KR100997203B1 - Image processing apparatus and method thereof - Google Patents

Abstract

The present invention relates to an image processing apparatus and a method thereof, and more particularly, to an image processing apparatus and a method for correcting image distortion due to camera shake.

The image processing apparatus according to the present invention includes a reference image acquisition unit for acquiring two reference images by applying different shutter times and ISO sensitivity settings, and a shorter shutter time among the shutter times according to the luminance ratio and the color difference ratio of the two reference images. It includes a color information correction unit for correcting the color information of the obtained input image.

According to the present invention, there is an effect such as correcting image distortion due to camera shake.

Image stabilization, luminance histogram, color difference information, shutter time, ISO sensitivity settings

Description

Image processing apparatus and method thereof

The present invention relates to an image processing apparatus and a method thereof, and more particularly, to an image processing apparatus and a method for correcting image distortion due to camera shake.

Conventionally, in order to correct distortion of a still image due to camera shake, a method of properly correcting a position of a lens or a sensor using a gyrometer is mainly used in a digital camera. In other words, by moving the lens or sensor in the opposite direction of the gyrometer measurement, the method of removing the physical shaking parameter was used. On the other hand, a short shutter time was used to take a plurality of images and calculate a position change between them to correct them.

However, 1) In the case of using a gyro meter, the basic camera module needs a separate hardware device to move the position of the lens or sensor as well as the gyro meter. This is a burdensome method to apply, especially from the perspective of mobile phone cameras, which are becoming smaller in size. Also, the method of calculating and correcting the position difference using multiple dark images requires a separate frame memory for storing multiple images, and the amount of calculation is also very large so that it is directly mounted on the camera module. There are many difficulties to do this.

An object of the present invention to solve this problem is to provide an image processing apparatus and a method for correcting the distortion of the still image due to camera shake without using a separate additional device such as a gyro meter.

Another object of the present invention is to provide an image processing apparatus and method for efficiently correcting distortion of a still image caused by camera shake while reducing the amount of memory computation.

In addition, an object of the present invention is to provide an image processing apparatus and method for solving the problems such as the shaking and noise of the image caused by the long shutter time of the lens in the dark environment and insufficient color reproduction.

The image processing apparatus according to the present invention for achieving the technical problem is a reference image acquisition unit for acquiring two reference images by applying different shutter times and ISO sensitivity settings to the luminance ratio and color difference ratio of the two reference images. Accordingly, a color information corrector configured to correct color information of an input image obtained by applying a shorter shutter time among the shutter times.

The reference image acquisition unit obtains a first reference image by applying a first shutter time and a first ISO sensitivity setting value, and has a second shutter time longer than the first shutter time and a second ISO sensitivity smaller than the first ISO sensitivity setting value. It is preferable to obtain a second reference image by applying the set value.

Preferably, the second shutter time is four times or more and eight times or less than the first shutter time, and the first ISO sensitivity setting value is four or more times and eight times or less of the second ISO sensitivity setting value.

The resolution of the reference image is preferably lower than the resolution of the input image.

The color information corrector may include a luminance histogram analyzer configured to analyze a luminance histogram of the first reference image and a luminance histogram of the second reference image, and a luminance histogram conversion operation between the first reference image and the second reference image. A luminance correction calculator for correcting luminance of the input image, a color difference information extractor extracting color difference information of corresponding pixels of the first reference image and the second reference image, and the color difference information based on the color difference information. It is preferable to include a color difference information correction calculation unit for correcting the color difference information.

The luminance histogram analyzer defines a first level having a value equal to or greater than a predetermined number of pixels in the luminance histogram of the first reference image as a first minimum level, and a value equal to or greater than the predetermined number of pixels in the luminance histogram of the first reference image. Defines a last level having a first maximum level, defines a first level having a value greater than or equal to the predetermined number of pixels in a luminance histogram of the second reference image as a second minimum level, Preferably, the last level having a value equal to or greater than the predetermined number of pixels in the luminance histogram is defined as a second maximum level.

Preferably, the luminance correction calculator stretches the luminance histogram of the input image based on a difference between the second minimum level and the first minimum level and a difference between the second maximum level and the first maximum level.

The chrominance information extracting unit includes first blue difference information that is an average of a blue difference signal of a first NⅹN region where a corresponding pixel of the first reference image is located, and a first red that is an average of red difference signals of the first NⅹN region. Second blue difference information that is an average of the difference information, a blue difference signal of a second N_N region where the corresponding pixel of the second reference image is located, and a second red difference that is an average of the red difference signal of the second N_N region It is desirable to extract the information.

