JP2009194550A - Image quality adjustment device, image quality adjusting method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve output image quality by performing proper image quality adjustment of only a needed part during reproducing content. <P>SOLUTION: There is provided the image quality adjustment device including: a characteristic point extracting part 60 for analyzing a video signal of content recorded in a recording medium and extracting characteristic point information of the content; an output image quality adjusting part 70 for adjusting output image quality of video of the content during reproducing the content recorded in the recording medium; and an image quality adjustment control part 114 for controlling the output image quality adjusting part on the basis of the characteristic point information of the content. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image quality adjustment device, an image quality adjustment method, and a program, and more particularly, to an image quality adjustment device, an image quality adjustment method, and a program for improving output image quality.

  As a digital recording / reproducing apparatus capable of recording and reproducing video / audio digital data such as television broadcast program content, for example, a digital video apparatus, a DVD (Digital Versatile Disk) recorder / player, and an HDD (Hard Disk Drive) recorder / player Etc. are prevalent. These digital recording / reproducing apparatuses can record high-definition images of not only conventional analog terrestrial broadcasting and BS broadcasting, but also digital HDTV (High Definition TeleVision) broadcasting.

  Such a recording / reproducing apparatus is required to improve the output image quality and to provide the user with a better image quality when reproducing the recorded video content. For this reason, conventionally, a technique has been proposed in which an output image quality adjustment block provided in a recording / playback apparatus controls the output image quality according to a unique algorithm during content playback.

JP 2005-328395 A

  However, in the above-described conventional output image quality control technology, the output image quality adjustment block performs uniform image quality control (for example, noise reduction function) on the input image according to preset conditions regardless of the characteristics of the content image. (Only on / off control). There was also a technology that controls the output image quality in consideration of the video characteristics, but even with this technology, image quality is improved by referring to a part of the video (for example, several frames before and after) instead of the entire program content. It was something to try. For example, image quality control such as noise reduction is performed by controlling the output image quality adjustment block using information of several frames before and after the location where the image quality improvement is applied.

  In such a conventional method, the entire content is not analyzed when the content is recorded, and the entire configuration of the program represented by the content is not known. Therefore, unnecessary image quality control or inappropriate image quality control is performed on the entire content. There was a possibility of going. For example, even though it is a high-quality movie content with no noise, unnecessary image quality adjustment is performed, or the same image quality adjustment is applied to the main video and CM video that make up the program content. Sometimes

  As described above, conventionally, there has been a method of controlling the output image quality by analyzing a part of the information of the reproduced video when reproducing the recorded content. However, by analyzing the characteristic information of the entire content in advance, None of the output image quality was controlled using the feature information during playback.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to improve output image quality by performing appropriate image quality adjustment only on necessary portions during content playback. It is an object of the present invention to provide a new and improved image quality adjustment apparatus, image quality adjustment method, and program capable of performing the above.

  In order to solve the above-described problem, according to one aspect of the present invention, a feature point extraction unit that analyzes a video signal of content recorded on a recording medium and extracts feature point information of the video of the content; An output image quality adjusting unit that adjusts an output image quality of video of the content when reproducing the content recorded on a recording medium; and an image quality that controls the output image quality adjusting unit based on the feature point information of the content An image quality adjusting apparatus comprising: an adjustment control unit.

  With this configuration, the feature point extraction unit analyzes the video signal of the content recorded on the recording medium, extracts the feature point information of the video of the content, and adjusts the image quality when reproducing the content recorded on the recording medium. The control unit controls an output image quality adjustment unit that adjusts the output image quality of the content video based on the feature point information of the content. Thereby, the feature point information of the content is extracted in advance at the time of recording or reproducing the content, and the output image quality of the content video can be suitably adjusted according to the feature point information at the next reproduction of the content.

  In addition, a control routine creating unit that creates a control routine for controlling the output image quality adjusting unit for each content based on the feature point information is provided, and the content recorded on the recording medium is reproduced. The image quality adjustment control unit may control the output image quality adjustment unit based on the control routine corresponding to the content. With this configuration, a control routine for controlling the output image quality adjustment unit is created for each content based on the feature point information by the control routine creation unit, and based on the control routine corresponding to the content when the content is played back The output image quality adjustment unit is controlled. As a result, a control routine corresponding to the feature point information of the content is created in advance at the time of recording or playback of the content, and the output image quality of the content video is suitably adjusted according to the control routine at the next playback of the content. it can.

  Furthermore, an attribute information acquisition unit that acquires attribute information of the content is further provided, and the control routine creation unit creates the control routine for each content based on the feature point information and the content attribute information. It may be. With this configuration, the attribute information acquisition unit acquires content attribute information, and the control routine generation unit generates a control routine for each content based on the feature point information and attribute information of the content. The output image quality adjustment unit is controlled based on this control routine. Thus, a control routine corresponding to the feature point information and attribute information of the content is created in advance at the time of recording or playback of the content, and the output image quality of the content video is set according to the control routine at the next playback of the content. It can adjust suitably.

  In order to solve the above-described problem, according to another aspect of the present invention, a video signal of the content is recorded when the content is recorded on a recording medium or when the content recorded on the recording medium is reproduced. And a feature point extracting step of extracting feature point information of the video of the content; and an output for adjusting an output image quality of the video of the content when the content recorded on the recording medium is reproduced next An image quality adjustment step of adjusting an output image quality of a video of the content while controlling an image quality adjustment unit based on the feature point information of the content. .

  In order to solve the above-described problem, according to another aspect of the present invention, a video signal of the content is recorded when the content is recorded on a recording medium or when the content recorded on the recording medium is reproduced. And a feature point extracting step of extracting feature point information of the video of the content; and an output for adjusting an output image quality of the video of the content when the content recorded on the recording medium is reproduced next There is provided a program for causing a computer to execute an output image quality adjustment step of adjusting an output image quality of a video of the content while controlling an image quality adjustment unit based on the feature point information of the content.

  As described above, the feature point information obtained by analyzing the entire video of the content is recorded when the content is recorded in advance on the recording medium, and the feature point information of the content is recorded when the content recorded on the recording medium is reproduced. Accordingly, reproduction can be performed while dynamically controlling the output image quality adjustment unit.

  As described above, according to the present invention, it is possible to improve the output image quality by performing appropriate image quality adjustments only on necessary portions during content reproduction.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

  First, an outline of a recording / reproducing apparatus to which the image quality adjusting apparatus according to the first embodiment of the present invention is applied will be described. The recording / reproducing apparatus according to the present embodiment is an apparatus capable of recording video content provided from the outside on a recording medium such as an HDD or an optical disk and reproducing the video content recorded on the recording medium. This recording / reproducing apparatus is configured, for example, as a composite machine of an optical disk recorder using an optical disk as a recording medium and an HDD recorder using a hard disk as a recording medium (see FIG. 1).

  Here, the video content (hereinafter may be simply referred to as “content”) is, for example, a television broadcast program content received from a broadcasting station, an externally input video program, a cell DVD, or a BD (Blu- video program read out from (ray DISk) or the like. Note that television broadcasts include, for example, terrestrial digital / analog broadcasts, BS (Broadcasting Satellite) broadcasts, CS (Communication Satellite) broadcasts, broadcast program contents via broadcast radio waves, cable TV broadcasts, IPTV ( Also included are programs that distribute program content via a network, such as Internet Protocol TV (VOD) or Video On Demand (VOD).

  Next, features of the recording / reproducing apparatus according to the present embodiment will be schematically described. The recording / reproducing apparatus according to the present embodiment analyzes the entire video of the video content at the time of recording or reproducing the video content, acquires in advance feature point information representing a characteristic part of the content, and the video The feature point information is applied to image quality adjustment of the reproduced video at the next reproduction of the content. That is, the recording / reproducing apparatus according to the present embodiment analyzes the contents of the program when recording the program content and records information (feature point information) representing the video characteristics of the program. Then, when the program content is reproduced next time, the recording / reproducing apparatus uses the feature point information to dynamically control the output image quality adjustment function of the program content, thereby improving the image quality of the output video. be able to.

  More specifically, the recording / reproducing apparatus analyzes the entire video content video when recording video content such as a television broadcast program or a movie, for example, scene change, fade, crossfade, A scene where a person appears or a scene with a large telop is detected and recorded as feature point information. When controlling the output image quality adjustment function during playback of video content, feedback is given to the control parameters for normal image quality adjustment processing using the above feature point information, and output image quality adjustment is dynamically performed according to the video characteristics. To control. At this time, the user can select how much the feature point information is reflected in the image quality adjustment by switching the released setting items. Hereinafter, the configuration of the recording / reproducing apparatus according to the present embodiment for realizing such characteristics will be described in detail.

  Next, a hardware configuration of the recording / reproducing apparatus 10 according to the present embodiment will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of a recording / reproducing apparatus 10 according to the present embodiment. In FIG. 1, “A” indicates an audio signal, and “V” indicates a video signal.

