JPH0662431A - Quantizing/inverse quantizing method for color picture element data - Google Patents
Quantizing/inverse quantizing method for color picture element dataInfo
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- JPH0662431A JPH0662431A JP4216846A JP21684692A JPH0662431A JP H0662431 A JPH0662431 A JP H0662431A JP 4216846 A JP4216846 A JP 4216846A JP 21684692 A JP21684692 A JP 21684692A JP H0662431 A JPH0662431 A JP H0662431A
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- Prior art keywords
- color difference
- difference signal
- digital
- signal
- quantized
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、カラ−画像の画素デ−
タを量子化および逆量子化する方法に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the pixel data of a color image.
The present invention relates to a method of quantizing and dequantizing data.
【０００２】[0002]
【従来の技術】従来、このような分野の技術としては、
ＣＣＩＲ（International Radio Consultative Committ
ee）勧告６０１に規定されるものがあった。ＣＣＩＲ勧
告６０１では、カラ−画像の表色信号である１種の輝度
信号Ｙと２種の色差信号Ｃb、Ｃrが規定され、Ｒ、Ｇ、
Ｂの３原色からの変換式が示されている。Ｒ、Ｇ、Ｂの
アナログ信号の大きさがそれぞれＥR、ＥG、ＥBのと
き、Ｙ、Ｃb、Ｃrのアナログ信号の大きさＥY、ＥCb、
ＥCrはそれぞれ次の式（１）のように定められている。2. Description of the Related Art Conventionally, as a technique in such a field,
CCIR (International Radio Consultative Committ
ee) Some were prescribed in Recommendation 601. CCIR Recommendation 601 defines one type of luminance signal Y and two types of color difference signals Cb and Cr, which are color signals of color images, and R, G,
A conversion formula from the three primary colors of B is shown. When the R, G, B analog signal magnitudes are ER, EG, EB, respectively, the Y, Cb, Cr analog signal magnitudes EY, ECb,
The ECr is defined by the following equation (1), respectively.
【０００３】 [0003]
【０００４】さらに、Ｙ、Ｃb、Ｃr信号をそれぞれ８ビ
ットのディジタル信号に量子化する時の関係式は、Ｙ、
Ｃb、Ｃr信号のディジタル信号の大きさをそれぞれＤ
Ｙ、ＤＣb、ＤＣrとすると、次の式（２）のように表さ
れる。Further, the relational expression when quantizing each of the Y, Cb, and Cr signals into an 8-bit digital signal is Y,
Db is the magnitude of the digital signal of the Cb and Cr signals.
Assuming Y, DCb, and DCr, they are expressed by the following equation (2).
【０００５】 [0005]
【０００６】輝度信号と色差信号は図５に示すようにそ
れぞれ独立に量子化を行う。また、公称値として、黒レ
ベル １６、白レベル ２３５、色差（ゼロ） １２８、
色差（ピ−ク値） １６，２４０ に定められているの
で、ＤＹ、ＤＣb、ＤＣrのディジタル信号の有効範囲は
次の式（３）のようになる。The luminance signal and the color difference signal are quantized independently as shown in FIG. Also, as the nominal values, a black level of 16, a white level of 235, a color difference (zero) of 128,
Since the color difference (peak value) is set to 16,240, the effective range of the digital signals of DY, DCb, and DCr is given by the following expression (3).
【０００７】 [0007]
【０００８】[0008]
【発明が解決しようとする課題】ここで、前記式（２）
のディジタル色差信号は式（１）を代入すると次の式
（４）のようになり、輝度信号をパラメ−タとした値で
あることがわかる。[Formula (2)]
When the equation (1) is substituted, the digital color difference signal of is expressed by the following equation (4), and it can be seen that the luminance signal has a parameter value.
【０００９】 ＤＣb ＝ 126 （ＥB − ＥY）＋ 128 ＤＣr ＝ 160 （ＥR − ＥY）＋ 128 （４）DCb = 126 (EB−EY) +128 DCr = 160 (ER−EY) +128 (4)
【００１０】そこで、さらに式（４）に式（２）の輝度
信号を代入すると、ディジタル輝度信号に対する色差信
号の関係は次の式（５）のようになり、この関係を図
６、図７に示す。Therefore, by substituting the luminance signal of the equation (2) into the equation (4), the relationship of the color difference signal with respect to the digital luminance signal becomes as shown in the following equation (5), and this relationship is shown in FIGS. 6 and 7. Shown in.
