KR101266919B1 - System for converting color of images cinematograph and method thereof - Google Patents

Abstract

The present invention relates to a color conversion system and a color conversion system, and more particularly, to a color conversion system and a color conversion system, A color data extracting unit for extracting color information of a color table included in the reference image, a color extracting unit extracting color information extracted from the color table included in the reference image, A control unit for detecting a change value in comparison with color information included in the original color table and generating a lookup table for converting the color of the color table included in the reference image into a desired color; And an image conversion unit for converting the color of the action image using the color characteristic When a captured image is input from two or more cameras, the application unit uses one of the cameras as a reference camera and corrects the images photographed by the other camera to the same color as the image photographed by the reference camera.

Shooting image, color reference plate image, action image, color conversion

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a color conversion system for a captured image,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color conversion system and a method thereof, and more particularly, to a system and a method for converting color of a photographed image.

Generally, as a digital camera is widely used, a method of calibrating a photograph taken with a digital camera is widely used. As a method of correcting a photographed image using a digital camera, there is a method of correcting a photographed image in a form desired by a user by using various programs for correcting a photographed image on a personal computer (PC) .

On the other hand, digital technology is being applied in various forms to the movie industry. For example, digital cameras are used to produce movies, and computer-based special effects are used.

In the case of such a movie, the film is shot over several months or years, and the shooting is done in various forms. Cinematography consists of a variety of scenes and cuts, and a movie is made by combining the sections separated by each scene and cuts. When making movies like this, even when using the same lighting and the same camera when shooting the same or similar gods or cuts, the difference in sunshine due to the difference in time may cause them to have different feelings, or the captured images may change to an undesired form .

This may cause similar problems not only in film shooting but also in TV production process, and also in CF shooting. Therefore, it is often the case that film directors, CF directors or producers of TVs must perform corrections on the generated images. In other words, if a color image captured by a camera needs to be corrected in a movie production, a CF shooting, or a TV production, the camera stores the image in a computer and performs color correction in the editing process.

However, in the case of these color corrections, each supervisor should depend only on his / her own view. Therefore, there is a problem that correction to an accurate color is difficult. In addition, at each photographing site, only the information about the scene displayed on the clapper board is photographed, but the color information which can be utilized as a reference of color correction in the future is not photographed. For this reason, since there is no color information that can be used as a reference, the color of the photographed image is a color that is completely independent of the image photographed by another camera . ≪ / RTI >

There are the following problems in order to correct these points. First, since each captured image needs to be corrected only by the visual sense of the director, an enormous amount of manual work is required. Secondly, there is a problem that lighting or color characteristics of a shooting site can not accurately reproduce colors suitable for other cameras.

Accordingly, the present invention provides a system and method for easily converting a photographed image into a desired color.

In addition, the present invention provides a system and method for correcting a photographed image to a desired accurate color.

In addition, the present invention provides a system and method for performing color correction so that an image photographed by a camera having different characteristics becomes an image photographed by a camera having one feature.

A system according to an embodiment of the present invention is a system for converting a color of a photographed image, the system comprising: a color characteristic applying unit for correcting a color of the photographed image according to a camera characteristic or a display characteristic, An image separator for separating an image from the color characteristic applying unit into a reference image and an action image including a color table; a color data extracting unit for extracting color information of a color table included in the reference image; A lookup table for detecting a change value by comparing the color information extracted from the color table included in the reference image with the color information included in the original color table and converting the color of the color table included in the reference image into a desired color, And a control unit for converting the color of the action image using the generated lookup table Wherein the color characteristic applying unit uses one camera as a reference camera when the images photographed from two or more cameras are inputted and corrects the images photographed by the other camera to the same color as the image photographed by the reference camera, do.

A method according to an embodiment of the present invention is a method for converting a color of a photographed image, the method comprising: applying a color characteristic to correct the color of the photographed image according to a camera characteristic or a display characteristic, process; Separating the image corrected in advance in the application of the color characteristic into a reference image including a color table and an action image; Extracting color information of a color table included in the reference image; Comparing the color information extracted from the color table included in the reference image with the color information included in the original color table to detect the degree of change; Generating a lookup table for transforming the color of the color table included in the reference image according to the detected change and input color information; And converting the color of the action image using the generated lookup table, wherein the color characteristic application process includes the steps of: when one of the cameras is input as a reference camera, Is corrected to the same color as the image captured by the reference camera.

Using the system and method according to the present invention, it is possible to facilitate correction of each image photographed by the camera, and to correct the image photographed at another time on the same day, can do.

