WO2010070731A1 - Video signal processing device, video display device, video signal processing method, program thereof, and recording medium containing the program - Google Patents

Video signal processing device, video display device, video signal processing method, program thereof, and recording medium containing the program Download PDF

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WO2010070731A1
WO2010070731A1 PCT/JP2008/072845 JP2008072845W WO2010070731A1 WO 2010070731 A1 WO2010070731 A1 WO 2010070731A1 JP 2008072845 W JP2008072845 W JP 2008072845W WO 2010070731 A1 WO2010070731 A1 WO 2010070731A1
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video signal
signal processing
monotonic
degree
input
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PCT/JP2008/072845
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French (fr)
Japanese (ja)
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賢司 奥道
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パイオニア株式会社
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Priority to PCT/JP2008/072845 priority Critical patent/WO2010070731A1/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/20—Circuitry for controlling amplitude response
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
    • G06T5/00—Image enhancement or restoration
    • G06T5/20—Image enhancement or restoration by the use of local operators

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  • the present invention relates to a video signal processing device, a video display device, a video signal processing method, a program thereof, and a recording medium on which the program is recorded.
  • a digital video signal input to a receiver such as a television is quantized.
  • a digital video signal is quantized to about 8 bits.
  • the gradation part is particularly discontinuous and smooth gradation characteristics may not be obtained. Therefore, techniques for expanding the number of bits of an input video signal in order to faithfully reproduce the original video signal have been disclosed (for example, Patent Documents 1, 2, and 3).
  • Patent Document 1 discloses signal processing that includes an expansion unit that expands the number of low-frequency components limited to V bits to W (> V) bits, and increases the number of gray levels of a quantized signal. An apparatus is described. Patent Document 2 describes that an input image signal quantized with n bits is expanded to m bits (n ⁇ m) and simultaneously smoothed to generate a smooth signal. Patent Document 3 describes that a N-bit digital signal is expanded to an N + M-bit digital signal by a circuit having a bit number expansion function to obtain a smooth output waveform.
  • An object of the present invention is to generate an output signal for smoothly displaying a gradation portion and maintain a sense of detail, a video signal processing device, a video display device, a video signal processing method, a program thereof, and a program thereof It is an object to provide a recording medium on which is recorded.
  • a video signal processing apparatus is a video signal processing apparatus that processes an input video signal and outputs an output video signal, wherein the signal level monotonously increases and monotonously decreases in a predetermined region of an input image of the input video signal. Only when the signal level is monotonously increasing or monotonically decreasing based on at least one of the signal level state detecting means for detecting at least one of the degrees and the degree of monotonic increase and the degree of monotonic decrease. And a gradation characteristic adjusting unit that calculates a correction amount for an input video signal in a predetermined area and generates an output video signal in accordance with the correction amount.
  • a video display device includes the above-described video signal processing device and video display means for displaying an output video signal generated by the video signal processing device.
  • the video signal processing method of the present invention is a video signal processing method for processing an input video signal by an arithmetic means and outputting an output video signal, wherein the arithmetic means is provided in a predetermined region of an input image of the input video signal. Detecting at least one of the monotonic increase and monotonic decrease of the signal level, and the signal level is monotonously increasing or monotonically decreasing based on at least one of the monotonic increase and monotonic decrease Only in this case, a correction amount for the input video signal in the predetermined area is calculated, and an output video signal is generated according to the correction amount.
  • the video signal processing program according to the present invention is characterized by causing an arithmetic means to execute the video signal processing method described above.
  • the recording medium of the present invention is characterized in that the above-mentioned video signal processing program is recorded so as to be readable by a calculation means.
  • FIG. 1 is a block diagram showing a schematic configuration of a video signal processing apparatus according to a first embodiment of the present invention.
  • Explanatory drawing which shows the method to detect at least any one among the monotone increase degree of the gradation part in the said 1st Embodiment, and a monotone decrease degree.
  • Explanatory drawing which shows the method to detect at least any one among the monotone increase degree of the detail part in the said 1st Embodiment, and a monotone decrease degree.
  • FIG. 3 is a flowchart showing a flow of operations of the video signal processing apparatus in the first embodiment.
  • the block diagram which shows schematic structure of the gradation characteristic adjustment means of 2nd Embodiment concerning this invention.
  • Explanatory drawing which shows the procedure which converts the input video signal in the said 2nd Embodiment.
  • Explanatory drawing which shows the procedure which converts the input video signal in the said 2nd Embodiment.
  • the video signal processing apparatus is provided in the preceding stage of a video display means (not shown), and the bit length of the input signal corresponding to each pixel constituting the video is expanded from, for example, 8 bits to 10 bits.
  • a video signal processing apparatus capable of outputting the obtained 10-bit signal will be described as an example.
  • FIG. 3 is a block diagram showing a schematic configuration of the video signal processing apparatus according to the first embodiment of the present invention.
  • FIG. 4 is an explanatory diagram illustrating a method for detecting at least one of the monotonic increase degree and the monotonic decrease degree of the gradation portion in the first embodiment.
  • FIG. 5 is an explanatory diagram illustrating a method for detecting at least one of the monotonic increase degree and the monotonic decrease degree of the detail portion in the first embodiment.
  • FIG. 6 is an explanatory diagram showing a correction amount calculation method in the first embodiment.
  • FIG. 7 is a flowchart showing the flow of the operation of the video signal processing apparatus in the first embodiment.
  • the video signal processing apparatus 100 as a calculation unit includes a signal level state detection unit 110 and a gradation characteristic adjustment unit 120.
  • the signal level state detection unit 110 detects at least one of the monotonic increase degree and the monotonic decrease degree of the signal level of the input video signal.
  • the subject of the signal level is not particularly limited, and is selected from, for example, luminance, chromaticity, saturation, and the like.
  • the luminance is described as an example. Referring to FIG. 4 and FIG. 5, FIG. 4 shows a fluctuation state of the luminance level of the pixels continuous in the horizontal direction in the gradation portion of the input image of the input video signal.
  • the luminance level increases every 4/1023 (including 0).
  • an arbitrary pixel is set as a processing target pixel CDAT.
  • the cumulative value DIF of the adjacent difference and the cumulative value DIFa of the absolute value of the adjacent difference are calculated by the following equations.
  • the difference value DEL between the cumulative value DIF of the adjacent difference and the cumulative value DIFa of the absolute value of the adjacent difference is set as a monotonic increase degree or a monotone decrease degree.
  • the difference value DEL is 0 when monotonously increasing or monotonically decreasing, and the difference value DEL is large when not monotonously increasing or monotonically decreasing.
  • the determination of whether or not the monotonic increase and the monotonic decrease may be made based on whether or not the difference value DEL is 0, but may be appropriately adjusted according to the magnitude of the difference value DEL.
  • the above processing is performed by two-dimensional processing of the input video signal in the horizontal direction and the vertical direction, and a value obtained by adding the respective calculation results is detected as a monotone increase degree and a monotone decrease degree.
  • the detection method is not limited to the above-described method as long as it can detect the monotonic increase degree and the monotonic decrease degree.
  • the gradation characteristic adjusting unit 120 calculates a correction amount for improving the gradation characteristic, and outputs an output video signal obtained by multiplying the input video signal by the correction amount according to the detected monotonic increase and monotonic decrease.
  • FIG. 6 shows the processing target pixel CDAT and the comparison target pixels LDAT and RDAT adjacent to the processing target pixel CDAT.
  • the luminance level of the processing target pixel CDAT is LCDAT
  • the luminance level of the comparison target pixel LDAT is LLDAT
  • the luminance level of the comparison target pixel RDAT is LRDAT.
  • DIFL
  • DIFR
  • the difference absolute values DIFL and DIFR between the processing target pixel CDAT and the comparison target pixels LDAT and RDAT are large, it is a contour portion (edge portion), and thus correction for maintaining the edge portion is performed.
  • the MLDAT and MRDAT values used in the calculation are determined.
  • the threshold S of the difference absolute values DIFL and DIFR is determined, and the difference absolute values DIFL and DIFR are compared with the threshold S.
  • the threshold value S is set small when it is important to display the edge portion more clearly, and the threshold value S is set large when importance is given to improving the gradation characteristics. For example, when the threshold value S is set to 4/1023, the gradation characteristics can be improved with an accuracy of 8 bits or more by connecting gradations of 4/1023 or less.
