JPS6376686A - Adaptation type difference encoding system - Google Patents
Adaptation type difference encoding systemInfo
- Publication number
- JPS6376686A JPS6376686A JP61221639A JP22163986A JPS6376686A JP S6376686 A JPS6376686 A JP S6376686A JP 61221639 A JP61221639 A JP 61221639A JP 22163986 A JP22163986 A JP 22163986A JP S6376686 A JPS6376686 A JP S6376686A
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- 230000006978 adaptation Effects 0.000 title description 2
- 238000013139 quantization Methods 0.000 claims abstract description 57
- 238000000034 method Methods 0.000 claims description 25
- 230000003044 adaptive effect Effects 0.000 claims description 5
- 230000006866 deterioration Effects 0.000 abstract description 6
- 239000003086 colorant Substances 0.000 abstract description 3
- 230000004075 alteration Effects 0.000 abstract 1
- 230000005540 biological transmission Effects 0.000 description 10
- 230000000007 visual effect Effects 0.000 description 8
- 238000001514 detection method Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 241000282412 Homo Species 0.000 description 3
- 238000013144 data compression Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000000873 masking effect Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T9/00—Image coding
- G06T9/004—Predictors, e.g. intraframe, interframe coding
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Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、カラー画像信号を圧縮するための適応形差分
符号化方式に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adaptive differential encoding method for compressing color image signals.
近年、ＴＶ会議システムやフルカラー静止画像伝送を実
用化するために、ディジタル画像情報の圧縮伝送方式の
開発が活発化しており、狭帯域伝送路による画像情報の
ディジタル伝送に有効な方法として、差分パルス・コー
ド変調（ＤＰＣＭ）方式が注目されている。ＤＰＣＭ方
式は、基本的には、入力信号と予測信号との差分を量子
化し、符号化して伝送する方式である。カラー画像の表
色系には、ＹＩＱ、Ｙ−Ｒ−Ｙ−Ｂ−Ｙ、ＣＩＥＬＡＢ
、ＣＩＥＬＵＢ等があるが、例えばＲＧＢやＹＩＱのよ
うに、３つのパラメータを用い、色彩を表現する。ＤＰ
ＣＭによる従来の予測符号化方式では、これら表色系の
３つのパラメータ毎に、個々に差分をとり量子化してい
た。In recent years, in order to put TV conference systems and full-color still image transmission into practical use, the development of compressed transmission methods for digital image information has become active, and differential pulse is an effective method for digitally transmitting image information using narrowband transmission channels.・The code modulation (DPCM) method is attracting attention. The DPCM method is basically a method in which the difference between an input signal and a predicted signal is quantized, encoded, and transmitted. Color systems for color images include YIQ, Y-R-Y-B-Y, and CIELAB.
, CIELUB, etc., but colors are expressed using three parameters, such as RGB and YIQ. DP
In the conventional predictive encoding method using CM, differences are individually taken and quantized for each of these three parameters of the color system.
ところがこれらの表色系は、人間の視覚特性から考えて
必ずしも均一な空間ではない。即ち、同一のノルムを持
つ色彩の変化に対し人間が知覚する色差は、表色系に占
める位置によって大きく異なる。従って従来の予測符号
化方式方式では、人間の視覚特性に適合したデータ圧縮
を行っておらず、適切なものでは無かった。However, these color systems are not necessarily uniform spaces considering human visual characteristics. That is, the color difference that humans perceive when a color has the same norm varies greatly depending on its position in the color system. Therefore, conventional predictive encoding methods do not perform data compression that is compatible with human visual characteristics, and are not appropriate.
そこで本発明は、カラー画像を表現している表色糸の各
成分に対する人間の視覚特性の許容量子化誤差を考慮し
、簡単な回路構成でカラー画像信号のが良く、且つ画質
劣化の少ない適応形差分符号化方式を提示することを目
的とする。Therefore, the present invention takes into account the permissible quantization error of human visual characteristics for each component of the color representation thread that expresses a color image, and provides an adaptation method that provides a good color image signal with a simple circuit configuration and reduces image quality deterioration. The purpose of this paper is to present a differential encoding method.
本発明に係る適応形差分符号化方式は、カラー画像信号
を標本化して標本化信号を得て、前記標本化信号から差
分信号を形成し、前記差分信号を量子化して符号化する
方式であって、カラー画像を表現する各成分毎の許容量
子化誤差を色彩の明るさを表す成分の予測値に従い設定
し、設定された前記許容量子化誤差の大きさに応じて適
応的に各成分の差分信号の量子化特性を調定する方式で
ある。The adaptive differential encoding method according to the present invention is a method in which a color image signal is sampled to obtain a sampled signal, a difference signal is formed from the sampled signal, and the difference signal is quantized and encoded. Then, the allowable quantization error for each component representing the color image is set according to the predicted value of the component representing the brightness of the color, and the allowable quantization error for each component is adaptively set according to the size of the set allowable quantization error. This method adjusts the quantization characteristics of the differential signal.