Further, by using the system and the method according to the present invention, it is possible to more easily correct each image, thereby shortening the time required for correction after photographing and reducing the cost required for correcting the photographed image have.

Hereinafter, the present invention will be described with reference to the accompanying drawings. In describing the present invention, portions obvious to those skilled in the art will be omitted so as not to disturb the gist of the present invention. Also, it is to be understood that the following terms are used only to facilitate the understanding of the present invention, and that each manufacturer, research group, or supervisor of the scene shooting the image may be used in different terms, Should be.

First, the present invention will be briefly described. In the present invention, when a clapper board is used, an image is captured using a clapper board having a color reference board. Thereafter, using the color of the color reference plate included in the clapper board, the color of the subsequently captured images is corrected using a computer or the like. At this time, the photographed images can be applied to different digital cameras, or to images taken by different analog cameras or digital cameras and analog cameras.

The correction system according to the present invention performs the following operations.

First, the color of the image photographed together with the color reference plate is transformed to match the user's desired illumination environment using the color information colorimetrically measured from the color reference plate under specific illumination.

Second, since the characteristics of the color are different when the manufacturer or the model of the camera is different, the color of the image photographed by any specific camera is converted into the color of the image corresponding to the color characteristic of the camera desired by the user.

Third, by adjusting the color, brightness, and saturation of the color of the image taken with the color reference plate, it is converted into the color desired by the director or producer.

Fourth, the color of the B view image photographed at the photographing point B is automatically converted into the color of the A view image photographed at the photographing point A.

First, in the present invention, as described above, the scene display panel and the color reference panel are sequentially photographed first in the imaging start step of each scene, and then the action scene is taken immediately thereafter. The recorded images are stored in the studio's computer. At this time, the image is separated into a color reference plate image (reference image) and an action image. And displays the separated color reference plate image and action image on the monitor screen. Then, color data is extracted from the reference plate image portion.

Then, the user inputs the color information and the difference between the photographed color reference plate image and the previously stored color, and transmits the color data to the CIE (Commission Internationale de l'Eclairage) L * a * b * color space, and generates a three-dimensional look-up table for the converted data. The lookup table thus generated is applied to the action image stored in the action image storage unit to perform coordinate transformation, and the coordinate-transformed image is stored in the transformed image storage unit, thereby converting the image into a desired image.

First, a clapper board generally used when photographing a movie, a CF, a TV, or the like will be described with reference to FIG.

1, the clapper board 100 includes a region 101 describing a scene number, a region 102 describing a cut (CUT) number, a region 103 describing a take (TAKE) An area 106 for describing a roll number, an area 107 for describing a director, an area 108 for describing a cameraman, . These areas are intended to describe the elements necessary for photographing. In some cases, only necessary parts may be described, and the remaining parts may not be described.

However, the clapper board 100 shown in FIG. 1 is not made in a form that can confirm the color, but is merely composed of black and white. Therefore, it is impossible to confirm a change in color due to illumination or natural light, that is, a change in color, illuminance, brightness or the like, or a change in color, illuminance, or brightness depending on the characteristics of the camera. Accordingly, the present invention proposes a clapper board as shown in FIG.

2 is a view illustrating a clapper board according to an embodiment of the present invention.

The clapper board 200 according to an embodiment of the present invention is provided with a hue plate 210 at the lower end of a generally used clapper board 100. This color plate 210 has several columns of reference colors, and portions 211 and 212 of each column correspond to one color. Although the clapper board 200 according to the embodiment of FIG. 2 is attached to the lower end of the generally used clapper board 100, it may be attached to the upper end, left or right side, You can also use one of them. That is, in the present invention, a general clapper board 100 is further provided with a color table (color plate).

3 is a diagram illustrating a color table according to the present invention.

In FIG. 3, each of the columns 310, 320, 330, 340, 350, 360 represents a predetermined change in hues. For example, white is located at the bottom of the first column 310, and black is located at the bottom of the last column 360. In the first column 310, the color change of the red color series is displayed. In the second column 320, the color change of the green color series is shown. In the third column 330, The fourth column 340 shows color changes of the sky blue series, the fifth column 350 shows the purple color variation, and the last column 360 shows the yellow color variation. Respectively. Such a color change may be realized in colors that can detect a change according to color, illumination, camera characteristics, etc. in the system according to the present invention. Therefore, the configuration of such a color conversion table is not specifically defined as six columns, and may have fewer or more color columns as required, and the color conversion column may be set to a smaller number of values or a larger number of variations have.

4 is a diagram illustrating a three-dimensional look-up table of a color conversion table according to the present invention.

