WO2022225148A1

WO2022225148A1 - Method for calibrating multi-display and apparatus for calibrating multi-display

Info

Publication number: WO2022225148A1
Application number: PCT/KR2022/001513
Authority: WO
Inventors: 안토니자쿠비아크; 체자리흐샤노프스키; 파웰키스; 로만프레제크
Original assignee: 삼성전자주식회사
Priority date: 2021-04-20
Filing date: 2022-01-27
Publication date: 2022-10-27
Also published as: KR20220144530A

Abstract

A method for calibrating a multi-display, whereby the multi-display can be calibrated irrespective of the characteristics of a plurality of display devices, comprises the steps in which: the multi-display displays each of a first image and a second image; a camera captures the multi-display, thereby acquiring first image data corresponding to the first image and second image data corresponding to the second image; and calibration functions are determined for each of pixels of the multi-display on the basis of difference values between data values for each of pixels included in the first image data and data values for each of pixels included in the second image data.

Description

Multi-display calibration method and multi-display calibration device

The present disclosure relates to a multi-display calibration method and a multi-display calibration apparatus, and more particularly, to a method and apparatus for calibrating a multi-display using a camera.

The multi-display is a configuration for displaying one image using a plurality of display devices (eg, a display panel or a projector).

When a plurality of display apparatuses are used, color deviation or brightness deviation between the display apparatuses may occur as the characteristics of each display apparatus are different.

Since the plurality of display devices each include a non-linear gamma correction function, it is difficult to calibrate the multi-display so that the plurality of display devices display a unified image.

An aspect of the disclosed invention provides a multi-display calibration method and a multi-display calibration apparatus capable of calibrating multi-displays regardless of characteristics of a plurality of display devices.

An aspect of the disclosed invention provides a multi-display calibration method and a multi-display calibration apparatus capable of calibrating multi-displays regardless of ambient light.

A multi-display calibration method according to an embodiment of the disclosed invention includes: displaying, by a multi-display, a first image and a second image, respectively; obtaining, by a camera, first image data corresponding to the first image and second image data corresponding to the second image by photographing the multi-display; determining a correction function for each pixel based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data; and correcting the multi-display based on the correction function for each pixel.

In addition, the first image may be a full white image, and the second image may be a full black image.

The determining of the correction function for each pixel may include calculating a first difference value between a data value of a first pixel included in the first image data and a data value of the first pixel included in the second image data. to do; determining the darkest pixel based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data; and determining a correction function of the first pixel based on the data value of the darkest pixel and the first difference value.

The method may further include calculating a second difference value between a data value of a second pixel included in the first image data and a data value of the second pixel included in the second image data; and determining a correction function of the second pixel based on the data value of the darkest pixel and the second difference value.

In addition, the correction function of the first pixel is a response function for normalizing the first difference value based on the data value of the darkest pixel, and the correction function of the second pixel is the second difference value. It may be a response function for normalizing based on the data value of the darkest pixel.

In addition, the multi-display correction method may include: displaying, by the multi-display, a third image; obtaining, by the camera, third image data corresponding to the third image by photographing the multi-display; and mapping the plurality of pixels included in the image data of the third image and the plurality of pixels included in the third image data; may further include.

In addition, the mapping of the plurality of pixels included in the image data of the third image and the plurality of pixels included in the third image data may include: It may include; mapping the pixel to any one of the plurality of pixels included in the third image data.

In addition, the multi-display correction method may include: displaying a third image and a fourth image at different timings, respectively, by a plurality of display devices constituting the multi-display; obtaining, by the camera, third image data corresponding to the third image and fourth image data corresponding to the fourth image by photographing the multi-display; estimating a luminance value of each of the plurality of display devices based on a luminance data value included in the third image data and a luminance data value included in the fourth image data; and determining a global correction function applied to all pixels of each of the plurality of display devices based on the luminance values of each of the plurality of display devices.

The determining of the global correction function may include: determining a minimum luminance value among luminance values of each of the plurality of display devices; and determining a global correction function corresponding to each of the plurality of display devices based on the minimum luminance value and the respective luminance values of the plurality of display devices.

Also, the global correction function corresponding to the first display device among the plurality of display devices may be a response function for limiting the luminance value of the first display device based on the minimum luminance value.

