Image processing device, image processing method, and program

Abstract

A video processing device comprising: an acquisition unit (110) for acquiring video data including video data including video and metadata indicating a first frequency band, which is a band of spatial frequencies where the video exists, through a predetermined transmission line; an adjustment unit (120) for adjusting a sharpness gain of video such that a sharpness gain in a second region belonging to a second frequency band, which is a band outside the first frequency band, is smaller than a sharpness gain in a first region belonging to the first frequency band indicated by the metadata from among a plurality of regions constituting the video included in the video data acquired by the acquisition unit (110); and an output unit (130) for outputting the video adjusted by the adjustment unit (120).

Description

[Technical field]

[0001] The present disclosure relates to an image processing device, an image processing method, and a program that adjusts the sharpness gain of an image, or an image generating device, an image generating method, and a program that generate image data including metadata. [Background technology]

[0002] Patent Document 1 discloses an image processing device that performs edge enhancement by reducing the shoot component for a frame having a larger proportion of pixels in which the luminance difference between adjacent pixels constituting the frame is equal to or greater than a predetermined first value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2014-512740 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides an image processing device and the like that can suppress the amplification of noise caused by increasing the sharpness gain. [Means for solving the problem]

[0005] An image processing device according to one embodiment of the present disclosure includes an acquisition unit that acquires image data including an image and metadata indicating a first frequency band, which is a spatial frequency band in which the image exists; an adjustment unit that adjusts the sharpness gain of the image so that, among multiple regions constituting the image included in the image data acquired by the acquisition unit, a sharpness gain of a second region belonging to a second frequency band, which is a band outside the first frequency band, is smaller than a sharpness gain of a first region belonging to the first frequency band indicated by the metadata; and an output unit that outputs the image adjusted by the adjustment unit.

[0006] Furthermore, an image processing method according to one embodiment of the present disclosure is an image processing method performed by an image processing device that adjusts the sharpness gain of an image, which acquires image data including an image and metadata indicating a first frequency band, which is a spatial frequency band in which the image exists, and adjusts the sharpness gain of the image such that, among multiple regions constituting the image included in the acquired video data, the sharpness gain of a second region belonging to a second frequency band, which is a band outside the first frequency band, is smaller than the sharpness gain of a first region belonging to the first frequency band indicated by the metadata, and outputs the adjusted image.

[0007] In addition, an image generating device according to one embodiment of the present disclosure includes an identification unit that identifies a first frequency band, which is a spatial frequency band in which an image exists, a generation unit that generates image data including the image and metadata indicating the identified first frequency band, and an output unit that outputs the generated video data.

[0008] Furthermore, an image generation method according to one embodiment of the present disclosure is an image generation method performed by an image generation device that generates image data including metadata, which identifies a first frequency band that is a spatial frequency band in which an image exists, generates image data including the image and metadata indicating the identified first frequency band, and outputs the generated video data.

[0009] In addition, these general or specific aspects may be realized by a system, an integrated circuit, a computer program, or a non-transitory recording medium such as a computer-readable CD-ROM, or may be realized by any combination of a system, an integrated circuit, a computer program, and a non-transitory recording medium. Effect of the Invention

[0010] The image processing device and the like according to the present disclosure can suppress the amplification of noise caused by increasing the sharpness gain. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing an outline of a video system according to the present embodiment. [Diagram 2] FIG. 2 is a block diagram showing an example of a hardware configuration of the information processing device according to the present embodiment. [Diagram 3] FIG. 3 is a block diagram showing an example of a hardware configuration of the display device according to the present embodiment. [Figure 4] FIG. 4 is a block diagram showing an example of the configuration of the distribution side device according to the present embodiment. [Diagram 5] FIG. 5 is a diagram showing a distribution of a plurality of regions into which an image according to the present embodiment is frequency-divided. [Figure 6] FIG. 6 is a block diagram showing an example of a functional configuration of the display device according to the present embodiment. [Figure 7] FIG. 7 is a block diagram illustrating an example of a detailed configuration of the extraction unit. [Figure 8] FIG. 8 is a diagram for explaining a plurality of regions divided into frequencies. [Figure 9] FIG. 9 is a diagram for defining a plurality of regions into which a horizontal frequency band is divided. [Figure 10] FIG. 10 is a diagram for defining a plurality of regions into which a frequency band in the vertical direction is divided. [Figure 11] FIG. 11 is a histogram showing the number of pixels belonging to each region in the vertical columns of region V2. [Figure 12] FIG. 12 is a graph showing a first offset curve of the sharpness gain corresponding to each region in the vertical row of the region V2. [Figure 13] FIG. 13 is a table showing the offset values ​​of the sharpness gain corresponding to each area. [Figure 14] FIG. 14 is a block diagram illustrating an example of a detailed configuration of the first correction unit. [Figure 15]FIG. 15 is a block diagram showing an example of a detailed configuration of the detection unit. [Figure 16] FIG. 16 is a diagram showing a detail threshold value for determining the type of area that constitutes an image. [Figure 17] FIG. 17 is a diagram showing an example of the determination result of the type of area. [Figure 18] FIG. 18 is a graph showing the second offset curve. [Figure 19] FIG. 19 is a table showing an example of detail set data. [Figure 20] FIG. 20 is a block diagram illustrating an example of a detailed configuration of the second correction unit. [Figure 21] FIG. 21 is a flowchart of a video generating method by a distribution device. [Figure 22] FIG. 22 is a flowchart of a video processing method performed by the display device. [Figure 23] FIG. 23 is a flowchart of a process for adjusting the sharpness gain. [Figure 24] FIG. 24 is a flowchart of the first calculation. [Diagram 25] FIG. 25 is a flowchart of the calculation process of the second offset value. [Figure 26] FIG. 26 is a flowchart of the second calculation. [Figure 27] FIG. 27 is a flowchart of a process for adjusting the sharpness gain of video data. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (The knowledge that formed the basis of the invention) The present inventors have found that the following problems occur with the video processing device described in the "Background Art" section.

[0013] The video processing device acquires video data generated on the distribution side, and performs a process of increasing the sharpness gain of the video data obtained by decoding the acquired video data. Since the video processing device acquires video data via a predetermined transmission means, for example, the acquired video data may contain noise due to the influence of the predetermined transmission means. Furthermore, the video data decoded by the video processing device may contain noise generated during encoding by the distribution side device, or noise generated during decoding by the video processing device. In this way, noise may occur in the video finally output for display between the time when the video obtained by shooting is encoded by the distribution side device and the time when it is decoded by the video processing device. In this case, since the video data contains noise, when the video processing device performs a process of increasing the sharpness gain of the video data obtained by decoding, the contour of the noise contained in the video data is emphasized, which may make the noise more noticeable.

[0014] Therefore, the present disclosure provides an image processing device and the like that can suppress the amplification of noise caused by increasing the sharpness gain.

[0015] An image processing device according to one embodiment of the present disclosure includes an acquisition unit that acquires image data including an image and metadata indicating a first frequency band, which is a spatial frequency band in which the image exists; an adjustment unit that adjusts the sharpness gain of the image so that, among multiple regions constituting the image included in the image data acquired by the acquisition unit, a sharpness gain of a second region belonging to a second frequency band, which is a band outside the first frequency band, is smaller than a sharpness gain of a first region belonging to the first frequency band indicated by the metadata; and an output unit that outputs the image adjusted by the adjustment unit.

[0016] Therefore, the sharpness gain of the video data can be adjusted so that the sharpness gain of the second region belonging to the second frequency band does not increase more than that of the first region. Therefore, when performing processing to increase the sharpness gain, it is possible to suppress the noise belonging to the second frequency band, which occurs between the time when the video obtained by shooting is encoded by the distribution side device and the time when it is decoded by the video processing device, from being amplified more than that of the first region. Therefore, by performing processing to increase the sharpness gain, it is possible to reduce the noise from being more noticeable than other videos.

[0017] The second frequency band may be included in a band lower than a lowest frequency that defines the first frequency band, or a band higher than a highest frequency that defines the first frequency band.

[0018] Therefore, the sharpness gain of the video data can be adjusted so that the sharpness gain of a second region belonging to a second frequency band included in a band lower than the lowest frequency defining the first frequency band or a band higher than the highest frequency defining the first frequency band is not higher than that of the first region.

[0019] Moreover, the adjustment section may adjust the sharpness gain of the image by adding a first offset value, which is a value equal to or less than a first threshold, to the sharpness gain of the second region.

[0020] Therefore, the sharpness gain of the video data can be adjusted so that the sharpness gain of the second region belonging to the second frequency band where no video exists does not increase or decreases. Therefore, when performing processing to increase the sharpness gain, it is possible to suppress amplification of noise belonging to the second frequency band that occurs between when the video obtained by shooting is encoded by the distribution device and when it is decoded by the video processing device. In particular, since noise is often included in a frequency band higher than a predetermined frequency, by adjusting the sharpness gain of the video data so that the sharpness gain of the second region belonging to the second frequency band does not increase or decreases, it is possible to more effectively suppress deterioration of image quality due to noise.

