KR20070012099A - Image processing apparatus for digital camera, and method thereof - Google Patents

Abstract

An image processing apparatus for a digital camera and a method thereof are provided to perform color interpolation after correcting a dead pixel for image data from an image sensor by using one LM, thereby quickly processing signals and making production of a small size possible, and reducing production costs. An image processing apparatus(200) for a digital camera comprises the followings: an LM(Line Memory) which stores image data for dead pixel correction and color interpolation; a color interpolation unit(214) which corrects a dead pixel for the image data of the LM and performs the color interpolation by using the LM for the image data in which the dead pixel is corrected; a preprocessing unit(230) which performs preprocessing for the image data from the color interpolation unit(214); an image processing unit(250) which performs color tuning, anti-aliasing, MPEG(Moving Picture Experts Group) processing, and white balancing for the image data from the preprocessing unit(230).

Description

Image processing apparatus and method for digital cameras {IMAGE PROCESSING APPARATUS FOR DIGITAL CAMERA, AND METHOD THEREOF}

1 is a block diagram of a conventional image processing apparatus for a digital camera.

2A to 2D are pixel structure diagrams of a 5x5 window of the image sensor of FIG.

3 is a pixel structure diagram of a 3x3 window that is color interpolated by the color interpolator of FIG.

4 is a configuration diagram of an image processing apparatus according to the present invention.

5 is an overall flowchart showing an image processing method according to the present invention.

FIG. 6 is a flowchart illustrating a dead pixel correction process of FIG. 5.

7A to 7D are pixel structure diagrams of a 5x5 window of the image sensor of FIG.

Explanation of symbols on the main parts of the drawings

LM: line memory 210: color interpolation unit

212: dead pixel correction unit 214: color interpolation unit

230: preprocessor 250: image processor

TW1: Inspection window of the first size TW2: Inspection window of the first size

MV: Pixel average value OP: Target pixel

DP: Dead Pixel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus applied to a camcorder or a digital camera. In particular, by implementing a color interpolation using a single line memory after dead pixel correction for image data from an image sensor, fast signal processing is possible. In addition, the present invention relates to an image processing apparatus and method for a digital camera capable of miniaturization and reducing manufacturing costs.

In general, with the development of video communication technology using wired / wireless high-speed communication networks and image input and recognition technology such as digital cameras, the adoption of digital camera modules in mobile communication terminals such as mobile phones has increased, resulting in images applied to digital camera modules. Research and development on image sensors and image processing devices are being actively conducted. An image sensor is a sensor for detecting a subject image by detecting light reflected by a subject, which is largely a charge coupled device (CCD) type and a complementary metal oxide semiconductor (CMOS) type according to manufacturing process technology. Semiconductor).

Representative technologies related to such image sensors include Bayer pattern (or mosaic pattern) technology for color filter arrays, and three photodiode color sensors (Three capable of detecting three colors in each pixel). photodiode color sensor) technology. The Bayer Pattern technology is currently used in most image sensors, and three colors are separated by a color filter to sense light at each pixel.

As such, color interpolation must be preceded in order to process image by receiving image data from a mosaic (or Bayer) type image sensor. This color interpolation is due to the structural characteristics of the image sensor. This is because the sensing unit of the circuit has a structure of a color filter array (CFA), which can only record one color value per pixel.

Using such an image sensor, all color values of R, G, and B should be calculated by receiving only one color value of R, G, and B in one pixel. This process is called image interpolation. For such image interpolation, the value of the target pixel as well as the neighboring pixel should be considered.

As described above, in order to calculate a color value using the value of the target pixel or its neighboring pixels, a memory device for referencing the values of the neighboring pixels is required, and a line memory in the form of a line buffer is usually used to implement it in hardware. shall.

On the other hand, the image data obtained from the image sensor is composed of an array of MxN image pixels of the image sensor. Nowadays, millions of pixels of high pixel image sensors form the mainstream, and in the process of making integrated circuits, there are some pixels that do not function properly due to process errors and the like. It is called (defective pixel).

This kind of dead pixel reacts inadequately depending on the illuminance. More specifically, for example, a cold pixel that always outputs only dark pixel values as output and a hot pixel that always outputs only light pixel values as output. There is. These appear as bright or dark spots in the final image, which is a major cause of significant degradation of the image quality.