  • the luminance level after improving the gradation characteristics of the processing target pixel CDAT is an average value AVE of MLDAT and MRDAT expressed by the following equation.
  • AVE (MLDAT + MRDAT) / 2
  • a value obtained by subtracting the luminance level LCDAT of the processing target pixel CDAT from the AVE is the correction amount COR of the processing target pixel CDAT.
  • COR AVE-LCDAT
  • the gradation characteristics can be improved in a wider range by increasing the radius of the processing target pixel and the comparison target pixel. Then, the monotonic increase and monotonic decrease detected by the signal level state detection unit 110 are added to the calculated correction amount COR. Specifically, when the increase is not monotonically increasing or decreasing, the correction amount COR is set to 0, or the correction amount COR is adjusted according to the monotonic increase degree and the monotonic decrease degree.
  • a video signal from a broadcasting station is input to the video signal processing apparatus 100 via an antenna (not shown).
  • the signal level state detection unit 110 detects at least one of the monotonic increase degree and the monotonic decrease degree of the input video signal by the above-described method (step S1).
  • the gradation characteristic adjusting unit 120 calculates a correction amount for improving the gradation characteristic of the input video signal by the above-described method (step S2).
  • the correction amount of the portion to be the edge portion is adjusted based on the above-described threshold value S at the portion where the monotone increases or decreases monotonously.
  • the gradation characteristic adjusting unit 120 determines the correction amount calculated in step S2 based on the monotonic increase and monotonic decrease detected in step S1 (step S3). For example, if the degree of monotone increase or the degree of monotone decrease is 0, that is, if the monotone increase or monotonic decrease is YES, the determination is YES, and the input video signal is corrected using the correction amount calculated in step S2 (step S4). On the other hand, when the degree of monotone increase and the degree of monotonic decrease are larger than 0, that is, when the monotonic increase and monotonic decrease are not, NO is determined and the correction process is not performed. Then, the gradation characteristic adjusting unit 120 outputs the output video signal generated by the correction or the input video signal that has not been corrected as the output video signal (step S5), and ends.
  • the video signal processing apparatus 100 detects at least one of the monotonic increase degree and the monotonic decrease degree based on the luminance level of each pixel of the input image of the input video signal.
  • the signal level state detection unit 110 detects a gradation part, and the gradation characteristic adjustment unit 120 performs correction for improving the gradation characteristic only in the gradation part that is monotonously increasing and monotonically decreasing, and monotonically increasing and monotonic. No correction is made for detail parts that have not decreased. Accordingly, it is possible to improve the gradation characteristics of only the gradation portion with high accuracy, and to maintain the detail feeling of the detail portion.
  • the gradation characteristic adjusting unit 120 calculates the correction amount
  • the difference between the luminance levels of the adjacent pixels is compared with a preset threshold S, and the luminance level of the adjacent pixels is calculated.
  • the correction amount is adjusted to be 0 assuming that the difference is an edge portion. Therefore, the edge portion can be easily detected by setting the threshold value S, and correction processing is not performed on the edge portion, so that the edge portion can be displayed more clearly.
  • the correction process for improving the gradation characteristics is performed only on the gradation portion. Therefore, the gradation part is more excellent in gradation characteristics, and the detail feeling can be maintained in the detail part and the edge part.
  • FIG. 8 is a block diagram showing a schematic configuration of the gradation characteristic adjusting means of the second embodiment according to the present invention.
  • FIG. 9 is an explanatory diagram showing a procedure for converting an input video signal in the second embodiment.
  • FIG. 10 is an explanatory diagram showing a procedure for converting an input video signal in the second embodiment.
  • FIG. 11 is a diagram showing an output video signal in the second embodiment.
  • the gradation characteristic adjusting unit 130 includes a low-pass filter (hereinafter referred to as LPF) processing unit 131, an expansion processing unit 132, an adding unit 133, a threshold comparison unit 134, and a correction processing unit. 135.
  • LPF processing unit 131 performs filtering on the m-bit input video signal and outputs an LPF signal expanded to m + n bits. For example, when a signal is input in FIG. 9, the LPF processing unit 131 converts the signal into an LPF signal.
  • the extension processing means 132 outputs an extension signal obtained by extending an m-bit input video signal to m + n bits. Specifically, the input signal is multiplied by 2n . In FIG. 9, in order to extend an 8-bit input signal to 10 bits, the input signal is multiplied by the square of 2, that is, 4 times. Specifically, the result of quadrupling the input signal of each pixel is shown in the row C of FIG.
  • the adding means 133 adds the aforementioned LPF signal and the extension signal, and outputs an n-bit signal. Specifically, the n-bit signal is generated by subtracting the extension signal C from the LPF signal B in FIG.
  • the threshold comparison unit 134 performs threshold processing on the n-bit signal.
  • An n-bit signal output by the adding means 133 is shown in FIG. In FIG. 10, the threshold value is set to ⁇ 1 or more and 1 or less for an n-bit signal, and a signal whose value is larger or smaller than the threshold value is determined to be a contour portion. The signal at this time is zero.
  • the correction processing unit 135 generates an output video signal by adding the n-bit signal adjusted by the threshold comparison unit 134 to the input video signal. At this time, the monotonic increase and monotonic decrease detected by the signal level state detection unit 110 are taken into account.
  • the correction amount is set to 0, or the correction amount is adjusted according to the monotonic increase and monotonic decrease.
  • An output video signal output by the above processing is shown in FIG. As shown in FIG. 11, tone characteristics are improved in a monotonically increasing or decreasing portion, and correction is not performed when the difference between adjacent signals is large, so that a sense of detail can be maintained. it can.
  • the signal level state detection means detects at least one of the monotonic increase degree and the monotonic decrease degree for the input video signal.
  • the polarity is positive (+) when it is monotonously increasing
  • the polarity is constant at minus (-) when it is monotonically decreasing
  • plus and minus are mixed when it is a detail portion.
  • the monotonic increase degree and the monotonic decrease degree may be detected based on a mixture ratio of plus and minus.
  • no polarity is set. The above processing is performed by two-dimensional processing of the input video signal in the horizontal direction and the vertical direction, and a value obtained by adding the respective calculation results is detected as a monotone increase degree and a monotone decrease degree.
  • the present invention is not limited to the above-described embodiment, and can be appropriately changed to other configurations as long as the object of the present invention can be achieved.
  • the third embodiment may be applied to the second embodiment described above.
  • Each function described above may be constructed as a program, or may be configured by hardware such as a circuit board or an element such as a single integrated circuit (IC), and can be used in any form.
  • IC integrated circuit
  • the video signal processing apparatus includes a signal level state detection unit that detects at least one of the monotonic increase degree and the monotonic decrease degree based on the luminance level of each pixel of the input video signal; A gradation characteristic adjusting unit that calculates a correction amount for improving the gradation characteristic of the video signal and corrects the input video signal according to at least one of the monotonic increase degree and the monotonic decrease degree; It was. In other words, only the gradation part that is monotonously increasing or monotonically decreasing is corrected to improve the gradation characteristics, and the detail part that is not monotonically increasing or decreasing is not corrected, so the gradation part is displayed smoothly.
  • the output signal to be generated can be generated, and a detail feeling can be maintained in the detail portion.
  • the present invention relates to a video signal processing device, a video display device, a video signal processing method, a program thereof, and a recording medium on which the program is recorded, which is used in playback equipment such as a plasma display, liquid crystal display, DVD player, etc. Available.

Abstract

A video signal processing device (100) is provided with a signal level state detection means (110) and a gradation property adjustment means (120). The signal level state detection means (110) detects at least monotonic increase or monotonic decrease of an input video signal. The gradation property adjustment means (120) calculates a correction amount for improving gradation property and outputs an output video signal given by multiplying the input video signal by the correction amount according to the detected monotonic increase and/or monotonic decrease. Moreover, when the differential absolute value of the signal level of an adjacent pixel is large in the case of the monotonic increase or monotonic decrease, possibility of being an outline portion (detail portion) is considered.