[0021] Moreover, the adjustment unit may adjust the sharpness gain of the image by adding a second offset value, which is a value larger than the first threshold value, to the sharpness gain of the first region.

[0022] Therefore, the sharpness gain of the first region in which the image exists can be improved, and the image quality can be improved effectively.

[0023] In addition, the first frequency band may include a plurality of bands that are different from each other, the second offset value may include a plurality of third offset values ​​that respectively correspond to the plurality of bands, and the adjustment unit may count the number of pixels that belong to each of the plurality of bands, and determine the plurality of third offset values ​​so that the third offset values ​​become larger as the number of pixels that belong to each of the plurality of bands increases.

[0024] Therefore, the sharpness gain increases as the number of pixels increases, and image quality can be improved effectively.

[0025] The first threshold may be zero.

[0026] In addition, the adjustment unit may further calculate a maximum difference for each of a plurality of pixels in the image based on the pixel values ​​of a plurality of pixels across a predetermined width in the horizontal or vertical direction based on the pixel, and adjust the sharpness gain of the image so that a fifth offset value to be further added to the sharpness gain of a second pixel for which the maximum difference outside the predetermined range is calculated is smaller than a fourth offset value to be further added to the sharpness gain of a first pixel for which the maximum difference within the predetermined range is calculated.

[0027] Therefore, the sharpness gain can be adjusted so that the sharpness gain in the first pixel, where image quality is more likely to be improved by increasing the sharpness gain, is higher than the sharpness gain in the second pixel, thereby effectively improving image quality.

[0028] Furthermore, the maximum difference within the predetermined range may be a value smaller than the maximum difference outside the predetermined range, or a value larger than the maximum difference outside the predetermined range.

[0029] The fourth offset value may be a value greater than 0, and the fifth offset value may be 0.

[0030] Furthermore, an image processing method according to one embodiment of the present disclosure is an image processing method performed by an image processing device that adjusts the sharpness gain of an image, which acquires image data including an image and metadata indicating a first frequency band, which is a spatial frequency band in which the image exists, and adjusts the sharpness gain of the image such that, among multiple regions constituting the image included in the acquired video data, the sharpness gain of a second region belonging to a second frequency band, which is a band outside the first frequency band, is smaller than the sharpness gain of a first region belonging to the first frequency band indicated by the metadata, and outputs the adjusted image.

[0031] Therefore, the sharpness gain of the video data can be adjusted so that the sharpness gain of the second region belonging to the second frequency band where no video exists does not increase more than the first region. Therefore, when performing processing to increase the sharpness gain, it is possible to suppress the noise belonging to the second frequency band that occurs between when the video obtained by shooting is encoded by the distribution device and when it is decoded by the video processing device from being amplified more than the first region. Therefore, by performing processing to increase the sharpness gain, it is possible to reduce the noise being more noticeable than other videos.

[0032] In addition, an image generating device according to one embodiment of the present disclosure includes an identification unit that identifies a first frequency band, which is a spatial frequency band in which an image exists, a generation unit that generates image data including the image and metadata indicating the identified first frequency band, and an output unit that outputs the generated video data.

[0033] According to this, since video data including metadata indicating the first frequency band is output, the video processing device that receives the video data can easily perform processing to suppress the amplification of noise caused by increasing the sharpness gain.

[0034] Furthermore, an image generation method according to one embodiment of the present disclosure is an image generation method performed by an image generation device that generates image data including metadata, which identifies a first frequency band that is a spatial frequency band in which an image exists, generates image data including the image and metadata indicating the identified first frequency band, and outputs the generated video data.

[0035] According to this, since video data including metadata indicating the first frequency band is output, the video processing device that receives the video data can easily perform processing to suppress the amplification of noise caused by increasing the sharpness gain.

[0036] In addition, these general or specific aspects may be realized by a system, an integrated circuit, a computer program, or a non-transitory recording medium such as a computer-readable CD-ROM, or may be realized by any combination of a system, an integrated circuit, a computer program, and a non-transitory recording medium.

[0037] Hereinafter, the embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

[0038] The inventor provides the accompanying drawings and the following description so that those skilled in the art can fully understand the present disclosure, and does not intend for them to limit the subject matter described in the claims.

[0039] (Embodiment) Hereinafter, the embodiment will be described with reference to FIGS. 1 to 14. FIG.

[0040] [1. Configuration] FIG. 1 is a diagram showing an outline of a video system according to the present embodiment.

[0041] As shown in FIG. 1, a video system 1 includes a distribution device 200 that distributes data to be distributed, and a display device 100 that receives the distributed data to be distributed.

[0042] The distribution side device 200 is composed of a camera 201 and an information processing device 202. The information processing device 202 converts video captured by the camera 201, such as a video camera, into data for distribution to be transmitted to the display device 100, and transmits the data for distribution to the display device 100 via a transmission means. The data for distribution may be coded data in which video data has been compressed (coded), or may be coded data generated by compressing and then multiplexing the video data and audio data.

[0043] Here, the transmission means is a means for sending out broadcast waves in accordance with a predetermined television broadcasting standard, a means for distributing to a network such as the Internet in accordance with a predetermined communication protocol, or a means for recording on a predetermined package medium and selling the predetermined package medium. In this embodiment, an example will be described in which a means for sending out broadcast waves in accordance with a predetermined television broadcasting standard is used as the transmission means.

[0044] The display device 100 receives data for distribution and displays a video represented by the video data included in the received data for distribution. The display device 100 has the appearance of a typical flat panel display with a display device including a display panel housed in a housing. The display device 100 is, for example, a liquid crystal display, an organic electroluminescence display, or the like.

[0045] The display device 100 is an example of a video processing device, and the information processing device 202 is an example of a video generating device.

[0046] FIG. 2 is a block diagram showing an example of a hardware configuration of the information processing device according to the present embodiment.

[0047] As shown in FIG. 2, the information processing device 202 includes, as its hardware configuration, a processor 203, a main memory 204, a storage 205, a communication IF (Interface) 206, an input IF (Interface) 207, and a display 208.

[0048] The processor 203 is a processor that executes a program stored in the storage 205 or the like.

[0049] The main memory 204 is a volatile storage area used as a work area when the processor 203 executes a program.

[0050] The storage 205 is a non-volatile storage area that holds various data such as programs.

[0051] The communication IF 206 is a communication interface for transmitting data between the camera 201 and an external device. The communication IF 206 may be an interface for wireless communication, such as a wireless LAN interface or a Bluetooth (registered trademark) interface. The communication IF 206 may be an interface for wired communication, such as a USB (Universal Serial Bus) or a wired LAN interface. The communication IF 206 is not limited to the above, and may be a communication interface for transmitting data between the camera 201 and an external device via a communication network. The communication IF 206 may be a reader for reading data stored in a recording medium, such as a memory card. The information processing device 202 is communicatively connected to the camera 201 through the communication IF 206, and acquires video data from the camera 201 through the communication IF 206.

[0052] The input IF 207 is an interface for receiving input from a person. The input IF 207 may be a pointing device such as a mouse, a touch pad, a touch panel, or a trackball, or may be a keyboard.

[0053] The display 208 is a master monitor that displays the video represented by the video data in order to master the video data. For example, the display 208 is a liquid crystal display, an organic EL display, or the like.

[0054] FIG. 3 is a block diagram showing an example of a hardware configuration of the display device according to the present embodiment.

[0055] As shown in FIG. 3, the display device 100 includes a tuner 101, a decoder 102, a control circuit 103, a memory 104, and a display device 105.

[0056] The tuner 101 converts an analog signal constituting a broadcast wave received by an antenna (not shown) into coded data, which is a digital signal, and outputs the coded data obtained by the conversion to the decoder 102 .

[0057] The decoder 102 decodes the coded data obtained from the tuner 101, and outputs the video data obtained by decoding to the control circuit 103. When the coded data is multiplexed, the decoder 102 may decode the coded data for video and the coded data for audio obtained by demultiplexing the coded data into video data and audio data, respectively. The decoder 102 may obtain metadata, which is additional data for the video data, from the tuner 101 together with the video data, and decode the metadata. The decoded metadata is temporarily written in the memory 104 by the control circuit 103, which will be described later. The metadata is added to the video data in advance by the distribution side device 200 and then transmitted.

[0058] The control circuit 103 performs video processing on the video data output by the decoder 102 in accordance with the metadata. The control circuit 103 outputs the video obtained by performing the video processing to the display device 105. This allows the display device 105 to display a video that matches the characteristics of the display device 105 and the metadata. The decoder 102 and the control circuit 103 may be realized by the same circuit. The control circuit 103 may be realized by a general-purpose processor such as a CPU that executes a predetermined program, or may be realized by a dedicated circuit. In other words, the functions of the display device 100 described later may be realized by software or hardware.