Such dead pixels may be improved by correcting image data acquired from an image sensor. Normally, the correction method of the dead pixel uses the values of neighboring pixels similarly to the color image interpolation method, that is, if the value of the target pixel and the neighboring pixels are too high or low, it can be defined as a dead pixel. The dead pixels defined in this way can be corrected by substituting a median or an average value among neighboring pixels. In this case, like the color interpolation, a memory in the form of a line buffer is required.

This conventional image processing apparatus will be described with reference to FIG.

1 is a block diagram of a conventional image processing apparatus for a digital camera.

Referring to FIG. 1, a conventional image processing apparatus for a digital camera includes an image sensor 10 for sensing an image of a subject, including a microlens and a color filter array, and an image data from the sensor 10. , An image signal processor 20 for performing color interpolation, preprocessing, dead pixel correction, and image processing, and a display device 30 for outputting an image processed by the image signal processor 20 to a screen. In this case, the image data input from the image sensor 10 is usually in the form of a bayer or mosaic, and has image data having only one value of R, G, and B per pixel.

The image signal processor 20 pre-processes the color interpolation unit 21 that receives image data from the image sensor 10 and performs color interpolation, and a signal from the color interpolation unit 21. A preprocessing unit 22 for performing the operation, a dead pixel correction unit 23 for performing correction on the dead pixels of the image signal from the preprocessing unit 22, and an image signal from the dead pixel correction unit 23 And an image processor 24 for performing color tuning, contour correction, MPEG processing, and white balancing on the digital camera.

2A to 2D are pixel structure diagrams of a 5 × 5 window of the image sensor of FIG. 1.

2 (a) to 2 (d) show four pixel structures of a Bayer or mosaic image sensor, wherein one specific color value among R, G, and B is included in one pixel. Includes only. The color interpolation method performed by the image interpolation unit 21 with respect to the pixel structure of the 5x5 window will be described below.

First, referring to FIG. 2A, in the 5 × 5 window pixel structure, a method of calculating R, G, and B at the center G33 pixel is shown in Equation 1 below.

In Equation 1, a to g are weight factors for the sum of each pixel value, and high weights are given to pixels close to the current pixel position G33.

The dead pixel correction performed after such color interpolation will be described with reference to FIG. 3.

FIG. 3 is a pixel structure diagram of a 3x3 window that is color interpolated by the color interpolator of FIG. 1.

3 shows pixels of 3x3 windows of R, G, and B after performing the color interpolation. After performing color interpolation, the correction for the dead pixel is performed according to each of the R, G, and B channels, and the dead pixel correction for each channel is performed as in Equation 2 below.

In Equation 2, each threshold value is added to an average value of the current pixels G22, B22, and R22 and eight neighboring pixels of each current pixel, and the value difference between the neighboring pixel and the current pixel is compared with each other. The dead pixel can be determined according to the size, and the dead pixel determined in Equations 4 and 5 is replaced with an average value of surrounding pixels and corrected.

However, since the color interpolation and the dead pixel correction process in the conventional image signal processor are performed at different stages, each line memory must be used separately, thereby increasing the memory capacity to be used.

In addition, since the dead pixel correction process is performed for all pixels, there is a problem in that the signal processing time is increased due to an increase in the amount of computation.

In addition, since color correction and dead pixel correction are performed by separate hardware apparatuses, and line memories that are independent of each other must be provided for each operation, there is a problem that the IC unit cost is increased by increasing the implementation size of the IC.

SUMMARY OF THE INVENTION The present invention has been proposed to solve the above problems, and an object thereof is to use color interpolation after the dead pixel correction for image data from an image sensor in an image processing apparatus applied to a camcorder or a digital camera. The present invention provides an image processing apparatus and method for a digital camera capable of performing a quick signal processing and making a small production, thereby reducing a manufacturing cost.

In order to achieve the above object of the present invention, an image processing apparatus for a digital camera of the present invention includes a line memory for storing image data for dead pixel correction and color interpolation; A color interpolation unit for correcting a dead pixel of the image data of the line memory and performing color interpolation on the image data of which the dead pixel is corrected using the line memory; A preprocessing unit which performs a preprocessing process on the image data from the color interpolation unit; And an image processor for performing color tuning, contour correction, MPEG processing, and white balancing on the image data from the preprocessor.