Description

映像信号処理装置、映像表示装置、映像信号処理方法、そのプログラムおよびそのプログラムを記録した記録媒体VIDEO SIGNAL PROCESSING DEVICE, VIDEO DISPLAY DEVICE, VIDEO SIGNAL PROCESSING METHOD, PROGRAM THEREOF, AND RECORDING MEDIUM CONTAINING THE PROGRAM
　本発明は、映像信号処理装置、映像表示装置、映像信号処理方法、そのプログラムおよびそのプログラムを記録した記録媒体に関する。 The present invention relates to a video signal processing device, a video display device, a video signal processing method, a program thereof, and a recording medium on which the program is recorded.
　従来、テレビなどの受像機に入力されるデジタル映像信号は量子化されている。量子化の程度を表す量子化ビット数は、その値が高いほど元の映像信号を忠実に再現することができ、一般的に、デジタル映像信号は８ビット程度に量子化される。８ビットに量子化された映像信号をそのままテレビなどの受像機に表示させると、特に、グラデーション部が不連続となり、滑らかな階調特性が得られない場合がある。
　そこで、元の映像信号を忠実に再現するために、入力された映像信号のビット数を拡張する技術が開示されている（例えば、特許文献１、２および３）。 Conventionally, a digital video signal input to a receiver such as a television is quantized. The higher the value of the number of quantization bits representing the degree of quantization, the more accurately the original video signal can be reproduced. Generally, a digital video signal is quantized to about 8 bits. When a video signal quantized to 8 bits is displayed as it is on a receiver such as a television, the gradation part is particularly discontinuous and smooth gradation characteristics may not be obtained.
Therefore, techniques for expanding the number of bits of an input video signal in order to faithfully reproduce the original video signal have been disclosed (for example, Patent Documents 1, 2, and 3).
　特許文献１に記載のものは、Ｖビットに制限された低周波成分のビット数をＷ（＞Ｖ）ビットに拡張する拡張手段を備え、量子化された信号の階調数を増加させる信号処理装置が記載されている。
　特許文献２に記載のものは、ｎビットで量子化された入力画像信号をｍビット（ｎ＜ｍ）に拡張すると同時に平滑化を行い、滑らかな信号を生成することが記載されている。
　特許文献３に記載のものは、ビット数拡張機能を備えた回路によって、Ｎビットのデジタル信号をＮ＋Ｍビットのデジタル信号に拡張し、滑らかな出力波形を得ることが記載されている。 Patent Document 1 discloses signal processing that includes an expansion unit that expands the number of low-frequency components limited to V bits to W (> V) bits, and increases the number of gray levels of a quantized signal. An apparatus is described.
Patent Document 2 describes that an input image signal quantized with n bits is expanded to m bits (n <m) and simultaneously smoothed to generate a smooth signal.
Patent Document 3 describes that a N-bit digital signal is expanded to an N + M-bit digital signal by a circuit having a bit number expansion function to obtain a smooth output waveform.
特開２００７－２２１５６９号公報JP 2007-22169 A 特開平８－２３７６６９号公報JP-A-8-237669 特開平７－９５０７６号公報JP 7-95076 A
　しかしながら、特許文献１、２および３に記載の構成では、図１に示されるように、入力映像信号のグラデーション部においては、ビット数を拡張した出力信号の輝度分布が滑らかとなり、自然なグラデーションを表示させることができるものの、図２に示されるように、入力映像信号のグラデーション部以外の部分（以下、ディテール部と言う）についても階調数を増加させることになり、特に、ディテール部の輪郭（図２のＡ部分）がぼやけて表示される場合があるという問題が一例として挙げられる。 However, in the configurations described in Patent Documents 1, 2, and 3, as shown in FIG. 1, in the gradation portion of the input video signal, the luminance distribution of the output signal with the expanded number of bits becomes smooth, and natural gradation is obtained. Although it can be displayed, as shown in FIG. 2, the number of gradations is also increased in a portion other than the gradation portion of the input video signal (hereinafter referred to as a detail portion), and in particular, the contour of the detail portion. The problem that (the A part of FIG. 2) may be displayed blurry is mentioned as an example.
　本発明の目的は、グラデーション部を滑らかに表示させる出力信号を生成することができるとともに、ディテール感を維持することができる映像信号処理装置、映像表示装置、映像信号処理方法、そのプログラムおよびそのプログラムを記録した記録媒体を提供することを一つの目的とする。 SUMMARY OF THE INVENTION An object of the present invention is to generate an output signal for smoothly displaying a gradation portion and maintain a sense of detail, a video signal processing device, a video display device, a video signal processing method, a program thereof, and a program thereof It is an object to provide a recording medium on which is recorded.
　本発明の映像信号処理装置は、入力映像信号を処理して出力映像信号を出力する映像信号処理装置であって、前記入力映像信号の入力画像の所定領域における信号レベルの単調増加度および単調減少度のうち少なくともいずれか一方を検出する信号レベル状態検出手段と、前記単調増加度および単調減少度のうち少なくともいずれか一方に基づいて、前記信号レベルが単調増加または単調減少している場合のみ前記所定領域の入力映像信号に対する補正量を算出し、この補正量に応じて出力映像信号を生成する階調特性調整手段と、を備えたことを特徴とする。 A video signal processing apparatus according to the present invention is a video signal processing apparatus that processes an input video signal and outputs an output video signal, wherein the signal level monotonously increases and monotonously decreases in a predetermined region of an input image of the input video signal. Only when the signal level is monotonously increasing or monotonically decreasing based on at least one of the signal level state detecting means for detecting at least one of the degrees and the degree of monotonic increase and the degree of monotonic decrease. And a gradation characteristic adjusting unit that calculates a correction amount for an input video signal in a predetermined area and generates an output video signal in accordance with the correction amount.
　本発明の映像表示装置は、前述の映像信号処理装置と、この映像信号処理装置で生成された出力映像信号を表示する映像表示手段と、を具備したことを特徴とする。 A video display device according to the present invention includes the above-described video signal processing device and video display means for displaying an output video signal generated by the video signal processing device.
　本発明の映像信号処理方法は、演算手段により、入力映像信号を処理して出力映像信号を出力する映像信号処理方法であって、前記演算手段は、前記入力映像信号の入力画像の所定領域における信号レベルの単調増加度および単調減少度のうち少なくともいずれか一方を検出し、前記単調増加度および単調減少度のうち少なくともいずれか一方に基づいて、前記信号レベルが単調増加または単調減少している場合のみ前記所定領域の入力映像信号に対する補正量を算出し、この補正量に応じて出力映像信号を生成することを特徴とする。 The video signal processing method of the present invention is a video signal processing method for processing an input video signal by an arithmetic means and outputting an output video signal, wherein the arithmetic means is provided in a predetermined region of an input image of the input video signal. Detecting at least one of the monotonic increase and monotonic decrease of the signal level, and the signal level is monotonously increasing or monotonically decreasing based on at least one of the monotonic increase and monotonic decrease Only in this case, a correction amount for the input video signal in the predetermined area is calculated, and an output video signal is generated according to the correction amount.
　本発明の映像信号処理プログラムは、前述の映像信号処理方法を演算手段に実行させることを特徴とする。 The video signal processing program according to the present invention is characterized by causing an arithmetic means to execute the video signal processing method described above.
　本発明の記録媒体は、前述の映像信号処理プログラムが演算手段にて読取可能に記録されたことを特徴とする。 The recording medium of the present invention is characterized in that the above-mentioned video signal processing program is recorded so as to be readable by a calculation means.
従来技術におけるグラデーション部の入力信号と出力信号を示す図。The figure which shows the input signal and output signal of the gradation part in a prior art. 従来技術におけるディテール部の入力信号と出力信号を示す図。The figure which shows the input signal and output signal of a detail part in a prior art. 本発明にかかる第１実施形態の映像信号処理装置の概略構成を示すブロック図。1 is a block diagram showing a schematic configuration of a video signal processing apparatus according to a first embodiment of the present invention. 前記第１実施形態におけるグラデーション部の単調増加度および単調減少度のうち少なくともいずれか一方を検出する方法を示す説明図。Explanatory drawing which shows the method to detect at least any one among the monotone increase degree of the gradation part in the said 1st Embodiment, and a monotone decrease degree. 前記第１実施形態におけるディテール部の単調増加度および単調減少度のうち少なくともいずれか一方を検出する方法を示す説明図。Explanatory drawing which shows the method to detect at least any one among the monotone increase degree of the detail part in the said 1st Embodiment, and a monotone decrease degree. 前記第１実施形態における補正量の算出方法を示す説明図。Explanatory drawing which shows the calculation method of the correction amount in the said 1st Embodiment. 前記第１実施形態における映像信号処理装置の動作の流れを示すフローチャート。3 is a flowchart showing a flow of operations of the video signal processing apparatus in the first embodiment. 本発明にかかる第２実施形態の階調特性調整手段の概略構成を示すブロック図。The block diagram which shows schematic structure of the gradation characteristic adjustment means of 2nd Embodiment concerning this invention. 前記第２実施形態における入力映像信号を変換する手順を示す説明図。Explanatory drawing which shows the procedure which converts the input video signal in the said 2nd Embodiment. 前記第２実施形態における入力映像信号を変換する手順を示す説明図。Explanatory drawing which shows the procedure which converts the input video signal in the said 2nd Embodiment. 前記第２実施形態における出力映像信号を示す図。The figure which shows the output video signal in the said 2nd Embodiment.