The multi-display calibration method may further include calibrating each of the plurality of display devices based on a global correction function applied to all pixels of each of the plurality of display devices.

The determining of the correction function for each pixel based on a difference value between the data value for each pixel included in the first image data and the data value for each pixel included in the second image data is included in the first image data. and determining a correction function for each pixel group of the multi-display based on a difference value between the data value for each pixel and the data value for each pixel included in the second image data.

A multi-display apparatus according to an embodiment of the disclosed invention includes: a communication interface for receiving, by a camera, first image data and second image data obtained by photographing the multi-display; and determining a correction function for each pixel of the multi-display based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data, and to the correction function for each pixel. It may include; a processor for correcting the multi-display based on the.

The processor is further configured to calculate a first difference value between a data value of a first pixel included in the first image data and a data value of the first pixel included in the second image data, and the first image data The darkest pixel is determined based on a difference value between a data value for each pixel included in the , and a data value for each pixel included in the second image data, and the darkest pixel is determined based on the data value of the darkest pixel and the first difference value. A correction function of the first pixel may be determined.

In addition, the processor calculates a second difference value between a data value of a second pixel included in the first image data and a data value of the second pixel included in the second image data, and The correction function of the second pixel may be determined based on the data value and the second difference value.

In addition, the communication interface receives third image data and fourth image data obtained by photographing the multi-display by the camera, and the processor includes a luminance data value included in the third image data and the fourth image A global correction function that estimates the luminance value of each of the plurality of display devices based on the luminance data value included in the data, and is applied to all pixels of each of the plurality of display devices based on the luminance value of each of the plurality of display devices may be determined, and each of the plurality of display devices may be corrected based on a global correction function applied to all pixels of each of the plurality of display devices.

In addition, the processor determines a minimum luminance value from among the luminance values of each of the plurality of display apparatuses, and based on the minimum luminance value and the luminance values of each of the plurality of display apparatuses, a global corresponding to each of the plurality of display apparatuses. A correction function can be determined.

Also, the processor may determine a correction function for each pixel group of the multi-display based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data. .

According to an aspect of the disclosed invention, it is possible to correct the multi-display regardless of the ambient light of the multi-display or the characteristic difference between the plurality of display devices constituting the multi-display.

According to an aspect of the disclosed invention, a unified image may be provided to a user using a multi-display.

1 is a diagram illustrating an example of a multi-display according to an embodiment.

2 is a diagram illustrating another example of a multi-display according to an embodiment.

3 is a block diagram of a multi-display calibration apparatus according to an exemplary embodiment.

4 is an integrated flowchart of a multi-display calibration method according to an exemplary embodiment.

5 shows an example of pixel mapping according to an embodiment.

6 and 7 are flowcharts of a specific embodiment of a multi-display calibration method according to an embodiment.

The configuration shown in the embodiments and drawings described in this specification is only a preferred example of the disclosed invention, and there may be various modifications that can replace the embodiments and drawings of the present specification at the time of filing of the present application.

The terminology used herein is used to describe the embodiments, and is not intended to limit and/or limit the disclosed invention.

For example, a singular expression herein may include a plural expression unless the context clearly dictates otherwise.

In addition, terms such as "comprise" or "have" are intended to express the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features, It does not exclude the possibility of additional presence or addition of numbers, steps, acts, elements, parts, or combinations thereof.

In addition, terms including an ordinal number, such as "first" and "second", are used to distinguish one element from another element, and do not limit the one element.

In addition, terms such as "~ part", "~ group", "~ block", "~ member", and "~ module" may mean a unit for processing at least one function or operation. For example, the terms may refer to at least one process processed by at least one hardware such as a field-programmable gate array (FPGA)/application specific integrated circuit (ASIC), at least one software stored in a memory, or a processor. have.

Hereinafter, an embodiment of the disclosed invention will be described in detail with reference to the accompanying drawings. The same reference numbers or reference numerals presented in the accompanying drawings may indicate parts or components that perform substantially the same functions.

Hereinafter, the working principle and embodiments of the present invention will be described with reference to the accompanying drawings.

Referring to FIG. 1 , a multi-display 10 may include a plurality of display devices 10 - 1 and 10 - 2 . In an embodiment, each of the plurality of display devices 10 - 1 and 10 - 2 may include an independent display panel (eg, an LED panel or a liquid crystal panel).

