KR20100099556A - Photographing apparatus and method of processing image in photographing apparatus - Google Patents

Abstract

PURPOSE: An image pickup apparatus and an image process method of the same for obtaining a clear image by using the distance to a subject are provided to implement an image process suitable for each pixel in consideration of distance to the subject. CONSTITUTION: An image pickup apparatus changes an image into an electric signal(S100). The electric signal is distributed into a plurality of areas(S110). A distance to the subject is calculated about each area(S120, S130). The weighted value included in the domain frame of each pixel is calculated according to the distance(S140). The image process is processed about each pixels by multiplexing an image processing parameter(S150).

Description

Image processing apparatus and an image processing method of the image pickup apparatus {Photographing apparatus and method of processing image in photographing apparatus}

The present invention relates to an image pickup apparatus and an image processing method of an image pickup apparatus, and more particularly, to divide an image picked up by an image pickup device into a plurality of regions, and to capture the image based on the distance to the subject in the divided regions. An image capturing apparatus and an image processing method of an image capturing apparatus which perform image processing by varying parameters for each pixel of a captured image.

In general, a digital camera is a device that converts light reflected from a subject into an electrical signal, stores the image data, and processes or reproduces the stored image data. Such digital cameras are able to directly check an image of a photographed subject without complicated film printing work performed in a conventional film camera, and are rapidly replacing film cameras due to the advantage of easy editing and processing using a digital medium.

When the digital camera shoots, a digital image processing operation is performed on the image picked up by the image pickup device. The conventional digital image processing operation is performed by applying the same filter parameter to the entire area of the captured image. According to this method, the image is clear only for the portion where the user focuses using the auto focusing function, and the other portions except for the focused portion are not in focus, thereby obtaining a blurry image as a whole. For example, if the AF is adjusted for a person in the center of the captured image, the far background behind the person obtains a blurred image as a result.

An object of the present invention is to provide an image pickup device and an image processing method of the image pickup device.

Another object of the present invention is to make it possible to obtain a clear image by performing image processing suitable for each pixel in consideration of the distance from the imaging device to the subject.

It is still another object of the present invention to provide an image pickup apparatus and an image processing method of the image pickup apparatus that apply different filter parameters for image processing for each pixel according to the distance to the subject.

The present invention divides an image picked up by an imaging device into a plurality of areas, and executes image processing by varying parameters for each pixel of the picked-up image based on the distance to the subject in the divided areas. An imaging device and an image processing method of the imaging device are provided.

An image processing method of an imaging device according to the present invention includes an imaging step in which an imaging device converts an image into an electrical signal for imaging, a dividing step of dividing an image represented by the electrical signal into a plurality of regions, and for each region. A distance calculation step of calculating a distance to a subject; a weighting step of calculating weights of pixels included in regions according to the obtained distance; and multiplying the weight by an image processing parameter to perform image processing on each pixel. And an image processing step.

In the present invention, the distance calculation step may include an auto focus adjustment step of adjusting a focus on a plurality of areas.

In the present invention, the auto focus adjustment step may calculate an auto focus value representative of the focus state of the regions.

In the present invention, the auto focus adjustment step may set the maximum value of the high frequency component of the regions as the auto focus value.

In the present invention, the weight calculation step may calculate the weight by adding the values of the autofocus values of the areas adjacent to the pixel for obtaining the weight multiplied by the area of a rectangle having a straight line connecting the centers of the areas adjacent to the pixel. .

An imaging device according to the present invention comprises an image pickup device, a focus detector for dividing an image picked up by the image pickup device into a plurality of areas, and obtaining an autofocus value for each area, and an image using the autofocus value. And a weight calculating section for calculating weights for each pixel, and an image processing section for performing image processing on each pixel by multiplying the weight of each pixel by an image processing parameter.

The image pickup apparatus and image processing method of the present invention as described above have suitable image processing (weighted multiplied) for each pixel in consideration of the distance to the subject without applying the same parameters to the entire image when performing image processing. Parameter) to get a clear image.

If necessary, image processing may be performed to adjust the weight of the remaining portion of the entire image except for the subject area that is the subject of auto focus adjustment, that is, the background portion that is located at a relatively long distance, so that the image is more blurred than the subject. . Therefore, more various image processing can be realized by applying different filter parameters for image processing for each pixel according to the distance to the subject.