[0059] A control program may be stored in the memory 104. The memory 104 is, for example, a non-volatile memory.

[0060] The display device 105 displays the image output by the control circuit 103. The display device 105 is a display panel, and is configured, for example, by a liquid crystal panel, an organic EL panel, or the like.

[0061] FIG. 4 is a block diagram illustrating an example of a functional configuration of the distribution device according to the present embodiment.

[0062] As shown in FIG. 4, the distribution device 200 includes a capture unit 210, a mastering unit 220, a frequency conversion unit 230, and an encoder 240.

[0063] The capture unit 210 acquires video data of a subject photographed by the camera 201, and outputs the acquired video data. The capture unit 210 is realized by, for example, the camera 201 and a communication IF 206 connected to the camera 201.

[0064] The mastering unit 220 sets a MAX CF (maximum video horizontal frequency or maximum video vertical frequency) or a MIN CF (minimum video horizontal frequency or minimum video vertical frequency) in response to an input from the producer, and generates video data showing a video according to the set MAX CF and / or MIN CF. For example, the mastering unit 220 displays the video data obtained from the capture unit 210 on a master monitor while executing a process of adjusting the video according to the input from the video producer so that the video has the MAX CF and MIN CF intended by the producer, thereby generating master data, which is video data showing a video for distribution.

[0065] Specifically, the mastering unit 220 may generate master data by filtering the video data to cut frequency components outside the range between MIN CF and MAX CF set according to the input, so that the frequency components included in the video data are within the range. The mastering unit 220 may also set the minimum frequency of the horizontal frequency components included in the video data to MIN CHF, and the maximum frequency of the horizontal frequency components to MAX CHF. Similarly, the mastering unit 220 may set the minimum frequency of the vertical frequency components included in the video data to MIN CVF, and the maximum frequency of the vertical frequency components to MAX CVF.

[0066] This allows the producer to generate master data while checking the video being edited displayed on a master monitor (not shown) and the frequency-converted horizontal / vertical frequency distribution data. The mastering unit 220 specifies the MAX CHF, MAX CVF, MIN CHF, and MIN CVF obtained by setting the frequency as effective frequency bands in which the video exists. The effective frequency bands are an example of the first frequency band.

[0067] The mastering unit 220 may set the MAX CF and MIN CF so as to filter the frequency bands where no video exists (e.g., HHLL, HHLH, HHHL, HHHH). The frequency bands where no video exists are set according to an input made by the producer while checking the distribution of a plurality of bands into which the video is divided in frequency (e.g., four bands in the horizontal direction and four bands in the vertical direction, totaling 16 bands), as shown in FIG. 5, for example. The mastering unit 220 may set the MAX CHF to 0.75, the MAX CVF to 1.00, the MIN CHF to 0, and the MIN CVF to 0.25, for example. Note that the MAX CHF is the MAX CF in the horizontal direction, the MAX CVF is the MAX CF in the vertical direction, the MIN CHF is the MIN CF in the horizontal direction, and the MIN CVF is the MIN CF in the vertical direction. A MAX CHF of 1.00 indicates that the frequency is 1 / 2 of the horizontal clock frequency of the video data. Furthermore, a MAX CVF of 1.00 indicates that the frequency is half the vertical clock frequency of the video data.

[0068] The mastering unit 220 may frequency-divide the video and then frequency-synthesize the video of the frequency-divided multiple bands. The mastering unit 220 may also filter all or a part of the video of the frequency-divided multiple bands and frequency-synthesize the filtered multiple videos. Note that a part of the video refers to n videos (n is a natural number) of the videos of the multiple bands. For example, the mastering unit 220 may perform filtering processing to cut the relevant bands as filters for LLLL, LHLL, HLLL, HHLH, HHHL, and HHHH among the video of the frequency-divided multiple bands, or filtering processing to reduce the gain of the relevant bands.

[0069] When a frequency band is divided into 16 bands, each band is indicated by a four-digit combination of L and H, as shown in Fig. 5. Of the four-digit combinations indicating each band, the first two digits indicate the horizontal frequency band, and the latter two digits indicate the vertical frequency band. The two-digit characters in each direction indicate the frequency bands with increasing frequency, for example, LL, LH, HL, and HH.

[0070] The frequency band is not limited to being divided into 16 bands in total, 4 bands in the horizontal direction and 4 bands in the vertical direction, but may be divided into 9 bands in total, 3 bands in the horizontal direction and 3 bands in the vertical direction. The number of bands divided in the horizontal direction and the number of bands divided in the vertical direction may be equal or different.

[0071] Although it has been stated that the mastering unit 220 determines MAX CHF, MAX CVF, MIN CHF, and MIN CVF, it is sufficient for the frequency band containing the video to be indicated, and therefore it is sufficient to determine at least one of MAX CHF, MAX CVF, MIN CHF, and MIN CVF.

[0072] In addition, the mastering unit 220 may generate master data, which is video data representing video for distribution, by displaying the video data obtained from the capture unit 210 on a master monitor while performing a process of adjusting the video data in accordance with input from the video producer so that the video is displayed with the brightness and color intended by the producer.

[0073] The mastering unit 220 is realized, for example, by the processor 203, the main memory 204, and the storage 205 of the information processing device 202. The mastering unit 220 is realized by the processor 203 executing a program stored in the storage 205 using the main memory 204.

[0074] The frequency conversion unit 230 frequency-divides the video of the video data adjusted by the mastering unit 220, and returns the video data of the video frequency-divided into a plurality of bands to the mastering unit 220. The frequency conversion unit 230 may frequency-divide the video using, for example, a discrete cosine transform (DCT) or a discrete wavelet transform (DWT). The frequency conversion unit 230 is realized by, for example, the processor 203, the main memory 204, and the storage 205 of the information processing device 202. The frequency conversion unit 230 is realized by the processor 203 executing a program stored in the storage 205 using the main memory 204.

[0075] The encoder 240 generates video data by encoding the master data generated in the mastering unit 220 and at least one of MAX CHF, MAX CVF, MIN CHF, and MIN CVF. MAX CHF, MAX CVF, MIN CHF, and MIN CVF are metadata (frequency information) indicating a frequency band in which the determined video exists. The encoder 240 performs encoding on the master data according to a video compression standard. The encoder 240 outputs video data including the encoded data for the encoded video and the metadata to a transmission path. Although not shown, the distribution data including the compressed encoded data for the video output by the encoder 240 may include encoded data for other types of media such as audio and subtitles in addition to the video. The metadata may also include information other than the frequency information, for example, information indicating the maximum value and average value of the luminance value. The encoder 240 is realized by, for example, the processor 203, the main memory 204, the storage 205, and the communication IF 206 of the information processing device 202. The encoder 240 is realized by the processor 203 executing a program stored in the storage 205 using the main memory 204 .

[0076] Note that the distribution side device 200 sets the specified frequency band to the frequency band in which the video exists by adjusting the video data so that it is set to the frequency band specified in response to the producer's input, but without being limited thereto, the frequency band in which the video exists may also be identified by analyzing the frequency distribution of the video in the video data.

[0077] As described above, the distribution device 200 generates video data including the set MAX CF and MIN CF as metadata, and distributes data for distribution (encoded data) in which the generated video data is encoded. This allows the distribution device 200 to indicate a valid frequency range in which the content exists in the video data of the content video (hereinafter referred to as "content"). Note that a frequency band in which the content (video) exists in the video data is called a valid frequency band, and a frequency band in which the content (video) does not exist is called an invalid frequency band that is not valid. The invalid frequency band is an example of a second frequency band.

[0078] Therefore, the display device 100 on the receiving side can appropriately perform contour correction processing and noise reduction processing, which are image quality improvement processing when displaying an image represented by video data, by referring to the metadata indicating the effective frequency range. Specifically, the display device 100 may perform processing to lower or turn off the gain of the contour correction processing for a high frequency band equal to or higher than the MAX CF, or to increase the gain of the noise reduction processing, as the image quality improvement processing. The display device 100 may also perform processing to lower or turn off the gain of the contour correction processing for a low frequency band equal to or lower than the MIN CF, or to increase the gain of the noise reduction processing, as the image quality improvement processing. By performing such image quality improvement processing, the display device 100 can appropriately perform image quality processing for an ineffective frequency band of the actual content to be distributed. Therefore, the display device 100 can reduce unnecessary noise components generated in the transmission path between the distribution side device 200 and the display device 100 on the receiving side, and can effectively improve image quality such as resolution and sharpness in the effective frequency band of the video signal processing. Furthermore, the display device 100 can reduce noise that occurs during encoding in the distribution device 200 or noise that occurs during decoding in the display device 100.

[0079] Furthermore, in the encoding of video data on the distribution side, MPEG2 and H.265 are widely used for television broadcasting and Internet distribution, and the compression rate is improved by frequency converting the video data, dividing it horizontally and vertically, and adjusting the quantization coefficient for each band. In encoding, by utilizing the human visual characteristics that make it difficult to detect degradation in high-resolution image parts, the quantization coefficients of bands with high frequency components (for example, the bands HHLL, HHLH, HHHL, and HHHH shown in Figure 5) are reduced or set to zero. This makes it possible to improve the compression rate of video data during encoding while suppressing degradation of image quality.

