KR102317035B1 - Display device and method for controlling the same - Google Patents

Abstract

A display device and a method for controlling the same are disclosed. A display device according to an embodiment of the present invention includes a content including an image having a high dynamic range and a receiver configured to receive metadata of the content (the metadata indicates a dynamic range of the image) information, including at least one of information indicating the peak luminance of the image and information indicating the luminance curve of the image), and a controller, wherein the controller includes an Average Picture (APL) of the image included in the received content. level), detects the peak luminance of the display unit corresponding to the acquired APL, and performs tone mapping of the image based on the detected peak luminance and the received metadata.

Description

Display device and its control method

The present invention relates to a display device and a method for controlling the same.

HDR (High Dynamic Range) content is content produced to provide an image having a wide dynamic range in order to give a feeling similar to a human seeing a real phenomenon with their eyes. However, since there is a limit to processing an image of a wide dynamic range with a general display device, a process called tone mapping is required to reproduce HDR content on a general display device. Here, the tone mapping refers to a technology for converting an image of HDR content into an image having a limited dynamic range that can be reproduced on a display device. Recently, a standard for maximizing the dynamic range of HDR content in a display device is being discussed, but only tone mapping based on a fixed peak luminance is being discussed. There are problems that cannot be reproduced.

SUMMARY OF THE INVENTION The present invention aims to solve the above and other problems. Another object is to provide a display device capable of reproducing the image detail of HDR content by performing tone mapping of the image in consideration of the physical peak luminance of the display device, as well as the characteristics of the input image and the black level of the display device, and a method for controlling the same. intended to provide

Another object of the present invention is to provide a display device capable of realizing an optimal HDR effect even in a display device exhibiting different peak luminance according to the APL of an input image, and a method for controlling the same.

Another object of the present invention is to provide a display device capable of variably applying a luminance curve for tone mapping according to characteristics of an input image, and a method for controlling the same.

The technical problems to be achieved in the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. will be able

A display device according to an embodiment of the present invention includes a content including an image having a high dynamic range and a receiver configured to receive metadata of the content (the metadata indicates a dynamic range of the image) information, including at least one of information indicating the peak luminance of the image and information indicating the luminance curve of the image), and a controller, wherein the controller includes an Average Picture (APL) of the image included in the received content. level), detecting the peak luminance of the display unit corresponding to the obtained APL, and performing tone mapping of the image based on the detected peak luminance, the received metadata, and the black level of the display unit do.

A method of controlling a display device according to an embodiment of the present invention includes the steps of receiving content including an image having a high dynamic range and metadata of the content (the metadata is the dynamic range of the image) obtaining an average picture level (APL) of an image included in the received content and information indicating a range, information indicating a peak luminance of the image, and information indicating a luminance curve of the image) and detecting a peak luminance of the display unit corresponding to the obtained APL, and performing tone mapping of the image based on the detected peak luminance, the received metadata, and a black level of the display unit. includes

The effects of the display device and the control method thereof according to the present invention will be described as follows.

According to an embodiment of the present invention, it is possible to provide a display device that performs tone mapping of an image in consideration of not only the physical peak luminance of the display device, but also characteristics of an input image and a black level of the display device, and a method for controlling the same.

In addition, according to an embodiment of the present invention, it is possible to provide a display device capable of realizing an optimal HDR effect even in a display device having different peak luminance according to the APL of an input image, and a method for controlling the same.

In addition, according to an embodiment of the present invention, it is possible to provide a display device capable of variably applying a luminance curve for tone mapping according to characteristics of an input image, and a method for controlling the same.

Further scope of applicability of the present invention will become apparent from the following detailed description. However, it should be understood that the detailed description and specific embodiments such as preferred embodiments of the present invention are given by way of illustration only, since various changes and modifications within the spirit and scope of the present invention may be clearly understood by those skilled in the art.

1 is a diagram schematically illustrating a service system including a display device according to an embodiment of the present invention.
2 is a block diagram illustrating a display device according to an embodiment of the present invention.
3 is a block diagram illustrating a detailed configuration of the control unit of FIG. 2 according to an embodiment of the present invention.
4 is a diagram illustrating an input means connected to the display device of FIG. 2 according to an embodiment of the present invention.
5 is a diagram illustrating a luminance curve of a display unit included in a specific display device.
6 is a flowchart illustrating an example of a method of performing tone mapping of an HDR image in a display device according to an embodiment of the present invention.
7 is a diagram illustrating an example of a luminance curve for tone mapping of an image in a display device according to an embodiment of the present invention.
8 is a flowchart illustrating another example of a method of performing tone mapping of an HDR image in a display device according to an embodiment of the present invention.
9 is a diagram illustrating an example of a specific frame constituting an HDR image.
10 is a block diagram illustrating a display device according to an embodiment of the present invention.

Hereinafter, the embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, but the same or similar components are assigned the same reference numerals regardless of reference numerals, and overlapping descriptions thereof will be omitted. The suffixes "module" and "part" for the components used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have a meaning or role distinct from each other by themselves. In addition, in describing the embodiments disclosed in the present specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed herein is not limited by the accompanying drawings, and all changes included in the spirit and scope of the present invention , should be understood to include equivalents or substitutes.

Terms including an ordinal number, such as first, second, etc., may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

When a component is referred to as being “connected” or “connected” to another component, it is understood that the other component may be directly connected or connected to the other component, but other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that no other element is present in the middle.

The singular expression includes the plural expression unless the context clearly dictates otherwise.

In the present application, terms such as "comprises" or "have" are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

1 is a diagram schematically illustrating a service system including a display device according to an embodiment of the present invention.

Referring to FIG. 1 , the service system includes a content provider 10 , a service provider 20 , a network provider 30 and a Home Network End User (HNED) (Customer). (40). Here, the HNED 40 includes, for example, the client 100, that is, the display device according to the present invention.

The content provider 10 produces and provides various types of content. As shown in FIG. 1 , such a content provider 10 as a terrestrial broadcaster, a cable broadcaster (cable SO (System Operator)) or MSO (Multiple SO), a satellite broadcaster, various Internet broadcasters, individuals Content providers and the like can be exemplified. Meanwhile, the content provider 10 may produce and provide various services or applications in addition to broadcast content.