The color interpolator may include: a dead pixel corrector for determining whether a dead pixel is present for all pixels of the image data of the line memory, and correcting the dead pixel if a dead pixel exists; And a color interpolator for performing color interpolation on the image data of the line memory in which the dead pixel is corrected by the dead pixel corrector.

The dead pixel corrector is configured to store the target within the inspection window of the first size when the number of pixels having the same color as that of the target pixel is sufficient in the inspection window of the first size previously set centered on the target pixel in the image data. Performs dead pixel correction by determining whether the target pixel is a dead pixel based on a pixel average value for the pixel, and if the number of pixels of the same color as the target pixel is not sufficient, a second size preset in advance around the target pixel. And determining whether the target pixel is a dead pixel on the basis of a pixel average value for the target pixel in the inspection window of to perform dead pixel correction.

In addition, in order to achieve the object of the present invention, the image processing method for a digital camera of the present invention, the data acquisition step of obtaining image data; A dead pixel correction step of determining whether a dead pixel is present for all pixels of the image data acquired in the data acquiring step, and correcting the dead pixel if a dead pixel exists; And a color interpolation step of performing color interpolation for performing color interpolation on image data after the dead pixel correction step.

The dead pixel correction step may include: a color number determining step of determining whether the number of pixels having the same color as that of the target pixel is sufficient in the inspection window of a first size previously set centered on the target pixel in the image data; A first dead pixel for performing dead pixel correction by determining whether the target pixel is a dead pixel based on a pixel average value for the target pixel in the first sized inspection window when the number of pixels having the same color as the target pixel is sufficient A correction step; And when the number of pixels having the same color as the target pixel is not sufficient, determining whether the target pixel is a dead pixel based on a pixel average value for the target pixel in a second preset inspection window centering on the target pixel. And a second dead pixel correction step of performing dead pixel correction.

The first dead pixel correction step may include: a first pixel average calculation step of calculating a pixel average value for the target pixel in the first sized inspection window when the number of pixels having the same color as the target pixel is sufficient; A first dead pixel determination step of determining whether or not the target pixel is a dead pixel based on the pixel average value in the first pixel average calculation step; And a first dead pixel correction step of performing a dead pixel correction on the target pixel when the target pixel is determined to be a dead pixel in the first dead pixel determination step.

The second dead pixel correction step may include: a second pixel average calculation step of calculating a pixel average value for the target pixel in the inspection window of the first size when the number of pixels having the same color as the target pixel is not sufficient; A suspect dead pixel determination step of determining whether the target pixel is a suspect dead pixel or not based on the pixel average value in the second pixel average calculation step; A third pixel average calculation for calculating a pixel average value for the target pixel within a second preset inspection window centering on the target pixel when the target pixel is determined to be a suspect dead pixel in the suspected dead pixel determination step; step; A second dead pixel determination step of determining whether the target pixel is a dead pixel based on the pixel average value of the third pixel average calculation step; And a second dead pixel correction step of performing a dead pixel correction on the target pixel when the target pixel is determined to be a dead pixel in the second dead pixel determination step.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings referred to in the present invention, components having substantially the same configuration and function will use the same reference numerals.

4 is a block diagram of an image processing apparatus according to the present invention.

Referring to FIG. 4, an image processing apparatus 200 for a digital camera according to the present invention includes a line memory LM for storing image data for dead pixel correction and color interpolation, and image data of the line memory LM. A color interpolation unit 210 for correcting a dead pixel with respect to the dead pixel, and performing color interpolation on the image data in which the dead pixel is corrected using the line memory LM, and an image from the color interpolation unit 210. A preprocessor 230 for preprocessing data, and an image processor 250 for performing color tuning, contour correction, MPEG processing, and white balancing on the image data from the preprocessor 230. .

In addition, the image processing apparatus 200 according to the present invention receives image data from the image sensor 10 and stores the image data in the line memory LM, and after processing the signal for the image data, the display apparatus 30. Outputs through the screen.