The color difference information correction calculator corrects the blue difference information of the input image by applying a weighted ratio between the second blue difference information and the first blue difference information, and between the second red difference information and the first red difference information. Preferably, the ratio is weighted to correct red difference information of the input image.

The color difference information correction calculator corrects the blue difference information of the input image by applying a weighted ratio between the first blue difference information and the blue difference information of the corresponding pixel of the input image.

Preferably, the red difference information of the input image is corrected by applying a weighted ratio between the first red difference information and the red difference information of the corresponding pixel of the input image.

The color difference information correction calculator corrects blue difference information of the input image by weighting a ratio between the second blue difference information and a blue difference signal of a corresponding pixel of the second reference image, and corrects the second red difference information and the Preferably, the ratio of the red difference information of the corresponding pixel of the second reference image is weighted to correct the red difference information of the input image.

The apparatus may further include a noise removing unit configured to remove noise included in the input image based on edge information of the input image.

The noise removing unit extracts the directional information of the luminance change of the image in which the color information is corrected, and a luminance change directional information extracting unit, and an edge extracting the edge information of the image in which the color information is corrected based on the luminance change directional information. It is preferable to include an information extracting unit and a noise attenuation calculating unit for attenuating the noise of the image whose color information is corrected based on the edge information.

The luminance change directional information may be generated based on the luminance change amounts of the eight directions of the ROI where the ROI is located.

The apparatus may further include a luminance corrector configured to correct the luminance of the image in which the color information is corrected according to a gamma curve based on the luminance histogram of the image in which the color information is corrected.

The luminance correction unit extracts the luminance information of the image corrected with the color information based on the luminance histogram of the image whose color information is corrected, and the gamma based on the luminance information of the image corrected with the color information. It is preferable to include a gamma curve generating unit for generating a curve and a gamma curve applying unit for applying the gamma curve to the image whose color information is corrected.

Luminance histogram of the corrected image and the color information are N _H - is preferably generated by a quantization (N _H -Quantized) method.

In the image processing method according to the present invention, a reference image acquisition step of acquiring two reference images by applying different shutter times and ISO sensitivity settings and a shorter one of the shutter times according to the luminance ratio and the color difference ratio of the two reference images. And a color information correcting step of correcting color information of an input image obtained by applying a shutter time.

In the obtaining of the reference image, a first reference image is obtained by applying a first shutter time and a first ISO sensitivity setting value, and a second shutter time longer than the first shutter time and a second smaller than the first ISO sensitivity setting value. It is preferable to obtain the second reference image by applying the ISO sensitivity setting value.

Preferably, the second shutter time is four times or more and eight times or less than the first shutter time, and the first ISO sensitivity setting value is four or more times and eight times or less of the second ISO sensitivity setting value.

The resolution of the reference image is preferably lower than the resolution of the input image.

The color information correction step is based on a luminance histogram analysis step of analyzing the luminance histogram of the first reference image and the luminance histogram of the second reference image, and a luminance histogram conversion operation between the first reference image and the second reference image. A luminance correction calculating step of correcting luminance of the input image, a color difference information extraction step of extracting color difference information of corresponding pixels of the first reference image and the second reference image, and the input based on the color difference information It is preferable to include a color difference information correction calculation step of correcting color difference information of the image.

In the luminance histogram analysis step, the first level having a value equal to or greater than a predetermined number of pixels in the luminance histogram of the first reference image is defined as a first minimum level, and the predetermined number of pixels in the luminance histogram of the first reference image. The last level having the above value is defined as the first maximum level, and the first level having the value equal to or greater than the predetermined number of pixels in the luminance histogram of the second reference image is defined as the second minimum level, and the second reference Preferably, the last level having a value equal to or greater than the predetermined number of pixels in the luminance histogram of the image is defined as the second maximum level.

In the luminance correction operation, it is preferable to stretch the luminance histogram of the input image based on the difference between the second minimum level and the first minimum level and the difference between the second maximum level and the first maximum level.

In the color difference information extraction step, first blue difference information which is an average of a blue difference signal of a first NⅹN region in which the corresponding pixel of the first reference image is located, and a second difference which is an average of red difference signals of the first NⅹN region. First red difference information, second blue difference information which is an average of a blue difference signal of a second N_N region where a corresponding pixel of the second reference image is located, and a second red difference signal which is an average of a red difference signal of the second N_N region; It is preferable to extract the red difference information.