In an embodiment, each of the plurality of display devices 10 - 1 and 10 - 2 may include a plurality of pixels, and each of the plurality of pixels includes a red sub-pixel emitting red light and a green light emitting green light. The sub-pixel may include a blue sub-pixel emitting blue light.

In the multi-display 10 , a plurality of display devices 10 - 1 and 10 - 2 may be arranged in a two-dimensional matrix form or may be arranged in one dimension. The multi-display 10 according to an exemplary embodiment does not limit a method in which a plurality of display devices are arranged or the number of independent display devices constituting one display panel.

Referring to FIG. 2 , in an embodiment, each of the plurality of display apparatuses 10 - 3 and 10 - 4 constituting the multi-display 10 may include an independent image projection apparatus (eg, a beam projector).

The plurality of display apparatuses 10 - 3 and 10 - 4 may configure one screen by projecting an image on the same projection area.

According to various embodiments, the multi-display 10 may be configured as a combination of a display panel and an image projection apparatus.

A plurality of display devices constituting the multi-display 10 may have different characteristics (eg, a gamma correction curve, a maximum gray value for each pixel, and the number of pixels). Even if a plurality of display devices constituting the multi-display 10 are the same model produced in the same factory, they have different characteristics due to a change in characteristics according to the period of use.

Accordingly, the unity of the images output by the multi-display 10 may be deteriorated. For example, if the sharpness and/or gradation value for each pixel of one display device is different from the sharpness and/or gradation value for each pixel of an adjacent display device, the user may feel a sense of difference due to the difference in sharpness and/or brightness.

In order to improve the uniformity of the images output from the multi-display 10 , each display device should be calibrated according to the characteristics of each display device, or image data input to each display device should be calibrated.

In the present specification, calibrating the multi-display may include both calibrating a plurality of display devices constituting the multi-display and calibrating image data input to each display device.

Meanwhile, since characteristics (eg, response functions) of a plurality of display devices constituting the multi-display 10 are different, it is difficult to calibrate each display device to be unified.

In an embodiment, the multi-display calibration apparatus 100 may generate a per-pixel calibration function and/or a global calibration function based on the display image of the multi-display 10 acquired through the camera 200 .

Referring to FIG. 3 , the multi-display calibration apparatus 100 according to an embodiment includes a communication interface 110 capable of communicating directly or indirectly with the camera 200 and/or the multi-display 10 , and at least one The processor 120 and at least one memory 130 may be included.

In one embodiment, the communication interface 110 may include a short-range communication module and/or a wireless communication module and/or a wireless communication module.

In addition to Wifi, WiBro, GSM (Global System for Mobile Communication), CDMA (Code Division Multiple Access), WCDMA (Wideband Code Division Multiple Access), UMTS (Universal Mobile Telecommunications System), It may include at least one of various wireless communication modules that can be connected to the Internet network in a wireless communication method such as Time Division Multiple Access (TDMA), Long Term Evolution (LTE), 4th generation mobile communication, 5th generation mobile communication, and the like.

Short-distance communication module includes Bluetooth module, infrared communication module, RFID (Radio Frequency Identification) communication module, WLAN (Wireless Local Access Network) communication module, NFC communication module, Zigbee communication module, Z-Wave communication It may include at least one of various short-range communication modules for transmitting and receiving signals using a wireless communication network in a short distance, such as a module, a Wi-Fi direct communication module, and a low-power Bluetooth module (BLE).

The wired communication module may include a local area network (LAN) communication module or a power line communication module.

According to various embodiments, the communication interface 110 may include one or more that the multi-display calibration device 100 may be used to directly or wirelessly connect with an external electronic device (eg, the multi-display 10 and the camera 200). It can support specified protocols.

For example, the communication interface 110 may include a high definition multimedia interface (HDMI), a universal serial bus (USB) interface, or an SD card interface.

In an embodiment, the communication interface 110 may include a connector that can be physically connected to an external electronic device (eg, the multi-display 10 or the camera 200) through a connection terminal. For example, the communication interface 110 may include an HDMI connector, a USB connector, or an SD card connector.

In an embodiment, the at least one memory 130 may store a program and data for calibrating the multi-display 10 , and may store temporary data generated while calibrating components included in the multi-display.