符号の説明Explanation of symbols
１００…演算手段としての映像信号処理装置
１１０…信号レベル状態検出手段
１２０…階調特性調整手段 DESCRIPTION OF SYMBOLS 100 ... Video signal processor 110 as a calculation means ... Signal level state detection means 120 ... Tone characteristic adjustment means
（第１実施形態）
　以下、本発明の第１実施形態を図面に基づいて説明する。
　映像信号処理装置は、図示しない映像表示手段などの前段に設けられるものであり、映像を構成する各画素に対応する入力信号のビット長を、例えば、８ビットから１０ビットに拡張し、その結果得られる１０ビットの信号を出力可能な映像信号処理装置を例示して説明する。 (First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
The video signal processing apparatus is provided in the preceding stage of a video display means (not shown), and the bit length of the input signal corresponding to each pixel constituting the video is expanded from, for example, 8 bits to 10 bits. A video signal processing apparatus capable of outputting the obtained 10-bit signal will be described as an example.
　［映像信号処理装置の構成］
　まず、映像信号処理装置の構成について説明する。
　図３は、本発明にかかる第１実施形態の映像信号処理装置の概略構成を示すブロック図である。図４は、前記第１実施形態におけるグラデーション部の単調増加度および単調減少度のうち少なくともいずれか一方を検出する方法を示す説明図である。図５は、前記第１実施形態におけるディテール部の単調増加度および単調減少度のうち少なくともいずれか一方を検出する方法を示す説明図である。図６は、前記第１実施形態における補正量の算出方法を示す説明図である。図７は、前記第１実施形態における映像信号処理装置の動作の流れを示すフローチャートである。 [Configuration of video signal processing device]
First, the configuration of the video signal processing apparatus will be described.
FIG. 3 is a block diagram showing a schematic configuration of the video signal processing apparatus according to the first embodiment of the present invention. FIG. 4 is an explanatory diagram illustrating a method for detecting at least one of the monotonic increase degree and the monotonic decrease degree of the gradation portion in the first embodiment. FIG. 5 is an explanatory diagram illustrating a method for detecting at least one of the monotonic increase degree and the monotonic decrease degree of the detail portion in the first embodiment. FIG. 6 is an explanatory diagram showing a correction amount calculation method in the first embodiment. FIG. 7 is a flowchart showing the flow of the operation of the video signal processing apparatus in the first embodiment.
　図３に示すように、演算手段としての映像信号処理装置１００は、信号レベル状態検出手段１１０と、階調特性調整手段１２０と、を備えている。
　信号レベル状態検出手段１１０は、入力された映像信号の信号レベルの単調増加度および単調減少度のうち少なくともいずれか一方を検出する。ここで、信号レベルの主体は特に限定されず、例えば、輝度、色度、彩度などから選ばれる。なお、本実施形態では、輝度を例示して説明する。
　図４および図５を参照すると、図４には、入力映像信号の入力画像のグラデーション部における水平方向に連続する画素の輝度レベルの変動状況が示されている。入力映像信号は８ビットに量子化されているため、輝度レベルは４／１０２３（０含む）ごとに増加する。ここで、任意の画素を処理対象画素ＣＤＡＴとする。処理対象画素ＣＤＡＴに対して所定の処理半径Ｒ（例えば、Ｒ＝４）以内のそれぞれの画素における輝度レベルの隣接差分Ａ，Ｂ，Ｃ，Ｄ，Ｅ，Ｆ，Ｇ，Ｈを取得し、この隣接差分の累積値ＤＩＦと、隣接差分の絶対値の累積値ＤＩＦａとを以下の式で算出する。 As shown in FIG. 3, the video signal processing apparatus 100 as a calculation unit includes a signal level state detection unit 110 and a gradation characteristic adjustment unit 120.
The signal level state detection unit 110 detects at least one of the monotonic increase degree and the monotonic decrease degree of the signal level of the input video signal. Here, the subject of the signal level is not particularly limited, and is selected from, for example, luminance, chromaticity, saturation, and the like. In the present embodiment, the luminance is described as an example.
Referring to FIG. 4 and FIG. 5, FIG. 4 shows a fluctuation state of the luminance level of the pixels continuous in the horizontal direction in the gradation portion of the input image of the input video signal. Since the input video signal is quantized to 8 bits, the luminance level increases every 4/1023 (including 0). Here, an arbitrary pixel is set as a processing target pixel CDAT. The luminance level adjacent differences A, B, C, D, E, F, G, and H are obtained for each pixel within a predetermined processing radius R (for example, R = 4) with respect to the processing target pixel CDAT. The cumulative value DIF of the adjacent difference and the cumulative value DIFa of the absolute value of the adjacent difference are calculated by the following equations.
　ＤＩＦ＝Ａ＋Ｂ＋Ｃ＋Ｄ＋Ｅ＋Ｆ＋Ｇ＋Ｈ
　ＤＩＦａ＝｜Ａ｜＋｜Ｂ｜＋｜Ｃ｜＋｜Ｄ｜＋｜Ｅ｜＋｜Ｆ｜＋｜Ｇ｜＋｜Ｈ｜ DIF = A + B + C + D + E + F + G + H
DIFa = | A | + | B | + | C | + | D | + | E | + | F | + | G | + | H |
　そして、隣接差分の累積値ＤＩＦと隣接差分の絶対値の累積値ＤＩＦａとの差分値ＤＥＬを単調増加度または単調減少度とする。差分値ＤＥＬは以下の式で算出される。
　ＤＥＬ＝ＤＩＦａ－｜ＤＩＦ｜ Then, the difference value DEL between the cumulative value DIF of the adjacent difference and the cumulative value DIFa of the absolute value of the adjacent difference is set as a monotonic increase degree or a monotone decrease degree. The difference value DEL is calculated by the following formula.
DEL = DIFa- | DIF |
　すなわち、単調増加または単調減少している場合は差分値ＤＥＬが０となり、単調増加および単調減少でない場合は差分値ＤＥＬが大きい値となる。単調増加および単調減少であるか否かの判定は、差分値ＤＥＬが０か否かで判定してもよいが、差分値ＤＥＬの大きさに応じて適宜調整してもよい。
　ここで、図４を上記式に適用すると、ＤＩＦ＝１２、ＤＩＦａ＝１２という結果が得られ、これらの差分値ＤＥＬ＝０が検出される。すなわち、図４は、単調増加または単調減少しているため、グラデーション部であることを示す。
　また、図５を上記式に適用すると、ＤＩＦ＝４、ＤＩＦａ＝１２という結果が得られ、これらの差分値ＤＥＬ＝８が検出される。すなわち、図５は、単調増加および単調減少ではなく、ディテール部であることを示す。 That is, the difference value DEL is 0 when monotonously increasing or monotonically decreasing, and the difference value DEL is large when not monotonously increasing or monotonically decreasing. The determination of whether or not the monotonic increase and the monotonic decrease may be made based on whether or not the difference value DEL is 0, but may be appropriately adjusted according to the magnitude of the difference value DEL.
Here, when FIG. 4 is applied to the above equation, the results of DIF = 12, DIFa = 12, and the difference value DEL = 0 is detected. That is, FIG. 4 shows a gradation portion because it monotonously increases or monotonously decreases.
Further, when FIG. 5 is applied to the above equation, the result of DIF = 4 and DIFa = 12, and the difference value DEL = 8 is detected. That is, FIG. 5 shows a detail portion, not a monotone increase and a monotone decrease.
