Image signal processor and method for processing image signal

1 . An image signal processor comprising:

an image binning circuit configured to output a second image that is upscaled by summing pixel values of a first image, which is an original image, on a sub-pixel array basis;

an input image selection circuit configured to select the first image and the second image as a first input or a second input; and

an integrated filtering circuit configured to perform a filtering operation for a selected image by selecting the input image selection circuit in response to an input order of the first input and the second input, and output one of a noise-removed image and a sharpened image,

wherein:

the input image selection circuit is configured to, in response to a first selection signal, set a pixel value of the first image to the first input and set a pixel value of the second image to the second input; and

the input image selection circuit is configured to, in response to a second selection signal, set a pixel value of the second image to the first input and set a pixel value of the first image to the second input.

2 . The image signal processor according to claim 1 , further comprising an image analysis circuit configured to analyze the first image and the second image, and generate the first selection signal and the second selection signal for selecting the first input and the second input.

3 . The image signal processor according to claim 2 , wherein the image analysis circuit is configured to:

output the first selection signal when a result of analyzing the first image and the second image indicates that image requiring sharpening processing is included in the first image and the second image; and

output the second selection signal when a result of analyzing the first image and the second image indicates that image requiring noise processing is included in the first image and the second image.

4 . The image signal processor according to claim 1 , wherein the integrated filtering circuit including arithmetic expression for performing filtering processing operation,

wherein the integrated filtering circuit configured to perform a calculation using pixel values of the first image and the second image as input values of the arithmetic expression; and

output one of the noise-removed image and the sharpened image when an output value of the arithmetic expression is changed in response to the first input and the second input.

5 . The image signal processor according to claim 1 , wherein the integrated filtering circuit includes:

a variance/covariance calculation circuit configured to calculate a variance value and a covariance value based on pixel values of the first input and the second input;

a filtering coefficient calculation circuit configured to calculate a filtering coefficient in response to the variance value and the covariance value; and

a filtering circuit configured to perform the filtering operation for the selected image by applying a weight to the filtering coefficient.

6 . The image signal processor according to claim 5 , wherein the variance/covariance calculation circuit is configured to:

calculate the variance value in response to the second input and an expectation operator; and

calculate the covariance value in response to the first input, the second input, and the expectation operator.

7 . The image signal processor according to claim 5 , wherein the filtering coefficient calculation circuit is configured to calculate an arithmetic expression in which the variance value corresponding to the second input is used as a denominator and the covariance value corresponding to the first input and the second input is used as a numerator.

8 . The image signal processor according to claim 7 , wherein:

the filtering coefficient calculation circuit is configured to calculate the filtering coefficient such that, when the pixel value of the second image is set to the second input, the filtering coefficient is greater than a first coefficient value; and

the filtering coefficient calculation circuit is configured to calculate the filtering coefficient such that, when the pixel value of the first image is set to the second input, the filtering coefficient is less than the first coefficient value.

9 . The image signal processor according to claim 8 , wherein the variance value of the second input is less than the variance value of the first input.

10 . The image signal processor according to claim 8 , wherein the filtering circuit is configured to adjust an intensity of detail during the filtering operation in response to the filtering coefficient.

11 . The image signal processor according to claim 10 , wherein:

the filtering circuit is configured to output the sharpened image when the intensity of detail is increased up to a first level in a situation where the filtering coefficient is greater than the first coefficient value; and

the filtering circuit is configured to output the noise-removed image when the intensity of detail is increased up to a second level in a situation where the filtering coefficient is less than the first coefficient value.

12 . The image signal processor according to claim 5 , wherein the filtering circuit is configured to:

calculate a first value by multiplying the filtering coefficient by a value obtained by subtracting the second input from the first input;

calculate a second value by multiplying a pixel value of the first image by an expectation operator;

calculate a third value by calculating a sum of the first value and the second value and multiplying a weight value by the sum of the first value and the second value;

calculate a fourth value by multiplying the pixel value of the first image by a value obtained by subtracting the weight value from a predetermined constant value; and

perform calculation for the filtering operation for the selected image by summing the third value and the fourth value.

13 . A method for processing an image signal, the method comprising:

generating a second image that is upscaled by summing pixel values of a first image, which is an original image, on a sub-pixel array basis;

in response to a first selection signal, setting a pixel value of the first image to a first input and setting a pixel value of the second image to a second input;

in response to a second selection signal, setting a pixel value of the second image to the first input and setting a pixel value of the first image to the second input; and

performing one of a first filtering process operation for the first image or the second image and a second filtering process operation for the first image or the second image in response to an input order of the first input and the second input.

14 . The method according to claim 13 , further comprising:

determining whether the first image includes detailed image or a blurring signal by analyzing the first image; and

outputting one of the first selection signal and the second selection signal based on a result of the determining.

15 . The method according to claim 14 , further comprising, when the first image includes the detailed image, setting the pixel value of the first image to the first input, setting the pixel value of the second image to the second input, and performing a calculation for the first filtering process operation by substituting the set first input and the second input into a predetermined arithmetic expression.

16 . The method according to claim 15 , wherein the first filtering process operation includes a sharpening process of adjusting an intensity of detail of the first image.

17 . The method according to claim 14 , further comprising, when the first image includes the blurring signal, performing a calculation for the second filtering process operation by substituting the set first input and the second input into a predetermined arithmetic expression,

wherein the second filtering process operation includes a process of removing noise included in the first image.