上述の方式によりカラー画像を表現する各成分毎に許容
量子化誤差に応じて量子化特性を調定し、量子化を行う
ことにより、量子化誤差による画質劣化を抑え、また量
子化効率を高めることが出来る。By adjusting the quantization characteristics according to the allowable quantization error for each component expressing a color image using the above method and performing quantization, image quality deterioration due to quantization error is suppressed and quantization efficiency is increased. I can do it.
先ず、表色系に対する人間の視覚特性について検討する
。画像データを量子化する場合、量子化雑音が視覚特性
にどのような影響を与えるかが重要な問題である。量子
化とは、ある値範囲内にある値をその範囲内の特定の値
で代表させ、連続量を離散化することであり、その離散
化の幅乃至は最小単位が量子化雑音と呼ばれ、平坦で制
限された振幅の一様雑音と考えることが出来る。従って
量子化雑音が人間の視覚特性に与える影響は、表色系の
パラメータに対し振幅の制限された一様雑音を予め加算
し、その振幅に対する検知限を調べればよく、それによ
り、色調によってどの程度の量子化誤差が許容可能かを
知ることが出来る。First, we will consider human visual characteristics regarding color systems. When quantizing image data, an important issue is how quantization noise affects visual characteristics. Quantization is the process of discretizing a continuous quantity by making values within a certain value range represented by a specific value within that range, and the width or minimum unit of this discretization is called quantization noise. , can be thought of as a flat, limited amplitude, uniform noise. Therefore, the influence of quantization noise on human visual characteristics can be determined by adding uniform noise with limited amplitude to the parameters of the color system in advance and examining the detection limit for that amplitude. It is possible to know whether a certain degree of quantization error is acceptable.
例えば、Ｙ−Ｒ−Ｙ−Ｂ−Ｙ空間において、一つの色彩
を設定し、この色彩の各成分をｙｉ ｒｙ、ｂｙとす
る。これに対し、最大振幅をａ、とする一様雑音をｙに
加え、ｙｉａｙ、ｒｙ 、ｂｙとして観察し、雑音を検
知出来るか否かの検知限を調べる。この検知限を６７と
する。この調査から、成る色彩３’、ｒｙ、ｂｙにおい
て、Ｙ信号に対し誤差として認識されないレベルδ、を
知ることが出来る。同様にして、Ｒ−Ｙ信号およびＢ−
Ｙ信号に対しても、雑音の検知限δＲＶ＋ δｍｙを
知ることが出来る。For example, in the Y-R-Y-BY space, one color is set, and each component of this color is yi ry, by. On the other hand, uniform noise with maximum amplitude a is added to y and observed as yiay, ry, and by, and the detection limit of whether or not the noise can be detected is examined. This detection limit is set to 67. From this investigation, it is possible to know the level δ that is not recognized as an error for the Y signal in the colors 3', ry, and by. Similarly, the R-Y signal and the B-
The noise detection limit δRV+δmy can also be determined for the Y signal.
これらδ７．δＩＩＶ＋ δＢＹはそれぞれ色彩の変
数（ｙ、 ｒＦ＋ ｂｙ）に依存したが、３つのパ
ラメータの内、明るさに大きく依存することが判明した
。即ち、Ｙ、Ｒ−Ｙ、Ｂ−Ｙ空間では、それぞれのパラ
メータの許容量子化誤差は、色（Ｒ−Ｙ。These δ7. Although δIIV+ δBY each depended on the color variables (y, rF+ by), it was found that out of the three parameters, it was largely dependent on brightness. That is, in the Y, R-Y, B-Y space, the allowable quantization error for each parameter is the color (R-Y).
Ｂ−Ｙ）よりは輝度（Ｙ）の値に大きく依存し、第２図
に示すような特性を示した。但し、第２図は、色パラメ
ータ（Ｒ−Ｙ、Ｂ−Ｙ’）の全範囲における一様雑音の
検知限の最小値を示し、図示の曲線より小さい誤差は基
本的に許容されることを意味する。It depended more on the value of luminance (Y) than B-Y), and exhibited the characteristics shown in FIG. However, Figure 2 shows the minimum detection limit for uniform noise in the entire range of color parameters (R-Y, B-Y'), and it is understood that errors smaller than the curve shown in the diagram are basically acceptable. means.
人間の視覚にはまた、画像の変化の激しい部分では振幅
誤差が画像データに生じていても検知され難いというマ
スキング現象がある。即ち、信号が急激に変化している
部分と、あまり変化せず平−５＝
坦な部分とでは、誤差の許容レベルが異なり、急激に信
号強さが変化する部分ではかなり大きな誤差が許容され
る。Human vision also has a masking phenomenon in which it is difficult to detect amplitude errors even if they occur in image data in parts of the image where there are rapid changes. In other words, the allowable level of error is different between a part where the signal changes rapidly and a part where the signal does not change much and is flat -5, and a considerably large error is allowed in a part where the signal strength changes rapidly. Ru.