　以上の処理を、入力映像信号の水平方向と垂直方向の２次元処理で行い、各計算結果を合算した値を単調増加度および単調減少度として検出する。
　なお、検出方法としては、単調増加度および単調減少度を検出できる方法であれば、上述の方法に限られない。 The above processing is performed by two-dimensional processing of the input video signal in the horizontal direction and the vertical direction, and a value obtained by adding the respective calculation results is detected as a monotone increase degree and a monotone decrease degree.
Note that the detection method is not limited to the above-described method as long as it can detect the monotonic increase degree and the monotonic decrease degree.
　階調特性調整手段１２０は、階調特性を向上させるための補正量を計算し、検出された単調増加度および単調減少度に応じて、補正量を入力映像信号に乗算した出力映像信号を出力する。
　補正量の計算方法の具体例を、図６を用いて説明する。図６には、処理対象画素ＣＤＡＴと、処理対象画素ＣＤＡＴに隣接する比較対象画素ＬＤＡＴおよびＲＤＡＴが示されている。ここで、処理対象画素ＣＤＡＴの輝度レベルをＬＣＤＡＴ、比較対象画素ＬＤＡＴの輝度レベルをＬＬＤＡＴ、比較対象画素ＲＤＡＴの輝度レベルをＬＲＤＡＴとする。
　まず、処理対象画素ＣＤＡＴと比較対象画素ＬＤＡＴおよびＲＤＡＴとの差分絶対値ＤＩＦＬおよびＤＩＦＲを以下の式により取得する。 The gradation characteristic adjusting unit 120 calculates a correction amount for improving the gradation characteristic, and outputs an output video signal obtained by multiplying the input video signal by the correction amount according to the detected monotonic increase and monotonic decrease. To do.
A specific example of the correction amount calculation method will be described with reference to FIG. FIG. 6 shows the processing target pixel CDAT and the comparison target pixels LDAT and RDAT adjacent to the processing target pixel CDAT. Here, the luminance level of the processing target pixel CDAT is LCDAT, the luminance level of the comparison target pixel LDAT is LLDAT, and the luminance level of the comparison target pixel RDAT is LRDAT.
First, absolute difference values DIFL and DIFR between the processing target pixel CDAT and the comparison target pixels LDAT and RDAT are obtained by the following equations.
　ＤＩＦＬ＝｜ＬＣＤＡＴ－ＬＬＤＡＴ｜
　ＤＩＦＲ＝｜ＬＣＤＡＴ－ＬＲＤＡＴ｜ DIFL = | LCDAT-LLDAT |
DIFR = | LCDAT-LRDAT |
　ここで、処理対象画素ＣＤＡＴと比較対象画素ＬＤＡＴおよびＲＤＡＴとの差分絶対値ＤＩＦＬおよびＤＩＦＲが大きい場合は輪郭部（エッジ部）であるので、このエッジ部を維持するための補正を行い、後述の計算で用いるＭＬＤＡＴおよびＭＲＤＡＴの値を決定する。
　具体的には、差分絶対値ＤＩＦＬおよびＤＩＦＲの閾値Ｓを定め、差分絶対値ＤＩＦＬおよびＤＩＦＲと閾値Ｓとを比較する。エッジ部をより明確に表示させることを重要視する場合は閾値Ｓを小さく設定し、階調特性をより向上させることを重要視する場合は閾値Ｓを大きく設定する。例えば、閾値Ｓを４／１０２３に設定すると、４／１０２３以下の階調を繋いで８ビット以上の精度に階調特性を向上させることができる。 Here, when the difference absolute values DIFL and DIFR between the processing target pixel CDAT and the comparison target pixels LDAT and RDAT are large, it is a contour portion (edge portion), and thus correction for maintaining the edge portion is performed. The MLDAT and MRDAT values used in the calculation are determined.
Specifically, the threshold S of the difference absolute values DIFL and DIFR is determined, and the difference absolute values DIFL and DIFR are compared with the threshold S. The threshold value S is set small when it is important to display the edge portion more clearly, and the threshold value S is set large when importance is given to improving the gradation characteristics. For example, when the threshold value S is set to 4/1023, the gradation characteristics can be improved with an accuracy of 8 bits or more by connecting gradations of 4/1023 or less.
　差分絶対値ＤＩＦＬおよびＤＩＦＲが閾値Ｓ以下の場合はグラデーション部であるので、隣接する画素に基づいて補正量を算出するためにＭＬＤＡＴ＝ＬＬＤＡＴ、ＭＲＤＡＴ＝ＬＲＤＡＴとする。また、差分絶対値ＤＩＦＬまたはＤＩＦＲが閾値Ｓを超える場合はエッジ部であるので、元の信号レベルを維持するためにＭＬＤＡＴ＝０またはＭＲＤＡＴ＝０とする。
　上記式に図６を適用すると、ＤＩＦＬ＝０、ＤＩＦＲ＝ｄである。ｄが閾値Ｓ以下の場合はＭＬＤＡＴ＝ＬＬＤＡＴ、ＭＲＤＡＴ＝ＬＲＤＡＴとなり、ｄが閾値Ｓより大きい場合は、ＭＬＤＡＴ＝ＬＬＤＡＴ、ＭＲＤＡＴ＝０となる。 When the difference absolute values DIFL and DIFR are equal to or smaller than the threshold value S, it is a gradation portion. Therefore, MLDAT = LLDAT and MRDAT = LRDAT in order to calculate a correction amount based on adjacent pixels. Further, when the absolute difference value DIFL or DIFR exceeds the threshold value S, it is an edge portion, so that MLDAT = 0 or MRDAT = 0 is set in order to maintain the original signal level.
When FIG. 6 is applied to the above equation, DIFL = 0 and DIFR = d. When d is less than or equal to the threshold S, MLDAT = LLDAT and MRDAT = LRDAT, and when d is greater than the threshold S, MLDAT = LLDAT and MRDAT = 0.
　そして、処理対象画素ＣＤＡＴの階調特性を向上させた後の輝度レベルは、以下の式で示されるＭＬＤＡＴとＭＲＤＡＴの平均値ＡＶＥである。
　ＡＶＥ＝（ＭＬＤＡＴ＋ＭＲＤＡＴ）／２
　また、このＡＶＥから処理対象画素ＣＤＡＴの輝度レベルＬＣＤＡＴを減算した値が処理対象画素ＣＤＡＴの補正量ＣＯＲである。
　ＣＯＲ＝ＡＶＥ－ＬＣＤＡＴ The luminance level after improving the gradation characteristics of the processing target pixel CDAT is an average value AVE of MLDAT and MRDAT expressed by the following equation.
AVE = (MLDAT + MRDAT) / 2
A value obtained by subtracting the luminance level LCDAT of the processing target pixel CDAT from the AVE is the correction amount COR of the processing target pixel CDAT.
COR = AVE-LCDAT
　なお、処理対象画素と比較対象画素の半径を大きくすることで、より広範囲に階調特性を向上させることができる。
　そして、算出された補正量ＣＯＲに対して、信号レベル状態検出手段１１０で検出された単調増加度および単調減少度を加味する。具体的には、単調増加または単調減少でない場合は補正量ＣＯＲを０とするか、または、単調増加度および単調減少度に応じて補正量ＣＯＲを調整する。 Note that the gradation characteristics can be improved in a wider range by increasing the radius of the processing target pixel and the comparison target pixel.
Then, the monotonic increase and monotonic decrease detected by the signal level state detection unit 110 are added to the calculated correction amount COR. Specifically, when the increase is not monotonically increasing or decreasing, the correction amount COR is set to 0, or the correction amount COR is adjusted according to the monotonic increase degree and the monotonic decrease degree.
［映像信号処理装置の動作］
　次に、映像信号処理装置１００の動作を図７に基づいて説明する。
　まず、図示しないアンテナなどを介して放送局からの映像信号が映像信号処理装置１００に入力される。信号レベル状態検出手段１１０は、前述の方法により、入力された映像信号の単調増加度および単調減少度のうち少なくともいずれか一方を検出する（ステップＳ１）。
　続いて、階調特性調整手段１２０は、前述の方法により、入力映像信号について階調特性を向上させるための補正量を計算する（ステップＳ２）。このとき、単調増加または単調減少している箇所において、前述の閾値Ｓに基づいてエッジ部とされる部分の補正量が調整される。 [Operation of video signal processor]
Next, the operation of the video signal processing apparatus 100 will be described with reference to FIG.