For example, the memory 130 may include a program for generating a per-pixel correction function, a program for calibrating the multi-display 10 according to the per-pixel correction function, a program for generating a global correction function, and a multi-function according to the global correction function. A program for calibrating the display 10 may be included.

As another example, the memory 130 may store image data (eg, full black image data, full white image data, full red image data) used to correct the multi-display 10 . data, full green image data, full blue image data, pattern image data) can be stored. When the image data value for each pixel is defined as 8 bits (0 to 255), the full black image data means image data in which data values for all pixels are a first preset value (0 to 10), and a full white image Data may mean image data in which data values for all pixels are second preset values (250 to 255).

The memory 130 includes a non-volatile memory such as a read only memory and a flash memory for storing data for a long period of time, and a static random access memory (S-RAM) and D for temporarily storing data. -Volatile memory such as RAM (Dynamic Random Access Memory) may be included.

The at least one processor 120 may calibrate the multi-display 10 according to the program and data stored in the at least one memory 130 .

In an embodiment, the at least one processor 120 may include an arithmetic circuit that performs logical operations and arithmetic operations, and a memory circuit that stores the calculated data.

In an embodiment, the camera 200 may acquire image data corresponding to an image output from the multi-display 10 by photographing the multi-display 10 .

In this specification, "the camera 200 photographing the multi-display 10" may mean "the camera 200 photographing the display area of the multi-display 10".

According to various embodiments, when the multi-display 10 is composed of a plurality of beam projectors, "the camera 200 shoots the multi-display 10" means "taking the projection surface of the beam projector". can mean

In one embodiment, camera 200 may include one or more lenses, image sensors, image signal processors, or flashes.

According to various embodiments, the multi-display calibrating apparatus 100 may be provided as a component of the camera 200 or may be provided as a component separate from the camera 200 .

Hereinafter, a method of correcting the multi-display 10 will be described in detail.

4 is an integrated flowchart of a multi-display calibration method according to an embodiment, and FIG. 5 shows an example of pixel mapping according to an embodiment.

Referring to FIG. 4 , the multi-display calibrating apparatus 100 may map pixels of image data obtained through the camera 200 and pixels of the multi-display 10 ( 1000 ).

In an embodiment, the processor 120 may transmit image data for mapping (hereinafter, 'mapping image data') (eg, image data including a phase shift pattern) through the communication interface 110, and multi-display 10 may display an image corresponding to the mapping image data (hereinafter, 'mapping image'), and the camera 200 captures the multi-display 10 to obtain image data corresponding to the mapping image (hereinafter, 'pattern image data'). ') can be obtained.

The processor 120 may match the domain of the multi-display 10 with the domain of the camera 200 based on the pattern image data obtained from the camera 200 and the mapping image data.

According to various embodiments, the processor 120 may control the angle of the lens of the camera 200 or control the focus function of the camera 200 so that the mapping image data and the pattern image data match. In addition, the processor 120 may control the angle of the lens of the image projection apparatus constituting the multi-display 10 so that the mapping image data and the pattern image data match, or control the focus function of the image projection apparatus.

Also, the processor 120 may generate a response function for the pattern image data to match the mapping image data with the pattern image data.

Referring to FIG. 5 , the processor 120 may map a plurality of pixels included in the mapping image data MI and a plurality of pixels included in the pattern image data CI.

In the case of the multi-display 10 , relatively many pixels are used to output one image by a plurality of display devices, whereas relatively few pixels are used in the case of the camera 200 .

According to various embodiments, the processor 120 may map at least one pixel among a plurality of pixels included in the mapping image data MI and any one pixel among a plurality of pixels included in the pattern image data CI. have.

For example, the processor 120 may map ten pixels included in the mapping image data M1 and one pixel included in the pattern image data CI.

According to an embodiment, the pixels of each of the plurality of display devices constituting the multi-display 10 may match the domains of the pixels of the image obtained through the camera 200 .

Referring back to FIG. 4 , the processor 120 may acquire first image data and second image data from the camera 200 ( 1100 ).

Specifically, the processor 120 may transmit image data (hereinafter, 'first corrected image data') corresponding to the first image (eg, a full-white image) to the multi-display 10 through the communication interface 110 . In addition, the multi-display 10 may display the first image, and the camera 200 may acquire the first image data corresponding to the first image by photographing the multi-display 10 .

