KR100908118B1 - Method for generating illumination charateristic data around image disaplay - Google Patents

Abstract

The present invention relates to a method for generating illumination characteristic data around an image display apparatus, wherein the illumination characteristic data generating method includes illumination characteristic data including at least one of color temperature values of illumination light and coordinate values of chromaticity coordinate system of illumination light. Generating a representative type block; And generating brightness characteristic data into brightness blocks representing brightness information of illumination light corresponding to numerical brightness values expressed in units of Lux.

According to the present invention, the color characteristics of the first input image can be reproduced in the output image of the image display apparatus, and the illumination characteristic data structure can be expressed in a universally compatible data form, so that the image can be wired / wirelessly to various image display apparatuses. It can be widely used to perform color shift compensation for lighting effects in the supplying service system.

Description

Method for generating illumination characteristic data around image display device {Method for generating illumination charateristic data around image disaplay}

1 is a block diagram showing the configuration of an illumination characteristic data generating apparatus.

2 is a flowchart illustrating a method of generating lighting characteristic data according to the present invention.

3 is a conceptual diagram illustrating a format of illumination characteristic data according to the present invention.

4 is a block diagram illustrating a configuration of a color shift compensation device.

FIG. 5 is a block diagram illustrating a configuration of the illumination characteristic data unit of FIG. 4.

6 is a block diagram illustrating a configuration of the color shift compensation unit of FIG. 4.

FIG. 7 is a flowchart illustrating a color shift compensation method of applying color characteristic data generated by an apparatus and a method for generating light characteristic data to compensate for color shift with respect to lighting effects.

8 illustrates a mapping table for a transformation relationship between semantic and numeric values.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image processing, and more particularly, to a method of generating illumination characteristic data around an image display apparatus.

Conventional color image reproduction methods include device independent color processing methods based on the characterization of color input / output devices. This is based on the device characterization method of setting the relationship between the device color signal and the standard color signal of the color input / output device. Using this method, colorimetric color matching between the input image and the displayed image can be achieved. As described above, there are many methods for visually matching the color characteristics of the image displayed on the image display apparatus with the color characteristics of the first input image or visually improving the color characteristics of the displayed image. However, since these methods do not consider the influence of the illumination light around the image display device, if the lighting characteristics of the place where the image display device is located may not be intended to achieve the intended color matching or visual improvement.

In addition, although the types and locations of video display apparatuses used by the same user are almost limited in the past, the types and places of use of the apparatuses are gradually diversified due to the development of wired / wireless networks. In addition, if the image display apparatus cannot perform the compensation conversion function, the image must be converted in advance on the service device / device that supplies the image to the display apparatus and then transferred to the display apparatus. At this time, the lighting characteristic information that is the input of the transformation should be delivered to the image supply device / device, and the lighting characteristic information transmitted is preferably displayed in a general data structure such as XML.

SUMMARY OF THE INVENTION The present invention provides a method for generating illumination characteristic data around an image display apparatus, which may acquire and record characteristics of an illumination environment around the image display apparatus when an image is displayed on an image display apparatus used by a user. To provide.

According to the present invention for achieving the above technical problem, the method for generating illumination characteristic data around an image display apparatus includes illumination characteristic data including at least one of color temperature values of illumination light and coordinate values of chromaticity coordinate system of illumination light. Generating a representative type block; And generating brightness characteristic data into brightness blocks representing brightness information of illumination light corresponding to numerical brightness values expressed in units of Lux.

Hereinafter, a method of generating illumination characteristic data around an image display apparatus according to the present invention will be described in detail with reference to the accompanying drawings. 1 is a block diagram showing the configuration of an illumination characteristic data generating apparatus. 2 is a flowchart illustrating a method of generating lighting characteristic data according to the present invention. The illumination characteristic data generating apparatus includes an illumination characteristic acquisition unit 100 and an illumination characteristic data generation unit 150.

The illumination characteristic acquisition unit 100 acquires illumination characteristic data around the image display apparatus (step 220), and includes at least one of the user interface unit 10 and the measurement sensor 20.

The user interface unit 10 provides an interface that can directly obtain the characteristics of the lighting environment from the user. The measurement sensor 20 obtains illumination characteristic data through a measurement sensor such as a radiometer attached to the image display device or positioned around the image display device.