First, a video signal from a broadcasting station is input to the video signal processing apparatus 100 via an antenna (not shown). The signal level state detection unit 110 detects at least one of the monotonic increase degree and the monotonic decrease degree of the input video signal by the above-described method (step S1).
Subsequently, the gradation characteristic adjusting unit 120 calculates a correction amount for improving the gradation characteristic of the input video signal by the above-described method (step S2). At this time, the correction amount of the portion to be the edge portion is adjusted based on the above-described threshold value S at the portion where the monotone increases or decreases monotonously.
　そして、階調特性調整手段１２０は、ステップＳ１で検出された単調増加度および単調減少度に基づいて、ステップＳ２で算出した補正量を決定する（ステップＳ３）。例えば、単調増加度または単調減少度が０、すなわち単調増加または単調減少している場合はＹＥＳとなり、ステップＳ２で算出した補正量を用いて入力映像信号を補正する（ステップＳ４）。一方、単調増加度および単調減少度が０より大きい場合、すなわち単調増加および単調減少していない場合はＮＯとなり、補正処理を行わない。
　そして、階調特性調整手段１２０は、補正により生成された出力映像信号または補正されていない入力映像信号を出力映像信号として出力して（ステップＳ５）、終了する。 Then, the gradation characteristic adjusting unit 120 determines the correction amount calculated in step S2 based on the monotonic increase and monotonic decrease detected in step S1 (step S3). For example, if the degree of monotone increase or the degree of monotone decrease is 0, that is, if the monotone increase or monotonic decrease is YES, the determination is YES, and the input video signal is corrected using the correction amount calculated in step S2 (step S4). On the other hand, when the degree of monotone increase and the degree of monotonic decrease are larger than 0, that is, when the monotonic increase and monotonic decrease are not, NO is determined and the correction process is not performed.
Then, the gradation characteristic adjusting unit 120 outputs the output video signal generated by the correction or the input video signal that has not been corrected as the output video signal (step S5), and ends.
［第１実施形態の作用効果］
　上述したように、第１実施形態の映像信号処理装置では、以下のような作用効果を奏することができる。
　（１）上述の第１実施形態では、映像信号処理装置１００は、入力映像信号の入力画像の各画素の輝度レベルに基づいて、単調増加度および単調減少度のうち少なくともいずれか一方を検出する信号レベル状態検出手段１１０と、入力映像信号の階調特性を向上させるための補正量を計算し、単調増加度および単調減少度に応じて入力映像信号を補正する階調特性調整手段１２０と、を備えることとした。
　すなわち、信号レベル状態検出手段１１０はグラデーション部を検出し、階調特性調整手段１２０は単調増加および単調減少しているグラデーション部にのみ階調特性を向上させるための補正を行い、単調増加および単調減少していないディテール部には補正を行わない。したがって、高い精度でグラデーション部のみの階調特性を向上させることができるとともに、ディテール部のディテール感を維持することができる。 [Effects of First Embodiment]
As described above, the video signal processing apparatus according to the first embodiment can provide the following operational effects.
(1) In the first embodiment described above, the video signal processing apparatus 100 detects at least one of the monotonic increase degree and the monotonic decrease degree based on the luminance level of each pixel of the input image of the input video signal. A signal level state detection unit 110; a gradation characteristic adjustment unit 120 that calculates a correction amount for improving the gradation characteristic of the input video signal and corrects the input video signal according to the monotonic increase degree and the monotonic decrease degree; It was decided to prepare.
That is, the signal level state detection unit 110 detects a gradation part, and the gradation characteristic adjustment unit 120 performs correction for improving the gradation characteristic only in the gradation part that is monotonously increasing and monotonically decreasing, and monotonically increasing and monotonic. No correction is made for detail parts that have not decreased. Accordingly, it is possible to improve the gradation characteristics of only the gradation portion with high accuracy, and to maintain the detail feeling of the detail portion.
　（２）また、階調特性調整手段１２０において、補正量を計算する際に、隣接する画素との輝度レベルの差と予め設定された閾値Ｓとを比較し、隣接する画素との輝度レベルの差分絶対値ＤＩＦＬまたはＤＩＦＲが閾値Ｓよりも大きい場合はエッジ部であるとして、補正量が０となるように調整した。
　したがって、閾値Ｓを設定することによって簡単にエッジ部を検出でき、エッジ部には補正処理を行わないので、エッジ部をより明確に表示させることができる。
　以上より、上述の第１実施形態では、高い精度でグラデーション部とディテール部とエッジ部とを検出することができ、この検出結果に基づいてグラデーション部にのみ階調特性を向上させる補正処理を行うので、グラデーション部においてはより階調特性に優れるとともに、ディテール部およびエッジ部においてはディテール感を維持することができる。 (2) In addition, when the gradation characteristic adjusting unit 120 calculates the correction amount, the difference between the luminance levels of the adjacent pixels is compared with a preset threshold S, and the luminance level of the adjacent pixels is calculated. When the difference absolute value DIFL or DIFR is larger than the threshold value S, the correction amount is adjusted to be 0 assuming that the difference is an edge portion.
Therefore, the edge portion can be easily detected by setting the threshold value S, and correction processing is not performed on the edge portion, so that the edge portion can be displayed more clearly.
As described above, in the first embodiment described above, it is possible to detect the gradation portion, the detail portion, and the edge portion with high accuracy, and based on this detection result, the correction process for improving the gradation characteristics is performed only on the gradation portion. Therefore, the gradation part is more excellent in gradation characteristics, and the detail feeling can be maintained in the detail part and the edge part.
（第２実施形態）
　図８は、本発明にかかる第２実施形態の階調特性調整手段の概略構成を示すブロック図である。図９は、前記第２実施形態における入力映像信号を変換する手順を示す説明図である。図１０は、前記第２実施形態における入力映像信号を変換する手順を示す説明図である。図１１は、前記第２実施形態における出力映像信号を示す図である。 (Second Embodiment)
FIG. 8 is a block diagram showing a schematic configuration of the gradation characteristic adjusting means of the second embodiment according to the present invention. FIG. 9 is an explanatory diagram showing a procedure for converting an input video signal in the second embodiment. FIG. 10 is an explanatory diagram showing a procedure for converting an input video signal in the second embodiment. FIG. 11 is a diagram showing an output video signal in the second embodiment.
　第２実施形態では、階調特性調整手段による処理方法が異なる以外は第１実施形と同様であるので、説明を省略する。
　［階調特性調整手段の構成］
　図８に示されるように、階調特性調整手段１３０は、ローパスフィルター（以下、ＬＰＦと言う）処理手段１３１と、拡張処理手段１３２と、加算手段１３３と、閾値比較手段１３４と、補正処理手段１３５と、を備えている。
　ＬＰＦ処理手段１３１は、ｍビットの入力映像信号に対してフィルタ処理を行い、ｍ＋ｎビットに拡張したＬＰＦ信号を出力する。例えば、図９において信号が入力されると、ＬＰＦ処理手段１３１は、ＬＰＦ信号に変換する。具体的には、任意の画素ＣＤＡＴとこれに隣接する隣接画素ＬＤＡＴおよびＲＤＡＴについて、輝度レベルをそれぞれＬＣＤＡＴ、ＬＬＤＡＴ，ＬＲＤＡＴとすると、画素ＣＤＡＴのＬＰＦ信号は、ＬＰＦ＝ＬＬＤＡＴ＋２×ＬＣＤＡＴ＋ＬＲＤＡＴの式で算出される。各画素の算出結果は、図９のＢの行に示されている。 Since the second embodiment is the same as the first embodiment except that the processing method by the gradation characteristic adjusting means is different, the description thereof is omitted.
[Configuration of gradation characteristic adjusting means]
As shown in FIG. 8, the gradation characteristic adjusting unit 130 includes a low-pass filter (hereinafter referred to as LPF) processing unit 131, an expansion processing unit 132, an adding unit 133, a threshold comparison unit 134, and a correction processing unit. 135.
The LPF processing unit 131 performs filtering on the m-bit input video signal and outputs an LPF signal expanded to m + n bits. For example, when a signal is input in FIG. 9, the LPF processing unit 131 converts the signal into an LPF signal. Specifically, for an arbitrary pixel CDAT and adjacent pixels LDAT and RDAT adjacent thereto, assuming that the luminance level is LCDAT, LLDAT, and LRDAT, the LPF signal of the pixel CDDAT is calculated by the following formula: LPF = LLDAT + 2 × LCDAT + LRDAT The The calculation result of each pixel is shown in the row B of FIG.