In addition, the processor 120 may transmit image data (hereinafter, 'second corrected image data') corresponding to the second image (eg, a full black image) to the multi-display 10 through the communication interface 110 , , the multi-display 10 may display a second image, and the camera 200 may acquire second image data corresponding to the second image by photographing the multi-display 10 .

That is, the multi-display 10 outputs a monochromatic grayscale image (eg, a full black image, a full white image, or a full gray image), and the camera 200 shoots the multi-display 10 that outputs a monochromatic grayscale image, The multi-display calibration apparatus 100 may receive image data obtained from the camera 200 .

According to various embodiments, the monochromatic grayscale image may be a full-red image, a full-green image, or a full-blue image in order to obtain correction data for each color channel.

The processor 120 may determine a correction function for each pixel (eg, a correction function for each pixel of the camera 200 or a correction function for each pixel of the multi-display 10 ) based on the first image data and the second image data (eg, a correction function for each pixel of the multi-display 10 ). 1200).

When the image projection apparatus is included in the display apparatus constituting the multi-display 10 , the processor 120 may determine a correction function for each pixel in consideration of the characteristics of the image projection surface. To this end, the user may input information on the image projection surface through an input device such as a remote control.

In an embodiment, the user may be provided with a projection surface (eg, a flat board having uniform visual characteristics) used to calibrate the image projection device, and the user may use the projection surface to calibrate the multi-display according to an embodiment method can be used.

According to various embodiments, the processor 120 may compare the first image data and/or the second image data with pre-stored comparison image data to determine a characteristic of the corresponding image projection surface.

A detailed process of determining the correction function for each pixel will be described later with reference to FIG. 6 .

According to an embodiment, since the domain of the camera 200 and the domain of the multi-display 10 are mapped, the per-pixel correction function of the camera 200 or the per-pixel correction function of the multi-display 10 are all multi-display (10) can be used to correct

According to various embodiments, the processor 120 may determine a global correction function based on the first image data and the second image data ( 1300 ). In the present specification, the global correction function may mean a single correction function applied to each of the display devices 10-1, 10-2, 10-3, and 10-4 constituting the multi-display 10 . Details of determining the global correction function will be described later with reference to FIG. 7 .

In an embodiment, the per-pixel correction function and/or the global correction function may refer to a response function to input image data input to a pixel.

For example, when the data value of the input image data applied to the first pixel of the multi-display 10 is “R: 100, G: 255, B: 50”, the data value is corrected by a correction function that halves the data value. The input image data value may be "R: 50, G: 123, B: 25".

In an embodiment, the processor 120 may calibrate the multi-display 10 by applying a pixel-by-pixel correction function or a global correction function to the multi-display 10 ( 1400 ).

Specifically, FIG. 6 shows a process of determining a correction function for each pixel, and FIG. 7 shows a process of determining a global correction function.

Referring to FIG. 6 , the processor 120 may calculate a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data ( 2000 ).

Accordingly, the processor 120 may determine a minimum value (hereinafter, referred to as a 'minimum difference value') among a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data.

In other words, the processor 120 may determine the darkest pixel among pixels included in the first image data and the second image data. For example, the processor 120 may determine the pixel having the smallest difference value as the darkest pixel.

In an embodiment, the processor 120 may determine a correction function for each pixel based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data ( 2100 , 2100 ). 2200, 2300).

For example, the processor 120 determines a correction function for each pixel based on difference values between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data and a minimum difference value. can

In other words, the processor 120 may determine the correction function for each pixel based on the data value of the darkest pixel.

According to an exemplary embodiment, since a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data is calculated, interference caused by ambient light may be minimized. .

Since the first image data and the second image data are obtained by photographing the multi-display 10 that outputs different monochromatic grayscale images, when a plurality of display devices constituting the multi-display 10 have the same characteristics, the pixel All differences are assumed to be constant.

For example, the first image data is image data obtained by photographing the multi-display 10 that outputs a full-white image, and the second image data is image data obtained by photographing the multi-display 10 that outputs a full-black image. In the case of image data, it is preferably estimated that the difference value for each pixel is in the range of 240 to 255.