  As shown in FIG. 1, the recording / reproducing apparatus 10 includes an analog tuner 11, an A / D converter 12, an analog input terminal 13, a DV (Digital Video) input terminal 14, a DV decoder 15, and a digital tuner 16. And i. LINK terminal 17, USB terminal 18, communication unit 19, AV encoder 20, stream processor 30, AV decoder 40, scaler 42, audio processor 44, hard disk drive (HDD) 52, Optical disk drive 54, feature point extraction block 60, output image quality adjustment block 70, graphic processing unit 80, display processing unit 82, D / A converter 84, ROM (Read Only Memory) 92, RAM ( Random Access Memory (94), a user interface 96, and a CPU (Central Processing Unit) 100 are provided.

  The analog tuner 11 selects a target channel from broadcast radio waves received by the antenna 1 for analog broadcasting, performs demodulation processing of the radio waves of the channel, and receives a program content reception signal (video and audio analog signal). Generate. Further, the analog tuner 11 performs predetermined video signal processing such as intermediate frequency amplification processing, color signal separation, color difference signal generation, synchronization signal extraction, and the like on the received signal, and outputs a video signal. To do. The A / D converter 12 converts video and audio analog signals input from the analog tuner 11, the analog input terminal 13, and the like into digital signals at a predetermined sampling frequency, and outputs the digital signals to the AV encoder 20. Note that video and audio analog signals are input from the external device 2 to the analog input terminal 13. The DV input terminal 14 is supplied with video and audio DV signals from an external device 3 such as a DV digital video camera. The DV decoder 15 decodes this DV signal and outputs it to the AV encoder 20.

  The digital tuner 16 selects a target channel from broadcast radio waves received by the antenna 4 for sanitary broadcasting or terrestrial digital broadcasting, and the stream processor 30 selects video and audio digital data (bitstream) of program content of the channel. Output to. I. External devices 5 and 6 such as HDV (High Definition Video) type digital video cameras are connected to external input terminals such as the LINK terminal 17 and the USB terminal 18. Video and audio HDV signals (streams) transferred from the external device 5 by the IEEE 1394 method are i. The signal is input to the stream processor 30 via the LINK terminal 17. The communication unit 19 transmits and receives various data to and from an external device (not shown) via an IP network such as Ethernet (registered trademark) 7. For example, the communication unit 19 receives video and audio signals of IPTV program content distributed via the Ethernet 7 or the like, and outputs them to the stream processor 30.

  The AV encoder 20 is hardware configured as an example of an encoding unit that encodes (compresses and encodes) video and audio signals. The AV encoder 20 compresses and encodes video and audio digital signals input from the A / D converter 12, DV decoder 15, scaler 42, audio processor 44, and the like described above in a predetermined compression encoding format. . The AV encoder 20 is a high-performance encoder that can handle HD (High Definition) video and SD (Standard Definition) video, and can encode not only SD resolution video signals but also HD resolution video signals. The AV encoder 20 is an encoder that can handle stereo audio and multi-channel audio, and can encode not only 2-channel audio signals but also multi-channel audio signals. The AV encoder 20 encodes the video signal or audio signal of the content to be recorded at a bit rate corresponding to the recording mode determined by the CPU 100. Further, the AV encoder 20 outputs the compressed data (bit stream) of the video / audio signal thus encoded to the stream processor 30.

  The stream processor 30 performs predetermined data processing on data to be recorded or reproduced (stream) at the time of recording or reproducing data on the recording medium. For example, at the time of data recording, the stream processor 30 multiplexes and encrypts the compressed data encoded by the AV encoder 20 and performs buffer control while recording data in the recording unit 50 (HDD 52 or optical disk drive 54). Record on media. During data reproduction, the stream processor 30 decrypts and separates (DeMultiplex) the compressed data read from the recording medium of the recording unit 50 (such as the HDD 52 or the optical disk drive 54) and outputs the compressed data to the AV decoder 40. .

  The AV decoder 40 is hardware configured as an example of a decoding unit that decodes (decodes) compressed video and audio signals. The AV decoder 40 decodes (decompresses compressed data) the compressed video and audio data input from the stream processor 30 using a predetermined compression encoding method.

  As the compression encoding method (codec type) used in the AV encoder 20 and the AV decoder 40 as described above, for example, MPEG2, H. H.264 AVC (Advanced Video Coding), VC1 and the like can be used. For audio, for example, Dolby AC3, MPEG2 AAC (Advanced Audio Coding), LPCM (Linear Pulse Code Modulation) and the like can be used.

  As described above, various types of video / audio signals are input to the recording / reproducing apparatus 10 from the outside. As the format (image size) of this video signal, there are, for example, “480i”, “480p”, “720p”, “1080i”, “1080p”, etc., depending on the quality of the video. For example, “1080i” has 1080 effective scanning lines in the vertical direction (1125 total scanning lines), is an interlaced scanning method, and is transmitted at a frame rate of “30 frames / second”. Represents a signal (resolution: “1920 × 1080” or “1440 × 1080” pixels). “720p” has 720 effective scanning lines in the vertical direction (total scanning lines of 750), and is transmitted in a progressive scan system with a frame rate of “60 frames / second”. Represents the signal (resolution: “1280 × 720” or “960 × 1080” pixels). Among these video signal formats, video signals such as “480i” and “480p” are classified into categories of SD video with a small number of scanning lines (hereinafter referred to as “SD category”). On the other hand, video signals such as “720p”, “1080i”, and “1080p” are classified into high-definition HD video categories (hereinafter referred to as “HD categories”) having a large number of scanning lines.

  The audio signal format (number of channels) is, for example, “1CH”, “2CH”, “5.1CH”, “6.1CH”, “7.1CH”, “4CH”, “5CH”, “ 6CH "etc. For example, “5.1CH” has six speakers including a speaker arranged in front, right front, left front, right rear, and left rear of a viewer and a low-frequency output subwoofer speaker (LFE: Low Frequency Effect). Represents a multi-channel audio signal output from a speaker. Among these audio signal formats, audio signals such as “1CH (monaural)” and “2CH (stereo)” fall into the category of low-quality stereo audio with a relatively small number of channels (hereinafter referred to as “stereo category”). being classified. On the other hand, audio signals such as “5.1CH”, “6.1CH”, “7.1CH”, “4CH”, “5CH”, and “6CH” have a relatively large number of channels and high-quality multichannel audio. It is classified into a category (hereinafter referred to as “multi-channel category”).

  In addition, the recording / reproducing apparatus 10 includes a format conversion unit for converting the format of various video / audio signals input as described above into a predetermined recording format corresponding to the recording medium. The format conversion unit includes a scaler 42 (video format conversion unit) and an audio processor 44 (audio format conversion unit).

  The scaler 42 converts the format of the video signal input from the AV decoder 40 into a predetermined recording format (that is, adjusts the image size) based on an instruction from the CPU 100. For example, when video signals in a format such as “720p” and “1080p” belonging to the HD category are input, the scaler 42 converts these video signals into a predetermined recording format “1080i” that can be supported by the recording medium. Convert to The scaler 42 outputs a video signal whose image size has been converted to the AV encoder 20. As described above, the scaler 42 not only has an image size conversion function between HD video and SD video as in the conventional scaler, but also an image size conversion function between various formats belonging to the same video format category ( For example, it also has a function of converting “720p” to “1080i” in the HD category.

  The audio processor 44 converts the format of the audio signal input from the AV decoder 40 into a predetermined recording format (that is, changes the number of channels) based on an instruction from the CPU 100. For example, when video signals of a format such as “7.1CH”, “4CH”, “5CH” belonging to the multi-channel category are input, the audio processor 44 causes the recording / reproducing apparatus 10 to output these audio signals. It is converted into a predetermined recording format “5.1CH” of a compatible multi-channel category. The audio processor 44 outputs an audio signal obtained by converting the number of channels to the AV encoder 20. As described above, the audio processor 44 not only converts the number of channels between different audio format categories but also converts the number of channels between various formats belonging to the same audio format category (for example, within the multi-channel category). A function of converting “5CH” to “5.1CH”).

  Further, the recording / reproducing apparatus 10 includes a recording unit 50 that records video and audio data of content on a recording medium. The recording unit 50 of the recording / reproducing apparatus 10 according to the present embodiment includes, for example, a hard disk drive (HDD) 52 and an optical disk drive 54.

  The HDD 52 writes / reads various information to / from a hard disk as a recording medium. For example, the HDD 52 records the video / audio signal stream input from the stream processor 30 on a hard disk. Also, the HDD 52 reads out data recorded on the hard disk and outputs it to the stream processor 30. Similarly, the optical disc drive 54 also writes / reads various information to / from the optical disc that is a recording medium. For example, by loading a commercially available removable recording medium (cell DVD, BD, etc.) on which video content is recorded onto the optical disc drive 54, the video content can be read from the removable recording medium and reproduced.