【００１１】[0011]
【数１】 [Equation 1]
【００１２】図６が色差信号Ｃb、図７が色差信号Ｃrの
場合を示しており、図中の斜線部は信号の有効範囲を示
している。図６、図７からわかるように、ディジタル色
差信号は任意のディジタル輝度信号に対して約７ビット
分の情報量しか持っていないので、色差信号を最適に量
子化すれば７ビットのビット幅で、同等の情報量を持つ
ことができ、８ビットの場合と同質の画像を表現でき
る。しかしながら、従来のＣＣＩＲ勧告６０１の手法で
は、図５に示すように色差信号のレンジを固定し、輝度
信号と色差信号を独立に量子化しているので、すべての
信号にそれぞれ８ビットが一律に割当てられており、約
半分のレンジの値は表現する必要がなく、色差信号には
それぞれ約１ビット分冗長であった。FIG. 6 shows the case of the color difference signal Cb and FIG. 7 shows the case of the color difference signal Cr, and the shaded area in the drawing shows the effective range of the signal. As can be seen from FIGS. 6 and 7, the digital color difference signal has an information amount of about 7 bits with respect to an arbitrary digital luminance signal. Therefore, if the color difference signal is optimally quantized, a bit width of 7 bits is obtained. , Can have the same amount of information, and can represent an image of the same quality as in the case of 8 bits. However, in the method of the conventional CCIR recommendation 601, since the range of the color difference signal is fixed and the luminance signal and the color difference signal are independently quantized as shown in FIG. 5, 8 bits are uniformly assigned to all signals. However, it is not necessary to represent the value in the range of about half, and each color difference signal is redundant by about 1 bit.
【００１３】本発明は、ディジタル輝度信号のレベルに
相関して、ディジタル色差信号の範囲を設定し、色差信
号を指定したビット数で量子化するカラ−画素デ−タの
量子化方法、および該量子化されたカラ−画素デ−タを
逆量子化する方法を提供するものである。The present invention sets a range of a digital color difference signal in correlation with the level of a digital luminance signal, and quantizes the color difference signal with a specified number of bits, and a method of quantizing color pixel data. The present invention provides a method for dequantizing quantized color pixel data.
【００１４】[0014]
【課題を解決するための手段】本発明は、前記問題点を
解決するために、輝度信号、色差信号をそれぞれ独立に
固定レンジで量子化し、該量子化したディジタル輝度信
号のレベルに相関してディジタル色差信号のダイナミッ
クレンジの下限を算出し、該量子化したディジタル色差
信号から、該ダイナミックレンジの下限を減じ、該減算
されたディジタル色差信号を予め指定したビット数に揃
える補正を行うようにしている。さらに、量子化したデ
ィジタル輝度信号のレベルに相関してディジタル色差信
号のダイナミックレンジの下限を算出し、量子化したデ
ィジタル色差信号に前記ダイナミックレンジの下限を加
算し、加算したディジタル色差信号を静的な範囲のデー
タに変換し逆量子化している。In order to solve the above-mentioned problems, the present invention independently quantizes a luminance signal and a color difference signal in a fixed range, and correlates them with the level of the quantized digital luminance signal. The lower limit of the dynamic range of the digital color difference signal is calculated, the lower limit of the dynamic range is subtracted from the quantized digital color difference signal, and the subtracted digital color difference signal is corrected to a predetermined number of bits. There is. Further, the lower limit of the dynamic range of the digital color difference signal is calculated in correlation with the level of the quantized digital luminance signal, the lower limit of the dynamic range is added to the quantized digital color difference signal, and the added digital color difference signal is statically added. The data is converted into a range of data and inversely quantized.
【００１５】[0015]
【作用】本発明によれば、以上のようにカラ−画素デー
タの量子化方法を構成したので、ディジタル輝度信号の
レベルに相関してディジタル色差信号の範囲を設定する
ことで、色差信号を少ないビット数で最適に量子化する
ことができる。従って、前記課題を解決できるのであ
る。According to the present invention, since the color pixel data quantization method is constructed as described above, the color difference signal is reduced by setting the range of the digital color difference signal in correlation with the level of the digital luminance signal. It can be quantized optimally by the number of bits. Therefore, the above problem can be solved.