The service provider 20 provides the HNED 40 by service packetizing the content produced by the content provider 10 . For example, the service provider 20 packages for a service at least one or more of contents produced by a first terrestrial broadcast, a second terrestrial broadcast, a cable MSO, a satellite broadcast, various Internet broadcasts, applications, and the like, and the HNED ( 40) is provided.

The service provider 20 provides a service to the client 100 in a uni-cast or multi-cast method. Meanwhile, the service provider 20 may transmit data to a plurality of pre-registered clients 100 at once. For this purpose, an Internet Group Management Protocol (IGMP) protocol or the like may be used.

The above-described content provider 10 and service provider 20 may be the same entity. For example, by packaging the content produced by the content provider 10 and providing it to the HNED 40 , the function of the service provider 20 may also be performed or vice versa.

The network provider 30 provides a network for exchanging data between the content provider 10 or/and the service provider 20 and the client 100 .

The client 100, as a consumer belonging to the HNED 40, receives data by, for example, building a home network through the network provider 30, and receives data related to various services or applications such as VoD and streaming. It can also send/receive.

Meanwhile, the content provider 10 and/or the service provider 20 in the service system may use conditional access or content protection means to protect transmitted content. Accordingly, the client 100 may use processing means such as a CableCARD (or POD: Point of Deployment), DCAS (Downloadable CAS), etc. in response to the conditional access or content protection.

In addition, the client 100 may also use the interactive service through the network. Accordingly, the client 100 may rather perform the role or function of the content provider, and the service provider 20 may receive it and transmit it to another client or the like.

In FIG. 1 , the content provider 10 and/or the service provider 20 may be a server providing a service to be described later in this specification. In this case, the server may mean owning or including the network provider 30 as necessary. Hereinafter, even if not specifically mentioned, the service or service data includes an internal service or application as well as the service or application received from the outside described above, and these services or applications may mean service or application data for the client 100 . .

2 is a block diagram illustrating a display device according to an embodiment of the present invention.

Referring to FIG. 2 , the display device 200 includes a broadcast receiving unit 205 , an external device interface unit 235 , a storage unit 240 , a user input interface unit 250 , a control unit 270 , and a display unit 280 . ), an audio output unit 285 , a power supply unit 290 , and a photographing unit (not shown). Here, the broadcast receiving unit 205 may include at least one tuner 210 , a demodulator 220 , and a network interface unit 230 . However, in some cases, the broadcast receiving unit 205 may include the tuner 210 and the demodulator 220 but not the network interface unit 230 , and vice versa. In addition, although not shown, the broadcast receiving unit 205 includes a multiplexer to provide a signal demodulated by the demodulator 220 through the tuner 210 and a signal received through the network interface unit 230 . can also be multiplexed. In addition, although not shown, the broadcast receiving unit 225 includes a demultiplexer to demultiplex the multiplexed signal or to demultiplex the demodulated signal or the signal that has passed through the network interface unit 230. can

The tuner 210 receives an RF broadcast signal by tuning a channel selected by a user or all channels stored in advance among radio frequency (RF) broadcast signals received through an antenna. Also, the tuner 210 converts the received RF broadcast signal into an intermediate frequency (IF) signal or a baseband signal.

For example, if the received RF broadcast signal is a digital broadcast signal, it is converted into a digital IF signal (DIF), and if it is an analog broadcast signal, it is converted into an analog baseband image or audio signal (CVBS/SIF). That is, the tuner 210 may process both a digital broadcast signal and an analog broadcast signal. An analog baseband video or audio signal (CVBS/SIF) output from the tuner 210 may be directly input to the controller 270 .

Also, the tuner 210 may receive an RF broadcast signal of a single carrier or a multiple carrier. Meanwhile, the tuner 210 sequentially tunes and receives the RF broadcast signals of all broadcast channels stored through the channel storage function among the RF broadcast signals received through the antenna, and receives them as an intermediate frequency signal or a baseband signal (DIF: Digital Intermediate). frequency or baseband signal).

The demodulator 220 may receive and demodulate the digital IF signal DIF converted by the tuner 210 , and may perform channel decoding and the like. To this end, the demodulator 220 includes a trellis decoder, a de-interleaver, a Reed-Solomon decoder, or the like, or a convolution decoder, a deinterleaver and a read. - A Solomon decoder, etc. may be provided.

The demodulator 220 may output a stream signal TS after demodulation and channel decoding are performed. In this case, the stream signal may be a signal in which an image signal, an audio signal, or a data signal is multiplexed. For example, the stream signal may be an MPEG-2 transport stream (TS) in which an MPEG-2 standard video signal, a Dolby AC-3 standard audio signal, and the like are multiplexed.

The stream signal output from the demodulator 220 may be input to the controller 270 . The controller 270 may control demultiplexing, image/audio signal processing, and the like, and may control output of an image through the display unit 280 and audio through the audio output unit 285 .

The external device interface unit 235 provides an interface environment between the display device 200 and various external devices. To this end, the external device interface unit 235 may include an A/V input/output unit (not shown) or a wireless communication unit (not shown).

External device interface unit 235, DVD (Digital Versatile Disk), Blu-ray (Blu-ray), game device, camera, camcorder (Camcorder), computer (laptop), tablet PC, smart phone, Bluetooth device (Bluetooth) device) and an external device such as a cloud, and the like, may be connected via wired/wireless. The external device interface unit 235 transmits a signal including data such as an image, video, and voice input through a connected external device to the controller 470 of the digital device. The controller 270 may control the processed image, video, audio, etc. to output a data signal to a connected external device. To this end, the external device interface unit 435 may further include an A/V input/output unit (not shown) or a wireless communication unit (not shown).

The A/V input/output unit includes a USB terminal, a CVBS (Composite Video Banking Sync) terminal, a component terminal, an S-video terminal (analog), It may include a Digital Visual Interface (DVI) terminal, a High Definition Multimedia Interface (HDMI) terminal, an RGB terminal, a D-SUB terminal, and the like.