EMBODIMENT OF THE INVENTION Hereinafter, the structure and operation | movement of the imaging device and image processing method of the imaging device which concern on this invention are demonstrated in detail through the embodiment of an accompanying drawing.

1 is a block diagram schematically illustrating components of an image pickup apparatus according to an embodiment of the present invention.

The image pickup device shown in FIG. 1 includes an image pickup device 20 for picking up an image and converting the image into an electrical signal, and dividing the image picked up by the image pickup device into a plurality of areas, thereby autofocusing values for the respective areas. A focus detector 44 for obtaining the?, A weight calculator 46 for calculating a weight for each pixel constituting the image using an auto focus value, and multiplying the weight of each pixel by an image processing parameter to each pixel. An image processing unit 47 for performing image processing for the image is provided.

The optical system 10 disposed in front of the image pickup device 20 includes a plurality of lenses 12 to perform the function of imaging external image light on the image pickup surface of the image pickup device 20. The lenses 12 are arranged to be variable in distance from each other. When the distance between the lenses 12 is changed, the zoom magnification and the focus of the optical system 10 may be adjusted.

The lenses 12 are driven by the zoom driver 11 and the focus driver 13 having a driving means such as a zoom motor or a focus motor, so that their positions with respect to each other may be varied. The lenses 12 may include a zoom lens that enlarges or reduces the size of the subject and a focus lens that adjusts the focus of the subject. The zoom driver 11 and the focus driver 13 operate by receiving a control signal from the driving circuit 42 of the controller 40. Accordingly, the zoom driver 11 may drive the optical system 10 such that the optical system 10 has any one of a plurality of magnifications.

The imaging device 20 includes a photoelectric conversion device such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), and the image light incident through the optical system 10 is an image that is an electrical signal. Convert to a signal. The process of converting image light into an electrical signal may include detailed steps such as first converting an analog signal and converting an analog signal into a digital signal. The image conversion unit 41 converts the electrical signal of the image pickup device 20 into image data capable of performing image processing. The image data generated by the image conversion unit 41 may be stored in the memory 15 or may be processed by the image processing unit 47.

The controller 40 is electrically connected to the image pickup device 20, the zoom driver 11, the focus driver 13, the display unit 30, and the like, and controls these components and control signals to control the operation of each component. It performs functions such as sending and receiving data and processing data. The control unit 40 includes an image conversion unit 41, a driving circuit unit 42, a display control unit 43, a focus detection unit 44, a weight calculating unit 46, an image processing unit 47, and a memory ( 15 may be provided with a memory controller 45 for controlling data storage.

The controller 40 may be implemented as a microchip or a circuit board including the microchip, and each component included in the controller 40 may be implemented by software or circuits included in the controller 40. .

The memory control unit 45 controls the recording of the image data into the memory 15 and the reading of the image data and setting information recorded in the memory 15. The memory 15 is made of, for example, a semiconductor memory element such as SDRAM (synchronous DRAM) to store data of a captured image.

The display unit 30 is controlled by the display control unit 43 and operates to display an image captured by the imaging device 20, an image on which image processing has been performed, a menu for operating the imaging device, and various kinds of information. This is the part to perform. As the display unit 30, a display device such as a liquid crystal display (LCD) or an organic light emitting diode (OLED) may be used.

FIG. 2 is an exemplary diagram illustrating an example of dividing an image into a plurality of regions in the imaging apparatus of FIG. 1.

The focus detector 44 divides the image picked up by the image pickup device 20 into a plurality of areas as shown in FIG. 2, and performs a function of obtaining an autofocus value for each of the divided areas. The focus detector 44 may include an AF (auto focusing) detection circuit to obtain an auto focus value.

3 is a graph of auto focus values obtained for a specific region in the imaging apparatus of FIG. 1, and FIG. 4 is a graph of auto focus values obtained for a plurality of regions in the imaging apparatus of FIG. 1.

A conventionally known focusing technique can be used when the focus detector 44 detects auto focus for each area of the divided image, for example, a preset focus step as shown in FIG. 4. The autofocus value (AF evaluation value) can be acquired by driving a focus lens using. In other words, the focus position is calculated by moving the focus lens to extract high frequency components in the image signal and integrating the extracted signal. As the focus step is changed in one region, the graph of the AF evaluation value may be composed of a curve having one maximum value, and the maximum value of the AF evaluation value may be determined as the autofocus value.