[0080] Furthermore, in order to achieve a significant improvement in the compression ratio, it may be possible to lower the quantization coefficients of the low frequency bands (for example, LLLL, LHLL, HLLL, and HHLL shown in Figure 5) which have the largest amount of information after frequency conversion.

[0081] In this way, by including metadata in the content's video data, the distribution side device 200 can indicate the frequency range in which to reduce the quantization coefficient and compress it, so that the receiving side display device 100 can appropriately perform image quality improvement processes such as contour correction processing and noise reduction processing when displaying the image included in the content's video data, by referring to the frequency range indicated as metadata in the video data.

[0082] Specifically, the display device 100 may perform the image quality improvement process by lowering or turning off the gain of the contour correction process in a high frequency band equal to or higher than the MAX CF, or by increasing the gain of the noise reduction process. The display device 100 may also perform the image quality improvement process by lowering or turning off the gain of the contour correction process in a low frequency band equal to or lower than the MIN CF, or by increasing the gain of the noise reduction process. By performing such image quality improvement process, the display device 100 can appropriately perform image quality processing on a frequency band that deteriorates when encoding the video data of the actual content to be distributed, and can effectively reduce unnecessary noise components generated in the encoding process of the distribution device 200. Furthermore, by performing the image quality improvement process, the display device 100 can effectively improve image quality such as a sense of resolution and sharpness in an effective frequency band in which an image exists.

[0083] Next, the functional configuration of the display device will be described.

[0084] FIG. 6 is a block diagram showing an example of a functional configuration of the display device according to the present embodiment.

[0085] As shown in FIG. 6, the display device 100 includes, as its functional components, an acquisition section 110, an adjustment section 120, and an output section .

[0086] The acquisition unit 110 acquires data for distribution via a transmission means. The acquisition unit 110 then acquires video data by decoding the data for distribution. The acquisition unit 110 is realized by, for example, a tuner 101, a decoder 102, and the like.

[0087] The adjustment unit 120 includes a control unit 121, a storage unit 122, an extraction unit 123, a first correction unit 124, and a second correction unit 125.

[0088] The control unit 121 identifies an effective frequency band using MAX CHF, MAX CVF, MIN CHF, and MIN CVF, which are metadata included in the video data, and analyzes the video in the identified effective frequency band. Then, the control unit 121 adaptively generates frequency set data for frequency-dividing the video in the effective frequency band according to the video data. The control unit 121 reads out an initial value of the frequency set data stored in the storage unit 122 from the storage unit 122, and generates frequency set data using the read initial value of the frequency set data, the metadata included in the video data, and the video in the effective frequency band. The control unit 121 adaptively determines the values ​​of frequency thresholds HF1 and VF1 that specify the lowest band of the effective frequency band, and frequency thresholds HF4 and HF4 that specify the highest band. The threshold HF1 indicates the lowest frequency of the effective frequency band in the horizontal direction. The threshold VF1 indicates the lowest frequency of the effective frequency band in the vertical direction. The threshold HF4 indicates the highest frequency of the effective frequency band in the horizontal direction. The threshold value VF4 indicates the highest frequency of the effective frequency band in the vertical direction. The threshold values ​​HF1, VF1, HF4, and VF4 correspond to MAX CHF, MAX CVF, MIN CHF, and MIN CVF, respectively (see FIG. 8).

[0089] Moreover, the control unit 121 generates a detail threshold and detail set data. The detail threshold is a threshold for determining whether each region (for example, each pixel) constituting the image is a plain region, a detail region, or an edge region. The detail set data is data indicating a sharpness gain offset value to be applied to a region (pixel) determined to be a plain region, a sharpness gain offset value to be applied to a region (pixel) determined to be a detail region, and a sharpness gain offset value to be applied to a region (pixel) determined to be an edge region. Note that the plain region, detail region, and edge region indicate classification according to the maximum difference in the amplitude of pixel values ​​of the regions (pixels), and indicate that the maximum difference in the amplitude of pixel values ​​is larger in the detail region than in the plain region, and the maximum difference in the amplitude of pixel values ​​is larger in the edge region than in the detail region. The control unit 121 may read out from the memory unit 122 the initial value of the detail threshold and the initial value of the detail set data stored in the memory unit 122, and use a histogram indicating the number of pixels for each frequency band of the image in the valid frequency band to generate a detail threshold and detail set data according to the read initial value of the detail threshold and the initial value of the detail set data.

[0090] Furthermore, the control unit 121 generates a set table for setting a sharpness gain used in contour correction processing, using MAX CHF, MAX CVF, MIN CHF, and MIN CVF, and a histogram indicating the number of pixels for each frequency band of an image in a valid frequency band. The control unit 121 may read out the initial values ​​of the set table stored in the storage unit 122 from the storage unit 122, and generate a set table according to the frequency information and the histogram using the initial values ​​of the read set table, the frequency information, and the histogram.

[0091] Here, the contour correction process is a process performed on video data to improve the sense of resolution or sharpness of the image. Therefore, by performing the contour correction process on the video data, it is possible to improve the sense of resolution or sharpness of the image of the obtained video data. The sharpness gain is a parameter that determines the gain of the contour correction process. Note that the result of the contour correction process when the sharpness gain is 0 is the same as when the contour correction process is not performed. In this case, the sense of resolution or sharpness of the image does not change before and after the contour correction process.

[0092] The control unit 121 is realized by the control circuit 103. Specifically, the control unit 121 is realized by the control circuit 103 executing a predetermined program stored in the memory 104.

[0093] The storage unit 122 stores initial values ​​of the frequency set data, the detail threshold value, the detail set data, and the gain set table. The storage unit 122 is realized by the memory 104.

[0094] The extraction unit 123 extracts a plurality of bands by dividing the video of the video data into a plurality of horizontal frequency bands and a plurality of vertical frequency bands. The details of the extraction unit 123 will be described with reference to Figs. 7 to 13.

[0095] Fig. 7 is a block diagram showing an example of a detailed configuration of the extraction unit. Fig. 8 is a diagram for explaining a plurality of frequency-divided bands. Fig. 9 is a diagram for defining a plurality of bands divided in a horizontal frequency band. Fig. 10 is a diagram for defining a plurality of bands divided in a vertical frequency band. Fig. 11 is a histogram showing the number of pixels belonging to each band of a vertical band V2 row. Fig. 12 is a graph showing a first offset curve of the sharpness gain corresponding to each band of a vertical band V2 row. Fig. 13 is a table showing the offset value of the sharpness gain corresponding to each band.

[0096] As shown in FIG. 7, the extraction unit 123 has five horizontal extraction units 301-305, five vertical extraction units 311-315, and 25 counting units 321-345.

[0097] As shown in FIG. 8, the five horizontal extraction units 301 to 305 extract five bands obtained by dividing the video in the horizontal direction by filtering using thresholds HF1, HF2, HF3, and HF4 in the horizontal frequency bands indicated by the frequency set data. Specifically, the horizontal extraction unit 301 extracts a horizontal band H0 having a frequency band less than the threshold HF1. ​​The horizontal extraction unit 302 extracts a horizontal band H1 having a frequency band greater than the threshold HF1 and less than the threshold HF2. The horizontal extraction unit 303 extracts a horizontal band H2 having a frequency band greater than the threshold HF2 and less than the threshold HF3. The horizontal extraction unit 304 extracts a horizontal band H3 having a frequency band greater than the threshold HF3 and less than the threshold HF4. The horizontal extraction unit 305 extracts a horizontal band H4 having a frequency band greater than the threshold HF4.

[0098] The threshold value HF1 may be included in either horizontal band H0 or horizontal band H1. The threshold value HF2 may be included in either horizontal band H1 or horizontal band H2. The threshold value HF3 may be included in either horizontal band H2 or horizontal band H3. The threshold value HF4 may be included in either horizontal band H3 or horizontal band H4.

[0099] As shown in Fig. 9, the five horizontal extraction units 301 to 305 may be defined as being weighted into two bands divided by the threshold values ​​HF1, HF2, HF3, and HF4 in the bands around the threshold values ​​HF1, HF2, HF3, and HF4. That is, the band around the threshold value HF1 (that is, the band of the first range centered on the threshold value HF1) may be defined such that the weight of the horizontal band H1 increases as the frequency increases. For example, in the case of a pixel whose frequency is the threshold value HF1, the threshold value HF1 in Fig. 9 means that 0.5 pixels belong to the horizontal band H0 and 0.5 pixels belong to the horizontal band H1 because the gain corresponding to the horizontal band H0 is 0.5 and the gain corresponding to the horizontal band H1 is 0.5. In other words, when the frequency of a pixel belongs to a band around the threshold value, and the threshold value is a threshold value between the first horizontal band and the second horizontal band, the number of pixels indicated by the gain value of the first horizontal band corresponding to the pixel belongs to the first horizontal band, and the number of pixels indicated by the gain value of the second horizontal band corresponding to the pixel belongs to the second horizontal band.