  As described above, the recording / reproducing apparatus 10 according to the present embodiment includes the two recording units 50, that is, the HDD 52 and the optical disk drive 54. As a result, the content recorded on the HDD 52 can be recorded on the optical disk drive 54 and vice versa. As the recording medium, for example, a magnetic disk such as a hard disk, or an optical disk such as a next-generation DVD (Blu-Ray disk, etc.), DVD-R, DVD-RW, DVD-RAM or magneto-optical disk, or flash Any recording medium such as various semiconductor memories such as a memory can be used. Further, the recording medium may be a recording medium fixed in the recording / reproducing apparatus 10 or a removable recording medium detachable from the recording / reproducing apparatus 10.

  The feature point extraction block 60 is a configuration example of a part of the feature point extraction unit of the present invention. For example, the feature point extraction block 60 is configured by hardware having a function of analyzing a video signal and extracting information on a feature point of a video of content. The feature point extraction block 60, when recording content input from the outside on the recording medium of the recording unit 50 or reproducing the content recorded on the recording medium, in response to an instruction from the CPU 100 The video signal is analyzed, information representing the video feature point of the content is extracted from the video signal, and output to the CPU 100. Since the feature point extraction block 60 is a feature portion of the recording / reproducing apparatus 10 according to the present embodiment, details will be described later (see FIG. 2).

  The output image quality adjustment block 70 is a configuration example of the output image quality adjustment unit of the present invention. The output image quality adjustment block 70 is constituted by hardware having an output image quality adjustment function, for example. When the content recorded on the recording medium of the recording unit 50 is reproduced, the output image quality adjustment block 70 adjusts the output image quality of the content to be reproduced according to an instruction from the CPU 100. At this time, the CPU 100 dynamically controls the operation of the output image quality adjustment block 70 for each content based on the feature point information regarding the content to be reproduced. Since the output image quality adjustment block 70 is also a characteristic part of the recording / reproducing apparatus 10 according to the present embodiment, details will be described later (see FIG. 3).

  The graphic processing unit 80 generates display data, subtitles, and the like indicating operation settings and operation states of the recording / reproducing apparatus 10 during data reproduction, and these display data and subtitles are reproduced video output from the output image adjustment block. Overlay (overlay). The display processing unit 82 performs processing for shaping the image size and the like on the synthesized video generated by the graphic processing unit 80 according to the output format. Further, the D / A converter 84 converts the video digital signal input from the display processing unit 82 and the audio digital signal input from the AV decoder 40 into an analog signal and outputs the analog signal to the monitor 8 or the speaker 9. To do.

  The CPU 100 functions as an arithmetic processing device and a control device, and controls each device in the recording / reproducing device 10. The CPU 100 executes various processes while using the RAM 94 in accordance with a program stored in the ROM 92 or a program loaded from the recording unit 50 to the RAM 94. The ROM 92 stores programs and calculation parameters used by the CPU 100 and also functions as a buffer for reducing access from the CPU 100 to the recording unit 50. The RAM 94 temporarily stores programs used in the execution of the CPU 100, parameters that change as appropriate during the execution, and the like. The CPU 100 also functions as an attribute information acquisition unit, an analysis unit, a control routine creation unit, an image quality adjustment control unit, etc., details of which will be described later (see FIG. 4).

  The user interface 96 functions as an input unit for the user to input various instructions to the recording / reproducing apparatus 10. The user interface 96 includes, for example, operation keys such as buttons, switches, and levers, operation means such as a touch panel and a remote controller, and input control that generates an input signal according to an input operation on the operation means and outputs the input signal to the CPU 100. It consists of a circuit. The user of the recording / reproducing apparatus 10 can input various data and instruct processing operations to the recording / reproducing apparatus 10 by operating the user interface 96. When the CPU 100 receives user input to the user interface 96, the CPU 100 controls content recording processing and playback processing, and sets reservation recording of a broadcast program based on the user input.

  Next, the recording operation of the recording / reproducing apparatus 10 having the configuration shown in FIG. 1 will be described. This recording operation is performed between the HDD 52 and the optical disc drive 54, for example, when recording program content reserved for recording, directly recording program content according to a user instruction, or recording externally input content. This is executed when the content is dubbed with.

  First, a procedure for encoding an analog signal input from the outside and recording it on a recording medium will be described.

  For example, when an analog television broadcast is received by the antenna 1, the analog video signal and analog audio signal output from the analog tuner 11 are digitized by the A / D converter 12. Next, the digital video signal and the audio signal are encoded by the AV encoder 20, converted into a bit stream, further multiplexed and encrypted by the stream processor 30, and buffer-controlled, while the HDD 52 or the optical disc drive 54. Recorded on the recording medium.

  Although an example in which an analog signal output from the analog tuner 11 is recorded as an input signal has been described here, for example, (1) the input signal is transmitted from the external device 2 via the analog input terminal 13. Or (2) a DV signal input from an external device 3 such as a DV digital video camera via the DV input terminal 14 is decoded by the DV decoder 15 and captured. In some cases, the same procedure is performed.

  Next, a procedure when a digital signal (bit stream) input from the outside is decoded and then re-encoded in accordance with a digital recording format supported by the recording medium and recorded will be described.

  First, for example, when a digital television broadcast is received by the antenna 4, the bit stream output from the digital tuner 16 is descrambled by the stream processor 30 and then separated into a video signal and an audio signal. Input to the decoder 40. Next, the AV decoder 40 decodes the digital video signal and the digital audio signal. Further, the decoded digital video signal is resized to a predetermined image size by the scaler 42 and input to the AV encoder 20 as necessary. On the other hand, the decoded digital audio signal is converted into a predetermined number of channels by the audio processor 44 as necessary, and input to the AV encoder 20. Thereafter, the digital video / audio signal after the format conversion is encoded by the AV encoder 20 (re-encoding process), and then multiplexed and encrypted by the stream processor 30 as in the case of the analog signal described above. The data is recorded on the recording medium of the HDD 52 or the optical disk drive 54 while being buffer controlled.

  As described above, when the input signal to be recorded is a compression-encoded digital signal (stream), re-encoding processing is performed as necessary. In other words, the compressed and encoded digital signal is once decoded into stream data by the AV decoder 40, converted into a format by the scaler 42 and the audio processor 44, and then converted into a predetermined recording format that can be supported by the recording medium by the AV encoder 20. Re-encode and record. If the format of the input digital signal is originally a predetermined recording format that can be supported by the recording medium, the re-encoding process is not necessary.

  Although an example of recording a digital broadcast video / audio signal output from the digital tuner 16 has been described here, for example, (1) the input signal is an external device 5 such as an HDV video camera. To i. In the case of a stream (HDV signal) input via the LINK terminal 17, or (2) an IPTV input stream received via the Ethernet 7 and the communication unit 19, (3) direct from the outside to the HDD 52 or the like Reads a stream that has been recorded (for example, when an input stream from an external device 6 connected via the USB terminal 18 or an HD video stream of a received digital broadcast is directly recorded (recorded as it is) on a recording medium of the HDD 52) In the case of (4) a stream read from the optical disk of the optical disk drive 54 is recorded in the HDD 52, the same procedure is performed.

  Further, in the recording / reproducing apparatus 10 according to the present embodiment, when various contents provided from the outside as described above are recorded in the recording unit 50, the feature point information extraction process and the control routine of the content to be recorded are recorded. Creation processing is performed. Specifically, when content is recorded, a video signal of the content to be recorded is input from the stream processor 30 to the feature point extraction block 60. Then, the feature point extraction block 60 and the CPU 100 analyze the video signal, thereby extracting feature point information representing the characteristics of the entire video of the content to be recorded. Further, based on the feature point information, a control routine for controlling the output image quality adjustment block 70 at the time of image quality adjustment at the next reproduction is generated, and this control routine is stored in the HDD 52 of the recording unit 50 or the like. As described above, in the recording / reproducing apparatus 10 according to the present embodiment, when content is recorded on the recording unit 50, a control routine corresponding to the feature point information of the video of the content is created and recorded for each content. The details of the feature point extraction process will be described later.

  Next, the reproducing operation of the recording / reproducing apparatus 10 having the configuration shown in FIG. 1 will be described. This playback operation is executed when a previously recorded content is played back, or when chasing playback is performed to play back the currently recorded content from the beginning.

  First, the content data (video, audio, caption data, etc.) to be reproduced recorded on the recording medium is read by the HDD 52 or the optical disc drive 54 of the recording unit 50. The read data stream is decrypted by the stream processor 30 and separated into a video stream and an audio stream.

  Next, the video stream and the audio stream (compressed data) are respectively decoded by the AV decoder 40, and then the decoded video stream (reproduced video signal) is input to the output image quality adjustment block 70 for image quality adjustment processing. Is done. At this time, the CPU 100 controls the output image quality adjustment block in accordance with a control routine created in advance for each content based on the feature point information. As a result, appropriate image quality adjustment is performed at an appropriate location in the video of the content to be played.