The wireless communication unit may perform short-range wireless communication with another external device. The display device 200 includes, for example, Bluetooth, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB), ZigBee, and Digital Living Network Alliance (DLNA). It may be network-connected to other digital devices according to a communication protocol such as .

In addition, the external device interface unit 235 may be connected to the set-top box (STB) through at least one of the above-described various terminals to perform input/output operations with the set-top-box (STB).

Meanwhile, the external device interface unit 235 may receive an application or an application list in an adjacent external device and transmit it to the controller 270 or the storage unit 240 .

The network interface unit 230 provides an interface for connecting the display device 200 to a wired/wireless network including an Internet network. The network interface unit 230 may include, for example, an Ethernet (Ethernet) terminal for connection with a wired network, and for connection with a wireless network, for example, a WLAN (Wireless LAN) (Wi- Fi), Wibro (Wireless broadband), Wimax (World Interoperability for Microwave Access), HSDPA (High Speed Downlink Packet Access) communication standards, etc. may be used.

The network interface unit 230 may transmit or receive data with another user or another external device through the connected network or another network linked to the connected network. In particular, some content data stored in the display device 200 may be transmitted to a selected user or a selected external device among other users or other external devices previously registered in the display device 200 .

Meanwhile, the network interface unit 230 may access a predetermined web page through the connected network or another network linked to the connected network. That is, by accessing a predetermined web page through a network, it is possible to transmit or receive data with a corresponding server. In addition, content or data provided by a content provider or network operator may be received. That is, it is possible to receive content such as a movie, advertisement, game, VOD, broadcast signal, etc. and information related thereto provided from the content provider or the network provider through the network. Also, it is possible to receive firmware update information and an update file provided by a network operator. It may also transmit data to the Internet or to a content provider or network operator.

Also, the network interface unit 230 may select and receive a desired application from among applications open through a network.

The storage unit 240 may store a program for processing and controlling each signal in the control unit 270 , or may store a signal-processed image, audio, or data signal.

Also, the storage unit 240 may perform a function for temporarily storing an image, audio, or data signal input from the external device interface unit 235 or the network interface unit 230 . The storage unit 240 may store information about a predetermined broadcast channel through a channel storage function.

The storage unit 240 may store an application or an application list input from the external device interface unit 235 or the network interface unit 230 .

Also, the storage unit 240 may store various platforms to be described later.

The storage unit 240 is, for example, a flash memory type, a hard disk type, a multimedia card micro type, or a card type memory (eg, SD or XD). memory, etc.), a RAM (RAM), and a ROM (EEPROM, etc.) may include at least one type of storage medium. The digital device 400 may reproduce content files (movie files, still image files, music files, document files, application files, etc.) stored in the storage unit 240 and provide them to the user.

2 illustrates an embodiment in which the storage unit 440 is provided separately from the control unit 270, the present invention is not limited thereto. In other words, the storage unit 240 may be included in the control unit 270 .

The user input interface unit 250 transmits a signal input by the user to the control unit 270 or transmits a signal of the control unit 270 to the user.

For example, the user input interface unit 250 controls power on/off, channel selection, screen setting, etc. from the remote control device 400 according to various communication methods such as an RF communication method and an infrared (IR) communication method. The signal may be received and processed, or a control signal of the controller 270 may be transmitted to the remote control device 400 .

Also, the user input interface unit 250 may transmit a control signal input from a local key (not shown) such as a power key, a channel key, a volume key, and a setting value to the control unit 270 .

The user input interface unit 250 transmits a control signal input from a sensing unit (not shown) that senses a user's gesture to the control unit 270 or transmits a signal of the control unit 270 to the sensing unit. (not shown) can be transmitted. Here, the sensing unit (not shown) may include a touch sensor, a voice sensor, a position sensor, a motion sensor, and the like.

The controller 270 demultiplexes a stream input through the tuner 210 , the demodulator 220 , or the external device interface 235 or processes the demultiplexed signals to generate a signal for video or audio output. and output.

The image signal processed by the control unit 270 may be input to the display unit 280 and displayed as an image corresponding to the image signal. Also, the image signal processed by the controller 270 may be input to an external output device through the external device interface 235 .

The audio signal processed by the controller 270 may be audio output to the audio output unit 285 . Also, the audio signal processed by the controller 270 may be input to an external output device through the external device interface 235 .

Although not shown in FIG. 2 , the controller 270 may include a demultiplexer, an image processor, and the like.

The controller 270 may control the overall operation of the display device 200 . For example, the controller 270 may control the tuner 210 to tune an RF broadcast corresponding to a channel selected by the user or a pre-stored channel.

The controller 270 may control the display device 200 according to a user command input through the user input interface unit 250 or an internal program. In particular, by accessing a network, a user may download a desired application or an application list into the display device 200 .

For example, the controller 270 controls the tuner 210 to input a signal of a selected channel according to a predetermined channel selection command received through the user input interface 250 . And it processes the video, audio or data signal of the selected channel. The control unit 270 allows the user-selected channel information to be output through the display unit 280 or the audio output unit 285 together with the processed image or audio signal.

As another example, the control unit 270 may be configured to receive an external device image playback command received through the user input interface unit 250 from an external device input through the external device interface unit 235, for example, a camera or a camcorder. , an image signal or an audio signal may be output through the display unit 280 or the audio output unit 285 .

Meanwhile, the controller 270 may control the display 280 to display an image. For example, a broadcast image input through the tuner 210 , an external input image input through the external device interface unit 235 , an image input through the network interface unit, or an image stored in the storage unit 240 . , can be controlled to be displayed on the display unit 280 . In this case, the image displayed on the display unit 280 may be a still image or a moving image, and may be a 2D image or a 3D image.

Also, the controller 270 may control to reproduce the content. In this case, the content may be content stored in the display device 200 , received broadcast content, or external input content input from the outside. The content may be at least one of a broadcast image, an external input image, an audio file, a still image, a connected web screen, and a document file.

Meanwhile, when entering the application view item, the controller 270 may control to display an application or an application list downloadable from an internal or external network of the display device 200 .