[0100] 8, the five vertical extraction units 311-315 filter each of the horizontal bands H0-H4 extracted by the horizontal extraction units 301-305 using thresholds VF1, VF2, VF3, and VF4 in the vertical frequency bands indicated by the frequency set data. As a result, the five vertical extraction units 311-315 extract five bands divided vertically from each of the horizontal bands H0-H4 extracted by the horizontal extraction units 301-305. As a result, the video is divided into 25 bands, five in the horizontal direction and five in the vertical direction.

[0101] Specifically, the vertical extraction unit 311 extracts a vertical band V0 having a frequency band less than a threshold VF1. The vertical extraction unit 312 extracts a vertical band V1 having a frequency band greater than the threshold VF1 and less than a threshold VF2. The vertical extraction unit 313 extracts a vertical band V2 having a frequency band greater than the threshold VF2 and less than a threshold VF3. The vertical extraction unit 314 extracts a vertical band V3 having a frequency band greater than the threshold VF3 and less than a threshold VF4. The vertical extraction unit 315 extracts a vertical band V4 having a frequency band greater than the threshold VF4.

[0102] The threshold VF1 may be included in either vertical band V0 or vertical band V1. The threshold VF2 may be included in either vertical band V1 or vertical band V2. The threshold VF3 may be included in either vertical band V2 or vertical band V3. The threshold VF4 may be included in either vertical band V3 or vertical band V4.

[0103] In addition, the five vertical extraction units 311 to 315 may be defined as being weighted into two bands divided by the thresholds VF1, VF2, VF3, and VF4 in the bands around the thresholds VF1, VF2, VF3, and VF4, as shown in Fig. 10. That is, the band around the threshold VF1 (that is, the band of the first range centered on the threshold VF1) may be defined such that the weight of the vertical band V1 increases as the frequency increases. For example, in the case of a pixel whose frequency is the threshold VF1, the threshold VF1 in Fig. 10 means that the gain corresponding to the vertical band V0 is 0.5 and the gain corresponding to the vertical band V1 is 0.5, so that 0.5 pixels belong to the vertical band V0 and 0.5 pixels belong to the vertical band V1. In other words, when the frequency of a pixel belongs to a band around the threshold value and the threshold value is a threshold value between the first vertical band and the second vertical band, the number of pixels indicated by the gain value of the first vertical band corresponding to the pixel belongs to the first vertical band, and the number of pixels indicated by the gain value of the second vertical band corresponding to the pixel belongs to the second vertical band.

[0104] The difference between two adjacent thresholds among the thresholds HF1, HF2, HF3, and HF4 does not have to be a constant value. That is, the bandwidths of the horizontal bands H0 to H4 do not have to be equal to each other. For example, the bandwidths of the horizontal bands H0 and H4 may be smaller than the bandwidths of the other horizontal bands H1 to H3. Similarly, the difference between two adjacent thresholds among the thresholds VF1, VF2, VF3, and VF4 does not have to be a constant value. That is, the bandwidths of the vertical bands V0 to V4 do not have to be equal to each other. For example, the bandwidths of the vertical bands V0 and V4 may be smaller than the bandwidths of the other vertical bands V1 to V3.

[0105] The 25 counting units 321-345 count the number of pixels belonging to each of the 25 bands V0H0-V4H4 defined by each of the horizontal bands H0-H4 divided in the horizontal direction and each of the vertical bands V0-V4 divided in the vertical direction, as shown in Fig. 8. That is, the five counting units 321-325 count the number of pixels belonging to the band V0H0 defined by the vertical band V0 and the horizontal band H0, the band V0H1 defined by the vertical band V0 and the horizontal band H1, the band V0H2 defined by the vertical band V0 and the horizontal band H2, the band V0H3 defined by the vertical band V0 and the horizontal band H3, and the band V0H4 defined by the vertical band V0 and the horizontal band H4, respectively. The five counters 326-330 count the number of pixels belonging to a band V1H0 defined by vertical band V1 and horizontal band H0, a band V1H1 defined by vertical band V1 and horizontal band H1, a band V1H2 defined by vertical band V1 and horizontal band H2, a band V1H3 defined by vertical band V1 and horizontal band H3, and a band V1H4 defined by vertical band V1 and horizontal band H4. The five counters 331-335 count the number of pixels belonging to a band V2H0 defined by vertical band V2 and horizontal band H0, a band V2H1 defined by vertical band V2 and horizontal band H1, a band V2H2 defined by vertical band V2 and horizontal band H2, a band V2H3 defined by vertical band V2 and horizontal band H3, and a band V2H4 defined by vertical band V2 and horizontal band H4. The five counters 336-340 count the number of pixels belonging to a band V3H0 defined by vertical band V3 and horizontal band H0, a band V3H1 defined by vertical band V3 and horizontal band H1, a band V3H2 defined by vertical band V3 and horizontal band H2, a band V3H3 defined by vertical band V3 and horizontal band H3, and a band V3H4 defined by vertical band V3 and horizontal band H4. The five counters 341-345 count the number of pixels belonging to a band V4H0 defined by vertical band V4 and horizontal band H0, a band V4H1 defined by vertical band V4 and horizontal band H1, a band V4H2 defined by vertical band V4 and horizontal band H2, a band V4H3 defined by vertical band V4 and horizontal band H3, and a band V4H4 defined by vertical band V4 and horizontal band H4.

[0106] Each of the 25 counting units 321-345 counts the number of pixels in the corresponding band, thereby obtaining 25 pieces of extracted data that are count results. Note that the extracted data may include, for each of the 25 bands, band information for identifying the band and the number of pixels belonging to the band. The generated 25 pieces of extracted data are output to the first correction unit 124. Furthermore, the extraction unit 123 may output, for each of the 25 bands, band video data indicating band information for identifying the band and pixel information indicating one or more pixels belonging to the band to the first correction unit 124.

[0107] The extraction unit 123 generates a histogram indicating the number of pixels in each band using the 25 pieces of extraction data. The extraction unit 123 can generate a histogram as shown in FIG. 11 as a result of counting the number of pixels belonging to each of a plurality of bands in a vertical row of band V2, for example. Note that FIG. 11 shows the number of pixels belonging to a plurality of bands in a vertical row of band V2 as an example, but the histogram generated by the extraction unit 123 shows the result of counting the number of pixels belonging to each of the 25 bands. The generated histogram is output to the control unit 121. Note that the extraction unit 123 is realized by the control circuit 103. Specifically, the extraction unit 123 is realized by the control circuit 103 executing a predetermined program stored in the memory 104.

[0108] The control unit 121 adjusts the sharpness gain of the image so that the sharpness gain of a second region belonging to an invalid frequency band, which is a band outside the valid frequency band, is smaller than the sharpness gain of a first region belonging to a valid frequency band indicated by metadata among a plurality of regions constituting the image. The plurality of regions may be, for example, a plurality of pixels or a plurality of blocks. Specifically, the control unit 121 adjusts the sharpness gain of the image by adding a first offset value that is a value equal to or less than a first threshold value to the sharpness gain of the image of the invalid frequency band. Also, the control unit 121 adjusts the sharpness gain of the image by adding a second offset value that is a value greater than the first threshold value to the sharpness gain of the image of the valid frequency band. Note that the first threshold value is, for example, 0. That is, the first offset value for adjusting the sharpness gain of the second region belonging to the invalid frequency band is a value equal to or less than 0. Also, the second offset value for adjusting the sharpness gain of the first region belonging to the valid frequency band is a value greater than 0.

[0109] For example, in FIG. 13, the frequency bands V0H0-V4H0, V0H1, V4H1, V0H2, V4H2, V0H3, V4H3, and V0H4-V4H4, which are invalid frequency bands in the video data of the content set in the distribution side device 200, are frequency bands in which no video generated in the distribution side device 200 exists. For this reason, the control unit 121 calculates a first offset value that sets the sharpness gain in multiple bands belonging to the invalid frequency bands to 0 based on the sharpness gain that is the initial value of the gain set table. The first offset value is, for example, a negative number equal to the absolute value of the initial value of the gain set table. For example, in FIG. 12, the frequency bands V2H0 and V2H4 are invalid frequency bands generated in the distribution side device 200. For this reason, the control unit 121 determines a negative first offset value ΔGA in order to adjust the sharpness gain in the frequency bands V2H0 and V2H4 to 0 based on the initial value of the sharpness gain in the frequency bands V2H0 and V2H4. Note that the initial value of the sharpness gain is set to a positive value regardless of the frequency band, as shown in Fig. 12. As a result, the adjustment unit 120 does not increase the sharpness gain for the invalid frequency band video band of the actual content to be distributed, and therefore it is possible to suppress amplification of the sharpness gain for high-frequency band noise generated in the transmission path between the distribution side and the reception side, which would be caused by increasing the sharpness gain.