　拡張処理手段１３２は、ｍビットの入力映像信号をｍ＋ｎビットに拡張した拡張信号を出力する。具体的には、入力信号を２ｎ倍する。図９では、８ビットの入力信号を１０ビットに拡張するため、入力信号を２の２乗倍、すなわち４倍する。具体的に、各画素の入力信号を４倍した結果は図９のＣの行に示されている。
　加算手段１３３は、前述のＬＰＦ信号と拡張信号とを加算し、ｎビットの信号を出力する。具体的に、ｎビットの信号は、図９においてＬＰＦ信号Ｂから拡張信号Ｃを減算することによって生成される。 The extension processing means 132 outputs an extension signal obtained by extending an m-bit input video signal to m + n bits. Specifically, the input signal is multiplied by 2n . In FIG. 9, in order to extend an 8-bit input signal to 10 bits, the input signal is multiplied by the square of 2, that is, 4 times. Specifically, the result of quadrupling the input signal of each pixel is shown in the row C of FIG.
The adding means 133 adds the aforementioned LPF signal and the extension signal, and outputs an n-bit signal. Specifically, the n-bit signal is generated by subtracting the extension signal C from the LPF signal B in FIG.
　閾値比較手段１３４は、ｎビットの信号に対して閾値処理を実施する。加算手段１３３により出力されたｎビットの信号を図１０に示す。図１０では、ｎビットの信号に対して閾値を－１以上１以下と設定し、閾値よりも値が大きいまたは小さい信号については輪郭部であると判定する。このときの信号は０である。
　補正処理手段１３５は、閾値比較手段１３４で調整されたｎビットの信号を入力映像信号に加算することにより、出力映像信号を生成する。このとき、信号レベル状態検出手段１１０で検出された単調増加度および単調減少度を加味する。すなわち、単調増加または単調減少でない場合は補正量を０とするか、または、単調増加度および単調減少度に応じて補正量を調整する。
　以上の処理により出力される出力映像信号を図１１に示す。図１１に示されるように、単調増加または単調減少している部分においては階調特性が向上するとともに、隣接する信号との段差が大きい場合は補正を行わないため、ディテール感を維持することができる。 The threshold comparison unit 134 performs threshold processing on the n-bit signal. An n-bit signal output by the adding means 133 is shown in FIG. In FIG. 10, the threshold value is set to −1 or more and 1 or less for an n-bit signal, and a signal whose value is larger or smaller than the threshold value is determined to be a contour portion. The signal at this time is zero.
The correction processing unit 135 generates an output video signal by adding the n-bit signal adjusted by the threshold comparison unit 134 to the input video signal. At this time, the monotonic increase and monotonic decrease detected by the signal level state detection unit 110 are taken into account. In other words, if it is not monotonically increasing or monotonic decreasing, the correction amount is set to 0, or the correction amount is adjusted according to the monotonic increase and monotonic decrease.
An output video signal output by the above processing is shown in FIG. As shown in FIG. 11, tone characteristics are improved in a monotonically increasing or decreasing portion, and correction is not performed when the difference between adjacent signals is large, so that a sense of detail can be maintained. it can.
［第２実施形態の作用効果］
　第２実施形態では、第１実施形態で得られる作用効果のほかに以下の作用効果を奏することができる。
　（３）上述の第２実施形態では、ＬＰＦ処理手段１３１で処理されたＬＰＦ信号から拡張したｎビットを取得し、このｎビットについて、予め設定された閾値の範囲を超える画素に対する補正量が０となるように調整した。
　すなわち、拡張したｎビットについてのみ比較処理を行うので、計算量が少なくなるため、より簡単な小型化された装置とすることができる。 [Effects of Second Embodiment]
In the second embodiment, the following operational effects can be obtained in addition to the operational effects obtained in the first embodiment.
(3) In the second embodiment described above, n bits expanded from the LPF signal processed by the LPF processing unit 131 are acquired, and the correction amount for pixels exceeding the preset threshold range is 0 for the n bits. It adjusted so that it might become.
That is, since the comparison process is performed only for the expanded n bits, the amount of calculation is reduced, so that a simpler and smaller device can be obtained.
（第３実施形態）
　第３実施形態では、信号レベル状態検出手段の検出方法が異なる以外は第１実施形態と同様であるので、説明を省略する。
　［信号レベル状態検出手段の動作］
　信号レベル状態検出手段は、入力された映像信号について単調増加度および単調減少度のうち少なくともいずれか一方を検出する。図４において、処理対象画素ＣＤＡＴに対して所定の処理半径Ｒ（例えば、Ｒ＝４）以内のそれぞれの画素における輝度レベルの隣接差分Ａ，Ｂ，Ｃ，Ｄ，Ｅ，Ｆ，Ｇ，Ｈを取得し、この隣接差分の極性により単調増加度および単調減少度のうち少なくともいずれか一方を検出する。すなわち、単調増加している場合は極性がプラス（＋）で一定となり、単調減少している場合は極性がマイナス（－）で一定となり、ディテール部である場合はプラスとマイナスが混在する。したがって、極性がプラスまたはマイナスで一定となる場合を単調増加または単調減少していると判定する。このとき、プラスとマイナスの混在割合などにより単調増加度および単調減少度を検出してもよい。なお、隣接差分が０の場合は極性なしとする。
　以上の処理を、入力映像信号の水平方向と垂直方向の２次元処理で行い、各計算結果を合算した値を単調増加度および単調減少度として検出する。 (Third embodiment)
Since the third embodiment is the same as the first embodiment except that the detection method of the signal level state detection means is different, the description thereof is omitted.
[Operation of signal level state detection means]
The signal level state detection means detects at least one of the monotonic increase degree and the monotonic decrease degree for the input video signal. In FIG. 4, the adjacent differences A, B, C, D, E, F, G, and H of luminance levels in respective pixels within a predetermined processing radius R (for example, R = 4) with respect to the processing target pixel CDAT are shown. And at least one of the monotonic increase degree and the monotonic decrease degree is detected based on the polarity of the adjacent difference. That is, the polarity is positive (+) when it is monotonously increasing, the polarity is constant at minus (-) when it is monotonically decreasing, and plus and minus are mixed when it is a detail portion. Accordingly, when the polarity is positive or negative and constant, it is determined that the polarity is monotonously increasing or monotonically decreasing. At this time, the monotonic increase degree and the monotonic decrease degree may be detected based on a mixture ratio of plus and minus. When the adjacent difference is 0, no polarity is set.
The above processing is performed by two-dimensional processing of the input video signal in the horizontal direction and the vertical direction, and a value obtained by adding the respective calculation results is detected as a monotone increase degree and a monotone decrease degree.
［第３実施形態の作用効果］
　第３実施形態では、第１実施形態で得られる作用効果のほかに以下の作用効果を奏することができる。
　（４）上述の第３実施形態では、単調増加および単調減少の検出において、隣接する画素の隣接差分の極性に基づいて検出することとした。これにより、検出における計算量が少なくなるため、より簡単な小型化された装置とすることができる。 [Effects of Third Embodiment]
In the third embodiment, the following operational effects can be obtained in addition to the operational effects obtained in the first embodiment.
(4) In the above-described third embodiment, detection of monotonic increase and monotonic decrease is performed based on the polarity of the adjacent difference between adjacent pixels. Thereby, since the amount of calculation in detection decreases, it can be set as a simpler downsized apparatus.
［実施形態の変形］
　なお、本発明は、上述した実施形態に限定されるものではなく、本発明の目的を達成できる範囲で他の構成に適宜変更できる。
　例えば、上述の第２実施形態において、第３実施形態を適用してもよい。
　また、上述した各機能をプログラムとして構築したり、回路基板などのハードウェアあるいは１つのＩＣ（Integrated Circuit）などの素子にて構成するなどしてもよく、いずれの形態としても利用できる。なお、プログラムや別途記録媒体から読み取らせる構成とすることにより、取扱が容易で、利用の拡大が容易に図れる。 [Modification of Embodiment]
Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed to other configurations as long as the object of the present invention can be achieved.