The color interpolator 210 implements a dead pixel correction and color interpolation function in one IC. The dead pixel correction and color interpolation may be implemented in software or hardware, for example, hardware. If implemented as can be made as follows.

The color interpolation unit 210 determines whether the dead pixel is a dead pixel for all pixels of the image data of the line memory LM, and if there is a dead pixel, corrects the dead pixel. And a color interpolator 214 for performing color interpolation on the image data of the line memory LM in which the dead pixel is corrected by the dead pixel corrector 212.

The dead pixel corrector 212 is the same as the target pixel PO in the inspection window TW1 (eg, a 3x3 window) of a first size pre-installed around the target pixel OP in the image data. If the number of pixels of the color is sufficient, it is determined whether the target pixel OP is a dead pixel DP based on the pixel average value MV for the target pixel OP in the inspection window TW1 of the first size. When the dead pixel correction is performed and the number of pixels having the same color as that of the target pixel OP is not sufficient, the target pixel in the inspection window TW2 having a preset second size around the target pixel OP. The dead pixel correction is performed by determining whether the target pixel OP is a dead pixel DP based on the pixel average value MV of the control unit.

Here, the pixel average value MV of the target pixel OP corresponds to an average of pixel values of neighboring pixels of the target pixel OP, and the number of pixels having the same color as the target pixel OP is in the inspection window. The number of pixels for determining whether is sufficient may be set differently according to the size of the inspection window. For example, when the inspection window is a 3x3 window, the number of reference pixels may be set to two.

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

Referring to Figure 4 will be described with respect to the digital camera image processing apparatus 200 according to the present invention, first, when the image processing apparatus 200 of the present invention is applied to a digital camera, the image processing apparatus 200 of the present invention The image sensor receives image data from the image sensor 100 and performs signal processing such as dead pixel correction and color interpolation.

In detail, the color interpolation unit 210 of the image processing apparatus 200 stores the image data input from the image sensor 10 in the line memory LM for dead pixel correction and color interpolation. The dead pixel of the image data of the line memory LM is corrected, and color interpolation is performed on the image data of which the dead pixel is corrected and transferred to the preprocessor 230.

The preprocessor 230 performs a preprocessing process on the image data from the color interpolator 210 and transmits the preprocessing process to the image processor 250.

The image processor 250 performs color tuning, contour correction, MPEG processing, and white balancing on the image data from the preprocessor 230, and outputs the image data to the display device 30.

The color interpolation unit 210 performs dead pixel correction and color interpolation on the image data of one line memory LM, and performs color correction on the image data on which dead pixels are corrected after performing dead pixel correction. Perform interpolation.

In this regard, the dead pixel corrector 212 of the color interpolator 210 determines whether the dead pixel is a dead pixel for all pixels of the image data of the line memory LM, and when there is a dead pixel. Then, the dead pixel is corrected and provided to the color interpolator 214.

In detail, the dead pixel corrector 212 may have the same color as that of the target pixel PO in the inspection window TW1 of the first size pre-installed centering on the target pixel OP in the image data. If the number of pixels is sufficient, it is determined whether the target pixel OP is a dead pixel DP based on the pixel average value MV for the target pixel OP in the inspection window TW1 of the first size. Perform the calibration. When the number of pixels having the same color as that of the target pixel OP is not sufficient, the dead pixel corrector 212 may be positioned within the inspection window TW2 of a second size which is preset based on the target pixel OP. Determines whether the target pixel OP is a dead pixel DP based on the pixel average value MV of the target pixel, and performs dead pixel correction.

The color interpolator 214 performs color interpolation on image data of the line memory LM whose dead pixels are corrected by the dead pixel corrector 212.

EMBODIMENT OF THE INVENTION Hereinafter, the image processing method for digital cameras of this invention is demonstrated.

5 is an overall flowchart showing an image processing method according to the present invention.

Referring to FIG. 5, first, image data is acquired from the image sensor 10 in the data acquisition step S100.

Next, in the dead pixel correction step (S200), it is determined whether or not the dead pixel is for all pixels of the image data acquired in the data acquisition step (S100), and if there is a dead pixel, correction for the dead pixel is present. Do this. This will be described below in detail with reference to FIGS. 6 and 7.

Next, in the color interpolation step S300, after the dead pixel correction step S200, color interpolation is performed on image data.