The processor 120 calculates a first difference value between the data value of the first pixel included in the first image data and the data value of the first pixel included in the second image data, and based on the first difference value A correction function of the pixel may be determined ( 2100 ).

Specifically, the processor 120 may determine the correction function of the first pixel based on the first difference value and the data value (eg, the minimum difference value) of the darkest pixel.

Similarly, the processor 120 calculates a second difference value between the data value of the second pixel included in the first image data and the data value of the second pixel included in the second image data, and the second difference value is the darkest A correction function of the second pixel may be determined based on a data value (eg, a minimum difference value) of the pixel.

Assuming that the number of pixels mapped in the pixel mapping step 1000 is n, the processor 120 repeats the above process to include the data value of the nth pixel included in the first image data and the second image data. An n-th difference value of the data values of the n-th pixel may be calculated, and a correction function of the n-th pixel may be determined based on the n-th difference value.

According to various embodiments, the processor 120 compares the first difference value with the minimum difference value, and determines, as the correction function of the first pixel, a response function that allows the first difference value to fall within a range set by the minimum difference value. can

For example, assuming that the first difference value is "250" and the difference value of the darkest pixel is "230", the processor 120 generates a response function for normalizing the range [0,250] based on [0,230]. It can be determined as a correction function of 1 pixel.

Accordingly, the maximum grayscale value that can be output by the first pixel may be matched to “230” based on the response characteristic of the camera 200 .

In an exemplary embodiment, the processor 120 outputs a first monochromatic grayscale image (eg, a full-white image) from the multi-display 10 , and includes data about a first voltage value applied to the first pixel and a second monochromatic grayscale image. In order to output an image (eg, a full black image), data about a second voltage value applied to the first pixel may be received, and a difference value between the first voltage value and the second voltage value may be compared with the first difference value. Thus, a response function for correcting a voltage value applied to the first pixel may be determined.

The memory 130 may store a lookup table for a response function for normalizing the n-th difference value according to a preset reference range.

According to various embodiments, since one pixel included in the first image data or the second image data may be mapped to a pixel group (a group consisting of a plurality of pixels) of the multi-display 10 , the processor 120 may A correction function for each pixel group of the multi-display 10 may be determined based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data.

According to an embodiment, since the multi-display 10 is calibrated based on image data acquired through the camera 200 , it is not necessary to consider the characteristics of each of the plurality of display devices constituting the multi-display 10 . (10) can be corrected.

Also, according to an embodiment, the multi-display 10 may be calibrated based on all pixel data ranges (0 to 255) by using the full black image and the full white image.

Also, according to an exemplary embodiment, uniformity of an image may be achieved by correcting the remaining pixels based on the darkest pixel.

Referring to FIG. 7 , a process of determining a global correction function applied to all pixels of each of a plurality of display devices constituting the multi-display 10 may be confirmed.

According to various embodiments, the multi-display 10 includes a first display device (eg 10-1), a second display device (eg 10-2), and a third display device (eg 10-3). In this case, the processor 120 may include a first global correction function applied to all pixels of the first display device, a second global correction function applied to all pixels of the second display device, and a third global correction function applied to all pixels of the third display device. A global correction function can be determined.

In order to determine the global correction function of each of the plurality of display apparatuses, the multi-display calibration apparatus 100 controls the multi-display 10 so that each of the plurality of display apparatuses displays the third image and the fourth image at different timings. can

For example, after controlling the first display device to sequentially display the third image and the fourth image, the processor 120 may control the second display device to sequentially display the third image and the fourth image. have.

In an embodiment, the first display device may sequentially display a third image (eg, a full white image) and a fourth image (eg, a full black image), and the camera 200 displays the multi-display 10 . 3-1 th image data corresponding to the first display device and the third image and 4-1 th image data corresponding to the first display and the fourth image may be obtained by photographing.

Also, the processor 120 may acquire the 3-1 th image data and the 4-1 th image data through the communication interface 110 .

According to various embodiments of the present disclosure, the processor 120 generates 3-2 th image data corresponding to the second display device and the third image, 4-2 th image data corresponding to the second display and the fourth image, and the third 3-3 image data corresponding to the display device and the third image and 4-3 image data corresponding to the third display and the fourth image may be acquired.