In FIG. 4, reference numeral 400 denotes a direction indicating a change in red color, and R denotes a red color. In addition, reference numeral 410 denotes a direction indicating a change in blue, and B on the left denotes blue. Reference numeral 420 denotes a direction indicating a change in green, and G at the bottom indicates green. It is all three primary colors of light, allowing you to see the degree of color change in coordinates by the combination of each light.

An example of measuring the degree of color change with the coordinates will be described with reference to FIG.

FIG. 5 is a diagram for explaining an example of mapping the color table of FIG. 3 to the three-dimensional lookup table of FIG.

The hues of the color table of FIG. 3 described above may be respectively mapped to the three-dimensional lookup table described in FIG. A more detailed description will be given using coordinates not described in FIG. In FIG. 4, the coordinate (0, 0, 0) means black. That is, it is mapped as 502 in FIG. This is the case where all RGB values are not present in FIG. If all the RGB values are present, the result is white. Therefore, in FIG. 4, the coordinates (255, 255, 255) become white. Such coordinate conversion can be performed by coordinate conversion as indicated by reference numeral 501. [ Thus, each of the colors shown in FIG. 3 has a specific value of RGB, which can be mapped to the coordinates of FIG. 4 one by one.

In FIG. 4, each coordinate is divided into 256 coordinates for each axis. This means 2 ⁸ when expressed in binary to facilitate detection of digital changes. Thus, these coordinates can be expressed in more or fewer numbers as needed.

Hereinafter, an example of a system for performing color conversion of a photographed image according to the present invention will be described with reference to the accompanying drawings.

First, it should be noted that the images according to the present invention are pictures set in advance using a clapper board 200 having a color table according to the present invention as described above.

6 is a functional block diagram of a system for color conversion of a photographed image according to an embodiment of the present invention.

The original image captured by the camera including the clapper board 200 having the color table according to the present invention is input to the color characteristic application unit 601. The color characteristic applying unit 601 transforms the color characteristic to match the characteristic of the device that captured the image or converts the color characteristic to match the characteristic of the camera other than the currently measured device. In this case, when two or more images captured by the camera are input, one camera can be used as a reference camera and the images photographed by the other camera can be corrected to the same color as the image captured by the reference camera. The color characteristic applying unit 601 may be adapted to convert a color image to match a specific characteristic, or may be applied to an image to be initially input so as to have no characteristic. In addition, a value for correcting the color image may be input to the color characteristic applying unit 601 to express an accurate color according to the characteristics of the monitor on which the input captured image is displayed. That is, a value for correcting a specific degree of color change depending on the characteristics of the monitor may be set in advance. As described above, the color characteristic applying unit 601 can apply the color correction value according to the color characteristics of the photographed equipment and / or the monitor to the input image, if necessary.

In the above-described manner, the color correction unit 601 applies the corrected color image or the uncorrected image to the image separator 602. The image separating unit 602 separates and separates the photographed image portion of the clapper board 200 according to the present invention from the actually required image portion. The separation performed by the image separation unit 602 may be mechanically separated, or may be separated by sequentially reviewing a screen input by a user. (For example, a clapper board according to the present invention) exists for a predetermined time (for example, the first 2 seconds to 10 seconds range) using the degree of change of the image when mechanically separated, It is possible to constitute such that the image is divided into images having no determined shape. Accordingly, the image separated by the image separating unit 602 is divided into an action image for sending the image to a real film, CF or TV, and a color reference plate image having the clapper board 200 according to the present invention. Hereinafter, an image to be transmitted to an actual movie or CF or TV is referred to as an action image, and an image having the clapper board 200 according to the present invention is referred to as a color reference plate image (i.e., reference image).

The color reference plate image of the image separated by the image separating unit 602 according to the present invention is input to the color data extracting unit 604 and the action image is input to the first memory 605. [

First, the action image separated by the image separating unit 602 is input to the first memory 605 and stored. At this time, the action image may store two or more images, and each image may be an image captured by one camera or an image captured by a different camera. Each of the images stored in the first memory 605 may be displayed on the display unit 603 under the control of the control unit 611, which will be described later, or one or more action images.

Next, the color data extracting unit 604 extracts the color data from the color reference plate image. That is, the color information (color information) of the color plate 210 included in the clapper board 200 according to the present invention is converted into a digital value as described with reference to FIGS. 3 to 5, and is provided to the controller 611. In this case, when the input image is sequentially plural images, that is, images taken at different times or images taken by different cameras, the color plate 210 of the clapper board 200 according to the present invention is provided , Reads the color information of each color plate 210, converts the color information into digital values as described above, and provides the digital values to the controller 611.