The focus detector 44 obtains an autofocus value for each divided area of the image captured by the image pickup device 20 as shown in FIG. 4 (in FIG. 4, an example is performed for three areas for convenience. Referring to FIG. 4, it can be seen that the auto focus values obtained for each region may be different.

5 is an exemplary diagram illustrating an example of obtaining a weight of a specific pixel based on an autofocus value obtained for each region in the imaging apparatus of FIG. 1.

The weight calculator 46 calculates a weight for the pixels constituting each region by using the autofocus value for each region obtained by the focus detector 44. Various methods may be used to calculate the weight. In the present embodiment, as shown in Equation 1, the weight is calculated using an autofocus value of adjacent areas where pixels are located and an area from a pixel to an adjacent area. The weight was obtained.

Equation 1 is a weight 1, weight 2, weight of the center pixel of the areas 91, 92, 93, 94 obtained from the autofocus values of the adjacent areas 91, 92, 93, 94 of the pixel P in FIG. 3, the weight 4 of the pixel P can be obtained using the weight 4 and the areas a1, a2, a3, a4 from the pixels P to the regions 91, 92, 93, and 94.

Weight X = ((weight 1 x a4) + (weight 2 x a3) + (weight 3 x a2) + (weight 4 x a1)) / (a1 + a2 + a3 + a4)

The weight 1, weight 2, weight 3, and weight 4 are weights of the center pixels 91a, 91b, 91c, 91d of adjacent regions of the pixel P for which the weight is to be obtained, and the center pixels 91a, 91b, 91c, 91d. ) Is determined from the autofocus value of the regions. a1, a2, a3, and a4 are rectangular areas formed by the center pixels 91a, 91b, 91c, and 91d of adjacent areas from the pixel P for which the weight is to be obtained. When multiplying the weights of the center pixels 91a, 91b, 91c, and 91d by the area of the adjacent areas, the values located on the opposite sides of the diagonal lines are multiplied.

The image processing part 47 of FIG. 1 is a part which performs image processing by multiplying the weight of the pixels which make up the image picked up by the imaging element 20 by the image processing parameter for image processing.

In the image pickup device having the above-described configuration, the image processing unit 47 does not apply the same parameters to the entire image when performing the image processing, and image processing suitable for each pixel in consideration of the distance from the image pickup device to the subject. (Using the parameter multiplied by the weights), you get a clear image.

In addition, if necessary, image processing is performed to adjust the weight of the remaining portion of the entire image except for the subject area that is the subject of auto focus adjustment, that is, the background portion that is relatively far from the image pickup device, so that the image is more blurred than the subject. You can run Therefore, by using the imaging device of the above-described configuration, it is possible to implement more various image processing by applying different filter parameters for image processing for each pixel according to the distance to the subject.

6 is a flowchart showing steps of an image processing method according to an embodiment of the present invention.

The image processing method shown in FIG. 6 includes an imaging step (S100), a division step (S110) of dividing an image into a plurality of areas, and a distance calculation step (S120, S130) of calculating a distance from each area to a subject. ), A weight calculation step (S140) of obtaining weights of pixels constituting the image, and an image processing step (S150) of performing image processing on the pixels.

The imaging step S100 is a photoelectric conversion step in which the imaging device converts an image into an electrical image signal. The imaging step S100 may be applied to a photoelectric conversion device such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). Can be performed by

The dividing step S110 is a step of dividing the image picked up by the image pickup device into a plurality of regions as shown in FIG. 2.

The distance calculating steps S120 and S130 are operations for calculating a distance from each divided area to a subject, performing autofocus for each divided area (S120), and calculating an autofocus value (S130). It may include. Calculating the distance from each divided area to the subject may be implemented by various methods, but in this embodiment, a method of performing auto focusing on each area is used.

A conventionally known focusing technique can be used when detecting the auto focus for each area of the divided image in the step S120 of executing the auto focus. By adjusting the focus for each of the areas, an autofocus value representative of the focus state of the areas can be obtained. For example, an autofocus value (AF evaluation value) can be acquired by driving a focus lens using a preset focus step. Specifically, the focus position is calculated by moving the focus lens to extract high frequency components in the image signal and integrating the extracted signal.