For convenience of explanation, the 3-1, 3-2, and 3-3 image data are all referred to as third image data, and the 4-1, 4-2, and 4-3 image data are collectively referred to as the fourth image data. do.

The processor 120 may calculate a difference value between the luminance data value of the third image data and the luminance data value of the fourth image data (3000).

Specifically, the processor 120 may calculate a difference value between each of the 3-1, 3-2, and 3-3 image data and each of the 4-1, 4-2, and 4-3 image data.

The difference between the luminance data value of the third image data and the luminance data value of the fourth image data is the difference between the average value of the data values for each pixel included in the third image data and the average value of the data values for each pixel included in the fourth image data. It can contain values.

According to various embodiments, the processor 120 may estimate the luminance value of each of the plurality of display devices based on a difference value between the luminance data value of the third image data and the luminance data value of the fourth image data ( 3100 ). .

The luminance value of each display device may include a maximum luminance value that each display device can output, which may be different according to characteristics of each display device.

The processor 120 may determine a minimum luminance value from among luminance values of each of the plurality of display devices.

That is, the processor 120 may determine a display device having the darkest luminance characteristic among a plurality of display devices constituting the multi-display 10 .

The processor 120 may determine a global correction function applied to all pixels of each of the plurality of display apparatuses based on the luminance value of each of the plurality of display apparatuses and the determined minimum luminance value ( 3200 ).

For example, the processor 120 may determine a global correction function corresponding to the first display device among the plurality of display devices as a response function for limiting the luminance value of the first display device based on the minimum luminance value.

In an embodiment, when the luminance value of the first display apparatus is determined as "230", the luminance value of the second display apparatus is determined as "220", and the luminance value of the third display apparatus is determined as "225" , the processor 120 may determine a first global correction function applied to the first display apparatus and a third global correction function applied to the third display apparatus based on "220", which is the minimum luminance value.

For example, the processor 120 may determine a response function for limiting the luminance value of the first display device to “220” as the first global correction function, and limit the luminance value of the third display device to “220”. A response sum to be calculated may be determined as a third global correction function.

The processor 120 may calibrate each of the plurality of display devices based on a global correction function applied to each of the plurality of display devices constituting the multi-display 10 ( 1400 ).

According to an embodiment, the maximum grayscale value of a pixel may be determined by applying the maximum power and the minimum power to all pixels constituting the multi-display 10 , and the pixel having the smallest maximum grayscale value (the darkest pixel) ) based on a correction function for each pixel, and by applying maximum and minimum power to all display devices constituting the multi-display 10 , the maximum grayscale value of the display device can be determined, and the grayscale characteristic having the worst An image may be uniformed by determining a global correction function for each display device based on the display device (the darkest display device).

Also, according to an embodiment, the multi-display 10 may be calibrated using only the relative response characteristics inherent in the camera 200 irrespective of the characteristics of each display device constituting the multi-display 10 .

Also, according to an embodiment, the multi-display 10 may be corrected regardless of ambient light.

Meanwhile, the disclosed embodiments may be implemented in the form of a recording medium storing instructions executable by a computer. Instructions may be stored in the form of program code, and when executed by a processor, may generate program modules to perform operations of the disclosed embodiments. The recording medium may be implemented as a computer-readable recording medium.

The computer-readable recording medium includes any type of recording medium in which instructions readable by the computer are stored. For example, there may be a read only memory (ROM), a random access memory (RAM), a magnetic tape, a magnetic disk, the flash memory 130 , an optical data storage device, and the like.

In addition, the computer-readable recording medium may be provided in the form of a non-transitory storage medium. Here, 'non-transitory storage medium' is a tangible device and only means that it does not contain a signal (eg, electromagnetic wave). It does not distinguish the case where it is stored as For example, the 'non-transitory storage medium' may include a buffer in which data is temporarily stored.

According to one embodiment, the method according to various embodiments disclosed in this document may be provided in a computer program product (computer program product). Computer program products may be traded between sellers and buyers as commodities. The computer program product is distributed in the form of a machine-readable recording medium (eg compact disc read only memory (CD-ROM)), or through an application store (eg Play Store™) or on two user devices ( It can be distributed (eg downloaded or uploaded) directly, online between smartphones (eg: smartphones). In the case of online distribution, at least a portion of a computer program product (eg, a downloadable app) is a device-readable record, such as a server of a manufacturer, a server of an application store, or memory 130 of a relay server. At least temporarily stored in the medium, or may be temporarily created.