[0110] In addition, the control unit 121 sets the first offset value to a negative number equal to the absolute value of the initial value of the gain set table, but is not limited to this, and may set the first offset value to a negative number greater than the absolute value of the initial value of the gain set table. This makes it possible to set the sharpness gain in the pixels of the invalid frequency band to a negative value, and to provide a noise reduction effect to the pixels of the invalid frequency band.

[0111] 12, bands V2H1, V2H2, and V2H3 are valid frequency bands generated by the distribution device 200. For this reason, the control unit 121 determines a positive second offset value ΔGB to adjust the sharpness gain to a value larger than the initial value in the frequency bands V2H1, V2H2, and V2H3.

[0112] Furthermore, the control unit 121 may further use the histogram acquired from the extraction unit 123 to determine a plurality of third offset values ​​so that the value is larger as the number of pixels belonging to a plurality of bands in the frequency domain increases. The plurality of third offset values ​​may include the second offset value. For example, as shown in FIG. 12, the control unit 121 determines the largest offset value ΔGE for the band V2H3 having the largest number of pixels among the bands V2H1 to V2H3 belonging to the valid frequency bands in the plurality of bands V2H0 to V2H4 in the vertical column of the band V2. The control unit 121 determines the second largest offset value ΔGD for the band V2H1 having the second largest number of pixels. The control unit 121 determines the third largest offset value ΔGF for the band V2H3 having the third largest number of pixels.

[0113] For example, in FIG. 13, the frequency bands V1H1-V3H1, V1H2-V3H2, and V1H3-V3H3, which are effective frequency bands in the video data of the content set in the distribution device 200, are frequency bands in which the video generated by the distribution device 200 exists. Therefore, in order to increase the resolution or sharpness of the video in the effective frequency band, the control unit 121 calculates a second offset value that amplifies the sharpness gain based on the sharpness gain that is the initial value of the gain set table. The second offset value is, for example, a positive number. In addition, the control unit 121 calculates a third offset value based on the histogram so that the positive offset value (A to I) becomes larger as the number of pixels belonging to the third offset value increases. This allows the adjustment unit 120 to increase the sharpness gain for the video data of the frequency band having many pixels in the video, thereby improving the apparent sense of resolution and sharpness.

[0114] The control unit 121 generates a post-adjustment gain set table including the first offset value and the second offset value for each of the multiple frequency bands, and outputs the generated post-adjustment gain set table to the second correction unit 125.

[0115] Next, the first correction unit 124 will be described with reference to Figs. 14 to 19. Fig. 14 is a block diagram showing an example of a detailed configuration of the first correction unit. Fig. 15 is a block diagram showing an example of a detailed configuration of the detection unit. Fig. 16 is a diagram showing a detail threshold value for determining the type of area constituting an image. Fig. 17 is a diagram showing an example of a result of determining the type of area. Fig. 18 is a graph showing a second offset curve. Fig. 19 is a table showing an example of detail set data.

[0116] The first correction unit 124 has 25 detection units 401 to 425 as shown in Fig. 14. The 25 detection units 401 to 425 correspond to the 25 bands V0H0 to V4H4, respectively, and detect the type of area to which the pixels included in the corresponding band belong. Each of the 25 detection units 401 to 425 has a detail determination unit 431 and a curve generation unit 432 as shown in Fig. 15.

[0117] The detail determination unit 431 determines whether each pixel of the band video data is a plain area, a detail area, or an edge area based on the amplitude of the band video data input to the corresponding detection unit. The amplitude is specifically a value based on the pixel value of the pixel. For example, the amplitude is luminance Y when the video data is represented by a YUV signal, and is MaxRGB indicating the maximum value of the R component, G component, and B component in the pixel value of the pixel included in the video data when the video data is represented by an RGB signal. The detail determination unit 431 specifically calculates the maximum difference based on the pixel values ​​of a plurality of pixels in a predetermined width in the horizontal or vertical direction with the pixel to be processed as the reference (center) in the band video data. The predetermined width is, for example, a width of a predetermined number of clocks in the horizontal or vertical direction. The maximum difference is the difference between the maximum value and the minimum value of the pixel values ​​of a plurality of pixels included in the predetermined width.

[0118] The detail determination unit 431 adjusts the sharpness gain of the image using the band video data, the extraction data, and the detail threshold value so that the fifth offset value to be added to the sharpness gain of the second pixel where the maximum difference outside the predetermined range is calculated is smaller than the fourth offset value to be added to the sharpness gain of the first pixel where the maximum difference within the predetermined range is calculated. The predetermined range is a range determined to be a detail area as shown in FIG. 16, and is, for example, a range larger than the threshold value THP and smaller than the threshold value THD. The fourth offset value is, for example, +X, which is a value larger than 0, as shown in the detail set data of FIG. 19. The fifth offset value is, for example, ±0, as shown in the detail set data of FIG. 19.

[0119] As shown in (a) of FIG. 16 and FIG. 17, when the maximum difference ΔDp of the amplitude based on the pixel value of the pixel to be processed is less than the threshold THP, the detail determination unit 431 determines that the type of the region of the pixel is a plain region. Also, as shown in (b) of FIG. 16 and FIG. 17, when the maximum difference ΔDd of the amplitude based on the pixel value of the pixel to be processed is greater than the threshold THP and less than the threshold THD, the detail determination unit 431 determines that the type of the region of the pixel is a detail region. Also, as shown in (c) of FIG. 16 and FIG. 17, when the maximum difference ΔDe of the amplitude based on the pixel value of the pixel to be processed is greater than the threshold THD, the detail determination unit 431 determines that the type of the region of the pixel is an edge region. Note that a pixel whose maximum difference is the threshold THD may be determined to be either a plain region or a detail region. Also, a pixel whose maximum difference is the threshold THP may be determined to be either a detail region or an edge region. The detail determination unit 431 outputs the determination result to the curve generation unit 432 .

[0120] The curve generation unit 432 uses the determination result and the detail set data to generate an offset curve as shown in Fig. 18. The curve generation unit 432 obtains the detail set data from the control unit 121, and generates an offset curve in which the plain region and the edge region are ±0 and the detail region is +X based on the obtained detail set data. The curve generation unit 432 outputs detection data for further adding a fourth offset value to the sharpness gain for the band video data determined as the detail region to the second correction unit 125. This allows the first correction unit 124 to set a larger sharpness gain for the region of pixels determined as the detail region.

[0121] The detail area has a large effect on the apparent resolution of the image, and by increasing the sharpness gain of the detail area, the apparent resolution of the image can be effectively improved. In this example, the offset is set to ±0 when the area is determined to be a plain area or an edge area, but instead of ±0, an offset value that is a positive value smaller than +X may be set.

[0122] The first correction unit 124 is realized by the control circuit 103. Specifically, the first correction unit 124 is realized by the control circuit 103 executing a predetermined program stored in the memory 104.

[0123] Next, the second correction unit 125 will be described with reference to Fig. 20. Fig. 20 is a block diagram showing an example of a detailed configuration of the second correction unit.

[0124] As shown in FIG. 20, the second corrector 125 has 26 correctors 501-526 and 26 setting units 531-556.

[0125] Of the 26 correction units 501 to 526, 25 correction units 501 to 525 correspond to the 25 bands, respectively. The correction unit 526 corresponds to video data.

[0126] Of the 26 setting units 531-556, 25 setting units 531-555 correspond to 25 bands, respectively. Setting unit 556 corresponds to video data (i.e., video data showing an entire video). Using the initial value of the gain set table from control unit 121, setting unit 556 sets an initial value of sharpness gain in correction unit 526. Correction unit 526 generates and outputs overall contour correction data based on the initial value of sharpness gain.

[0127] Each of the 25 setting units 531-555 adds the offset value of the corresponding frequency band among the offset values ​​set in the adjusted gain set table and the offset value of the detection data of the corresponding frequency band for each pixel, calculates a sharpness gain based on the added offset value obtained by the addition, and sets the calculated sharpness gain to the corresponding correction unit 501-525. Each correction unit 501-525 generates and outputs pixel contour correction data used for contour correction processing based on the set sharpness gain. The pixel contour correction data is generated, for example, by performing a differentiation process using the target pixel and the pixels before and after it. When the sharpness gain is larger, the pixel contour correction data is amplified and output.

[0128] Thereby, the second correction unit 125 generates contour correction data for appropriately adjusting the sharpness gain for each frequency band and for each type of area by adding the pixel contour correction data generated by each of the correction units 501 to 525 and the overall contour correction data generated by the correction unit 526. The second correction unit 125 outputs the generated contour correction data to the output unit 130.