The controller 270 may control to install and drive an application downloaded from an external network along with various user interfaces. Also, by the user's selection, it is possible to control the display unit 280 to display an image related to the application being executed.

Meanwhile, although not shown in the drawings, a channel browsing processing unit for generating a thumbnail image corresponding to a channel signal or an external input signal may be further provided.

The channel browsing processing unit receives the stream signal TS output from the demodulator 220 or the stream signal output from the external device interface 235, and extracts an image from the input stream signal to generate a thumbnail image. can The generated thumbnail image may be input to the controller 270 as it is or encoded. Also, the generated thumbnail image may be encoded in a stream form and input to the controller 270 . The controller 270 may display a thumbnail list including a plurality of thumbnail images on the display 280 by using the input thumbnail images. Meanwhile, the thumbnail images in the thumbnail list may be updated sequentially or simultaneously. Accordingly, the user can easily grasp the contents of a plurality of broadcast channels.

The display unit 280 converts the image signal, the data signal, the OSD signal processed by the controller 270, or the image signal and the data signal received from the external device interface unit 235 into R, G, and B signals, respectively. generate a drive signal.

The display unit 280 may be a PDP, LCD, OLED, flexible display, or 3D display.

Meanwhile, the display unit 280 may be configured as a touch screen and used as an input device in addition to an output device.

The audio output unit 285 receives a signal processed by the control unit 270 , for example, a stereo signal, a 3.1 channel signal, or a 5.1 channel signal, and outputs the audio signal. The audio output unit 285 may be implemented with various types of speakers.

Meanwhile, in order to detect a user's gesture, as described above, a sensing unit (not shown) including at least one of a touch sensor, a voice sensor, a position sensor, and a motion sensor may be further provided in the display device 200 . . The signal sensed by the sensing unit (not shown) may be transmitted to the control unit 270 through the user input interface unit 250 .

On the other hand, a photographing unit (not shown) for photographing the user may be further provided. Image information captured by the photographing unit (not shown) may be input to the control unit 270 .

The controller 270 may detect a user's gesture by individually or in combination with an image captured by a photographing unit (not shown) or a signal sensed from a sensing unit (not shown).

The power supply 290 supplies corresponding power to the entire display device 200 .

In particular, to supply power to the control unit 270 that can be implemented in the form of a system on chip (SoC), the display unit 280 for displaying an image, and the audio output unit 285 for outputting audio. can

To this end, the power supply unit 290 may include a converter (not shown) that converts AC power into DC power. Meanwhile, for example, when the display unit 280 is implemented as a liquid crystal panel including a plurality of backlight lamps, an inverter capable of Pulse Width Modulation (PWM) operation for luminance variable or dimming driving (inverter) (not shown) may be further provided.

The remote control device 400 transmits a user input to the user input interface unit 250 . To this end, the remote control device 400 may use Bluetooth (Bluetooth), Radio Frequency (RF) communication, infrared (IR) communication, Ultra Wideband (UWB), ZigBee, or the like.

Also, the remote control device 400 may receive an image, audio, or data signal output from the user input interface unit 250 , and display it on the remote control device 400 or output voice or vibration.

The above-described display device 200 may be a digital broadcast receiver capable of processing a digital broadcast signal of a fixed or mobile ATSC method or a DVB method.

In addition, the display device according to the present invention may omit some of the illustrated components as needed, or may further include non-illustrated components. On the other hand, unlike the above, the display device does not include a tuner and a demodulator, and may receive and reproduce content through a network interface unit or an external device interface unit.

3 is a block diagram illustrating a detailed configuration of the control unit of FIG. 2 according to an embodiment of the present invention.

An example of the controller 270 is a demultiplexer 310 , an image processor 320 , an OSD generator 340 , a mixer 350 , and a frame rate converter (FRC) 355 . ), and a formatter 360 . In addition, although not shown, the control unit may further include a voice processing unit and a data processing unit.

The demultiplexer 310 demultiplexes an input stream. For example, the demultiplexer 310 may demultiplex the input MPEG-2 TS video, audio, and data signals. Here, the stream signal input to the demultiplexer 310 may be a stream signal output from a tuner or demodulator or an external device interface unit.

The image processing unit 320 performs image processing of the demultiplexed image signal. To this end, the image processing unit 320 may include an image decoder 325 and a scaler 335 .

The image decoder 325 decodes the demultiplexed image signal, and the scaler 335 scales the resolution of the decoded image signal to be output on the display unit.

The video decoder 325 may support various standards. For example, the video decoder 325 performs the function of an MPEG-2 decoder when the video signal is encoded in the MPEG-2 standard, and when the video signal is encoded in the DMB (Digital Multimedia Broadcasting) method or the H.264 standard, In this case, the function of the H.264 decoder may be performed.

Meanwhile, the image signal decoded by the image processing unit 320 is input to the mixer 350 .

The OSD generator 340 generates OSD data according to a user input or by itself. For example, the OSD generating unit 340 generates data for displaying various data in the form of graphics or text on the screen of the display unit 280 based on the control signal of the user input interface unit. The generated OSD data includes various data such as a user interface screen of a digital device, various menu screens, widgets, icons, and viewing rate information. The OSD generator 340 may generate data for displaying broadcast information based on a caption of a broadcast image or an EPG.

The mixer 350 mixes the OSD data generated by the OSD generator 340 and the image signal processed by the image processor and provides them to the formatter 360 . Since the decoded image signal and the OSD data are mixed, the OSD is overlaid and displayed on the broadcast image or the external input image.

The frame rate converter (FRC) 355 converts a frame rate of an input image. For example, the frame rate converter 355 may convert a frame rate of an input 60Hz image to have a frame rate of, for example, 120Hz or 240Hz according to an output frequency of the display unit. As described above, there may be various methods for converting the frame rate. For example, when the frame rate conversion unit 355 converts the frame rate from 60 Hz to 120 Hz, the same first frame is inserted between the first frame and the second frame, or a second frame predicted from the first frame and the second frame is inserted. It can be converted by inserting 3 frames. As another example, when converting the frame rate from 60 Hz to 240 Hz, the frame rate converter 355 may convert by inserting three more identical frames or predicted frames between existing frames. Meanwhile, when a separate frame conversion is not performed, the frame rate conversion unit 355 may be bypassed.