【００１６】[0016]
【実施例】図１は、本発明のカラ−画素データの量子化
方法の一実施例を示す図であり、図中、１、２は静的量
子化手段、３は動的量子化手段である。静的量子化手段
１、２はそれぞれ独立して、アナログの輝度信号ＥYと
色差信号ＥCb、ＥCrに対して、前記式（２）に示す量子
化を行う。動的量子化手段３は静的量子化手段１によっ
て量子化された輝度信号のレベルに相関して、色差信号
の量子化範囲を設定し、静的量子化手段２によって量子
化された色差信号をダイナミックレンジで再量子化す
る。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an embodiment of a method of quantizing color pixel data according to the present invention, in which 1 and 2 are static quantizing means and 3 is a dynamic quantizing means. is there. The static quantizers 1 and 2 independently perform the quantization shown in the above equation (2) on the analog luminance signal EY and the color difference signals ECb and ECr. The dynamic quantization unit 3 sets the quantization range of the color difference signal in correlation with the level of the luminance signal quantized by the static quantization unit 1, and the color difference signal quantized by the static quantization unit 2. Is requantized in the dynamic range.
【００１７】図２は動的量子化手段３の詳細な手順であ
る。図中、４は下限算出手段、５は減算手段、６は補正
手段である。下限算出手段４は、静的量子化手段１によ
って量子化されたディジタル輝度信号のレベルに相関し
てディジタル色差信号のダイナミックレンジの下限を算
出する。色差信号のダイナミックレンジの下限は、前記
式（５）においてＥB＝ＥR＝０とした値、ＤＣb0、ＤＣ
r0であり、次の式（６）のように表される。FIG. 2 shows a detailed procedure of the dynamic quantizing means 3. In the figure, 4 is a lower limit calculation means, 5 is a subtraction means, and 6 is a correction means. The lower limit calculation unit 4 calculates the lower limit of the dynamic range of the digital color difference signal in correlation with the level of the digital luminance signal quantized by the static quantization unit 1. The lower limit of the dynamic range of the color difference signal is the value where EB = ER = 0 in the equation (5), DCb0, DC
r0, which is expressed by the following equation (6).
【００１８】[0018]
【数２】 [Equation 2]
【００１９】減算手段５は静的量子化手段２によって量
子化されたディジタル色差信号から下限算出手段４によ
って算出されたダイナミックレンジの下限を減じる。ま
た、補正手段６は減算手段５によって算出されたディジ
タル色差信号を乗除算することにより７ビットに揃え
る。The subtracting means 5 subtracts the lower limit of the dynamic range calculated by the lower limit calculating means 4 from the digital color difference signal quantized by the static quantizing means 2. Further, the correction means 6 multiplies and divides the digital color difference signals calculated by the subtraction means 5 to make 7 bits.
【００２０】ここで、従来の量子化方法によって量子化
された色差信号Ｃrは図７に示すように、任意の輝度信
号に対して、７ビット以上の情報量を持っていたので、
補正手段６によって情報量はわずか減少するが、原画像
デ−タと量子化画像デ−タをＲＧＢ信号に変換したもの
のＳＮ比を調べると、実験を行ったほとんどの画像で５
０ｄＢを越えており、画質劣化はほとんどみられない。Here, since the color difference signal Cr quantized by the conventional quantization method has an information amount of 7 bits or more with respect to an arbitrary luminance signal as shown in FIG. 7,
Although the amount of information is slightly reduced by the correction means 6, when the SN ratio of the original image data and the quantized image data converted into RGB signals is examined, it is found that 5
It exceeds 0 dB, and the image quality is hardly deteriorated.
【００２１】図３は、本発明の逆量子化方法の一実施例
を示す図である。逆量子化は、前記量子化されたカラ−
画素デ−タのディジタル信号を、元のアナログ信号また
は従来技術によって量子化された信号に変換する。図中
７は動的逆量子化手段、８、９は静的逆量子化手段であ
る。動的逆量子化手段７は、ダイナミックレンジで量子
化された色差信号を輝度信号のレベルに相関して、静的
な範囲の色差信号に変換する。FIG. 3 is a diagram showing an embodiment of the inverse quantization method of the present invention. Inverse quantization is the quantized color.
The digital signal of the pixel data is converted into the original analog signal or the signal quantized by the conventional technique. In the figure, 7 is a dynamic inverse quantization means, and 8 and 9 are static inverse quantization means. The dynamic dequantization means 7 correlates the chrominance signal quantized in the dynamic range with the level of the luminance signal and converts it into a chrominance signal in a static range.