[0129] The second correction unit 125 generates contour correction data in which the sharpness gain is appropriately adjusted for each frequency band and for each type of region with respect to the effective frequency band of the content to be distributed, so that the sharpness gain of the pixel region corresponding to the detail region in the video data of the frequency band containing many pixels in each frequency band can be more effectively improved, thereby more effectively improving the apparent resolution of the video.

[0130] Furthermore, even if noise of an amplitude that is erroneously detected as a detail region is mixed in the transmission path in a frequency band in which the content to be distributed is not effective, the offset value of the sharpness gain can be set to 0 or a negative number in the frequency band of the video data in which the content to be distributed is not effective. Therefore, even if unnecessary noise components generated in the transmission path between the distribution side device 200 and the reception side display device 100 are erroneously detected as a detail region in which it is effective to improve the sharpness gain, it is possible to suppress amplification of the sharpness gain of the erroneously detected detail region or to perform noise reduction, so that amplification is less likely to occur or noise reduction is more likely to occur. Therefore, the image quality of the displayed image can be effectively improved.

[0131] The second correction unit 125 is realized by the control circuit 103. Specifically, the second correction unit 125 is realized by the control circuit 103 executing a predetermined program stored in the memory 104.

[0132] The adjustment unit 120 finally adds the contour correction data output by the second correction unit 125 to the image data acquired by the acquisition unit 110. That is, the adjustment unit 120 adds the pixel contour correction data, the overall contour correction data, and the image data. In this way, the adjustment unit 120 generates adjusted image data in which the sharpness gain is appropriately adjusted for each frequency band and for each type of area.

[0133] As described above, each processing unit included in adjustment unit 120 is realized by, for example, control circuit 103 and memory 104.

[0134] The output unit 130 displays the adjusted video data that has been output. The output unit 130 is realized by, for example, the display device 105. Note that the output unit 130 is not limited to the display device 105, and may be a transmission means for outputting the adjusted video data to an external device. The output unit 130 may be, for example, a video output terminal that outputs the adjusted video data to an external device, or a communication IF that outputs the adjusted video data to an external device by wired communication or wireless communication. Note that the video output terminal may be an HDMI (registered trademark) (High-Definition Multimedia Interface) terminal.

[0135] [2. Operation] Next, the operation of the video system 1 will be described.

[0136] First, there will be described the operation of the distribution device 200. Fig. 21 is a flowchart of a video generation method by the distribution device.

[0137] The distribution device 200 identifies an effective frequency band, which is a band of spatial frequencies of a video (S01).

[0138] Next, the distribution device 200 generates video data including a video and metadata indicating the identified effective frequency band (S02). The distribution device 200 generates encoded data for the video by, for example, encoding the video data including the video and the metadata.

[0139] Then, the distribution device 200 outputs the generated video data (S03). The distribution device 200 outputs the video data, for example, by outputting the encoded data to a transmission path.

[0140] Next, a description will be given of the operation of the display device 100. Fig. 22 is a flowchart of a video processing method performed by the display device.

[0141] The acquisition unit 110 of the display device 100 acquires video data including a video and metadata indicating a valid frequency band, which is a spatial frequency band in which the video exists (S11). The acquisition unit 110 of the display device 100 acquires the video data by, for example, acquiring encoded data and decoding the acquired encoded data.

[0142] Next, the adjustment unit 120 of the display device 100 adjusts the sharpness gain of the image such that the sharpness gain of a second region belonging to an invalid frequency band that is a band outside the valid frequency band, among a plurality of regions constituting the image included in the acquired image data, is smaller than the sharpness gain of a first region belonging to a valid frequency band indicated by the metadata (S12). Details of step S12 will be described later with reference to FIG.

[0143] Next, the output unit 130 of the display device 100 outputs the adjusted image (S13).

[0144] FIG. 23 is a flowchart of a process for adjusting the sharpness gain.

[0145] The adjustment unit 120 of the display device 100 performs a first calculation to calculate offset values ​​(first and second offset values) for adjusting the sharpness gain for each of a plurality of frequency bands (S21). Details of step S21 will be described later with reference to FIG.

[0146] The adjustment unit 120 performs a second calculation to calculate offset values ​​(fourth offset value and fifth offset value) for adjusting the sharpness gain for each of a plurality of pixels in the image according to the type of area to which the pixel belongs (S22). Details of step S22 will be described later with reference to FIG.

[0147] The adjustment unit 120 generates an image in which the sharpness gain has been adjusted using the results of the first calculation and the second calculation (S23). Details of step S23 will be described later with reference to FIG.

[0148] FIG. 24 is a flowchart of the first calculation.

[0149] The adjustment unit 120 divides the video into a plurality of bands separated by a plurality of frequency bands by dividing the video in both the horizontal and vertical directions of the frequency band (S31).

[0150] The adjustment unit 120 starts Loop 1 for each of the multiple bands. In Loop 1, steps S32 to S are performed.

[0151] The adjustment unit 120 determines whether the band to be processed is an invalid frequency band (S32).

[0152] When the adjustment section 120 determines that the band to be processed is an invalid frequency band (Yes in S32), it calculates a first offset value that is a value equal to or less than the first threshold value (S33).

[0153] When the adjustment unit 120 determines that the band to be processed is not an invalid frequency band, that is, is a valid frequency band (No in S32), it calculates a second offset value that is greater than the first threshold value (S34). Details of step S34 will be described with reference to FIG.

[0154] When the adjustment section 120 has executed the loop 1 for all of the multiple bands, the adjustment section 120 ends the loop 1.

[0155] FIG. 25 is a flowchart of the calculation process of the second offset value.

[0156] The adjustment unit 120 counts the number of pixels that belong to the band to be processed (S41).

[0157] The adjustment unit 120 determines a third offset value according to the number of pixels that belong to the band to be processed, obtained by counting (S42). Note that the third offset value may include the second offset value.

[0158] FIG. 26 is a flowchart of the second calculation.

[0159] Adjustment unit 120 starts loop 2 for each of the multiple pixels in the image. In loop 2, steps S51 to S are performed.

[0160] The adjustment unit 120 calculates the maximum difference in amplitude based on the pixel values ​​of a plurality of pixels within a predetermined width in the horizontal or vertical direction with the pixel to be processed as the reference (center) (S51).

[0161] The adjustment unit 120 determines whether the pixel to be processed belongs to the detail area or not based on the calculated maximum difference (S52). Specifically, the adjustment unit 120 determines whether the calculated maximum difference is within a predetermined range or not, and if it is within the predetermined range, determines that the pixel to be processed belongs to the detail area, and if it is outside the predetermined range, determines that the pixel to be processed belongs outside the detail area.

[0162] When it is determined that the pixel to be processed belongs to the detail area (Yes in S52), the adjustment unit 120 calculates a fourth offset value that increases the sharpness gain of the pixel (S53).

[0163] When the adjustment unit 120 determines that the pixel to be processed does not belong to the detail area, for example, when the adjustment unit 120 determines that the pixel belongs to the plain area or the edge area (No in S52), the adjustment unit 120 calculates a fifth offset value for adjusting the sharpness gain of the pixel (S54). The fifth offset value is a value smaller than the fourth offset value.

[0164] When adjustment section 120 has executed loop 2 for all of the plurality of pixels, adjustment section 120 ends loop 2.

[0165] Fig. 27 is a flowchart of a process for adjusting the sharpness gain of an image. Specifically, the entire process of the flowchart shown in Fig. 27 is performed for each of a plurality of pixels that constitute the image.

[0166] The adjustment unit 120 starts Loop 3 for each of the multiple bands. In Loop 3, step S61 is performed.

[0167] The adjustment unit 120 adds the first offset value or the second offset value calculated for the band to be processed to the initial value of the sharpness gain (S61).

[0168] When the adjustment section 120 has performed the loop 3 for all of the multiple bands, the adjustment section 120 ends the loop 3.

[0169] The adjustment unit 120 adds the fourth offset value or the fifth offset value calculated for the pixel to be processed to the sharpness gain resulting from step S61 that corresponds to the pixel (S62).

[0170] The adjustment unit 120 generates pixel contour correction data to be used in contour correction processing, based on the sharpness gain calculated for each pixel, which is obtained by executing the processing in step S62 (S63).

[0171] Meanwhile, the adjustment unit 120 generates overall contour correction data based on the initial value of the sharpness gain (S64).

[0172] The adjustment unit 120 adds together (S65) the pixel contour correction data obtained in step S63, the overall contour correction data obtained in step S64, and the image data acquired by the acquisition unit 110 in step S11. This generates image data in which the sharpness gain has been effectively adjusted.

[0173] Although the adjustment unit 120 adds the calculated offset value to the initial value of the sharpness gain in step S61, the adjustment unit 120 may not add the offset value to the initial value of the sharpness gain here. For example, the adjustment unit 120 may specify the offset value to be added in step S61 and the offset value to be added in step S62 for each pixel, and add both the offset value of step S61 and the offset value of step S62 to the initial value of the sharpness gain. For example, the adjustment unit 120 may execute loop 3 and step S64 in advance in accordance with the update cycle of the metadata (frequency information), add the results of loop 3 and step S64 in advance, and further add the data obtained by the addition in advance to the result of step S62 executed in the pixel cycle for each pixel.