The formatter 360 changes the output of the input frame rate converter 355 to match the output format of the display unit. For example, the formatter 360 may output R, G, and B data signals, and these R, G, and B data signals are output as a low voltage differential signal (LVDS) or mini-LVDS. can be In addition, when the output of the input frame rate converter 355 is a 3D video signal, the formatter 360 may support the 3D service through the display unit by composing and outputting it in a 3D form to match the output format of the display unit.

Meanwhile, the voice processing unit (not shown) in the control unit may perform voice processing of the demultiplexed voice signal. Such a voice processing unit (not shown) may support processing of various audio formats. As an example, even when the audio signal is encoded in a format such as MPEG-2, MPEG-4, AAC, HE-AAC, AC-3, BSAC, it can be processed with a corresponding decoder.

In addition, the voice processing unit (not shown) in the control unit may process a base (Base), a treble (Treble), volume control, and the like.

A data processing unit (not shown) in the control unit may perform data processing of the demultiplexed data signal. For example, the data processing unit may decode the demultiplexed data signal even when it is encoded. Here, the encoded data signal may be EPG information including broadcast information such as a start time and an end time of a broadcast program aired on each channel.

On the other hand, the above-described digital device is an example according to the present invention, and each component may be integrated, added, or omitted according to the specifications of the actually implemented digital device. That is, if necessary, two or more components may be combined into one component or one component may be subdivided into two or more components. In addition, the function performed by each block is for explaining the embodiment of the present invention, and the specific operation or device does not limit the scope of the present invention.

Meanwhile, the digital device may be an image signal processing device that performs signal processing of an image stored in the device or an input image. As another example of the image signal processing device, the set-top box (STB) in which the display unit 280 and the audio output unit 285 shown in FIG. 2 are excluded, the above-described DVD player, Blu-ray player, game device, computer and the like can be further exemplified.

4 is a diagram illustrating an input means connected to the display device of FIG. 2 according to an embodiment of the present invention.

A front panel (not shown) or a control means (input means) provided on the display device 200 may be used to control the display device 200 .

On the other hand, the control means is a user interface device (UID; User Interface Device) capable of wired and wireless communication, mainly implemented for the purpose of controlling the display device 200, the remote control 410, the keyboard 430, the pointing device 420, A touch-pad or the like is included, but a control means exclusively for external input connected to the display device 200 may also be included. In addition, the control means includes a mobile device such as a smart phone or a tablet PC that controls the display device 200 through mode switching, not for the purpose of controlling the display device 200 . However, in the present specification, a pointing device is described as an example for convenience, but is not limited thereto.

The input means are communication protocols such as Bluetooth, RFID (Radio Frequency Identification), infrared communication (IrDA), UWB (Ultra Wideband), ZigBee, DLNA (Digital Living Network Alliance), RS, etc. can communicate with a digital device by employing at least one or more as necessary.

The remote control 410 refers to a general input means provided with various key buttons necessary for controlling the display device 200 .

The pointing device 420 is equipped with a gyro sensor, etc. to implement a pointer corresponding to the screen of the display device 200 based on the user's movement, pressure, rotation, etc. ) to transmit a predetermined control command. The pointing device 420 may be named by various names such as a magic remote control, a magic controller, and the like.

The keyboard 430, as the display device 200 provides various services such as a web browser, an application, and a social network service (SNS) as an intelligent integrated digital device beyond the conventional broadcasting only, control is possible only with the conventional remote control 410 It was not easy, so it was implemented to improve the convenience of inputting text, etc. by implementing it similar to a PC keyboard.

On the other hand, the control means such as the remote control 410, the pointing device 420, the keyboard 430 is provided with a touch pad if necessary, so that text input, pointer movement, enlargement/reduction of pictures or videos, etc. are more convenient and various control purposes is available for

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 5 to 10 . In the present specification, it is assumed that at least one of the above-described content provider 10, service provider 20, and network provider 30 provides content including an image having a high dynamic range (HDR). . The dynamic range means including a contrast ratio, and may indicate whether a difference between two colors in an image can be expressed naturally as in the real world by a large shading difference. For convenience of description, content including an image having a high dynamic range may be referred to as an HDR content, and an image having a high dynamic range may be referred to as an HDR image. Here, the image may be a concept including a video image, a moving image, a still image, a panoramic image, a graphic image, and the like. Also, as an example, the high dynamic range may mean a dynamic range of ^{1:10 3 or more.}

5 is a diagram illustrating a luminance curve of a display unit included in a specific display device. With reference to FIG. 5 , before the present invention, problems of a method of performing tone mapping of HDR content in a display device will be described as follows.

5 shows an example of an APL versus luminance curve of a display unit including an OLED. When the display unit includes an OLED, the display unit may follow a luminance curve in which the peak luminance of the display unit decreases while the instantaneous peak current decreases as the APL of the image increases due to the characteristics of the current driving method of the OLED.

Meanwhile, when HDR content is received, the conventional display device performs tone mapping of the image according to a fixed luminance curve based on the maximum peak luminance physically achievable in the display unit. For example, when the dynamic range of the HDR content is 0.117 to 20,000 nits and the maximum peak luminance physically realizable in the display unit is 100 nits, the display device sets the dynamic range of the HDR content to within 100 nits, the maximum peak luminance of the display unit. Tone mapping is performed to convert to a low dynamic range that can be expressed in , and a fixed luminance curve by a preset technique (eg, gamma correction) is applied when the tone mapping is performed. Recently, as the maximum peak luminance that can be physically implemented in the display unit is increased, display devices capable of implementing luminance of 1000 nit or more have been proposed depending on the product. Although raw tone mapping can be performed, there is a limit to reproducing the detailed characteristics of HDR content.