The display unit 603 displays an action image input from the image or image separator 602 provided from the first memory 605.

The color memory (color memory) 612 stores reference color information (reference color information) of the color plate 210 included in the clapper board 200 according to the present invention. In the following description, the reference color information refers to information obtained by mapping the color information of the color plate as shown in Figs. 3 to 5. That is, it means information on an original color that is not a color photographed by a camera using an illumination or the like. In addition, the color memory 612 further includes an area in which a lookup table generated when a lookup table for color conversion is generated in the control unit 611 can be stored.

The input unit 613 is an input interface device of a user, and includes all devices capable of inputting user-desired information in various manners such as a keyboard, a mouse, a joystick, and a touch screen.

The control unit 611 controls the color conversion of the action image stored in the first memory 605 based on the information input from the input unit 613. [ That is, when the color data extracting unit 604 provides the color information corresponding to each color of the color plate 210 included in the clapper board 200 as digital information, the control unit 611 inputs the color information from the color memory 612 The degree of change with respect to the reference color information is checked. When a color change value according to a user's desired condition is further input, the controller 611 applies a conversion value to the color change value to generate a lookup table for color conversion.

Generation of the lookup table in the control unit 611 will be described in further detail. As described above, the color conversion has a three-dimensional color conversion value as described with reference to Figs. 3 to 5. Here, a calculation process for performing coordinate transformation of an image using a lookup table generated in the CIE L * a * b * color space will be described in detail.

The lookup table used for the coordinate transformation can apply a method of increasing the accuracy of the gray scale by making the steps of the L * axis and the a * b * axis different from each other. Also, the three axes of L *, a * The same steps may be applied to generate a look-up table.

The lookup table generated by the control unit 611 can be stored in the color memory 612 and is provided to the image conversion unit 606. [

The image converting unit 606 converts the color coordinates of the action images stored in the first memory 605 based on the lookup table provided from the controller 611 and converts the color coordinates into a desired image color.

The process performed by the image converting unit 606 will be described in more detail as follows. The RGB information of the pixel is sequentially read out for the taken action image stored in the first memory 605 and the position on the lookup table corresponding to the RGB value of the pixel is calculated by a trilinear interpolation method . Next, for the lookup table generated from the colorimetric data, the CIE L * a * b * value stored at the position on the lookup table corresponding to the pixel RGB value of the action image calculated by the above method is read. Next, the CIE L * a * b * values read from the lookup table are subjected to color space conversion using RGB color values used in the monitor.

By performing the above method on all the pixels of the input image, the coordinate conversion operation for the photographed image is completed.

The image converted by the image converting unit 606 is stored in the converted image storage unit 607 and provided to the display unit 603. [

7 is a flow chart of color correction of an image in the system according to the present invention. Hereinafter, the flow of color correction according to the present invention will be described with reference to FIGS. 6 and 7. FIG.

The color characteristics are applied by the color characteristic application unit 601 to the respective images captured and input in operation 700. The color characteristic applying unit 601 applies the color characteristic to the image separating unit 602 in step 702 and separates the color reference plate image into an action image. In step 704, The control unit 611 generates a lookup table for correction based on the change of the color plate 210 and the information input by the user. The lookup table thus generated is provided to the image conversion unit 606.

The image converting unit 606 performs color correction using the lookup table for correcting the color of the action image stored in the first memory 605 in step 708. [ In step 710, the color-corrected image is stored in the converted image storage unit 607.

The present invention described above can be summarized as follows.

The standard colors of the color reference plate are first photographed at the beginning of the shooting of each scene, and then the action scenes are taken immediately, and the photographed images are stored in the computer of the studio. Then, the separated color reference plate image and action image are displayed on the monitor screen, and the user can generate the changed color information by receiving the desired conversion information. Alternatively, the color information of the color reference plate image B of the B view image photographed at the photographing point B is generated based on the color reference plate image A of the A view image photographed at the photographing point A.

After the color reference plate image matched with the selected color information is extracted and displayed from the color reference plate image database, the color data matching the color reference plate image is extracted from the colorimetry data storage unit.

Dimensional lookup table is generated after extracting from the colorimetric data storage unit and a 3-dimensional lookup table is generated for the color data extracted from the color reference plate image by the same method. Then, for each pixel of the action image, two lookup tables The CIE L * a * b * values for the corresponding coordinates on the coordinates are calculated using a trilinear interpolation method.

The method for generating the lookup table from the colorimetric data first calculates the average value of RGB for each patch of the colorimetric data, and then converts the calculated RGB value into CIE L * a * b * color space. Using the converted L * a * b * value, the value of the lookup table is filled as shown in FIG. At this time, a value corresponding to one point of the lookup table is stored as the L * a * b * value for the patch.