Lighting characteristic information obtained from the user interface unit 10 is composed of the following semantic information. First, the illumination characteristic data includes information on the type of illumination and information on the brightness of the illumination. The information on the type of illumination is one of an incandenscene, a fluorescent lamp, daylight, and skylight. The information about the brightness of the illumination is one of four levels: dark, dim, bright and very bright.

The illumination characteristic information obtained from the measurement sensor 20 is composed of information on the type of illumination and information on the brightness of the illumination, and consists of the following numerical values. The information on the type of illumination light is composed of at least one of a color temperature value of the illumination light and a coordinate value of the chromaticity coordinate system of the illumination light. The color temperature refers to a color temperature value of the illumination light, and the expression of the color temperature value may be represented by 8 bits according to the data representation of the color temperature descriptor defined in ISO / IEC 15938-3. The coordinate value of the chromaticity coordinate system refers to the coordinate value in the xy chromaticity coordinate system of the illumination light represented by (x, y), where the xy chromaticity coordinate system uses a two-chromatic coordinate system defined from the CIE1931 tristimulus coordinate model. Can be. The information on the brightness of the illumination light of the illumination light is a numerical value for the brightness of the illumination, preferably expressed in units of Lux.

The illumination characteristic acquisition unit 100 that obtains the illumination characteristic data may output the data as it is or convert the data acquired by the user interface unit 10 into data acquired by the measurement sensor 20 and output the same. Can be. On the contrary, the data acquired by the measurement sensor 20 may be converted into data obtained by the user interface unit 10 and output. Conversion between the data acquired by the interface unit 10 and the data obtained by the measurement sensor 20 can be realized using a mapping table as shown in FIG. 8. The color temperature value and chromaticity coordinate value can be approximately converted using a daylight locus curve drawn in the chromaticity coordinate system.

There are various methods of acquiring the color temperature and chromaticity coordinate information of the illumination light from the signal output from the measurement sensor 20. As an example, the method of acquiring color temperature and (x, y) coordinates is as follows. First, when the signal output from the measurement sensor 20 is an RGB value for a plurality of pixels, the pixels corresponding to the lighting components are estimated and selected to obtain their average RBG values, and then the corresponding xy chromaticity coordinate system from the RGB coordinate values. You can calculate the (x, y) coordinates or color temperature of the phase. In addition, when the signal output from the measurement sensor 20 is a single RGB value, the (x, y) coordinate or color temperature on the corresponding x-y chromaticity coordinate system can be calculated directly from the RGB coordinate value.

Meanwhile, in FIG. 1, the illumination characteristic data generation unit 150 converts the illumination characteristic data obtained from the user interface unit 10 or the measurement sensor 20 into a type block indicating information on the type of illumination light and the brightness of the illumination light. A data block is generated in a data format including brightness blocks representing information about the data. (Step 250) FIG. 3 is a conceptual diagram illustrating a format of lighting characteristic data according to the present invention. And brightness block 350.

The type block of the data format includes a flag 310 and a type payload 320. The flag 310 indicates whether the data in the type payload 320 is the color temperature value 322 or the chromaticity coordinate value 324. In addition, when the flag 310 is extended, the flag may indicate whether the data in the type payload 320 is semantic information 326 regarding the type of lighting. When the flag 310 indicates semantic information, the semantic information preferably indicates any one of incandescent, fluorescent, daylight, and skylight data.

The flag 310 may have values of 0, 1, 2, and 3. When the flag is '0', the data in the type payload 320 represents the color temperature value 322 and is 8 bits according to the data representation of the color temperature descriptor defined in ISO / IEC 15938-3. Can be expressed by quantization.

If the flag 310 is '1', the data in the type payload 320 represents an x-y chromaticity coordinate value 324, and each coordinate value has a range of [0,1]. The coordinate value may be expressed in bits corresponding to MPEG7: ZeroToOneType as defined in ISO / IEC 15938-5.

If the flag 310 is '2', the data in the type payload 320 is semantic information 326. In addition, if the semantic information 326 is '0', it indicates incandescent lamp, '1' indicates fluorescent lamp, '2' indicates daylight, and '3' indicates skylight.