FIG. 6 is a flowchart illustrating a dead pixel correction process of FIG. 5.

Referring to FIG. 6, in a step S210 of determining the number of colors of the dead pixel correction step S200, the inspection window TW1 having a first size pre-installed centering on the target pixel OP in the image data ( For example, it is determined whether the number of pixels of the same color as the target pixel PO is sufficient in the 3x3 window.

Next, in the first dead pixel correction step S220, when the number of pixels having the same color as the target pixel OP is sufficient, a pixel average value for the target pixel OP in the inspection window TW1 of the first size. Based on MV, it is determined whether the target pixel OP is a dead pixel DP, and the dead pixel correction is performed.

Next, in the second dead pixel correction step S230, when the number of pixels having the same color as that of the target pixel OP is not sufficient, the inspection window TW2 having a preset second size around the target pixel OP is preset. (Eg, a 5x5 window) determines whether the target pixel OP is a dead pixel DP based on the pixel average value MV of the target pixel, and performs dead pixel correction.

7A to 7D are pixel structure diagrams of a 5 × 5 window of the image sensor of FIG. 5.

7 (a) to 7 (d) show pixel structures of four 5 × 5 windows for Bayer sensors or mosaic sensors.

Hereinafter, the first dead pixel correction step S220 and the second dead pixel correction step S230 will be described with reference to FIGS. 4 to 7.

First, the first dead pixel correction step S220 will be described in detail.

In the first pixel average calculation step S221 of the first dead pixel correction step S220, when the number of pixels having the same color as the target pixel OP is sufficient, the scan window TW1 of the first size may be used. The pixel average value MV of the target pixel OP is calculated. Next, in the first dead pixel determination step S222, it is determined whether the target pixel OP is the dead pixel DP based on the pixel average value MV in the first pixel average calculation step S221. do.

Referring to (a) and (b) of FIG. 7, when the inspection window TW1 of the first size is a 3x3 window and the inspection window TW2 of the second size is a 5x5 window, for example, Explain.

When the center pixel G33 in the 5x5 window shown in Figs. 7A and 7B is the target pixel OB, the target pixel OB is stored in the 3x3 window centered on the target pixel G33. The number of pixels of the green color (G), which are the same color, is sufficient as four, and accordingly, the pixel average value of the target pixel OP by using the 3X3 window corresponding to the dotted line in the 5x5 window of FIGS. 7A and 7B. (MV) is obtained and it is determined whether or not it is the dead pixel DP for the target pixel OP as shown in Equation 3 below.

In Equation 3, the threshold 1 is a coefficient for determining a hot pixel, and the threshold 2 is a coefficient for determining a cold pixel.

If the condition of Equation 3 is satisfied, the target pixel G33 is determined to be a dead pixel. Here, although the window for dead pixel determination may use the entire 5x5 window as needed, considering that the number of pixels of the same color as the target pixel is sufficient in the 3x3 window, and the number of operations increases when the 5x5 window is used, It is preferable to use a 3x3 window.

Next, in the first dead pixel correction step S223, when the target pixel OP is determined as the dead pixel DP in the first dead pixel determination step S222, a dead pixel with respect to the target pixel OP. Perform the calibration. This will be described with reference to FIGS. 7A and 7B.

For example, referring to FIGS. 7A and 7B, the pixel average value MV of the target pixel OP G33 is obtained in the 3 × 3 window, and the pixel average value MV is obtained from the dead pixel. By replacing the (DP) value, dead pixel correction is performed on the target pixel OP as shown in Equation 4 below.

After the dead pixel correction as described above, the color interpolation step S300 is performed. Referring to FIG. 7A, the color correction in the color interpolation step S300 is performed as in Equation 5 below. . Referring to FIG. 7B, color correction in the color interpolation step S300 is performed as in Equation 6 below.

In Equations 5 and 6, a to g are weighting factors for the sum of pixels of each pixel.

Next, the second dead pixel correction step S230 will be described in detail.

First, in the second pixel average calculation step S231 of the second dead pixel correction step S230, when the number of pixels having the same color as the target pixel OP is not sufficient, the inspection window TW1 having the first size. The pixel average value MV of the target pixel OP is calculated. Next, in the suspected dead pixel determination step S232, it is determined whether the target pixel OP is the suspected dead pixel DDP based on the pixel average value MV in the second pixel average calculation step S231. do.