In the color difference information correction calculation step, the ratio between the second blue difference information and the first blue difference information is weighted to correct the blue difference information of the input image, and the second red difference information and the first red difference. Preferably, the red difference information of the input image is corrected by weighting a ratio between the information.

In the color difference information correcting operation, the blue difference information of the input image is corrected by applying a weighted ratio between the first blue difference information and the blue difference information of the corresponding pixel of the input image, and the first red difference information and the input are performed. The red difference information of the input image may be corrected by applying a weighted ratio between the red difference information of the corresponding pixel of the image.

In the color difference information correcting operation, the blue difference information of the input image is corrected by applying a weighted ratio between the second blue difference information and a blue difference signal of a corresponding pixel of the second reference image, and the second red difference information. It is preferable to correct the red difference information of the input image by applying a weight to a ratio between the red difference information of the corresponding pixel of the second reference image.

The method may further include a noise removing step of removing noise included in the input image based on edge information of the input image.

The noise removing step may include: extracting brightness change direction information extracting directional information of brightness changes of the image in which the color information is corrected; extracting edge information of the image corrected in color information based on the brightness change directional information; It is preferable to include an edge information extraction step and a noise attenuation calculation step of attenuating the noise of the image whose color information is corrected based on the edge information.

The luminance change directional information may be generated based on the luminance change amounts of the eight directions of the ROI where the ROI is located.

The method may further include a luminance correction step of correcting the luminance of the image in which the color information is corrected according to a gamma curve based on the luminance histogram of the image in which the color information is corrected.

The brightness correction step may include extracting brightness information of an image in which the color information is corrected based on a brightness histogram of the image in which the color information is corrected, and based on brightness information of the image in which the color information is corrected. A gamma curve generating step of generating a gamma curve and a gamma curve applying step of applying the gamma curve to the image in which the color information is corrected may be included.

Luminance histogram of the corrected image and the color information are N _H - is preferably generated by a quantization (N _H -Quantized) method.

As described in detail above, according to the present invention, there is an effect of implementing the image processing apparatus and method for correcting the distortion of the still image due to the hand shake without using a separate additional device such as a gyro meter.

In addition, according to the present invention, there is an effect of implementing the image processing apparatus and method for efficiently correcting the distortion of the still image due to camera shake while reducing the amount of memory computation.

In addition, according to the present invention, there is an effect of implementing the image processing apparatus and method for solving the problems such as the shake and noise and insufficient color reproduction of the image caused by the long shutter time of the lens in a dark environment.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention;

1 is a diagram illustrating an image processing apparatus according to an exemplary embodiment. Referring to FIG. 1, an image processing apparatus according to an exemplary embodiment includes a reference image acquisition unit 2 and a color information correction unit 4.

The reference image acquisition unit 2 obtains two reference images of successive frames by applying different shutter times and ISO sensitivity settings.

The reference image acquisition unit 2 obtains a first reference image by applying a first shutter time and a first ISO sensitivity setting value, and a second shutter time longer than the first shutter time and a second smaller than the first ISO sensitivity setting value. It is preferable to obtain the second reference image by applying the ISO sensitivity setting value. The reason for doing this is as follows. That is, in general, the shutter time of the camera becomes longer in a dark environment, and the image acquired by the shaking of the human hand during the longer shutter time also shakes. In order to prevent this phenomenon, if you shorten the shutter time manually, the camera sensor may not receive enough light, resulting in very low brightness or color. To solve this lack of color, the noise in the image increases when the ISO sensitivity setting is acquired higher than usual. The present invention aims at simultaneously improving the characteristics having such a trade off relationship. To this end, in the present invention, when the camera shake correction function is driven, the shutter time is shortened to obtain a first reference image without shaking, and the shutter time is continuously extended to acquire a second reference image having sufficient brightness and color information. As described below, the luminance and color information can be sufficiently represented without shaking by using a method of applying to a full-size input image having a short shutter time by comparing luminance and color information between two reference images. Acquire an image that can be. This will be described in more detail as follows. That is, in a state where the shutter time is set to a long time, the image state is somewhat shaken, but a state in which the color or brightness is appropriate is obtained. When the shutter time is set to a short time, the image is almost not shaken, but the brightness is very dark, and the color information is not appropriate. In order to compensate for very low color information, the ISO sensitivity setting value may be set higher than usual, but in this case, there are many color noises in the image. These two types of images are used as preliminary information for correcting brightness and color information of a full-size input image having a short shutter time to be processed by a subsequent color information corrector. An input image is obtained by applying a short shutter time and a high ISO sensitivity setting value applied when the first reference image is acquired.