In particular, in the case of a display device including an OLED, as shown in FIG. 5 , the maximum peak luminance physically achievable in the display unit without considering the variability of the peak luminance even though the peak luminance of the display unit varies according to the APL of the image. If tone mapping of an image is performed according to a fixed luminance curve based on

Accordingly, the present invention provides a display device capable of reproducing details of HDR content by performing tone mapping of an image in consideration of the physical peak luminance of the display device, as well as characteristics of an input image and a black level of the display device, and a method for controlling the same I would like to suggest In particular, in the case of a display device having a variable peak luminance according to the APL of the image, the luminance curve for tone mapping of the image is varied and applied based on the variable peak luminance to input input within a range that can be implemented in the display device. We would like to propose a method that can reproduce the HDR characteristics of an image to the maximum.

6 is a flowchart illustrating an example of a method of performing tone mapping of an HDR image in a display device according to an embodiment of the present invention.

The controller 270 of the display device 200 controls the receiver 205 to receive content including an image having a high dynamic range (HDR) and metadata of the content (S610). Here, the receiving unit 210 may be the tuner 210 or the network interface unit 230 . According to an embodiment, when the content is received from an external device through the external device interface unit 235 , the external device interface unit 235 may serve as the receiving unit 205 .

The metadata of the content may include at least one of information indicating a dynamic range of the image, information indicating a peak luminance of the image, and information indicating a luminance curve of the image. The luminance curve of the image may be a luminance curve indicating a range between a minimum luminance and a maximum luminance according to the APL of the image in order to implement HDR of the content. The content provider 10, the service provider 20, and/or the network provider 30 that provides the content may provide information necessary for processing the HDR image in the display device 200 as metadata of the content. .

The controller 270 acquires an average picture level (APL) of an image included in the received content (S620). The controller 270 may decode an image included in the received content, and obtain an APL based on pixel data of the decoded image. The controller 270 may acquire the APL of the image at every preset time or every preset frame.

The control unit 270 detects the peak luminance of the display unit 280 corresponding to the obtained APL (S630). The peak luminance refers to the maximum luminance that the display unit 280 can provide. Depending on the embodiment, the peak luminance may be the same as a physical peak luminance that can be realized in the display unit 280 , or the display unit 280 . ) may be lower than the achievable physical peak luminance. For example, the peak luminance may vary according to the APL of the input image (image), or the peak luminance may be a fixed value regardless of the APL of the input image.

The controller 270 may determine the peak luminance of the display 280 based on a preset luminance curve according to the type of the display 280 . The luminance curve may be dependent on a characteristic based on the type of the display unit 280 . Here, the type of the display unit 280 means that the display unit 280 is a cathode ray tube (CRT) or a light emitting diode (LED). It may be determined by which one of an organic light emitting diode (OLED), a plasma display panel (PDP), a quantum dot (QD) display, and a QD LED display is included. For example, when the display unit 280 includes an OLED, a luminance curve in which the peak luminance of the display unit 280 decreases while the instantaneous peak current decreases when the APL of the image increases due to the characteristics of the current driving method of the OLED. When the display unit 280 includes an LCD, the peak luminance of the display unit 280 may follow a constant luminance curve irrespective of the APL of the image due to the characteristics of the voltage driving method of the LCD. The storage unit 240 may store data corresponding to the APL versus luminance curve of the corresponding display unit 280 . When the display unit 280 includes an OLED, the controller 270 may determine the peak luminance of the display unit 280 based on the luminance curve as shown in FIG. 5 stored in the storage unit 240 .

The control unit 270 performs tone mapping of the image based on the detected peak luminance of the display unit 280 and metadata of the received content (S540). Tone mapping of an image refers to a process of converting at least one of luminance, dynamic range, chromaticity, and saturation of an HDR image included in received content into an image having a dynamic range that can be implemented in the display device 200 . The control unit 270, the tone of the image based on the minimum luminance derived by a preset technique (eg, gamma correction), the detected peak luminance of the display unit 280, and the received metadata of the content Mapping can be done.

According to an embodiment, the controller 270 performs tone mapping of the image in consideration of the detected peak luminance of the display unit 280 and the black level of the display unit 280 together with metadata of the received content. can also be done The black level of the display unit 280 indicates the brightness level of the darkest part of the image output through the display unit 280 , and may be a preset fixed value according to the type of the display unit 280 . The storage unit 240 may store data corresponding to the black level of the corresponding display unit 280 .

In the conventional display device, the minimum luminance derived by a preset technique (eg, gamma correction) and the physical peak luminance realizable in the display unit without reflecting the black level of the display unit during tone mapping of the image Since only the fixed luminance curve based on the luminance curve was applied, there was a limit in expressing the contrast of the image to the maximum. However, according to an embodiment of the present invention, since the black level of the display unit 280 is also considered during tone mapping of the image, there is an advantage in that the image can be more realistically expressed from the low APL to the high APL of the image.

Specifically, the control unit 270 is configured to perform a luminance curve for tone mapping of the image based on the detected peak luminance of the display unit 280, metadata of the received content, and a black level of the display unit 280. can be decided Then, the controller 270 re-acquires the APL of the image at every preset time or every preset frame, detects the peak luminance of the display unit 280 corresponding to the re-acquired APL, and re-acquires the re-acquisition The determined luminance curve may be varied based on the peak luminance corresponding to the selected APL, metadata of the received content, and the black level of the display unit 280 . The controller 270 may process the image based on the determined luminance curve and control the luminance of the display unit 280 .

6 has been described as an example in which the peak luminance of the display unit 280 is variable according to the APL of the image like the display device 200 including an OLED, but the embodiment of the present invention according to FIG. It can also be applied to the case of the display device 200 in which the peak luminance of the display unit 280 does not vary according to the APL of . That is, in the latter case, the display device 200, according to a preset picture quality setting condition or a picture quality setting condition changed by a user, a physical peak luminance that can be implemented in the display unit 280, metadata of the received content, and A luminance curve for tone mapping of the image may be varied and applied based on the black level of the display unit 280 . At this time, since the physical peak luminance achievable in the display unit 280 and the black level of the display unit 280 are fixed values, the minimum luminance value and the peak luminance value for each APL of the variably applied luminance curve are also fixed. value, and the slope of the luminance curve may vary between the minimum luminance value and the peak luminance value. For example, when a movie-only picture quality condition is set by the user or a game-only picture quality condition is set, the controller 270 may vary and apply a luminance curve for tone mapping of an image according to the set picture quality condition.

