{n, m} by applying a second low-pass filter to the third image; A fifth image acquiring unit for acquiring a fifth image whose data at (n, m) pixels, which is an inverted image of the fourth image, is N _{n, m} ; I _{n, m} is (MGL + 1) / If is smaller than 2 (n, m) to the data F _{n, m} of the pixel is given by Equation _2, I _{n, m} is (MGL + 1) / 2 And a final image acquiring unit for acquiring a final image given data F _{n, m} at (n, m) pixels as shown in the following equation (3): " (3) " [Equation 1] H _{n, m} = I _{n, m} -L 1 _{n, m} + (MGL + 1) / 2 &Quot; (2) " F _{n, m} = N _{n, m} x I _{n, m} x 2 / (MGL + 1) &Quot; (3) " F _{n, m} = MGL- (MGL-N _{n, m} ) × (MGL-I _{n, m} ) × 2 / A digital image processing apparatus for processing an image in a range where the minimum gray level is 0 and the maximum gray level is MGL, characterized in that when data in (n, m) pixels of the first image is I _{n, m} , A second image acquiring unit acquiring a second image whose data at (n, m) pixels is I ' _{n, m} , which is an inverted image of the first image; A third image acquiring unit applying a first low pass filter to the second image to obtain a third image in which the data in the (n, m) pixel is L1 _{n, m} ; a fourth image acquiring unit for acquiring a fourth image whose data in (n, m) pixels is H _{n, m} according to the following equation (1); A fifth image acquiring unit for acquiring a fifth image whose data in (n, m) pixels is N _{n, m} by applying a second low-pass filter to the fourth image; And I _{n, m} is (MGL + 1) / If is smaller than 2 (n, m) to the data F _{n, m} of the pixel is given by Equation _2, I _{n, m} is (MGL + 1) / 2 And a final image acquiring unit for acquiring a final image given data F _{n, m} at (n, m) pixels as shown in the following equation (3): " (3) " [Equation 1] H _{n, m} = I _{n, m} -L 1 _{n, m} + (MGL + 1) / 2 &Quot; (2) " F _{n, m} = N _{n, m} x I _{n, m} x 2 / (MGL + 1) &Quot; (3) " F _{n, m} = MGL- (MGL-N _{n, m} ) × (MGL-I _{n, m} ) × 2 / A digital image processing apparatus for processing an image in a range where the minimum gray level is 0 and the maximum gray level is MGL, characterized in that when data in (n, m) pixels of the first image is I _{n, m} , A second image acquiring unit applying a first low pass filter to the first image to obtain a second image with data at (n, m) pixels being L1 _{n, m} ; a third image acquiring unit for acquiring a third image whose data in (n, m) pixels is H _{n, m} according to the following equation (1); A fourth image acquiring unit for acquiring a fourth image in which data in the (n, m) pixel, which is an inverted image of the third image, is H ' _{n, m} ; A fifth image acquiring unit for acquiring a fifth image whose data in (n, m) pixels is N _{n, m} by applying a second low-pass filter to the fourth image; And I _{n, m} is (MGL + 1) / If is smaller than 2 (n, m) to the data F _{n, m} of the pixel is given by Equation _2, I _{n, m} is (MGL + 1) / 2 And a final image acquiring unit for acquiring a final image given data F _{n, m} at (n, m) pixels as shown in the following equation (3): " (3) " [Equation 1] H _{n, m} = I _{n, m} -L 1 _{n, m} + (MGL + 1) / 2 &Quot; (2) " F _{n, m} = N _{n, m} x I _{n, m} x 2 / (MGL + 1) &Quot; (3) " F _{n, m} = MGL- (MGL-N _{n, m} ) × (MGL-I _{n, m} ) × 2 / A control method of a digital image processing apparatus for processing an image in a range in which a minimum gray level is 0 and a maximum gray level is MGL, characterized in that when data in (n, m) pixels of the first image is I _{n, m} , Applying a first low pass filter to the first image to obtain a second image _wherein the data at (n, m) pixels is L1 _{n, m} ; obtaining a third image in which the data in the (n, m) pixel is H _{n, m} according to Equation (1); Applying a second low pass filter to the third image to obtain a fourth image in which the data at (n, m) pixels is L2 _{n, m} ; Obtaining a fifth image in which the data in the (n, m) pixel, which is the inverted image of the fourth image, is N _{n, m} ; And I _{n, m} is (MGL + 1) / If is smaller than 2 (n, m) to the data F _{n, m} of the pixel is given by Equation _2, I _{n, m} is (MGL + 1) / 2 And obtaining a final image given data F _{n, m} in the (n, m) pixel as shown in the following Equation (3): " (3) " [Equation 1] H _{n, m} = I _{n, m} -L 1 _{n, m} + (MGL + 1) / 2 &Quot; (2) " F _{n, m} = N _{n, m} x I _{n, m} x 2 / (MGL + 1) &Quot; (3) " F _{n, m} = MGL- (MGL-N _{n, m} ) × (MGL-I _{n, m} ) × 2 / A control method of a digital image processing apparatus for processing an image in a range in which a minimum gray level is 0 and a maximum gray level is MGL, characterized in that when data in (n, m) pixels of the first image is I _{n, m} , Obtaining a second image with data at (n, m) pixels being an inverted image of the first image, I ' _{n, m} ; Applying a first low pass filter to the second image to obtain a third image with data at (n, m) pixels being L1 _{n, m} ; obtaining a fourth image in which the data in the (n, m) pixel is H _{n, m} according to Equation (1); Applying a second low pass filter to the fourth image to obtain a fifth image with data at (n, m) pixels N _{n, m} ; And I _{n, m} is (MGL + 1) / If is smaller than 2 (n, m) to the data F _{n, m} of the pixel is given by Equation _2, I _{n, m} is (MGL + 1) / 2 And obtaining a final image given data F _{n, m} in the (n, m) pixel as shown in the following Equation (3): " (3) " [Equation 1] H _{n, m} = I _{n, m} -L 1 _{n, m} + (MGL + 1) / 2 &Quot; (2) " F _{n, m} = N _{n, m} x I _{n, m} x 2 / (MGL + 1) &Quot; (3) " F _{n, m} = MGL- (MGL-N _{n, m} ) × (MGL-I _{n, m} ) × 2 / A control method of a digital image processing apparatus for processing an image in a range in which a minimum gray level is 0 and a maximum gray level is MGL, characterized in that when data in (n, m) pixels of the first image is I _{n, m} , Applying a first low pass filter to the first image to obtain a second image _wherein the data at (n, m) pixels is L1 _{n, m} ; obtaining a third image in which the data in the (n, m) pixel is H _{n, m} according to Equation (1); Obtaining a fourth image with data at (n, m) pixels being an inverted image of the third image is H ' _{n, m} ; Applying a second low pass filter to the fourth image to obtain a fifth image with data at (n, m) pixels N _{n, m} ; And I _{n, m} is (MGL + 1) / If is smaller than 2 (n, m) to the data F _{n, m} of the pixel is given by Equation _2, I _{n, m} is (MGL + 1) / 2 And obtaining a final image given data F _{n, m} in the (n, m) pixel as shown in the following Equation (3): " (3) " [Equation 1] H _{n, m} = I _{n, m} -L 1 _{n, m} + (MGL + 1) / 2 &Quot; (2) " F _{n, m} = N _{n, m} x I _{n, m} x 2 / (MGL + 1) &Quot; (3) " F _{n, m} = MGL- (MGL-N _{n, m} ) × (MGL-I _{n, m} ) × 2 / A recording medium storing a program for executing the method according to any one of claims 4 to 6.

Images