  Thereafter, an OSD (on-screen display), subtitles, and the like are added to the content video by the graphic processing unit 80 from the video stream whose image quality has been adjusted. Further, the video stream is input to the D / A converter 84 after the image size and the like are shaped according to the output format by the display processing unit 82. On the other hand, the audio stream output from the AV decoder 40 is input to the D / A converter 84 after being subjected to predetermined audio processing as necessary. As a result, each digital signal of the video stream / audio stream is converted into an analog signal by the D / A converter 84 and output to an external device such as the monitor 8 or the speaker 9. As a result, the monitor 8 displays the video of the reproduced content, and the speaker 9 outputs the audio of the reproduced content.

  In the recording / reproducing apparatus 10 according to the present embodiment, the feature point information can be extracted and analyzed for the content to be reproduced even when the content is reproduced as described above. For example, when content is provided to the recording / reproducing apparatus 10 by a removable recording medium such as a cell DVD or BD, the feature point information is extracted from the content recorded on the removable recording medium. Absent. Therefore, in such a case, when the content is reproduced (for example, at the first reproduction), feature point information extraction processing or the like is executed, and a control routine suitable for adjusting the image quality of the content is created. Specifically, when reproducing the content, the video signal of the content to be reproduced read from the recording unit 50 is input from the stream processor 30 to the feature point extraction block 60. Similarly to the above recording, feature point information of the content to be reproduced is extracted based on the analysis result of the video signal, a control routine is created based on the feature point information and the like, and is recorded in the recording unit 50. Keep it. Thereby, at the next reproduction of the content, the image quality of the content to be reproduced can be suitably adjusted based on the control routine.

  Next, the configuration of the feature point extraction block 60 according to the present embodiment will be described in detail with reference to FIG. FIG. 2 is a block diagram showing an internal configuration of the feature point extraction block 60 according to the present embodiment.

  As shown in FIG. 2, the feature point extraction block 60 includes a luminance signal analysis unit 61, a color difference signal analysis unit 62, and a noise signal analysis unit 63.

  The video signal input to the feature point extraction block 60 is first input to the luminance signal analysis unit 61. The luminance signal analysis unit 61 analyzes the luminance signal included in the video signal and divides the luminance signal of the entire image into fine blocks and converts them into various information. In the luminance signal block 61, based on the analysis result of the luminance signal, a luminance histogram, scene change, telop, fade, cross fade detection, contour detection, and the like in the image are performed. The luminance signal analysis unit 61 outputs information representing the detection result to the CPU 100 as basic data of feature point information.

  Next, the video signal is input to the color difference signal analysis unit 62. The color difference signal analysis unit 62 divides the color difference signal of the entire image into fine blocks and converts them into various information. The color difference signal analysis unit 62 analyzes the color difference signal analysis result in combination with the luminance signal analysis result obtained by the luminance signal analysis unit 61, so that a color difference histogram, person detection, skin color detection, etc. I do. The color difference signal analysis unit 62 outputs information representing the detection result to the CPU 100 as basic data of feature point information.

  Next, the video signal is input to the noise signal analysis unit 63. The noise signal analysis unit 63 performs noise detection by combining and analyzing the analysis result of the luminance signal and the color difference signal obtained by the luminance signal analysis unit 61 and the color difference signal analysis unit 62. The noise signal analysis unit 63 detects, for example, noisy noise, MPEG quantization noise, noise generated around the contour portion, and the like. The noise signal analysis unit 63 outputs information representing the noise detection result to the CPU 100 as basic data of feature point information.

  As described above, the feature point extraction block 60 analyzes the input video signal, and outputs the analysis result to the CPU 100 as basic data of feature point information representing the feature of the video signal.

  Next, the configuration of the output image quality adjustment block 70 according to the present embodiment will be described in detail with reference to FIG. FIG. 3 is a block diagram showing an internal configuration of the output image quality adjustment block 70 according to the present embodiment.

  As shown in FIG. 3, the output image quality adjustment block 70 includes a noise reduction unit 71, a brightness / contrast adjustment unit 72, a color density / hue adjustment unit 73, and a sharpness / low-pass filter adjustment unit 74. Prepare. Each of the units 71 to 74 is controlled by the CPU 100 based on data (content feature point information and attribute information) analyzed at the time of recording the content.

  The video signal input to the output image quality adjustment block 70 is first input to the noise reduction unit 71. The noise reduction unit 71 has a function of reducing and removing noise included in the input video signal. The CPU 100 controls the operation of the noise reduction unit 71 based on the result (control routine) of analyzing the video signal in advance. That is, the CPU 100 instructs the noise reduction unit 71 to determine where noise reduction / removal processing is necessary in the video represented by the video signal and what kind of noise is to be reduced / removed. The noise reduction unit 71 performs noise reduction / removal processing according to the instruction from the CPU 100.

  Next, the video signal is input to the brightness / contrast adjustment unit 72. The brightness / contrast adjustment unit 72 has a function of adjusting the brightness (BRIGHTNESS) and contrast (CONTRAST) of the video represented by the input video signal. The CPU 100 controls the brightness / contrast adjustment unit 72 based on the result of analyzing the video signal in advance (control routine). That is, the CPU 100 instructs the brightness / contrast adjustment unit 72 as to where the brightness and contrast need to be adjusted and the degree of adjustment. The brightness / contrast adjustment unit 72 executes brightness and contrast adjustment processing of the video signal in accordance with the instruction from the CPU 100.

  Next, the video signal is input to the color density / hue adjustment unit 73. The color density / hue adjusting unit 73 has a function of adjusting the color density (TINT), hue (HUE), color (COLOR), and the like of the video represented by the input video signal. The CPU 100 controls the color density / hue adjusting unit 73 based on the result of analyzing the video signal in advance (control routine). That is, the CPU 100 instructs the color density / hue adjustment unit 73 as to where the color density, hue, color, etc. need to be adjusted, and the degree of adjustment. The color density / hue adjustment unit 73 executes adjustment processing such as the color density, hue, and color of the video signal in accordance with the instruction from the CPU 100.

  Next, the video signal is input to the sharpness / low pass filter adjustment unit 74. The sharpness / low-pass filter adjustment unit 74 has a function of adjusting the sharpness of a video represented by the input video signal, a low-pass filter (a filter for reducing color moire, pseudo color, and the like). The CPU 100 controls the sharpness / low pass filter adjustment unit 74 based on the result (control routine) of analyzing the video signal in advance. That is, the CPU 100 instructs the sharpness / low-pass filter adjustment unit 74 as to where the sharpness or the low-pass filter needs to be adjusted and the degree of adjustment. The sharpness / low pass filter adjustment unit 74 executes adjustment processing such as the sharpness of the video signal and the low pass filter in accordance with the instruction from the CPU 100.

  As described above, the output image quality adjustment block 70 has a function of adjusting the image quality of the playback video of the content to be played back when the content is played back. The CPU 100 dynamically controls the image quality adjustment function by the output image quality adjustment block 70 at the time of reproduction according to the feature point information and attribute information of the content to be reproduced which has been analyzed in advance.

  Next, with reference to FIG. 4, the feature point extraction process and the output image quality adjustment process in the recording / reproducing apparatus 10 according to the present embodiment will be described in more detail. FIG. 4 is a block diagram schematically showing the configuration of the main part of the recording / reproducing apparatus 10 according to the present embodiment.

  As shown in FIG. 4, the CPU 100, the ROM 92, and the RAM 94 constitute a control unit in the recording / reproducing apparatus 10. This control unit has a function of controlling the operation of each unit in the recording / reproducing apparatus 10. The CPU 100 functions as an attribute information acquisition unit 102, an analysis unit 106, a control routine creation unit 110, and an image quality adjustment control unit 114 by operating according to a program stored in the ROM 92 or the HDD 52, for example. The memory such as the ROM 92 functions as the attribute information storage unit 104, the feature point information storage unit 108, and the control routine storage unit 112. Note that the attribute information storage unit 104, the feature point information storage unit 108, and the control routine storage unit 112 may be provided in a storage device such as the recording unit 50 such as the HDD 52 instead of the ROM 92 as in the example of FIG. Hereinafter, each part of CPU100 (control part) is demonstrated.

  The attribute information acquisition unit 102 acquires attribute information of content from the outside, and records and manages it in the attribute information storage unit 104. The content attribute information includes, for example, a content title (for example, a program name of a television broadcast program, a movie name of a video program, etc.), a genre (for example, movie, drama, sports, comedy, news), content ID, channel, Broadcast start / end time, content details (eg, characters, program overview), content time length, video / audio signal format (eg, number of pixels, number of channels, bit rate, quality level, etc.), compression coding System, input format (for example, analog / digital tuner input, S terminal input, composite input, DV input, USB input, i.LINK input, input via network 7, etc.). Such attribute information is reflected in a control routine at the time of image adjustment described later.

  The timing at which the attribute information acquisition unit 102 acquires the attribute information of the content is preferably before or simultaneously with the recording of the content, but may be after the recording of the content. When the attribute information can be acquired in advance before recording the content, or when it can be acquired simultaneously with the recording, the control routine creation unit 110 described later can create a control routine according to the attribute information when the content is recorded. On the other hand, when the attribute information of the content is acquired after the content is recorded, the control routine creating unit 110 can create a control routine according to the attribute information at the next reproduction of the content.