For example, referring to (c) and (d) of FIG. 7, when the inspection window TW1 of the first size is a 3x3 window and the inspection window TW2 of the second size is a 5x5 window. An example is demonstrated.

When the center pixel B33 in the 5x5 window shown in FIG. 7C is the target pixel OB, a blue color having the same color as that of the target pixel OB is formed in the 3x3 window centered on the target pixel B33. Since the number of pixels in (B) is only one pixel, this is not sufficient, and in this case, it is determined whether or not it is a suspect dead pixel by using an average value of the red (R) and green (G) pixels, which are neighboring pixels. can do.

In addition, when the center pixel R33 in the 5x5 window shown in FIG. 7D is the target pixel OB, the same color as the target pixel OB in the 3x3 window centered on the target pixel R33. Since the number of pixels of red (R) is only one pixel, it is not sufficient. It can be determined.

In (c) of FIG. 7, when the above equation (7) is satisfied, it is determined as a suspect dead pixel. In FIG.

Next, in the third pixel average calculation step S233, when the target pixel OP is determined to be a suspect dead pixel DDP in the suspicious dead pixel determination step S232, the preliminary search centering on the target pixel OP is performed. The pixel average value MV of the target pixel is calculated in the inspection window TW2 having the second size. Next, in the second dead pixel determination step S234, it is determined whether the target pixel OP is the dead pixel DP based on the pixel average value MV of the third pixel average calculation step S233. .

For example, referring to (c) and (b) of FIG. 7, if it is determined that the dead pixel is suspected above, a process of determining whether or not the dead pixel is needed is further required, and in this case, the window is expanded to a size of 5x5. Using pixels of the same color within a 5x5 window.

First, referring to FIG. 7C, when a dead dead pixel is determined in Equation 7, dead pixels are determined as in Equation 9 below.

When the above Equation 8 is satisfied, the target pixel B33 is determined as a dead pixel of a hot pixel or a cold pixel.

Next, referring to FIG. 7D, when it is determined that the suspect dead pixel is expressed in Equation 8, the dead pixel is determined as in Equation 10 below.

When the above Equation 10 is satisfied, the target pixel R33 is determined as a dead pixel of a hot pixel or a cold pixel.

Next, in the second dead pixel correction step S235, when the target pixel OP is determined to be a dead pixel DP in the second dead pixel determination step S234, a dead pixel with respect to the target pixel OP. Perform the calibration.

For example, referring to FIG. 7C, when it is determined as the dead pixel in Equation 9 as described above, a correction process for the target pixel determined as the dead pixel is performed as in Equation 11 below. do. In addition, referring to FIG. 7 (d), for example, when it is determined as a dead pixel in Equation 10 as described above, a correction process for the target pixel determined as a dead pixel as shown in Equation 12 below. This is done.

After the dead pixel correction as described above, the color interpolation step S300 is performed. Referring to FIG. 7C, the color correction in the color interpolation step S300 is performed as in Equation 13 below. . Referring to FIG. 7D, color correction in the color interpolation step S300 is performed as in Equation 14 below.

In Equations 13 and 14, h to l are weighting factors for the sum of pixel averages of each pixel.

According to the foregoing, the conventional method of performing dead pixel correction after color interpolation increases the size of the IC when the hardware is implemented in hardware, requiring line memory at each step, thereby increasing the manufacturing cost, Since the number of operations used in the step is large, there is a problem of increasing the power consumption. However, in the present invention, by reducing the memory size and processing the second step in one step, the power consumption can be reduced by reducing the number of operations, and the dead pixels Since color interpolation is performed after the correction, the noise after color interpolation caused by dead pixels can be removed in advance.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, but is defined by the claims, and the apparatus of the present invention may be substituted, modified, and modified in various ways without departing from the spirit of the present invention. It is apparent to those skilled in the art that modifications are possible.

According to the present invention as described above, in the image processing apparatus applied to a camcorder or a digital camera, by implementing a color interpolation using a single line memory after the dead pixel correction for the image data from the image sensor, Signal processing is possible, and it is possible to reduce the manufacturing cost by making a small production.