【００２２】図４は動的逆量子化手段７の詳細手順を示
したものであり、１０は補正手段、１１は下限算出手
段、１２は加算手段である。補正手段１０は、ダイナミ
ックレンジの色差信号のビット数を補正する。下限算出
手段は１１は、ディジタル輝度信号のレベルに相関して
ディジタル色差信号のダイナミックレンジの下限を算出
する。該下限は量子化の場合と同様にして求める。加算
手段１２は、補正されたディジタル色差信号に、ダイナ
ミックレンジの下限を加算し、もとの静的な色差信号に
変換する。FIG. 4 shows the detailed procedure of the dynamic dequantization means 7, 10 is a correction means, 11 is a lower limit calculation means, and 12 is an addition means. The correction unit 10 corrects the number of bits of the color difference signal in the dynamic range. The lower limit calculation means 11 calculates the lower limit of the dynamic range of the digital color difference signal in correlation with the level of the digital luminance signal. The lower limit is obtained in the same manner as in the case of quantization. The adding means 12 adds the lower limit of the dynamic range to the corrected digital color difference signal to convert it into the original static color difference signal.
【００２３】[0023]
【発明の効果】以上詳細に説明したように、本発明によ
れば、ほとんど画質の劣化なく、色差信号データを従来
の量子化に比べて少ないビット数で表現できる。従っ
て、画像デ−タを記憶装置に保存する場合などでは、ビ
ット単位で情報を記録できるメモリ−を使用すると、記
憶装置の節約が可能であり、また、８ビット単位でデ−
タを扱う場合でも、不要になったビットに原画像と異な
るデ−タ（文字や音声など）を多重して付加することが
できる。また、画像デ−タを扱うシステムにおいては、
ディジタル色差信号に対する処理は全て従来よりも少な
いビット数で行うことができ、システムの高速化や回路
の縮小化が可能となる。As described in detail above, according to the present invention, the color difference signal data can be expressed with a smaller number of bits than the conventional quantization, with almost no deterioration in image quality. Therefore, when storing image data in a storage device, a memory capable of recording information in bit units can be used to save the storage device, and data in 8-bit units can be saved.
Even when data is handled, data (characters, voice, etc.) different from the original image can be multiplexed and added to unnecessary bits. Also, in a system that handles image data,
All the processes for the digital color difference signals can be performed with a smaller number of bits than the conventional one, and the system can be speeded up and the circuit can be downsized.
【図１】本発明のカラ−画素デ−タの量子化方法の一実
施例を示す図である。FIG. 1 is a diagram showing an embodiment of a quantization method of color pixel data according to the present invention.
【図２】図１中の動的量子化手段の詳細を示す図であ
る。FIG. 2 is a diagram showing details of a dynamic quantization unit in FIG.
【図３】本発明のカラ−画素デ−タの逆量子化方法の一
実施例を示す図である。FIG. 3 is a diagram showing an embodiment of an inverse quantization method for color pixel data according to the present invention.
【図４】図３中の動的逆量子化手段の詳細を示す図であ
る。FIG. 4 is a diagram showing details of a dynamic inverse quantization means in FIG.
【図５】従来の量子化方法を示す図である。FIG. 5 is a diagram showing a conventional quantization method.
【図６】色差信号と輝度信号の関係を示す図である。FIG. 6 is a diagram showing a relationship between a color difference signal and a luminance signal.
【図７】色差信号と輝度信号の関係を示す図である。FIG. 7 is a diagram showing a relationship between a color difference signal and a luminance signal.
１ 静的量子化手段 ２ 静的量子化手段 ３ 動的量子化手段 ４ 下限算出手段 ５ 減算手段 ６ 補正手段 ７ 動的逆量子化手段 ８ 静的逆量子化手段 ９ 静的逆量子化手段 １０ 補正手段 １１ 下限算出手段 １２ 加算手段 1 Static Quantization Means 2 Static Quantization Means 3 Dynamic Quantization Means 4 Lower Limit Calculation Means 5 Subtraction Means 6 Correction Means 7 Dynamic Inverse Quantization Means 8 Static Inverse Quantization Means 9 Static Inverse Quantization Means 10 Correction means 11 Lower limit calculation means 12 Addition means
Claims (3)
度信号と２種のディジタル色差信号で表現する方法にお
いて、 ディジタル輝度信号のレベルに相関してディジタル色差
信号の量子化範囲を設定し、ディジタル色差信号を動的
に範囲が変化するダイナミックレンジとして量子化する
ことを特徴とするカラ−画素デ−タの量子化／逆量子化
方法。1. A method of expressing color pixel data by one type of digital luminance signal and two types of digital color difference signals, wherein a quantization range of the digital color difference signal is set in correlation with the level of the digital luminance signal. , A method of quantizing / dequantizing color pixel data, characterized in that a digital color difference signal is quantized as a dynamic range whose range dynamically changes.