The brightness block 350 of the data format represents data representing a numerical value in lux units. However, if the brightness block of the data format is extended and represented, it may be composed of a flag (Flag) 360 and a brightness payload (370). In this case, the flag 360 of the brightness block of the data format indicates whether the data in the brightness payload 370 is a numerical value 372 or a semantic value 374. If the flag 360 is information representing a numerical value, the brightness payload 370 may use a numerical value 372 in a lux unit, and if the flag indicates information representing a semantic value 374, 'dark'; It has data representing any of 'dim', 'bright' and 'very bright'. If the flag 360 is '0', the data in the brightness payload 370 represents a numerical value 372 in the Lux unit, and the numerical value 372 is a W3C Recommendation 02-May-2001. It can be expressed as a data type corresponding to the nonNegativeInteger data type according to the XML schema defined in this section. If the flag 360 is '1', the data in the brightness payload 370 represents a semantic value 372. 'Blank' if the semantic value 372 is '0', 'dim' if the semantic value is '1', 'bright' if the semantic value 372 is '2', the semantic If the value 372 is '3', it indicates 'very light'.

The expression format of the data format generated by the above-described lighting characteristic data generation unit 150 may be expressed as xml data according to xml-schema as follows.

1.Syntax for IlluminationCharacterics

<!-############################################## ##->

<!-Definition of IlluminationCharacteristics->

<!-############################################## ##->

<complexType name = "IlluminationCharacteristicsType">

  <complexContent>

    <extension base = "dia: NaturalEnvironmentCharacteristicsBaseType">

<sequence>

          <element name = "TypeOfIllumination" minOccurs = "0">

<complexType>

<sequence>

<choice>

<element name = "ColorTemperature"

type = "mpeg7: unsigned8" />

<element name = "Chromaticity">

<complexType>

<sequence>

<element name = "x" type = "mpeg7: zeroToOneType" />

<element name = "y" type = "mpeg7: zeroToOneType" />

</ sequence>

</ complexType>

</ element>

</ choice>

</ sequence>

</ complexType>

</ element>

               <element name = "Illuminance" type = "nonNegativeInteger" minOccurs = "0" />

</ sequence>

</ extension>

</ complexContent>

</ complexType>

2. Semantics for IlluminationCharacterics

IlluminationCharactericsType describes the overall illumination characteristics of the natural enviornment.

TypeOfIllumination describes the type of total illumination.

ColorTemperature refers to the correlated color temperature of the entire light. The representation of the value is obtained by quantizing the range of [1667,25000] to 8 bits in a non-uniform manner as specified in ISO / ECE 15938-3.

Chromaticity refers to the chromaticity of the entire light. x points to the x coordinate of the overall illumination in the chromaticity coordinate system and y points to the y coordinate. And the range of the coordinate value is [0,1].

Illuminance describes the brightness of the entire light in Lux units.

3. Example of IlluminationCharacterics

<DIA>

  <Description xsi: type = "UsageEnvironmentType">

      <UsageEnvironment xsi: type = "NaturalEnvironmentsType">

          <NaturalEnvironment xsi: type = "NaturalEnvironmentType">

<NaturalEnvironmentCharacteristic xsi: type =

"IlluminationCharacteristicsType">

<TypeOfIllumination>

<ColorTemperature> 159 </ ColorTemperature>

</ TypeOfIllumination>

<Illuminance> 500 </ Illuminance>

</ NaturalEnvironmentCharacteristic>

           </ NaturalEnvironment>

      </ UsageEnvironment>

   </ Description>

</ DIA>

The illumination characteristic data generated according to the present invention can be used as an input to the color shift compensation device. Next, a color shift compensation apparatus and method for compensating color shift for lighting effects by applying the lighting characteristic data generated by the method and apparatus for generating light characteristic data according to the present invention will be described. The chromaticity value of the illumination light and the brightness of the illumination light are input, and the degree of visual color shift of the image output to the image display device is predicted by the coordinates of the chromaticity space. By performing the disparity compensation transformation on the input image using the predicted disparity coordinate value and displaying the disparity compensation transformation on the display device, the influence of the illumination light can be canceled, so that the intended color characteristics of the input image can be reproduced.

4 is a block diagram illustrating the configuration of the color shift compensation device, and includes an illumination characteristic data unit 450 and a color shift compensation unit 400. In addition, according to a situation to which the present invention is applied, the image display unit 490 may be further provided.