The second shutter time which is the shutter time applied to the second reference image is preferably 4 times or more and 8 times or less than the first shutter time which is the shutter time applied to the first reference image, and the ISO sensitivity applied to the first reference image. The first ISO sensitivity setting value which is a set value is preferably 4 times or more and 8 times or less of the second ISO sensitivity setting value which is an ISO sensitivity setting value applied to the second reference image.

In addition, the resolution of the first reference image and the second reference image is preferably set lower than the resolution of the full-size input image in consideration of the amount of memory computation. For example, the first reference image and the second reference image may be obtained as an image having a preview size in consideration of the available memory size.

The color information corrector 4 may adjust luminance of the input image acquired by applying a shorter shutter time among two shutter times applied to the first reference image and the second reference image, between the first reference image and the second reference image. Correct according to ratio and color difference ratio.

Referring to FIG. 2, the color information correcting unit 4 includes a luminance histogram analyzing unit 42, a luminance correcting calculating unit 44, a color difference information extracting unit 46, and a color difference information correcting calculating unit 48. Can be configured.

The luminance histogram analyzer 42 obtains and analyzes the luminance histogram of the first reference image and the luminance histogram of the second reference image.

The luminance histogram analyzer 42 defines a first level having a value equal to or greater than a predetermined number of pixels in the luminance histogram of the first reference image as the first minimum level Min _LP , and selects the first level in the luminance histogram of the first reference image. Defines a last level having a value greater than or equal to the pixel number as a first maximum level Max _LP and defines a first level having a value greater than or equal to a predetermined number of pixels in the luminance histogram of the second reference image as the second minimum level (Min _SP). ), And a final level having a value equal to or greater than a predetermined number of pixels in the luminance histogram of the second reference image is defined as the second maximum level Max _SP . The operation of the luminance histogram analyzer 42 will be described with reference to FIG. 3. 3 is a diagram illustrating luminance histograms of two reference images. The horizontal axis of FIG. 3 indicates the luminance level, and the vertical axis of FIG. 3 indicates the number of pixels. For example, when the threshold is 10, the luminance histogram analyzer 42 may determine the first luminance level having a value of 10 or more in the luminance histogram of the first reference image and the second reference image, respectively. Min _LP ) and the second minimum level (Min _SP ), and the last luminance level having a value of 10 or more in the luminance histogram of the first reference image and the second reference image, respectively, is defined as the first maximum level Max _LP and This is defined as the second maximum level Max _SP .

The luminance correction calculator 44 corrects the luminance of the input image based on a luminance histogram conversion operation such that the shape of the luminance histogram between the first reference image and the second reference image is similar. This will be described in more detail as follows. The luminance correction calculator 44 is input based on a difference between the second minimum level Min _SP and the first minimum level Min _LP and a difference between the second maximum level Max _SP and the first maximum level Max _LP . The luminance of the input image is corrected by stretching the luminance histogram of the image. As described above, the first minimum level (Min _LP) and a first maximum level (Max _LP) is a value that reflects the luminance level of the first reference image applied to the shutter time becomes shorter, the second minimum level (Min _SP) and The second maximum level Max _SP reflects the luminance level of the second reference image to which the shutter time is long applied. As an example, the luminance correction calculator may include a lookup table including a first minimum level Min _LP , a second minimum level Min _SP , a first maximum level Max _LP , and a second maximum level Max _SP . look up table (LUT), by proportionally calculating the luminance of the input image, the luminance of the input image can be corrected.

The color difference information extractor 46 extracts color difference information of pixels corresponding to the first reference image and the second reference image. The color difference information extracting unit 46 may perform an operation of accumulating color difference information in a partial area of a predetermined size with respect to each pixel of the two reference images.

The chrominance information extracting unit 46 may include the first blue difference information Cb _{LP (NpⅹNp), which} is an average of the blue difference signals of the first NⅹN region where the corresponding pixel of the first reference image is located, and the first NⅹN region. The first red difference information Cr _{LP ( Np ⅹ Np )} , which is an average of the red difference signals, and the second blue difference information, which is an average of blue difference signals in a second NⅹN region where the corresponding pixel of the second reference image is located at the center ( It is preferable to extract Cb _{SP (Np SPNp)} and the second red difference information Cr _{SP (NpⅹNp)} which is an average of the red difference signals in the second NⅹN region.