  Here, an example of acquiring attribute information will be described. For example, the attribute information acquisition unit 102 acquires television broadcast program information, and acquires content attribute information from the program information. Specifically, the stream processor 30 includes service information (Service Information: hereinafter referred to as “SI”) included in a transport stream (hereinafter referred to as “TS”) of a digital television broadcast currently received by the digital tuner 16. Etc.), the program information is periodically extracted and sent to the CPU 100. The attribute information acquisition unit 102 of the CPU 100 creates and manages a database (not shown) of this program information, extracts necessary attribute information from this database, and records it in the attribute information storage unit 104. Update to the latest content. As the program information, for example, an electronic program guide (hereinafter referred to as “EPG”) can be used, which is created from the EIT (Event Information Table) information included in the TS received by the digital tuner 16. Is possible. The program information such as EPG includes various attributes relating to the program content of the television broadcast, such as broadcast program title, genre, content ID, channel, broadcast time, program content information, video / audio signal format information, and the like. Contains information.

  Also, when the recording / reproducing apparatus 10 records content externally input from the external devices 2, 3, 5, 6, etc., in the HDD 52, the attribute information acquisition unit 102 identifies the external input terminal to which the content is input. As a result, information representing the content input format (for example, S terminal input, composite input, DV input, USB terminal input, i.LINK terminal input, input via network 7, etc.) is acquired as attribute information of the content. .

  As described above, by acquiring the attribute information such as the program information of the content recorded on the recording medium, the control routine creation unit 110 to be described later displays not only the feature point information of the content but also the attribute information of the content. Therefore, it is possible to create a control routine for adjusting the image quality that reflects the above. If the attribute information cannot be acquired, the control routine creation unit 110 may create a control routine based only on the feature point information.

  The analysis unit 106 analyzes the data input from the feature point extraction block 60 and stores the analysis result in the feature point information storage unit 108 as feature point information. Note that the feature point extraction block 60 and the analysis unit 106 correspond to the feature point extraction unit of the present invention, and both cooperate to analyze the video signal of the content and obtain the feature point information of the entire video of the content. Extract.

  Here, the feature point information extraction process at the time of content recording will be described in detail. At the time of content recording, video and audio signals (video and audio streams) of the content to be stored are input from the stream processor 30 to the HDD 52 and recorded in the content storage unit 521 of the HDD 52. At this time, the video signal of the content to be stored is also input from the stream processor 30 to the feature point extraction block 60. The feature point extraction block 60 analyzes the video signal (luminance signal, color difference signal, etc.), detects a feature point of the video represented by the video signal, and generates basic data of feature point information representing the feature point. (See FIG. 2). The feature point extraction block 60 outputs the basic data of the feature point information to the CPU 100 as the analysis result of the video signal.

  The analysis unit 106 of the CPU 100 sequentially analyzes the basic data of the feature point information acquired from the feature point extraction block 60, and collectively analyzes the content points (for example, program units). Thereby, the analysis unit 106 extracts feature points of the entire video of the content to be recorded, generates feature point information of the content, and records the feature point information in the feature point storage unit 108.

  As described above, at the time of content recording, the feature point extraction block 60 and the analysis unit 106 of the CPU 100 cooperate to, for example, a program scene change, fade, cross fade, appearance scene of a person, a scene with a large telop, etc. Are extracted as feature point information of the video of the content to be recorded and stored in the feature point information storage unit 108.

  Based on the feature point information, the control routine creating unit 110 creates a control routine for controlling the image quality adjustment operation of the playback content in the output image quality adjustment block 70 for each content. At this time, if the attribute information acquisition unit 102 can acquire the content attribute information in advance, the control routine creation unit 110 combines the extracted feature point information and the acquired attribute information. Thus, a control routine for the content is created. Specifically, the control routine creation unit 110 should apply to each scene of the content video based on the feature point information read from the feature point information storage unit 108 and the attribute information read from the attribute information storage unit 104. Determine the appropriate image quality adjustment. Then, the control routine creation unit 110 corrects the normal parameters for controlling the output image quality adjustment block 70 according to the feature point information and the attribute information, so that the feature points of the video of each content and the content of each content are corrected. Create an appropriate control routine according to the attribute. The control routine creation unit 110 stores the control routine created for each content in this way in the control routine storage unit 112.

  When reproducing the content recorded on the HDD 52, the image quality adjustment control unit 114 controls the output image quality adjustment block 70 based on the feature point information and attribute information of the content to be reproduced, and Controls image quality adjustment. At this time, the image quality adjustment control unit 114 reads the control routine corresponding to the content to be reproduced from the control routine storage unit 112, and controls the image quality adjustment function by the output image quality adjustment block 70 according to the control routine.

  Here, the image quality adjustment control process will be described in detail. At the time of content playback, first, video and audio data of the content to be played back selected by the user is read from the content storage unit 521 of the HDD 52, input to the AV decoder 40 via the stream processor 30, and decoded. The Next, the decoded video data is input from the AV decoder 40 to the output image quality adjustment block 70, and image quality adjustment such as noise reduction, brightness adjustment, hue adjustment, and sharpness adjustment of the reproduced video is performed. Thereafter, the image data whose image quality has been adjusted is subjected to predetermined processing by the graphic processing 80 and the display processing unit 82 (see FIG. 1), and then converted into an analog signal by the D / A converter 84 to be monitored 8. Is displayed.

  In such a reproduction process, the output image quality adjustment block 70 having the plurality of types of image quality adjustment functions (see FIG. 3) performs various image quality adjustments in order to improve the image quality of the reproduced content video. At this time, the image quality adjustment control unit 114 controls the operation of the output image quality adjustment block 70 according to the control routine corresponding to the content to be reproduced, and a plurality of image quality adjustment functions according to the feature points and attributes of the content to be reproduced. And control to apply the necessary image quality adjustment to the required part of the video.

  A control routine used for this image quality adjustment control is created in advance for each content by the control routine creation unit 110 in accordance with feature point information that is an analysis result of the video content of the content and attribute information of the content. It is stored in the control routine storage unit 112. Therefore, when reproducing the content, first, the image quality adjustment control unit 114 selects a control routine corresponding to the content to be reproduced from among a plurality of control routines in the control routine storage unit 112. Next, the image quality adjustment control unit 114 dynamically controls the operation of each unit of the output image quality adjustment block 70 by applying a control routine corresponding to the content to be reproduced. As a result, the output image quality adjustment block 70 is suitable for a scene of a predetermined scene that requires image quality adjustment out of the content video to be reproduced, based on a control signal from the image quality adjustment control unit 114. Perform the appropriate type of image quality adjustment to an appropriate degree. At this time, since the control routine is created according to the attribute information (for example, the genre of the program) of the content to be played back, the output image quality adjustment block 70 is suitable for the overall configuration of the program represented by the content to be played back. Adjust the image quality.

  For example, when a beautiful high-definition video content that does not require noise removal is to be reproduced, the image quality adjustment control unit 114 outputs the image quality adjustment block 70 so that noise reduction processing is not performed on the entire main part of the movie. To control. In addition, when old movie content with a lot of film noise is a playback target, the image quality adjustment control unit 114 controls the output image quality adjustment block 70 so as to perform a strong noise reduction process on the entire main part of the movie. When a television broadcast program content composed of a program main part and a CM is a reproduction target, the image quality adjustment control unit 114 performs an image quality adjustment suitable for the program main part on the program main part video. The output image quality adjustment block 70 is controlled so as to perform image quality adjustment specialized for the CM.

  In general, the number of frames of image data of the content and the creation method differ depending on the type of content program (for example, animation, drama, movie, variety, news, etc.). Therefore, as described above, the image quality adjustment control unit 114 has each image quality adjustment function of the output image quality adjustment block 70 according to a control routine set according to the type of program of the content to be played back, the overall configuration of the program, etc. Control to be selectively applied as needed. Thus, appropriate image quality adjustment can be performed on the video of each scene of the reproduced content.

  As described above, the image quality adjustment control unit 114 according to the present embodiment dynamically controls the operation of the output image quality adjustment block 70 according to the control routine customized for each content during content reproduction. As a result, appropriate image quality adjustment processing can be performed on the appropriate part (scene) of the video of the content in accordance with the overall structure of the program of the content to be played, scene changes, etc. Adjustments and unnecessary image quality adjustments can be avoided. Therefore, the output image quality of the reproduced content video can be improved.

  Next, the feature point information extraction processing of the recorded video by the recording / reproducing apparatus 10 according to the present embodiment and the playback image quality adjustment processing using the feature point information will be described in more detail with specific examples. .

1. Feature Point Extracted Image Analysis First, image analysis processing for extracting feature points of recorded video will be described with reference to FIGS. Such image analysis processing for feature point extraction is performed by a feature point extraction unit (configured by the feature point extraction block 60 of FIG. 4 and the analysis unit 106 of the CPU 100).