The illumination characteristic data unit 450 is the same as the above-described illumination characteristic data generating apparatus, and includes an illumination characteristic acquisition unit 500 and an illumination characteristic data generation unit 550 as shown in FIG. And generating and outputting illumination characteristic data around the image display device having a data format consisting of the brightness blocks. If the data on the illumination characteristic has already been obtained, the illumination characteristic data unit 450 may be configured by only the illumination characteristic data generation unit 550.

The illumination characteristic acquisition unit 500 detects a user interface unit 50 and an actual illumination characteristic obtained directly from a user through a user interface in order to obtain illumination characteristic data regarding the type and brightness of illumination light around the image display apparatus. At least one of the measurement sensor 55 to measure by a numerical value.

The illumination characteristic data generator 550 generates the obtained illumination characteristic data in a data format including a type block representing information on the type of illumination light and a brightness block representing information on brightness of the illumination light.

The type block of the data format includes a flag indicating whether data in a type payload is a color temperature value or a chromaticity coordinate value, and a color temperature value if the flag is information representing a color temperature value, and a chromaticity coordinate value if the flag is information representing a chromaticity coordinate value. It contains a type payload indicating either. The brightness block of the data format represents a numerical value representing the brightness of the illumination.

In addition, the flag of the type block of the data format may further include information indicating whether data in a type payload is color temperature value, chromaticity coordinate value, or semantic information about an illumination type, wherein the flag is semantic information. The type payload indicates any one of incandescent light, fluorescent light, daylight, and skylight data.

The brightness block of the data format may have an embodiment consisting of a flag and a brightness payload. In this case, the flag indicates whether the data in the brightness payload is a numerical value or a semantic value, and the brightness payload is a numerical value in units of lux if the flag is information indicating a numerical value, and the flag is a semantic value. If the information indicates 'blink', 'dim', 'bright', 'very bright' any one.

The color shift compensator 400 analyzes the illumination characteristic data generated by the illumination characteristic data unit 450 with respect to the input image to compensate for the color shift according to the type of illumination and the brightness of the illumination, and analyzes the illumination characteristic data. The unit 600 includes a color temperature converter 610, a numerical converter 620, and a color shift adjuster 650.

The illumination characteristic data analyzer 600 analyzes the illumination characteristic data and decomposes the type block data and the brightness block data.

The color temperature converter 610 converts the type block data decomposed by the illumination characteristic data analyzer 600 into color temperature values. When the type block data has (x, y) coordinates, the type block data is converted into color temperature values by a method according to Korean Patent Application No. 1999-50596. When the type block data is a semantic value, it is converted into a color temperature value using a mapping table of FIG. 2.

When the brightness block data decomposed by the illumination characteristic data analyzer 600 is a meaningful value, the numerical conversion unit 620 converts the numerical value into a numerical Lux by a mapping table shown in FIG. 2. In the case of dark, the upper limit of the region may be taken, in the case of very bright, the lower limit of the region may be taken.

The color shift adjusting unit 650 converts the input image itself or adjusts the color temperature and brightness characteristics of the image display device to correspond to the numerical values for the color temperature and brightness of the illumination characteristic data, and the color temperature compensator 60 and the color brightness compensator. 65 is provided.

The color temperature compensator 60 converts the input image itself or increases the color temperature value of the displayed image when the color temperature value of the illumination is higher than the currently set illumination color temperature value or the color temperature value recommended for the image display device. Adjust the color temperature display characteristics of the display device. The color temperature compensator 60 converts the input image itself or displays an image to reduce the color temperature value of the displayed image when the color temperature value of the illumination is lower than the currently set illumination color temperature value or the color temperature value recommended for the image display device. Adjust the color temperature display characteristics of the device.

An example of a method of increasing or decreasing the color temperature of the input image itself is briefly described as follows. The difference between the preset reference color temperature and the variation of the reference color temperature due to illumination is calculated in consideration of the characteristics of the image display device. The difference between the input color temperature and the reference color temperature of the input image is estimated. The target color temperature is determined according to the ratio between the two calculated color temperature differences. The color temperature conversion coefficient for converting the color temperature of the input image to the target color temperature is calculated. The RGB matrix value of the final output image is obtained by multiplying the RGB matrix of each pixel of the input image by the calculated transformation matrix by the color temperature conversion coefficient. An example of a method of estimating a color temperature of an input image is to determine pixels corresponding to lighting components in an input image, obtain their average RGB values, calculate chromaticity coordinates corresponding to the values, and then calculate the same color temperature closest to the coordinates. The point on the curve is obtained and the color temperature of this point is set as the color temperature of the input image.