Among the values thus calculated, the CIE L * a * b * value calculated using the lookup table generated from the colorimetric data storage unit is automatically converted into a color desired by the user by performing color space conversion using RGB values used in the monitor .

8 is a functional block diagram of a system for color conversion according to another embodiment of the present invention.

Referring to FIG. 8, the captured image storage unit 800 is a portion in which the captured image of FIG. 6 is input. The color characteristic application unit 801 of the apparatus corresponds to the color characteristic application unit 601 of FIG. The image separating unit 802 corresponds to the image separating unit 602 of FIG. The image separator 602 may include an action image storage unit 803 for storing an action image, and a reference plate image storage unit 804 for temporarily storing a color reference plate image. The image display unit 806 corresponds to the display unit of Fig. The color data extracting unit 805 of FIG. 8 corresponds to the color data extracting unit 604 of FIG. The color reference plate image and the colorimetric data storage unit 808 correspond to the control unit 611 and the color memory 612. The color information input unit 807 corresponds to the user input unit 613 and the lookup table generating unit 809 can be regarded as a functional block of the control unit 611 shown in FIG. The lookup table recording unit 810 corresponds to a part of the color memory 612 described above. The image coordinate conversion unit 811 corresponds to the image conversion unit 606 and the converted image storage unit 812 corresponds to the converted image storage unit 607 of FIG.

Since the system configuration of Fig. 8 can be confirmed from the above correspondence, it will not be described in detail here.

While the present invention has been particularly shown and described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And falls within the scope of the invention.

FIG. 1 is an example of a clapper board generally used when photographing a movie, a CF or a TV,

FIG. 2 illustrates a clapper board according to an embodiment of the present invention. FIG.

3 is a diagram illustrating a color table according to the present invention,

FIG. 4 illustrates a three-dimensional look-up table of a color conversion table according to the present invention,

FIG. 5 is a diagram for explaining an example of mapping the color table of FIG. 3 to the three-dimensional lookup table of FIG. 4;

6 is a functional block diagram of a system for color conversion of a photographed image according to an exemplary embodiment of the present invention.

FIG. 7 is a flow chart of image color correction in the system according to the present invention,

8 is a functional block diagram of a system for color conversion according to another embodiment of the present invention.

Claims (13)

A system for converting color of a photographed image, A color characteristic application unit for previously correcting the color of the photographed image according to a camera characteristic or a display characteristic or a camera characteristic and a display characteristic, An image separation unit for separating the image from the color characteristic application unit into a reference image and an action image including a color table, A color data extracting unit for extracting color information of a color table included in the reference image, A lookup table for detecting a change value by comparing the color information extracted from the color table included in the reference image with the color information included in the original color table and converting the color of the color table included in the reference image into a desired color, And a control unit And an image converting unit converting the color of the action image using the generated lookup table, Wherein the color characteristic application unit comprises: Wherein when one of the cameras is used as a reference camera, images photographed by another camera are corrected to the same color as that of the image photographed by the reference camera. The method according to claim 1, A color memory for storing original color information to be provided to the controller, Wherein the color conversion system further comprises: The method according to claim 1, An input unit for receiving user's request information for color conversion and providing the received request information to the control unit Wherein the color conversion system further comprises: delete delete The method according to claim 1, A converted image storage unit for storing the action-corrected color image in the image conversion unit, Wherein the color conversion system further comprises: A method for converting a color of a photographed image, A color characteristic applying process of previously correcting the color of the photographed image according to a camera characteristic or a display characteristic or a camera characteristic and a display characteristic; Separating the image corrected in advance in the application of the color characteristic into a reference image including a color table and an action image; Extracting color information of a color table included in the reference image; Comparing the color information extracted from the color table included in the reference image with the color information included in the original color table to detect the degree of change; Generating a lookup table for transforming the color of the color table included in the reference image according to the detected change and input color information; And And converting the color of the action image using the generated lookup table, The color characteristic application process may include: A method of color conversion of an image, wherein when an image photographed from two or more cameras is input, one of the cameras is used as a reference camera and images photographed by another camera are corrected to the same color as the image photographed by the reference camera. 8. The method of claim 7, And displaying the reference image and the action image And converting the image into a color image. delete 8. The method of claim 7, The process of displaying the color-converted action image And converting the image into a color image. delete 8. The method of claim 7, The process of storing the color-converted action image And converting the image into a color image. 8. The method of claim 7, The process of storing the generated lookup table And converting the image into a color image.

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