[0174] [3. Effects, etc.] According to the display device 100 of the present embodiment, the sharpness gain of the image can be adjusted so that the sharpness gain of the second region belonging to the second frequency band does not increase more than that of the first region. Therefore, when performing a process of increasing the sharpness gain, it is possible to suppress the noise belonging to the second frequency band, which occurs between the time when the image obtained by shooting is encoded by the distribution side device 200 and the time when it is decoded by the display device 100, from being amplified more than that of the first region. Therefore, by performing a process of improving the sharpness gain, it is possible to reduce the noise from being more noticeable than other images.

[0175] Moreover, in the display device 100 according to the present embodiment, the adjustment unit 120 adjusts the sharpness gain of the image by adding a first offset value, which is a value equal to or less than 0, to the sharpness gain of the second region. Therefore, the sharpness gain of the image can be adjusted so that the sharpness gain of the second region belonging to the second frequency band in which no image exists does not increase or decreases. Therefore, when performing the process of increasing the sharpness gain, it is possible to suppress the amplification of noise belonging to the second frequency band that occurs between when the image obtained by shooting is encoded by the distribution side device 200 and when it is decoded by the display device 100. In particular, since noise is often included in a frequency band higher than a predetermined frequency, the sharpness gain of the image can be adjusted so that the sharpness gain of the second region belonging to the second frequency band does not increase or decreases, thereby more effectively suppressing the deterioration of image quality due to noise.

[0176] Furthermore, in display device 100 according to the present embodiment, adjustment unit 120 adjusts the sharpness gain of the image by adding, to the sharpness gain of the first region, a second offset value that is a value greater than 0. This makes it possible to improve the sharpness gain of the first region in which the image exists, thereby effectively improving image quality.

[0177] Moreover, in the display device 100 according to the present embodiment, the first frequency band includes a plurality of bands that are different from each other. The second offset value includes a plurality of third offset values ​​that respectively correspond to the plurality of bands. The adjustment unit 120 counts the number of pixels that belong to each of the plurality of bands, and determines a plurality of third offset values ​​so that the third offset value becomes larger as the number of pixels that belong to the plurality of bands increases. Therefore, the sharpness gain is improved as the number of pixels increases, and image quality can be effectively improved.

[0178] In addition, in the display device 100 according to the present embodiment, the adjustment unit 120 further calculates a maximum difference for each of a plurality of pixels in the image based on the pixel values ​​of a plurality of pixels across a predetermined width in the horizontal or vertical direction with respect to the pixel. The adjustment unit 120 further adjusts the sharpness gain of the image so that a fifth offset value to be added to the sharpness gain of the second pixel in which the maximum difference outside the predetermined range is calculated is smaller than a fourth offset value to be added to the sharpness gain of the first pixel in which the maximum difference within the predetermined range is calculated. Therefore, the sharpness gain can be adjusted so that the sharpness gain of the first pixel, in which the image quality is more likely to be improved by increasing the sharpness gain, is higher than the sharpness gain of the second pixel, thereby effectively improving the image quality.

[0179] [4. Modifications] In the above embodiment, the display device 100 is described as having the control unit 121 as a functional configuration, but the display device 100 does not necessarily have to have the control unit 121. In other words, the information calculated by the control unit 121 may be obtained from the outside, or may be stored in the storage unit 122 in advance.

[0180] In the above embodiment, the display device 100 is configured to include the tuner 101, and the acquisition unit 110 is realized by the tuner 101, but this is not limited thereto. The acquisition unit 110 may acquire video data by reading video data recorded on a recording medium (predetermined package medium) such as an optical disc. In this case, the acquisition unit 110 may be realized by an electric device having an optical pickup that reads the optical disc. The acquisition unit 110 may also acquire video data from an external server via a network such as the Internet. In this case, the acquisition unit 110 may be realized by a communication IF for communicating with the external server.

[0181] As described above, the embodiments have been described as examples of the technology in the present disclosure, and the accompanying drawings and detailed description have been provided for this purpose.

[0182] Therefore, among the components described in the attached drawings and the detailed description, not only are there components essential for solving the problem, but there may also be components that are not essential for solving the problem in order to illustrate the above technology. Therefore, the fact that such non-essential components are described in the attached drawings or the detailed description should not be interpreted as immediately indicating that such non-essential components are essential.

[0183] Furthermore, since the above-described embodiments are intended to illustrate the technology in the present disclosure, various modifications, substitutions, additions, omissions, and the like can be made within the scope of the claims or their equivalents. [Industrial Applicability]

[0184] INDUSTRIAL APPLICABILITY The present disclosure is useful as an image processing device, an image processing method, an image generating device, an image generating method, a program, and the like that can suppress the amplification of noise caused by increasing the sharpness gain. [Explanation of symbols]

[0185] 1. Video System 100 display device 101 Tuner 102 Decoder 103 Control circuit 104 Memory 105 Display Devices 110 Acquisition Department 120 Adjustment section 121 Control Unit 122 Storage section 123 Extraction part 124 First Correction Section 125 Second Correction Section 130 Output section 200 Distribution device 201 Camera 202 Information processing device 203 Processor 204 Main Memory 205 Storage 206 Communication Interface 207 Input IF 208 Display 210 Capture section 220 Mastering Department 230 Frequency conversion unit 240 Encoder 301~305 Horizontal extraction part 311~315 Vertical extraction section 321~345 Counting Department 401~425 Detector 431 Detail Judgment Section 432 Curve Generation Section 501~526 Correction section 531~556 Setting section

Claims

1. an acquisition unit that acquires video data including metadata indicating a first frequency band, which is a spatial frequency band in which the video exists; an adjustment unit that adjusts a sharpness gain of the image such that a sharpness gain of a second region that belongs to a second frequency band outside the first frequency band indicated by the metadata is smaller than a sharpness gain of a first region that belongs to the first frequency band indicated by the metadata, among a plurality of regions that constitute the image included in the image data acquired by the acquisition unit; an output unit that outputs the image adjusted by the adjustment unit; Image processing device.

2. The second frequency band is included in a band lower than a lowest frequency that defines the first frequency band, or a band higher than a highest frequency that defines the first frequency band. The video processing device according to claim 1 .

3. The adjustment unit adjusts the sharpness gain of the image by adding a first offset value, which is a value equal to or smaller than a first threshold, to the sharpness gain of the second region.

3. The image processing device according to claim 1.

4. The adjustment unit adjusts the sharpness gain of the image by adding a second offset value, which is a value greater than the first threshold, to the sharpness gain of the first region. The image processing device according to claim 3 .

5. The first frequency band includes a plurality of bands different from each other, the second offset value includes a plurality of third offset values ​​respectively corresponding to the plurality of bands; The adjustment unit counts the number of pixels belonging to each of the plurality of bands, and determines the plurality of third offset values ​​so that the third offset values ​​become larger as the number of pixels belonging to each of the plurality of bands increases. The image processing device according to claim 4.

6. The first threshold is 0. The image processing device according to claim 3 .

7. The adjustment unit further includes: Calculating a maximum difference for each of a plurality of pixels in the image based on pixel values ​​of a plurality of pixels across a predetermined width in a horizontal or vertical direction relative to the pixel; The sharpness gain of the image is adjusted so that a fifth offset value to be added to the sharpness gain of the second pixel for which the maximum difference outside the predetermined range is calculated is smaller than a fourth offset value to be added to the sharpness gain of the first pixel for which the maximum difference within the predetermined range is calculated. The image processing device according to claim 3 .

8. The maximum difference within the predetermined range is a value smaller than the maximum difference outside the predetermined range, or a value larger than the maximum difference outside the predetermined range. The image processing device according to claim 7.

9. the fourth offset value is greater than 0; The fifth offset value is 0.

9. The image processing device according to claim 7 or 8.

10. 1. An image processing method performed by an image processing device that adjusts a sharpness gain of an image, comprising: acquiring video data including a video and metadata indicative of a first frequency band in which the video exists; adjusting a sharpness gain of the image such that a sharpness gain of a second region belonging to a second frequency band that is a band outside the first frequency band indicated by the metadata is smaller than a sharpness gain of a first region belonging to the first frequency band indicated by the metadata among a plurality of regions constituting the image included in the acquired image data; Output the adjusted image Image processing method.

11. A program for causing a computer to execute an image processing method for adjusting the sharpness gain of an image, The image processing method includes: acquiring video data including a video and metadata indicative of a first frequency band in which the video exists; adjusting a sharpness gain of the image such that a sharpness gain of a second region belonging to a second frequency band that is a band outside the first frequency band indicated by the metadata is smaller than a sharpness gain of a first region belonging to the first frequency band indicated by the metadata among a plurality of regions constituting the image included in the acquired image data; Output the adjusted image program.

Images