The color brightness compensator 65 adjusts the input image itself so that the brightness value of the displayed image is increased when the lux value of the illumination is higher than the currently set illumination lux value or the recommended illumination lux value for the image display device. Or adjust the brightness characteristics of the video display device. In addition, the color brightness compensator 65 converts the input image itself so that the brightness value of the displayed image is reduced when the illumination lux value is lower than the currently set illumination lux value or the recommended illumination lux value for the image display device. Adjust the brightness characteristics of the video display device.

The brightness of the displayed image may be adjusted in the following manner. First, the Y value of the YCbCr color coordinate is calculated from each pixel of the image to be displayed, and the Y value of each pixel is input to a mapping function such as a Sigmoidal function to obtain new Y's, and then newly calculated. Converted Y'CbCr to original color coordinates. In addition, the brightness of the image can be adjusted by other existing methods.

In the case of changing the color temperature and brightness of the above-described image, it is preferable to change the brightness first and then the color temperature.

FIG. 7 is a flowchart illustrating a color shift compensation method for compensating color shifts for lighting effects by applying lighting characteristic data generated by an apparatus and a method for generating light characteristic data, referring to the color shift compensation apparatus described above. The explanation is as follows.

The illumination characteristic data generated by the illumination characteristic data unit 450 generates illumination characteristic data around the image display device having a data format including a type block and a brightness block (step 700). The color shift compensator 400 analyzes the illumination characteristic data and compensates for the color shift according to the type of illumination and the brightness of the illumination (step 720). The color shift compensated image is output by the image display unit 490. (Step 740)

The present invention can be embodied as code that can be read by a computer (including all devices having an information processing function) in a computer-readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer device is stored. Examples of computer-readable recording devices include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is 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 technical spirit of the appended claims.

By inputting the illumination characteristic data generated according to the illumination characteristic generation method and apparatus around the image display apparatus according to the present invention, the first input by performing a conversion to compensate for the visual color shift of the output image due to the influence of illumination Color characteristics of an image can be reproduced in an image output to an image display device. In addition, the data structure for recording the illumination characteristic information according to the present invention can be represented in a universal compatible data format such as XML, binary bitstream. Therefore, it can be widely used to perform color shift compensation conversion for lighting effects in various video display devices, video display software, and service systems that supply images to user devices by wire or wireless. It may be commonly used to generate an image corresponding to physical environment characteristics.

Claims (5)

Generating illumination characteristic data into a type block representing illumination light type information including at least one of a color temperature value of the illumination light and a coordinate value of the chromaticity coordinate system of the illumination light; Generating illumination characteristic data as brightness blocks representing brightness information of illumination light corresponding to numerical brightness values expressed in units of Lux; And Generating the type block and the brightness block in a predetermined data format; And a color temperature value of the illumination light is expressed as a quantized value of 8 bits. The method of claim 1, wherein the type block of the data format A flag indicating whether data in the type payload is a color temperature value or a chromaticity coordinate value; And And a type payload indicating any one of chromaticity coordinate values if the flag is information representing a color temperature value and if the flag is information representing a chromaticity coordinate value. . The method of claim 1, wherein the type block of the data format is A flag indicating whether data in the type payload is a color temperature value, a chromaticity coordinate value, or semantic information about an illumination type; And A color temperature value if the flag is information indicating a color temperature value, a chromaticity coordinate value if the flag is information representing a chromaticity coordinate value, and one of incandescent lamp, fluorescent lamp, daylight, and skylight data if the flag is information representing semantic information; A method of generating illumination characteristic data around an image display device, characterized in that it comprises a type payload. The method of claim 1, wherein the brightness block of the data format is A flag indicating whether data in the brightness payload is a numerical value or a semantic value; And If the flag is information representing a numerical value, it represents a numerical value in the unit of lux, and if the flag is information representing a semantic value, it represents one of 'dark', 'dim', 'bright', and 'very bright'. And a brightness payload corresponding to the data. delete

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