1.1 Outline of Feature Point Extraction Image Analysis The feature point extraction unit of the recording / reproducing apparatus 10 extracts feature point extraction target pixels (hereinafter, simply “ Feature point information is generated by analyzing information of a predetermined range (search area) around “target pixel” and “target pixel x”. FIG. 5 is an explanatory diagram showing a search area of 21 × 5 pixels around the target pixel. As shown in FIG. 5, for example, surrounding 21 × 5 pixels (21 pixels in the horizontal direction and 5 pixels in the vertical direction) centering on the target pixel can be set as a search area for the target pixel.

  The entire search area is 21 × 5 pixels, but in a single detection algorithm, detection processing is performed in units of a predetermined square area (for example, 3 × 3 pixels) smaller than the search area. A pixel region (for example, 3 × 3 pixels) serving as an individual detection unit of the detection algorithm is hereinafter referred to as a “detection unit region”. A plurality of detection unit regions (3 × 3 pixels) can be set at arbitrary positions as long as they are within the search region (21 × 5 pixels). For example, seven search unit areas (3 × 3 pixels) are arranged in the horizontal direction in a 21 × 3 pixel area (hatched area) in the search area (21 × 5 pixels) shown in FIG. Also good. As described above, the detection unit area may be set only to a 21 × 3 pixel area or to the entire 21 × 5 pixel search area according to a calculation part necessary for detecting a desired feature point. It may be set. Note that it is also possible to set a plurality of detection unit areas so that some of them overlap each other. Further, the size of the detection unit area is not limited to the example of 3 × 3 pixels.

  The feature point extraction unit analyzes the information of the pixels included in the search area, generates the feature point information of the target pixel, and based on the generated feature point information, the target pixel is a flat part, a grain part, Whether it is a mosquito noise part or a detail part is determined.

  Here, the flat portion is a region where the amplitude of the video signal of adjacent pixels is very small. In the flat portion, there are no points or edges.

  The grain portion is a region including a bright spot existing in a flat region. There may be a flicker like a dot in the region of the flat portion. Grain is an expression often used for film materials such as paintings, and is particularly called film grain.

  The mosquito noise part is an area including mosquito noise. Mosquito noise is fine and haze noise that appears at the contour of an image when a digitally compressed image (particularly a JPEG image) is played back. This noise is called this name because it looks like a group of mosquitoes clinging together. Mosquito noise is a phenomenon that occurs because the high frequency component of the spatial frequency of the image is lost. When a high compression ratio (low bit rate) is used, the image has a flat background and high contrast. It tends to appear around the area.

  The detail portion is a region where there is a difference of about a small amplitude between the video signals of adjacent pixels. Visually, an area including a pattern such as a clothes pattern or animal fur corresponds to a detail portion.

1.2 Specific Method of Feature Point Extraction Image Analysis Next, a specific method of image analysis for feature point extraction by the feature point extraction unit will be described. Examples of such analysis methods include the following methods (1) to (7).

(1) Relative Offset Detection of Luminance Signal The feature point extraction unit detects the difference between the luminance of pixels around the target pixel x and the luminance of the target pixel x by analyzing the luminance signal (Y signal). If the brightness difference (change amount range) is within a predetermined value, it can be determined that the target pixel x is a flat region (flat portion).

(2) Detection of change in luminance signal The feature point extraction unit detects a change in luminance of surrounding pixels with respect to the target pixel x by analyzing the luminance signal (Y signal). FIG. 6 shows a specific example of luminance change amount detection. In FIG. 6, the amount of change in luminance is obtained for the eight pixels a1 to a4 and a6 to a9 around the target pixel x (corresponding to a5) (up and down, left and right, and diagonal directions). For example, the feature point extraction unit calculates a luminance vector amount in the direction from the pixel a1 to the pixel a9 from the luminance change amounts of [a4-a6], [a2-a8], and [a1-a9].

(3) Edge Detection of Luminance Signal As shown in FIG. 7, the feature point extraction unit analyzes the luminance signal (Y signal), thereby obtaining the luminance of the target pixel x and the luminance of the surrounding pixels a1 to a9. The absolute value of the difference (V_a ^* = abs [x−a ^* ]) is calculated.
abs [x−a1] = V_a1
...
abs [x−a9] = V_a9

Furthermore, if V_a ^* is equal to or greater than a predetermined threshold (edge_TH), the feature point extraction unit counts as “edge”. As a result, if the counted number (edge) is equal to or greater than a predetermined count threshold (edge_TH_cnt), the feature point extraction unit determines that there is an edge.
edge> = edge_TH_cnt

  Such luminance edge detection is performed for all the calculation target pixels as shown in FIG. The calculation target pixels are, for example, the third to the 19th pixels arranged in the horizontal direction at the center in the vertical direction within the search area of 21 × 5 pixels. Note that the MNR target pixel in FIG. 7 is a pixel that requires MNR (MPEG Noise Reducer) processing.

(4) Large Edge Detection of Luminance Signal The feature point extraction unit searches for edge detection using the luminance signal not only in the surrounding pixels of the target pixel x but also in a 21 × 5 pixel search area (see FIG. 5). It is then determined whether there is a large edge in the search area. In order to detect this large edge, the feature point extraction unit analyzes the luminance signal (Y signal), and in the region separated from the target pixel in the search region, Absolute values (V_a ^* = abs [x−a ^* ]) of differences from the brightness of the surrounding pixels a are obtained and compared with a predetermined threshold value (see FIG. 14).

(5) Edge Detection of Color Difference Signal As shown in FIG. 8, the feature point extraction unit obtains the amount of change of Chroma with respect to the luminance of the target pixel by analyzing the color difference signal (Cb, Cr signal). If the amount of change is equal to or greater than a predetermined threshold, it is determined that the edge of the color difference signal (Edge). In actual video signals, Cb and Cr are alternately transmitted in the order of Cb, Cr, Cb, Cr,..., So it is necessary to perform calculation for color difference edge detection according to this transmission method. is there. Therefore, as shown in FIG. 8, the feature point extraction unit separates Cb and Cr in 6 × 3 pixels to form independent 3 × 3 pixel detection unit regions, and Cb and Cr respectively The absolute value of the difference in color difference between the target pixel at the center in the detection unit region and the eight pixels around it is calculated, and it is determined whether or not the absolute value of this difference is greater than or equal to a predetermined threshold value. As a result, when the difference is equal to or larger than a predetermined threshold, it is determined that the edge is detected.

(6) Skin Color Detection of Color Difference Signal As shown in FIG. 9, the feature point extraction unit analyzes the color difference signal (Cb, Cr signal), and if the values of Cb and Cr are within the specified range, Judge that there is. At this time, in addition to the color difference signal, the luminance signal may be analyzed if necessary.

Specifically, as shown in FIG. 9, based on the distribution of Cb and Cr of all pixels in a predetermined area (for example, 21 × 3 pixel area) in the search area of 21 × 5 pixels, the target pixel at the center It is determined whether or not the skin color portion. For example, the feature point extraction unit determines whether or not the values of Cb and Cr are within a predetermined range such as the following expression for pixels in the predetermined region, and is within the predetermined range In addition, it is counted as a counter value for skin color detection. This counting process is performed for all the pixels in the predetermined area (21 × 3 pixels), and if the counter value is equal to or greater than a predetermined threshold value, it is determined that the target pixel shown in FIG. 9 is the skin color area.
Cbmin <= Cb <= Cbmax
Crmin <= Cr <= Crmax

Further, when the luminance value Y having the same phase as Cb and Cr of the target pixel is not within a predetermined range as in the following expression, it is determined that the target pixel is not a skin color region. Thus, by detecting the skin color using the luminance signal, it is possible to avoid erroneous detection when the image is extremely dark or bright.
Ymin <= Y <= Ymax

(7) Luminance Signal Histogram As shown in FIG. 10, the feature point extraction unit uses the luminance signal histogram (luminance variation information) to determine the dark part and the bright part. Specifically, the feature point extraction unit collects histogram information in a predetermined region (for example, a 21 × 3 pixel region) in a 21 × 5 pixel search region, and enhances when the luminance distribution of the histogram is extremely biased. Reflect in processing.

1.3 Overview of Feature Point Information Counting and Image Discrimination The feature point extraction unit uses the following detected data to determine whether the target pixel corresponds to a flat part, a grain part, a mosquito noise part, or a detail part. And the number of pixels corresponding to each part in the screen is counted. Further, the feature point extraction unit determines what kind of image the target screen is from this count information, and determines the determined information as V units (that is, frame units of the video signal. For example, the video signal is 60 Hz). When it is transmitted, it is packetized in units of V = “1 / 60th of a second”) and stored in the external storage device.

1.4 Feature Point Extracted Image Analysis Discrimination Operation Next, a specific method for discriminating whether the target pixel corresponds to a flat portion, a grain portion, a mosquito noise portion, or a detail portion will be described.