7 is a diagram illustrating an example of a luminance curve for tone mapping of an image in a display device according to an embodiment of the present invention.

The controller 270 may variably apply a luminance curve for tone mapping of the image according to a characteristic (eg, APL) of the image included in the received content. For example, when the value of the peak luminance of the display unit 280 corresponding to the acquired APL is 5000 nits and the black level of the display unit 280 is 0.1 nit, the controller 270 may set the black level to 0.1 nit. When the tone mapping of the image is performed based on the graph A, and the peak luminance value of the display unit 280 corresponding to the obtained APL is 2000 nits and the black level of the display unit 280 is 0.1 nits, the black level is When the tone mapping of the image is performed based on the B graph of 0.1 nit, the peak luminance value of the display unit 280 corresponding to the obtained APL is 1000 nit and the black level of the display unit 280 is 0.1 nit Tone mapping of the image may be performed based on a C graph having a black level of 0.1 nit. As another example, when the value of the peak luminance of the display unit 280 corresponding to the obtained APL is 5000 nits and the black level of the display unit 280 is 0.01 nit, the controller 270 may set the black level to 0.01 nit. Tone mapping of the image may be performed based on the A graph. Of course, even when the value of the peak luminance of the display unit 280 corresponding to the obtained APL is 5000 nit and the black level of the display unit 280 is the same as 0.1 nit, the obtained APL, the Of course, the slope of the graph A may vary based on the peak luminance, the received metadata of the HDR content, and the black level of the display unit 280 .

When the obtained APL is changed according to an image frame during reproduction of the HDR content, the controller 270 re-detects the peak luminance of the display unit 280 corresponding to the changed APL, and accordingly, for tone mapping of the image The luminance curve can be variably applied.

According to the present embodiment, the optimized HDR content can be provided to the user by varying the luminance curve for tone mapping of the input image as the characteristics of the input image (image) change, and display during tone mapping of the input image By reflecting the difference in the black level of the unit 280, there is an effect of reproducing the HDR characteristics in more detail.

8 is a flowchart illustrating another example of a method of performing tone mapping of an HDR image in a display device according to an embodiment of the present invention. The content overlapping with the above in relation to FIGS. 5 to 7 will not be described in detail, and the differences will be mainly described below.

The controller 270 of the display device 200 controls the receiver 205 to receive content including an image having a high dynamic range (HDR) and metadata of the content (S810).

The controller 270 obtains an APL for each block of the image included in the received content (S820). The controller 270 may decode an image included in the received content, and may obtain an APL for each block based on pixel data of the decoded image. The controller 270 may acquire the APL of the image at every preset time or every preset frame.

9 is a diagram illustrating an example of a specific frame constituting an HDR image.

The controller 270 may divide a frame constituting an image included in the received content into a preset number of blocks (B), and obtain an APL for each block (B). For example, the number and size of the blocks B dividing the frame may be determined based on the size of the display unit 280 , and may depend on the number and size of the light emitting blocks of the backlight unit included in the display unit 280 . It may be determined by the number and size of the unit light emitting blocks capable of local dimming driving in the backlight unit included in the display unit 280 .

Since the image expressed through each block B is different, the APL for each block may have a different value for each block. _{For example, the APL value of the block B 1} corresponding to the bright image may be greater than the APL value of _{the block B 2} corresponding to the dark image.

Referring back to FIG. 8 , the control unit 270 detects the peak luminance of the display unit 280 corresponding to the obtained APL for each block ( S830 ). That is, in relation to the APL of each block of the image, the controller 270 may detect a maximum luminance value that can be emitted by the area of the display unit 280 corresponding to each block of the image. The controller 270 may determine the peak luminance of the display 280 based on a preset luminance curve according to the type of the display 280 .

Then, the control unit 270 performs tone mapping of the image for each block based on the peak luminance of the display unit 280 corresponding to the detected APL for each block and metadata of the received content (S840). ). Since the APL is different for each block of the image and, accordingly, the peak luminance of the display unit 280 corresponding to the APL is also different, the controller 270 may perform tone mapping of the image for each block.

According to an embodiment, the control unit 270 considers the black level of the display unit 280 along with the peak luminance of the display unit 280 corresponding to the detected APL for each block and metadata of the received content. Tone mapping of the image may be performed.

Specifically, the control unit 270 is configured for each block based on the peak luminance of the display unit 280 corresponding to the detected APL for each block, metadata of the received content, and the black level of the display unit 280 . A luminance curve for tone mapping of the image may be determined. Then, the controller 270 re-acquires the APL for each block of the image at every preset time or every preset frame, and detects the peak luminance of the display unit 280 corresponding to the re-acquired APL for each block, , the determined luminance curve may be varied for each block based on the re-obtained peak luminance corresponding to the APL for each block, metadata of the received content, and the black level of the display unit 280 .

Since the luminance curve for tone mapping of the image is similar to that described above with reference to FIG. 7 except that it varies for each block of the image, a detailed description thereof will be omitted.

According to the present embodiment, by reflecting the characteristics of each block of the input image (image) and changing the luminance curve for tone mapping of the input image, the display device 200 can reproduce the characteristics of HDR in more detail. there is

The embodiment shown in FIG. 8 is also described with reference to the case where the peak luminance of the display unit 280 is variable according to the APL of the image like the display device 200 including an OLED, as an example, but the embodiment shown in FIG. 8 Of course, it is also applicable to the case of the display device 200 in which the peak luminance of the display unit 280 does not vary according to the APL of the image.

10 is a block diagram illustrating a display device according to an embodiment of the present invention.

The display device 200 according to an embodiment of the present invention includes a video decoder 1010 , a color gamut mapping module 1020 , a tone mapping module 1030 , an APL analysis module 1040 , a peak luminance calculation module 1050 , and a display. It may include a unit 1060 and a black level analysis module 1070 . According to an embodiment, the video decoder 1010 , the color gamut mapping module 1020 , the tone mapping module 1030 , the APL analysis module 1040 , and the peak luminance calculation module 1050 may be implemented in the controller 270 of FIG. 2 . Also, the display unit 1060 may be implemented as the display unit 280 of FIG. 2 , and the black level analysis module 1070 may be implemented within the control unit 270 or the storage unit 240 of FIG. 2 .