As the focus step changes in one area, the graph of the AF evaluation value is composed of a curve having one maximum value. Therefore, in the auto focus value calculating step (S130), the maximum value of the AF evaluation value may be determined as the auto focus value. have.

The weight calculation step S140 is a step of obtaining weights of the pixels included in each of the divided regions, and is a preparation step for differently setting parameter values for image processing for each pixel in the image processing step.

In the weighting operation S140, the weight may be calculated by adding the autofocus values of the areas adjacent to the pixel for obtaining the weight and the values obtained by multiplying the area of a rectangle having a straight line diagonally connecting the centers of the areas adjacent to the pixel. . The present invention is not limited to this weight calculation method, and the weight can be obtained in various methods.

The image processing step S150 is a step of performing image processing on each pixel by multiplying the weight by an image processing parameter.

According to the image processing method described above, an image suitable for each pixel in consideration of the distance from the image pickup apparatus to the subject is not applied to the entire area of the image picked up by the image pickup device when performing image processing. Processing (using parameters multiplied by weights) is performed, so that a clear image can be obtained.

If necessary, image processing may be performed to adjust the weight of the remaining portion of the entire image except for the subject area that is the subject of auto focus adjustment, that is, the background portion that is located at a relatively long distance, so that the image is more blurred than the subject. . Therefore, using the image processing method of the above-described configuration, it is possible to implement a variety of image processing by applying different filter parameters for image processing for each pixel according to the distance to the subject.

Although the present invention has been described with reference to the above-described embodiments, these are merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the appended claims.

1 is a block diagram schematically illustrating components of an image pickup apparatus according to an embodiment of the present invention.

FIG. 2 is an exemplary diagram illustrating an example of dividing an image into a plurality of regions in the imaging apparatus of FIG. 1.

FIG. 3 is a graph of auto focus values obtained for a specific area in the imaging device of FIG. 1.

FIG. 4 is a graph of auto focus values obtained for a plurality of areas in the imaging device of FIG. 1.

5 is an exemplary diagram illustrating an example of obtaining a weight of a specific pixel based on an autofocus value obtained for each region in the imaging apparatus of FIG. 1.

6 is a flowchart showing steps of an image processing method according to an embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

10: optical system 42: drive circuit portion

11: zoom drive part 43: display control part

12: lenses 44: focus detector

13: focus driver 45: memory controller

15: memory 46: weight calculator

20: imaging device 47: image processing unit

30: display portions 91a, 91b, 91c, 91d: center pixels

40: control parts 91, 92, 93, 94: areas

41: image conversion unit

Claims (8)

An imaging step of imaging by the imaging device converting an image into an electrical signal for imaging; A dividing step of dividing an image represented by the electrical signal into a plurality of regions; A distance calculation step of calculating a distance to a subject for each of the areas; Calculating a weight of each pixel included in the areas according to the obtained distance; And And an image processing step of performing image processing on each of the pixels by multiplying the weights by an image processing parameter. The method of claim 1, And the distance calculating step includes an auto focus adjusting step of adjusting a focus on a plurality of the areas. The method of claim 2, And the auto focus adjusting step calculates an auto focus value representative of a focus state of the areas. The method of claim 3, And the auto focus adjusting step determines the maximum value of the high frequency component of the areas as the auto focus value. The method of claim 4, wherein The weight calculating step computes the weight by adding the values of the autofocus values of the regions adjacent to the pixel for obtaining the weight multiplied by the area of a rectangle with a diagonal line having a straight line connecting the centers of the regions adjacent in the pixel. Image processing method of the device. Imaging device; A focus detector for dividing the image picked up by the image pickup device into a plurality of areas to obtain an autofocus value for each area; A weight calculator configured to calculate a weight for each pixel of the image using the auto focus value; And And an image processing unit which multiplies the weight value of each pixel by an image processing parameter to execute image processing for each of the pixels. The method of claim 6, And said autofocus value obtained by said focus detector is a maximum value of high frequency components of a plurality of said areas. The method of claim 6, The weight obtained by the weight calculating unit is obtained by adding auto-focus values of the regions adjacent to the pixel for obtaining the weight by multiplying the area of a rectangle having a straight line diagonally connecting the centers of the regions adjacent to the pixel. An imaging device which calculates a weight.

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