(1) Discrimination of flat part As shown in FIG. 11, the feature point extraction unit converts a 21 × 5 pixel search area into square divided areas (for example, 3 × 3 pixel areas) arranged in the horizontal direction of the target pixel. ). Further, the feature point extraction unit detects, for each of the 3 × 3 pixel divided regions, a luminance difference between the pixel located at the center of each divided region and the surrounding pixels. Then, the feature point extraction unit determines whether or not the target pixel is a flat part by comparing the difference detected for each of the divided regions with a predetermined threshold value. Below, the specific example of the calculation method for performing flat part discrimination | determination is demonstrated.

First, as shown in the lower part of FIG. 11, for each 3 × 3 pixel divided region, the luminance difference between the pixel x located at the center of each divided region and the surrounding pixels a1 to a4 and a6 to a9. The absolute value (V_a ^* ) is calculated.
abs [x−a1] = V_a1
...
abs [x−a9] = V_a9

As a result, if the absolute value of the difference (V_a ^* ) is less than or equal to a predetermined threshold value (Flat_TH), it is counted as a counter value (Flat_cnt) indicating flatness.
V_a ^* <= Flat_TH

If the total counter value (Flat_cnt) of the pixels a1 to a4 and a6 to a9 in the divided area is equal to or less than a predetermined counter threshold (Flat_TH_cnt), it is determined that the divided area is flat, and Flat_cnt is If it is larger than Flat_TH_cnt, it is determined that the divided area is not flat.
Flat_cnt <= Flat_TH_cnt

  The flat determination described above is performed for all the divided regions around the target pixel (seven divided regions in the example of FIG. 11), and when it is determined that all the divided regions are flat, the target pixel is flat (that is, , Flat portion).

(2) Grain part discrimination | determination As shown in FIG. 12, in addition to the said flat determination, the feature point extraction part performs the grain determination with respect to an object pixel. That is, the feature point extraction unit detects a luminance difference between the target pixel and surrounding pixels in a 3 × 3 pixel divided region including the target pixel, and compares the detected difference with a predetermined threshold value. Thus, it is determined whether or not the target pixel is a grain portion. This grain portion determination process is performed on pixels that do not match the flat portion determination formula. Hereinafter, a specific example of the bright spot calculation method for determining the grain portion will be described.

First, as shown in the lower part of FIG. 12, in the 3 × 3 pixel divided region including the target pixel, the absolute value of the luminance difference between the target pixel x and the surrounding pixels a1 to a4 and a6 to a9 ( V_a ^* ) is calculated respectively.
abs [x−a1] = V_a1
...
abs [x−a9] = V_a9

As a result, if the absolute value of the difference (V_a ^* ) is greater than or equal to a predetermined threshold value (Point_TH), it is counted as a counter value (Point_cnt) indicating a bright spot. If the total counter value (Point_cnt) of the pixels a1 to a4 and a6 to a9 in the divided area is equal to or smaller than a predetermined counter threshold value (Point_TH_cnt), the target pixel x is a bright spot (that is, a grain portion). If Point_cnt is greater than Point_TH_cnt, it is determined that the target pixel x is not a bright spot.
Point_cnt <= Point_TH_cnt

(3) Determination of Mosquito Noise Part Next, a specific method for determining the mosquito noise part will be described. For example, the mosquito noise part can be determined using the following (3a) center edge detection, (3b) large edge detection, and (3c) distance determination from the large edge. The determination process of the mosquito noise part is performed on the pixels that do not correspond to either the flat part or the grain part after the determination process of the flat part and the grain part.

(3a) Center edge detection As shown in FIG. 13, the feature point extraction unit detects a luminance difference between the target pixel and surrounding pixels in a 3 × 3 pixel region centered on the target pixel, Whether or not the target pixel is a mosquito noise part is determined based on whether or not the detected difference is within a predetermined range. Specific examples thereof will be described below.

First, as shown in FIG. 13, in the 3 × 3 pixel area around the target pixel x, the absolute value (V_a) of the luminance difference between the target pixel x and each of the surrounding pixels a1 to a4 and a6 to a9. ^* Calculate each).
abs [x−a1] = V_a1
...
abs [x−a9] = V_a9

As a result, if the absolute value of the difference (V_a ^* ) is within a predetermined numerical range, that is, a predetermined lower limit value (MNRmin_TH) or more and a predetermined upper limit value (MNRmax_TH) or less, the counter value (MNR_cnt) indicating the center edge ). If the total counter value (MNR_cnt) of the pixels a1 to a4 and a6 to a9 in the region is equal to or smaller than a predetermined counter threshold value (MNR_TH_cnt), the target pixel x may be a mosquito noise part. Is determined.
MNR_cnt <= MNR_TH_cnt

(3b) Large Edge Detection As shown in FIG. 14, the feature point extraction unit performs a 21 × 5 pixel search region into a plurality of divided regions (for example, 3 × 3 pixel, for example) in the same manner as the above (1) flat portion determination. Area). Further, the feature point extraction unit detects a difference in luminance between a pixel located at the center of the divided region and a surrounding pixel with respect to the divided region separated by a predetermined block (for example, one block) from the divided region including the target pixel. To do. The feature point extraction unit determines whether the target pixel is a mosquito noise unit by comparing the detected difference with a predetermined threshold. Specific examples thereof will be described below.

First, as shown in FIG. 14, in a divided area (in the illustrated example, the first, second, sixth, and seventh divided areas from the left) that is one block or more away from the divided area including the target pixel, The absolute value (V_a ^* ) of the difference in luminance between the pixel x located in the pixel x and the surrounding pixels a1 to a4 and a6 to a9 is calculated.
abs [x−a1] = V_a1
...
abs [x−a9] = V_a9

As a result, if the absolute value of the difference (V_a ^* ) is greater than or equal to a predetermined threshold (MNRmax_TH), it is counted as a counter value (MNRBig_cnt) indicating a large edge. If the total counter value (MNRBig_cnt) of the pixels a1 to a4 and a6 to a9 in the area is equal to or greater than a predetermined counter threshold value (MNRBig_TH_cnt), the target pixel is determined to be a mosquito noise part. To do.
MNRBig_cnt> = MNRBig_TH_cnt

(3c) Distance Determination from Large Edge As shown in FIG. 15, the feature point extraction unit performs a 21 × 5 pixel search region in a plurality of divided regions (for example, 3 × Divided into 3 pixel regions). Further, the feature point extraction unit detects a difference in luminance between a pixel located at the center of the divided region and pixels around the divided region adjacent to the divided region including the target pixel. The feature point extraction unit determines whether the target pixel is a mosquito noise unit by comparing the detected difference with a predetermined threshold. Specific examples thereof will be described below.

First, as shown in FIG. 15, a pixel x located at the center of the divided region in the divided region including the target pixel (in the illustrated example, the third and fifth divided regions from the left), The absolute value (V_a ^* ) of the difference in luminance from the surrounding pixels a1 to a4 and a6 to a9 is calculated.
abs [x−a1] = V_a1
...
abs [x−a9] = V_a9

As a result, if the absolute value of the difference (V_a ^* ) is greater than or equal to a predetermined threshold (MNRmax_TH), it is counted as a counter value (MNRFarEdge_cnt) indicating a large edge. If the total counter value (MNRFarEdge_cnt) of the pixels a1 to a4 and a6 to a9 in the region is equal to or smaller than a predetermined counter threshold (MNRFarEdge_TH_cnt), it is determined that the target pixel may be a mosquito noise part. To do.
MNRFarEdge_cnt <= MNRFarEdge_TH_cnt

(4) Detail Part Determination As a result of the determinations (1) to (3) as described above, the feature point extraction unit determines a part that does not correspond to any of the flat part, grain part, and mosquito noise part as the detail part. Judge as.

2. Image Quality Adjustment Processing Using Feature Point Information Next, image quality adjustment processing of a reproduced image using image feature point information obtained as described above will be described. The image quality adjustment processing is performed by an image quality adjustment unit (consisting of the control routine creation unit 110 and image quality adjustment control unit 114 of the CPU 100 in FIG. 4 and the output image quality adjustment block 70). In the following example, an example will be described in which gain (NR intensity) when noise reduction (NR) is performed on a reproduced video is controlled using feature point information.

2.1 Outline of Noise Reduction Gain Control Using Feature Point Information In addition to the extracted feature point information, the image quality adjustment unit of the recording / reproducing apparatus 10 includes, for example, a CM detection function and program information (such as the type of video content). The information regarding the video content is obtained using the attribute information of the video content obtained by (). The image quality adjustment unit categorizes the video content into a plurality of types by combining the information finally obtained in this way. The video content classified here includes, for example, animation video (flat part: many, noise: small), dirty video with relatively low transfer rate (mosquito noise part: many), analog broadcast video ( Grain part: many, detail part: many), video of CM part unrelated to the main part broadcast (can be classified from CM detection result), and the like.

  Further, the image quality adjustment unit adopts the NR setting value tuned according to each type, and creates a control routine according to the type of video content.