The color difference information correction calculator 48 corrects the color difference information of the input image based on the color difference information received from the color difference information extractor 46.

The color difference information correction calculation unit 48, a second blue color difference information (Cb _{SP (NpⅹNp))} and the first blue color difference information (Cb _{LP (Np} ⅹNp)) ratio of weighted by a blue color difference information of the input image between (Cb _SF ) the correction, and the second red color difference information (Cr _{SP (NpⅹNp))} and the first red color difference information (Cr _{LP (Np ⅹ Np))} applied to a red color difference information of the input image is the ratio between weight (Cr _SF), the correction It is desirable to.

Meanwhile, the color difference information correction calculator 48 applies a weighted ratio between the first blue difference information Cb _{LP (NpⅹNp} ) and the blue difference information Cb _SF of the corresponding pixel of the input image to weight the blue difference information Cb of the input image. correcting _SF), and the first red color difference information (Cr _{LP (NpⅹNp))} and the input image red color difference information of the corresponding pixel (weighting the ratio between Cr _SF) applied to compensate for the red color difference information (Cr _SF) of the input image of the can do.

In addition, the color difference information correction calculator 48 applies a weighted ratio between the second blue difference information Cb _{SP (NpⅹNp} ) and the blue difference signal of the corresponding pixel of the second reference image to determine the blue difference information Cb _SF of the input image. The red difference information Cr _SF of the input image may be corrected by applying a weighted ratio between the second red difference information Cr _{SP (Np ⅹ Np)} and the red difference information of the corresponding pixel of the second reference image.

The image processing apparatus according to an embodiment of the present invention may further include a noise removing unit 6. The noise removing unit 6 removes noise included in the input image based on the edge information of the input image. That is, the noise removing unit 6 checks the existence of an edge by defining a correlation function with surrounding pixels with respect to the luminance signal of the image input from the color information correcting unit 4, and based on this, the noise removing unit 6 is included in the input image. It is to remove noise.

Referring to FIG. 4, the noise removing unit 6 may include a luminance change direction information extracting unit 62, an edge information extracting unit 64, and a noise attenuation calculating unit 66.

The luminance change directional information extracting unit 62 extracts the directional information of the luminance change of the image in which the color information received from the color information correcting unit 4 is corrected. The luminance change direction information may be generated based on the luminance change amount in eight directions of the ROI where the ROI is located.

The edge information extracting unit 64 extracts edge information of the image whose color information is corrected based on the luminance change directional information received from the luminance change directional information extracting unit 62.

The noise attenuation calculator 66 attenuates the noise of the image in which the color information is corrected based on the edge information of the image in which the color information received from the edge information extractor 64 is corrected.

The image processing apparatus according to an embodiment of the present invention may further include a luminance corrector 8. The luminance corrector 8 finally corrects the luminance of the image in which the color information is corrected according to a gamma curve based on the luminance histogram of the image in which the color information is corrected.

Referring to FIG. 5, the luminance correcting unit 8 may include a luminance information extracting unit 82, a gamma curve generating unit 84, and a gamma curve applying unit 86.

The luminance corrector 8 extracts luminance information of an image in which color information is corrected based on the luminance histogram of the image in which color information is corrected. Luminance histogram of the color information corrected image is N _H - may be generated in the quantization (N _H -Quantized) method.

The gamma curve generator 84 generates a gamma curve based on the luminance information of the image whose color information is corrected.

The gamma curve applying unit 86 generates an output image by applying the gamma curve to the image of which color information is corrected.

6 is a diagram illustrating an image processing method according to an exemplary embodiment. Referring to FIG. 6, an image processing method according to an exemplary embodiment may include a reference image acquisition step S2, a luminance histogram analysis step S42, a luminance correction calculation step S44, and a color difference information extraction step S46. And a color information correction step S4 including a color difference information correction calculation step S48, a noise removal step S6, and a luminance correction step S8.

Since the operation principle of the image processing method according to an embodiment of the present invention is substantially the same as the image processing apparatus according to an embodiment of the present invention described above in detail, a detailed description of the image processing method according to an embodiment of the present invention Replaces the detailed description of the image processing apparatus according to an embodiment of the present invention.

As described above, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the foregoing description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

1 is a diagram illustrating an image processing apparatus according to an exemplary embodiment.