That is, since color interpolation and dead pixel correction can be simultaneously performed by one color interpolation unit, power consumption can be reduced by reducing memory usage, reducing the size of integrated circuits, and reducing the amount of computation. In addition, in the conventional color interpolation including the dead pixel, noise may occur due to the effect of the dead pixel in the image. However, in the present invention, since color interpolation is performed after the dead pixel is corrected, noise generation may be suppressed.

Claims (7)

A line memory for storing image data for dead pixel correction and color interpolation; A color interpolation unit for correcting a dead pixel of the image data of the line memory and performing color interpolation on the image data of which the dead pixel is corrected using the line memory; A preprocessing unit which performs a preprocessing process on the image data from the color interpolation unit; And An image processor which performs color tuning, contour correction, MPEG processing, and white balancing on the image data from the preprocessor. Image processing apparatus for a digital camera comprising a. The method of claim 1, wherein the color interpolation unit A dead pixel corrector for determining whether a dead pixel is present for all pixels of the image data of the line memory, and correcting the dead pixel if a dead pixel exists; A color interpolator for performing color interpolation on the image data of the line memory in which the dead pixel is corrected by the dead pixel corrector; Image processing apparatus for a digital camera comprising a. The method of claim 2, wherein the dead pixel corrector, If the number of pixels of the same color as the target pixel is sufficient in the inspection window of the first size pre-set around the target pixel in the image data, the pixel average value for the target pixel in the inspection window of the first size is sufficient. Determining whether the target pixel is a dead pixel, and performing dead pixel correction. When the number of pixels having the same color as the target pixel is not sufficient, the second pixel is set in the inspection window having a preset second size around the target pixel. And determining whether the target pixel is a dead pixel based on a pixel average value for the target pixel to perform dead pixel correction. A data acquisition step of acquiring image data; A dead pixel correction step of determining whether a dead pixel is present for all pixels of the image data acquired in the data acquiring step, and correcting the dead pixel if a dead pixel exists; And After the dead pixel correction step, a color interpolation step of performing color interpolation for color interpolation on image data Image processing method for a digital camera comprising a. The method of claim 4, wherein the dead pixel correction step, A color number judging step of judging whether or not the number of pixels having the same color as the target pixel is sufficient in the inspection window of a first size previously set centered on the target pixel in the image data; A first dead pixel for performing dead pixel correction by determining whether the target pixel is a dead pixel based on a pixel average value for the target pixel in the first sized inspection window when the number of pixels having the same color as the target pixel is sufficient A correction step; And If the number of pixels having the same color as the target pixel is not sufficient, it is determined whether the target pixel is a dead pixel based on a pixel average value for the target pixel in a second preset inspection window centering on the target pixel. Second dead pixel correction step of performing dead pixel correction Image processing method for a digital camera comprising a. The method of claim 5, wherein the first dead pixel correction step, A first pixel average calculation step of calculating a pixel average value for the target pixel in the inspection window of the first size when the number of pixels of the same color as the target pixel is sufficient; A first dead pixel determination step of determining whether or not the target pixel is a dead pixel based on the pixel average value in the first pixel average calculation step; And A first dead pixel correction step of performing dead pixel correction on the target pixel when the target pixel is determined to be a dead pixel in the first dead pixel determination step; Image processing method for a digital camera comprising a. The method of claim 5, wherein the second dead pixel correction step is A second pixel average calculation step of calculating a pixel average value for the target pixel in the inspection window of the first size when the number of pixels having the same color as the target pixel is not sufficient; A suspect dead pixel determination step of determining whether the target pixel is a suspect dead pixel or not based on the pixel average value in the second pixel average calculation step; A third pixel average calculation for calculating a pixel average value for the target pixel within a second preset inspection window centering on the target pixel when the target pixel is determined to be a suspect dead pixel in the suspected dead pixel determination step; step; A second dead pixel determination step of determining whether the target pixel is a dead pixel based on the pixel average value of the third pixel average calculation step; And A second dead pixel correction step of performing dead pixel correction on the target pixel when the target pixel is determined to be a dead pixel in the second dead pixel determination step; Image processing method for a digital camera comprising a.

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