  In addition to the above, the image quality adjustment unit determines the composition ratio of the flat portion, the grain portion, the mosquito noise portion, and the detail portion in the screen by using the feature point information in video frame units (V units). Then, the image quality adjustment unit regards the video frame in which the composition ratio greatly changes as a scene change, and returns the NR intensity setting for the video after the scene change to the standard value. For the other parts, the image quality adjustment unit controls the NR operation according to the NR set specification. For this purpose, the image quality adjustment unit aggregates the increase / decrease values of the feature point information when the video content is recorded for 1 Pass, creates a set value of NR in advance, and stores a control routine reflecting the value in the control routine storage unit 112. Save it.

2.2 In the case of a system that can set the NR intensity for each screen area The image quality adjustment unit adjusts the NR intensity according to changes in the ratio (composition ratio) of the flat part, grain part, mosquito noise part, and detail part in the screen. To change. At this time, the NR intensity is changed for each screen area by using the change amount information of each part for each screen area.

  For example, (1) when the predetermined area of the screen changes from the flat part to the grain part or the mosquito noise part, the image quality adjustment part increases the NR intensity for the area. On the other hand, (2) when the predetermined area of the screen changes from the grain part or the mosquito part to the flat part, the image quality adjustment unit weakens the NR intensity for the area. (3) When the predetermined area of the screen changes from the flat part to the detail part, the image quality adjustment unit weakens the NR intensity for the area. On the other hand, (4) when the predetermined area of the screen changes from the detail area to the flat area, the image quality adjustment section increases the NR intensity for the area. By controlling the NR intensity in this way, it is possible to execute the noise removal process for each area of each screen constituting the video content with an appropriate NR intensity corresponding to the video characteristics of the area.

2.3 In the case of a system that can set the NR intensity in units of screens The image quality adjustment unit will display the entire screen if the ratio (composition ratio) of the flat, grain, mosquito noise, and detail parts in the screen is not extremely biased Using the NR intensity against the standard value,
Only when it is extremely biased, NR control processing is performed.

  For example, (1) when there are many flat parts, grain parts, and mosquito parts in the screen, the image quality adjustment unit increases the NR intensity for the entire screen. On the other hand, when there are many detail portions in the screen, the image quality adjustment portion weakens the NR intensity for the entire screen. By controlling the NR intensity in this way, the noise removal process can be executed for each screen constituting the video content with an appropriate NR intensity according to the video characteristics of the screen.

  Similarly, image adjustment processing other than NR can be realized by controlling the output image quality adjustment block 70 in V units (video frame units) based on the special point information.

  Heretofore, the recording / reproducing apparatus 10 according to the present embodiment and the image quality adjustment method thereof have been described in detail. According to the recording / reproducing apparatus 10 according to the present embodiment, the feature point information of the video content is recorded at the time of recording or reproducing the content, and the control routine according to the feature point information at the next reproduction of the content Is used to dynamically control the output image quality adjustment function of the reproduced video. Further, the recording / reproducing apparatus 10 sets the control routine in advance in consideration of not only the feature point information but also content attribute information (program information and the like). As a result, when the content is recorded for the first time, the content of the entire content program is analyzed in advance, and when the content is reproduced next time, an appropriate type of the necessary portion of the reproduced video is selected according to the analysis result. The output image quality can be adjusted to an appropriate level. That is, for each recorded content, appropriate image quality adjustment can be performed according to the feature points and attributes of the video of each content, and a beautiful reproduced video can be output. Therefore, the image quality can be improved more effectively and more efficiently than before.

  Conventionally, since the content is not analyzed at the time of recording the content, it has been impossible to dynamically adjust the reproduction image quality such as applying noise reduction to unnecessary portions. Conventionally, the image quality adjustment function is manually controlled. On the other hand, in the present embodiment, the image quality adjustment function can be dynamically controlled without extra user operation to improve the reproduction image quality. As a result, it is possible to provide a user with a comfortable reproduction image quality.

  Further, the CPU 100 controls the operation of the output image quality adjustment block 70 according to a control routine corresponding to the feature point information analyzed in advance. Therefore, the existing output image quality adjustment block 70 can be used as it is, and the versatility is high and the manufacturing cost can be reduced.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  For example, in the above-described embodiment, the example in which the image quality adjustment apparatus is applied to the recording / reproducing apparatus 10 capable of recording and reproducing the content has been described, but the present invention is not limited to such an example. The image quality adjustment apparatus of the present invention can be applied to an arbitrary image processing apparatus such as a reproduction-only apparatus that does not have a recording function and various information processing apparatuses.

  In the above embodiment, an example in which content feature point information is extracted when content is recorded on a recording medium has been described. However, the present invention is not limited to such an example. For example, when reproducing content recorded on a recording medium such as a cell DVD, the feature point information may be extracted, and the feature point information may be used at the next reproduction.

  In the above embodiment, the attribute information acquisition unit 102, the analysis unit 106, the control routine creation unit 110, and the image quality adjustment control unit 114 are realized as software by installing a program that causes the computer to execute the functions of these units. However, the present invention is not limited to this example, and can be realized by hardware having the functions of the above-described units.

It is a block diagram which shows the structure of the recording / reproducing apparatus concerning one Embodiment of this invention. It is a block diagram which shows the internal structure of the feature point extraction block concerning the embodiment. It is a block diagram which shows the internal structure of the output image quality adjustment block concerning the embodiment. It is a block diagram which shows roughly the structure of the principal part of the recording / reproducing apparatus concerning the embodiment. It is explanatory drawing which shows the search area | region of the surrounding pixel of the object pixel in the image analysis concerning the embodiment. It is explanatory drawing which shows the specific example of the luminance variation detection in the image analysis concerning the embodiment. It is explanatory drawing which shows the specific example of the edge detection of the luminance signal in the image analysis concerning the embodiment. It is explanatory drawing which shows the specific example of the edge detection of the color difference signal in the image analysis concerning the embodiment. It is explanatory drawing which shows the specific example of the skin color detection using the color difference signal in the image analysis concerning the embodiment. It is explanatory drawing which shows the specific example of the bright part and dark part detection by the luminance histogram in the image analysis concerning the embodiment. It is explanatory drawing which shows the specific example of discrimination | determination of the flat part in the image analysis concerning the embodiment. It is explanatory drawing which shows the specific example of discrimination | determination of the grain part in the image analysis concerning the embodiment. It is explanatory drawing which shows the specific example of discrimination | determination of the mosquito noise part in the image analysis concerning the embodiment. It is explanatory drawing which shows another specific example of discrimination | determination of the mosquito noise part in the image analysis concerning the embodiment. It is explanatory drawing which shows another specific example of discrimination | determination of the mosquito noise part in the image analysis concerning the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Recording / reproducing apparatus 11 Analog tuner 12 A / D converter 13 Analog input terminal 14 DV input terminal 15 DV decoder 16 Digital tuner 17 i. LINK terminal 18 USB terminal 19 communication unit 20 AV encoder 30 stream processor 40 AV decoder 42 scaler 44 audio processor 50 recording unit 52 hard disk drive 54 optical disk drive 60 feature point extraction block 70 output image quality adjustment block 80 graphic processing unit 82 display processing unit 84 D / A converter 92 ROM
94 RAM
96 User interface 100 CPU
102 attribute information acquisition unit 104 attribute information storage unit 106 analysis unit 108 feature point information storage unit 110 control routine creation unit 112 control routine storage unit 114 image quality adjustment control unit

Claims (5)

A feature point extraction unit that analyzes a video signal of content recorded on a recording medium and extracts feature point information of the content video;
An output image quality adjustment unit that adjusts an output image quality of a video of the content when reproducing the content recorded on the recording medium;
An image quality adjustment control unit that controls the output image quality adjustment unit based on the feature point information of the content;
An image quality adjusting device comprising: A control routine creating unit that creates, for each content, a control routine for controlling the output image quality adjusting unit based on the feature point information;
The image quality adjustment control unit controls the output image quality adjustment unit based on the control routine corresponding to the content when reproducing the content recorded on the recording medium. 2. The image quality adjusting apparatus according to 1. An attribute information acquisition unit for acquiring attribute information of the content;
The control routine creation unit
The image quality adjustment apparatus according to claim 2, wherein the control routine is created for each content based on the feature point information and the attribute information of the content. A feature point extraction step of analyzing the video signal of the content and extracting feature point information of the video of the content when recording the content on a recording medium or reproducing the content recorded on the recording medium When;
The next time the content recorded on the recording medium is reproduced, an output image quality adjustment unit that adjusts the output image quality of the video of the content is controlled based on the feature point information of the content. An output image quality adjustment step for adjusting the output image quality of the video;
An image quality adjustment method comprising: A feature point extraction step of analyzing the video signal of the content and extracting feature point information of the video of the content when recording the content on a recording medium or reproducing the content recorded on the recording medium When;
The next time the content recorded on the recording medium is reproduced, an output image quality adjustment unit that adjusts the output image quality of the video of the content is controlled based on the feature point information of the content. An output image quality adjustment step for adjusting the output image quality of the video;
A program that causes a computer to execute.

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