For example, the third embodiment may be applied to the second embodiment described above.
Each function described above may be constructed as a program, or may be configured by hardware such as a circuit board or an element such as a single integrated circuit (IC), and can be used in any form. In addition, by adopting a configuration that allows reading from a program or a separate recording medium, handling is easy, and usage can be easily expanded.
［実施形態の効果］
　上述の実施形態では、映像信号処理装置は、入力映像信号の各画素の輝度レベルに基づいて、単調増加度および単調減少度のうち少なくともいずれか一方をを検出する信号レベル状態検出手段と、入力映像信号の階調特性を向上させるための補正量を計算し、単調増加度および単調減少度のうち少なくともいずれか一方をに応じて入力映像信号を補正する階調特性調整手段と、を備えることとした。
　すなわち、単調増加または単調減少しているグラデーション部にのみ階調特性を向上させるための補正を行い、単調増加および単調減少していないディテール部には補正を行わないので、グラデーション部を滑らかに表示させる出力信号を生成することができるとともに、ディテール部においては、ディテール感を維持することができる。 [Effect of the embodiment]
In the above-described embodiment, the video signal processing apparatus includes a signal level state detection unit that detects at least one of the monotonic increase degree and the monotonic decrease degree based on the luminance level of each pixel of the input video signal; A gradation characteristic adjusting unit that calculates a correction amount for improving the gradation characteristic of the video signal and corrects the input video signal according to at least one of the monotonic increase degree and the monotonic decrease degree; It was.
In other words, only the gradation part that is monotonously increasing or monotonically decreasing is corrected to improve the gradation characteristics, and the detail part that is not monotonically increasing or decreasing is not corrected, so the gradation part is displayed smoothly. The output signal to be generated can be generated, and a detail feeling can be maintained in the detail portion.
　本発明は、プラズマディスプレイ、液晶、ＤＶＤプレーヤー等の再生機器やＰＣ搭載の動画再生ソフトに用いられる映像信号処理装置、映像表示装置、映像信号処理方法、そのプログラムおよびそのプログラムを記録した記録媒体として利用できる。
  The present invention relates to a video signal processing device, a video display device, a video signal processing method, a program thereof, and a recording medium on which the program is recorded, which is used in playback equipment such as a plasma display, liquid crystal display, DVD player, etc. Available.

Claims (8)

  1. 　入力映像信号を処理して出力映像信号を出力する映像信号処理装置であって、
    　前記入力映像信号の入力画像の所定領域における信号レベルの単調増加度および単調減少度のうち少なくともいずれか一方を検出する信号レベル状態検出手段と、
    　前記単調増加度および単調減少度のうち少なくともいずれか一方に基づいて、前記信号レベルが単調増加または単調減少している場合のみ前記所定領域の入力映像信号に対する補正量を算出し、この補正量に応じて出力映像信号を生成する階調特性調整手段と、を備えた
    　ことを特徴とする映像信号処理装置。     A video signal processing apparatus that processes an input video signal and outputs an output video signal,
    Signal level state detection means for detecting at least one of a monotonic increase degree and a monotone decrease degree of a signal level in a predetermined region of the input image of the input video signal;
    Based on at least one of the monotonic increase degree and the monotonic decrease degree, a correction amount for the input video signal in the predetermined area is calculated only when the signal level is monotonously increasing or monotonically decreasing. And a gradation characteristic adjusting means for generating an output video signal according to the video signal processing apparatus.
  2. 　請求項１に記載の映像信号処理装置において、
    　前記階調特性調整手段は、
    　前記入力映像信号の入力画像における所定範囲内の画素の信号レベルに基づいて、隣接する画素の信号レベルの差が所定値を超える場合は補正しない
    　ことを特徴とする映像信号処理装置。     The video signal processing device according to claim 1,
    The gradation characteristic adjusting means includes
    A video signal processing apparatus, wherein, based on a signal level of a pixel within a predetermined range in an input image of the input video signal, correction is not performed when a difference in signal level between adjacent pixels exceeds a predetermined value.
  3. 　請求項１または請求項２に記載の映像信号処理装置において、
    　前記単調増加度および単調減少度は、前記入力映像信号の入力画像における隣接する複数の画素の信号レベルの差分の絶対値の累積として算出された差分絶対値累積値と、前記差分の累積として算出された差分累積値の絶対値と、の差であり、
    　前記階調特性調整手段は、前記単調増加度および単調減少度に基づいて、単調増加または単調減少していない場合は補正しない
    　ことを特徴とする映像信号処理装置。     In the video signal processing device according to claim 1 or 2,
    The monotonic increase degree and the monotonic decrease degree are calculated as a cumulative absolute value of a difference and a cumulative absolute value of the difference calculated as a cumulative absolute value of a signal level difference between a plurality of adjacent pixels in the input image of the input video signal. The absolute value of the accumulated difference value,
    The video signal processing device according to claim 1, wherein the gradation characteristic adjusting unit does not perform correction on the basis of the monotonic increase degree and the monotonic decrease degree when the monotonic increase or monotonic decrease has not occurred.
  4. 　請求項１から請求項３のいずれかに記載の映像信号処理装置と、
    　この映像信号処理装置で生成された出力映像信号を表示する映像表示手段と、
    　を具備したことを特徴とする映像表示装置。     The video signal processing device according to any one of claims 1 to 3,
    Video display means for displaying the output video signal generated by the video signal processing device;
    A video display device comprising:
  5. 　演算手段により、入力映像信号を処理して出力映像信号を出力する映像信号処理方法であって、
    　前記演算手段は、
    　前記入力映像信号の入力画像の所定領域における信号レベルの単調増加度および単調減少度のうち少なくともいずれか一方を検出し、
    　前記単調増加度および単調減少度のうち少なくともいずれか一方に基づいて、前記信号レベルが単調増加または単調減少している場合のみ前記所定領域の入力映像信号に対する補正量を算出し、この補正量に応じて出力映像信号を生成する
    　ことを特徴とする映像信号処理方法。     A video signal processing method for processing an input video signal and outputting an output video signal by an arithmetic means,
    The computing means is
    Detecting at least one of a monotone increase degree and a monotone decrease degree of a signal level in a predetermined region of the input image of the input video signal;
    Based on at least one of the monotonic increase degree and the monotonic decrease degree, a correction amount for the input video signal in the predetermined area is calculated only when the signal level is monotonously increasing or monotonically decreasing. An output video signal is generated according to the video signal processing method.
  6. 　請求項５に記載の映像信号処理方法を演算手段に実行させる
    　ことを特徴とする映像信号処理プログラム。     A video signal processing program for causing a calculation means to execute the video signal processing method according to claim 5.
  7. 　演算手段を請求項１から請求項３のいずれかに記載の映像信号処理装置として機能させる
    　ことを特徴とする映像信号処理プログラム。     A video signal processing program for causing a calculation means to function as the video signal processing device according to any one of claims 1 to 3.
  8. 　請求項６または請求項７に記載のプログラムが演算手段にて読取可能に記録された
    　ことを特徴とする映像信号処理プログラムを記録した記録媒体。
          8. A recording medium on which a video signal processing program is recorded, wherein the program according to claim 6 or 7 is recorded so as to be readable by an arithmetic means.
PCT/JP2008/072845 2008-12-16 2008-12-16 Video signal processing device, video display device, video signal processing method, program thereof, and recording medium containing the program WO2010070731A1 (en)

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Citations (4)

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JPH0646294A (en) * 1991-09-30 1994-02-18 Nec Home Electron Ltd Contour correction device
JP2000244773A (en) * 1999-02-24 2000-09-08 Canon Inc Contour correcting device
JP2002314844A (en) * 2001-04-11 2002-10-25 Sanyo Electric Co Ltd Digital image edge correcting circuit
JP2007221569A (en) * 2006-02-17 2007-08-30 Sony Corp Signal processing apparatus and signal processing method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0646294A (en) * 1991-09-30 1994-02-18 Nec Home Electron Ltd Contour correction device
JP2000244773A (en) * 1999-02-24 2000-09-08 Canon Inc Contour correcting device
JP2002314844A (en) * 2001-04-11 2002-10-25 Sanyo Electric Co Ltd Digital image edge correcting circuit
JP2007221569A (en) * 2006-02-17 2007-08-30 Sony Corp Signal processing apparatus and signal processing method

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