2 is a diagram illustrating a color information correcting unit included in an image processing apparatus according to an embodiment of the present invention.

3 is a diagram illustrating an example of an operation of a luminance histogram analyzer included in an image processing apparatus according to an exemplary embodiment.

4 is a diagram illustrating a noise canceller included in an image processing apparatus according to an exemplary embodiment.

5 is a diagram illustrating a luminance corrector included in an image processing apparatus according to an exemplary embodiment.

6 is a diagram illustrating an image processing method according to an embodiment of the present invention.

***** Explanation of symbols for main parts of drawing *****

2: reference image acquisition unit

4: color information correction unit

6: noise canceling unit

8: luminance correction unit

42: luminance histogram analyzer

44: luminance correction calculator

46: color difference information extraction unit

48: color difference information correction calculator

62: luminance change direction information extraction unit

64: edge information extraction section

66: noise attenuation calculator

82: luminance information extraction unit

84: gamma curve generation unit

86: gamma curve application

Claims (12)

A reference image acquisition unit for obtaining two reference images by differently applying shutter times and ISO (International Standard Organization) sensitivity settings; And A color information correcting unit configured to correct luminance and color difference information of the input image based on the luminance histogram and the color difference information of the two reference images with respect to the input image acquired by applying a short shutter time among the shutter times; And And a luminance corrector configured to correct the luminance of the image in which the color information is corrected according to a gamma curve based on the luminance histogram of the image in which the color information is corrected. According to claim 1, The brightness correction unit A luminance information extracting unit extracting luminance information of an image in which the color information is corrected based on a luminance histogram of the image in which the color information is corrected; A gamma curve generating unit generating a gamma curve based on luminance information of the image in which the color information is corrected; And And a gamma curve applying unit configured to apply the gamma curve to the image in which the color information is corrected. According to claim 1, Analyzing the luminance histogram of the first reference image, which is one of the two reference images, and the second reference image, which is the other one, respectively, and based on the luminance histogram conversion operation between the first reference image and the second reference image, Compensates for And extracting color difference information of corresponding pixels of the first reference image and the second reference image, and correcting color difference information of the input image based on the extracted color difference information. According to claim 1, Image processing device And a noise remover configured to remove noise included in the input image based on the edge information of the input image. 5. The method of claim 4, The noise canceling unit A luminance change directional information extraction unit for extracting directional information of luminance change of the image in which the color information is corrected; An edge information extracting unit extracting edge information of the image whose color information is corrected based on the luminance change directional information; And And a noise attenuation calculator configured to attenuate noise of the image in which the color information is corrected based on the edge information. 6. The method of claim 5, And the luminance change directional information is generated based on a luminance change amount in eight directions of the ROI located at the center of the pixel of interest. Acquiring two reference images by applying different shutter times and ISO (International Standard Organization) sensitivity settings; And The luminance of the input image and the luminance difference of the input image are corrected based on the luminance histogram and the color difference information of the two reference images with respect to the input image acquired by applying a short shutter time among the shutter times. Color information correcting step; And And a luminance correction step of correcting the luminance of the image in which the color information is corrected according to a gamma curve based on the luminance histogram of the image in which the color information is corrected. 8. The method of claim 7, The brightness correction step A brightness information extraction step of extracting brightness information of an image in which the color information is corrected based on a luminance histogram of the image in which the color information is corrected; A gamma curve generation step of generating a gamma curve based on luminance information of the image in which the color information is corrected; And And applying a gamma curve to the image in which the color information is corrected. 8. The method of claim 7, Analyzing the luminance histogram of the first reference image, which is one of the two reference images, and the second reference image, which is the other one, respectively, based on a luminance histogram conversion operation between the first reference image and the second reference image, Compensates for And extracting color difference information of corresponding pixels of the first reference image and the second reference image, and correcting color difference information of the input image based on the extracted color difference information. 8. The method of claim 7, The image processing method, And a noise removing step of removing noise included in the input image based on edge information of the input image before the luminance correction step. The method of claim 10, The noise removing step A luminance change directional information extraction step of extracting directional information of luminance change of the image in which the color information is corrected; An edge information extraction step of extracting edge information of the image in which the color information is corrected based on the luminance change directional information; And And a noise attenuation calculation step of attenuating the noise of the image in which the color information is corrected based on the edge information. 12. The method of claim 11, The luminance change directional information is generated based on the amount of change in luminance in eight directions of the ROI where the ROI is located.

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