定レンジで量子化し、 該量子化したディジタル輝度信号のレベルに相関してデ
ィジタル色差信号のダイナミックレンジの下限を算出
し、 該量子化したディジタル色差信号から、該ダイナミック
レンジの下限を減じ、 該減算したディジタル色差信号を予め指定したビット数
に揃える補正を行うことを特徴とする請求項１記載のカ
ラ−画素デ−タの量子化／逆量子化方法。2. A luminance signal and a color difference signal are independently quantized in a fixed range, a lower limit of a dynamic range of the digital color difference signal is calculated in correlation with the level of the quantized digital luminance signal, and the quantized digital signal is quantized. 2. The quantization / inverse of color pixel data according to claim 1, wherein the lower limit of the dynamic range is subtracted from the color difference signal, and the subtracted digital color difference signal is corrected to have a predetermined number of bits. Quantization method.
に相関してディジタル色差信号のダイナミックレンジの
下限を算出し、 量子化したディジタル色差信号に前記ダイナミックレン
ジの下限を加算し、 該加算したディジタル色差信号を静的な範囲のデータに
変換し逆量子化することを特徴とする請求項１記載のカ
ラ−画素デ−タの量子化／逆量子化方法。3. The lower limit of the dynamic range of the digital color difference signal is calculated in correlation with the level of the quantized digital luminance signal, the lower limit of the dynamic range is added to the quantized digital color difference signal, and the added digital color difference is calculated. 2. The method of quantizing / dequantizing color pixel data according to claim 1, wherein the signal is converted into data in a static range and inversely quantized.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4216846A JPH0662431A (en) | 1992-08-14 | 1992-08-14 | Quantizing/inverse quantizing method for color picture element data |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4216846A JPH0662431A (en) | 1992-08-14 | 1992-08-14 | Quantizing/inverse quantizing method for color picture element data |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0662431A true JPH0662431A (en) | 1994-03-04 |
Family
ID=16694827
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4216846A Pending JPH0662431A (en) | 1992-08-14 | 1992-08-14 | Quantizing/inverse quantizing method for color picture element data |
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Cited By (7)
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|---|---|---|---|---|
| WO1998027736A2 (en) * | 1996-12-17 | 1998-06-25 | Thomson Consumer Electronics, Inc. | Pixel block compression apparatus in an image processing system |
| US6379244B1 (en) | 1997-09-17 | 2002-04-30 | Konami Co., Ltd. | Music action game machine, performance operation instructing system for music action game and storage device readable by computer |
| US6410835B2 (en) | 1998-07-24 | 2002-06-25 | Konami Co., Ltd. | Dance game apparatus and step-on base for dance game |
| US6582309B2 (en) | 1998-07-14 | 2003-06-24 | Konami Co., Ltd. | Game system and computer-readable recording medium |
| US6645067B1 (en) | 1999-02-16 | 2003-11-11 | Konami Co., Ltd. | Music staging device apparatus, music staging game method, and readable storage medium |
| WO2012140904A1 (en) * | 2011-04-15 | 2012-10-18 | パナソニック株式会社 | Image compression device, image compression method, integrated circuit, program, and image display device |
| US10757427B2 (en) | 2015-06-10 | 2020-08-25 | Interdigital Vc Holdings, Inc. | Method and device for obtaining color difference components for color picture data |
-
1992
- 1992-08-14 JP JP4216846A patent/JPH0662431A/en active Pending
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998027736A2 (en) * | 1996-12-17 | 1998-06-25 | Thomson Consumer Electronics, Inc. | Pixel block compression apparatus in an image processing system |
| WO1998027736A3 (en) * | 1996-12-17 | 1998-08-06 | Thomson Consumer Electronics | Pixel block compression apparatus in an image processing system |
| US6256347B1 (en) | 1996-12-17 | 2001-07-03 | Thomson Licensing S.A. | Pixel block compression apparatus in an image processing system |
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