The disclosed embodiments have been described with reference to the accompanying drawings as described above. Those of ordinary skill in the art to which the present invention pertains will understand that the present invention may be practiced in other forms than the disclosed embodiments without changing the technical spirit or essential features of the present invention. The disclosed embodiments are illustrative and should not be construed as limiting.

Claims

displaying the first image and the second image by the multi-display, respectively;

obtaining, by a camera, first image data corresponding to the first image and second image data corresponding to the second image by photographing the multi-display;

determining a correction function for each pixel based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data; and

Compensating the multi-display based on the correction function for each pixel; Multi-display calibration method comprising a.
According to claim 1,

The first image is a full white image, and the second image is a full black image.
According to claim 1,

The step of determining the correction function for each pixel comprises:

calculating a first difference value between a data value of a first pixel included in the first image data and a data value of the first pixel included in the second image data;

determining the darkest pixel based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data; and

and determining a correction function of the first pixel based on the data value of the darkest pixel and the first difference value.
4. The method of claim 3,

calculating a second difference value between a data value of a second pixel included in the first image data and a data value of the second pixel included in the second image data; and

and determining a correction function of the second pixel based on the data value of the darkest pixel and the second difference value.
5. The method of claim 4,

The correction function of the first pixel is,

a response function for normalizing the first difference value based on the data value of the darkest pixel;

The correction function of the second pixel is,

and a response function for normalizing the second difference value based on the data value of the darkest pixel.
According to claim 1,

displaying, by the multi-display, a third image;

obtaining, by the camera, third image data corresponding to the third image by photographing the multi-display; and

and mapping a plurality of pixels included in the image data of the third image with a plurality of pixels included in the third image data.
7. The method of claim 6,

The mapping of the plurality of pixels included in the image data of the third image to the plurality of pixels included in the third image data may include:

and mapping at least two pixels among a plurality of pixels included in the image data of the third image to any one pixel among a plurality of pixels included in the third image data.
According to claim 1,

displaying a third image and a fourth image at different timings, respectively, by a plurality of display devices constituting the multi-display;

obtaining, by the camera, third image data corresponding to the third image and fourth image data corresponding to the fourth image by photographing the multi-display;

estimating a luminance value of each of the plurality of display devices based on a luminance data value included in the third image data and a luminance data value included in the fourth image data; and

and determining a global correction function applied to all pixels of each of the plurality of display devices based on the luminance values of each of the plurality of display devices.
9. The method of claim 8,

Determining the global correction function comprises:

determining a minimum luminance value among luminance values of each of the plurality of display devices; and

and determining a global correction function corresponding to each of the plurality of display devices based on the minimum luminance value and the respective luminance values of the plurality of display devices.
10. The method of claim 9,

A global correction function corresponding to a first display device among the plurality of display devices,

and a response function for limiting the luminance value of the first display device based on the minimum luminance value.
9. The method of claim 8,

calibrating each of the plurality of display devices based on a global correction function applied to all pixels of each of the plurality of display devices;
According to claim 1,

determining a correction function for each pixel based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data,

determining a correction function for each pixel group of the multi-display based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data; Calibration method.
a communication interface for receiving the first image data and the second image data obtained by the camera photographing the multi-display; and

A correction function for each pixel of the multi-display is determined based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data, and based on the correction function for each pixel A multi-display calibration apparatus comprising a; a processor for calibrating the multi-display.
14. The method of claim 13,

The processor is

calculating a first difference value between a data value of a first pixel included in the first image data and a data value of the first pixel included in the second image data;

calculating a second difference value between a data value of a second pixel included in the first image data and a data value of the second pixel included in the second image data;

determining the darkest pixel based on a difference value between a data value for each pixel included in the first image data and a data value for each pixel included in the second image data;

determining a correction function of the first pixel based on the data value of the darkest pixel and the first difference value;

and determining a correction function of the second pixel based on the data value of the darkest pixel and the second difference value.
15. The method of claim 14,

The correction function of the first pixel is,

a response function for normalizing the first difference value based on the data value of the darkest pixel;

The correction function of the second pixel is,

and a response function for normalizing the second difference value based on the data value of the darkest pixel.