When an image having HDR and metadata of the image are received from an external server, the image may be input to the video decoder 1010 and metadata of the HDR image may be input to the tone mapping module 1030 .

The video decoder 1010 may decode the image and output the decoded image to the color gamut mapping module 1020 . In addition, the video decoder 1010 outputs the pixel data of the decoded image to the APL analysis module 1040, and the APL analysis module 1040 calculates the APL of the image based on the pixel data of the decoded image. can be obtained As described above, the APL analysis module 1040 may acquire the APL of the image every preset time or every preset frame, and obtain the APL for each block of the image every preset time or every preset frame. may be The APL analysis module 1040 may output the APL of the obtained image to the peak luminance calculation module 1050 .

The peak luminance calculation module 1050 detects the peak luminance of the display unit 1060 corresponding to the APL of the obtained image. The peak luminance calculation module 1050 may detect the peak luminance of the display unit 1060 corresponding to the APL of the acquired image based on a preset APL versus luminance curve according to the type of the display unit 1060 . . The peak luminance calculation module 1050 may output the peak luminance of the display unit 1060 corresponding to the APL of the obtained image to the tone mapping module 1030 .

Meanwhile, the color gamut mapping module 1020 maps a color gamut included in the decoded image to a color gamut that can be expressed in the display unit 1060 , and outputs the result to the tone mapping module 1030 . have.

Meanwhile, the black level analysis module 1070 may output the black level of the display unit 1060 to the tone mapping module 1030 .

The tone mapping module 1030 includes the peak luminance of the display unit 1060 corresponding to the APL of the image input from the peak luminance calculation module 1050, metadata of the received image, and a black level analysis module 1070 Based on the black level of the display unit 1060 input from , tone mapping of the image may be performed. Since the method of performing tone mapping of the image is similar to that described above with reference to FIGS. 5 to 9 , a detailed description thereof will be omitted.

In addition, the tone mapping module 1030 may output a tone-mapped image to the display unit 1060 , and the display unit 1060 may display an image in which HDR characteristics are reproduced.

According to the above-described embodiment of the present invention, when tone mapping of an image is performed using a luminance curve based on a fixed peak luminance in a display device displaying a peak luminance variable according to the APL of an input image, a desired HDR effect is not obtained. In addition, even in the case of a display device showing a fixed peak luminance regardless of the APL of the input image, the luminance curve for tone mapping of the image is variably applied by reflecting the characteristics of the input image, thereby limiting the device Despite the characteristics, there is an effect of implementing an excellent contrast ratio.

The present invention described above can be implemented as computer-readable code on a medium in which a program is recorded. The computer-readable medium includes all kinds of recording devices in which data readable by a computer system is stored. Examples of computer-readable media include Hard Disk Drive (HDD), Solid State Disk (SSD), Silicon Disk Drive (SDD), ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc. There is also a carrier wave (eg, transmission over the Internet) that is implemented in the form of. In addition, the computer may include a control unit of the terminal. Accordingly, the above detailed description should not be construed as restrictive in all respects but as exemplary. The scope of the present invention should be determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included in the scope of the present invention.

200: display device
270: control unit
280: display unit

Claims (16)

A receiver configured to receive content including an image having a high dynamic range and metadata of the content, wherein the metadata includes information indicating a dynamic range of the image, information indicating a peak luminance of the image, and the comprising at least one of information representing a luminance curve of the image; and
control unit;
including,
The control unit is
Every preset time or every preset frame,
acquiring an average picture level (APL) of an image included in the received content,
detecting the peak luminance of the display unit corresponding to the obtained APL,
and performing tone mapping of the image at every preset time or every preset frame based on the detected peak luminance and the received metadata. The method of claim 1,
A memory for storing the black level of the display unit; further comprising,
The controller is configured to perform tone mapping of the image based on the detected peak luminance, the received metadata, and a black level of the display unit. The method of claim 1,
The display device, wherein the peak luminance of the display unit corresponding to the APL is determined based on a preset luminance curve according to a type of the display unit. 3. The method of claim 2,
The control unit is
At every preset time or every preset frame, the APL of the image is re-acquired,
detecting the peak luminance of the display unit corresponding to the re-acquired APL,
and determining a luminance curve for tone mapping of the image based on the peak luminance corresponding to the re-acquired APL, the received metadata, and a black level of the display unit. 3. The method of claim 2,
The control unit is
Acquire APL for each block of the image,
detecting the peak luminance of the display unit corresponding to the obtained APL for each block,
and performing tone mapping of the image for each block based on the detected peak luminance corresponding to the APL for each block, the received metadata, and a black level of the display unit. 6. The method of claim 5,
The control unit is
Re-acquire APL for each block of the image at every preset time or every preset frame,
detecting the peak luminance of the display unit corresponding to the re-obtained APL for each block,
and determining a luminance curve for tone mapping of the image for each block based on the detected peak luminance corresponding to the APL for each block, the received metadata, and a black level of the display unit. 3. The method of claim 2,
The black level of the display unit is a fixed value preset according to a type of the display unit. The method of claim 1,
The tone mapping is to adjust at least one of luminance, dynamic range, chroma, and saturation of the image. Receiving content including an image having a high dynamic range and metadata of the content, wherein the metadata includes information indicating a dynamic range of the image, information indicating a peak luminance of the image, and the comprising at least one of information representing a luminance curve of the image;
acquiring an average picture level (APL) of an image included in the received content every preset time or every preset frame;
detecting a peak luminance of a display unit corresponding to the acquired APL at every preset time or every preset frame; and
and performing tone mapping of the image at every preset time or every preset frame based on the detected peak luminance and the received metadata. 10. The method of claim 9,
Obtaining the black level of the display unit from a memory; further comprising,
The tone mapping of the image is performed based on the detected peak luminance, the received metadata, and a black level of the display unit. delete delete delete delete delete delete

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