この視覚特性から次のことが分かる。即ち、前値予測の
符号化方式において、前値との差分を量子化する場合に
、画像の変化の激しい部分、つまり差分値の大きな部分
では量子化誤差が大きくても人間にはその誤差が認識さ
れず、従って、差分値の大きな部分では量子化範囲幅を
広くする非線形量子化を採用出来る。The following can be understood from this visual characteristic. In other words, in the previous value prediction encoding method, when quantizing the difference from the previous value, even if the quantization error is large in areas where the image changes rapidly, that is, in areas where the difference value is large, the error is difficult for humans to perceive. Therefore, non-linear quantization that widens the quantization range width can be adopted for portions where the difference value is large.
色彩信号が、第３図図示の如く時点ｉ−１における（
３’ ｉ−１＋ ｙｉ−１＋ ｂＩＴ！−１）か
ら、それに連続する時点ｉにおける（ｙｔ 、ｒｙｔ＋
ｔ）ｙｉ）に変化したとする。この場合に差分を量
子化するとき、各パラメータの許容量子化誤差δ７゛、
δＲ％” ＋δｍｙ”は、前値ｙｉ−＋に依存するが、
基本的に、第４図のように、差分の絶対値が太き（なる
程大きくでもよい。許容量子化誤差の最小値が上述のδ
Ｙ、δＩｔＶ＋ δＢ７であり、前値ｙｉ−＋によっ
て決まる。第４図の特性は、Ｖ＋−＋及びそれぞれの変
化量について許容できる誤差を調べることにより得るこ
とが出来、第４図に示す如く、許容量子化誤差はｙ、−
１及び変化量の値によって定められる。As shown in FIG. 3, the color signal is (
3' i-1+ yi-1+ bIT! −1) to (yt , ryt+
Suppose that it changes to t)yi). In this case, when quantizing the difference, the allowable quantization error of each parameter δ7゛,
δR%”+δmy” depends on the previous value yi−+,
Basically, as shown in Figure 4, the absolute value of the difference is large (it can be as large as possible.
Y, δItV+ δB7, which is determined by the previous value yi-+. The characteristics shown in Fig. 4 can be obtained by examining the allowable errors for V+-+ and their respective variations, and as shown in Fig. 4, the allowable quantization errors are y, -.
1 and the value of the amount of change.
この許容量子化誤差曲線に基づく非線形量子化特性は例
えば、原点を通り許容量子化誤差曲線と横軸との間で交
互し且つ横軸に４５度で交差する折れ線を引き、その折
れ線と許容量子化曲線との交点によって決定される。こ
の方法で設計した非線形量子化特性は例えば第５Ａ図や
第６Ａ図に示すような量子化特性となる。なお、第５Ｂ
図及び第６Ｂ図はそれぞれ第５Ａ図及び第６Ａ図の零点
付近の拡大図である。The nonlinear quantization characteristic based on this permissible quantization error curve can be obtained by, for example, drawing polygonal lines that pass through the origin and alternate between the permissible quantization error curve and the horizontal axis and intersect the horizontal axis at 45 degrees, and then determined by the intersection with the curve. The nonlinear quantization characteristic designed by this method becomes, for example, the quantization characteristic shown in FIGS. 5A and 6A. In addition, 5th B
5A and 6B are enlarged views of the vicinity of the zero point in FIGS. 5A and 6A, respectively.
このように表色パラメータ毎に許容量子化誤差を考慮す
ると、量子化誤差による画質劣化は人間には認識されず
、また、必要最小限の量子化でよいのでデータ圧縮率を
高めることが出来る。個々の色彩に対し許容量子化誤差
を決定する際に、本来的には全て３つの表色パラメータ
の予測値を考慮すべきであるが、本発明では、色彩の明
るさに関するデータから各表色パラメータの許容量子化
誤差を決定するので、その決定用回路を簡易に構成する
ことが出来る。In this way, when the permissible quantization error is considered for each color specification parameter, image quality deterioration due to quantization error is not noticeable to humans, and the data compression rate can be increased because the minimum necessary quantization is sufficient. When determining the allowable quantization error for each color, originally the predicted values of all three color parameters should be considered, but in the present invention, each color parameter is determined based on data regarding the brightness of the color. Since the allowable quantization error of the parameter is determined, a circuit for determining the parameter can be easily configured.
以下、図面を参照して、本発明の方式を実施する回路構
成例を図示した図面を参照・説明することにより、本発
明の詳細な説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings, which illustrate an example of a circuit configuration for implementing the method of the present invention.
第１図は、本発明に係る方式を実施する回路の送受信系
を示す。主に輝度信号Ｙの系列で説明するが、Ｒ−Ｙ信
号系列及びＢ−Ｙ信号系列においてＹ信号系列の回路要
素に対応する要素には、数値符号の後ろに、Ｙの代わり
にそれぞれＲ及びＢを付した。送信系Ａにおいて、加減
算器１０Ｙは、標本化されたｙｉと予測器１２Ｙからの
前画素の量子化された値（予測値）ｙｔ−＋”との差を
計算する。量子化器１４Ｙは、加減算器１０Ｙからの差
分値Ｙ ！ ３’ ＝−＋°を量子化する。量子化器
１４Ｙは、予測器１２Ｙからの予測値ｙ４−＋”によっ
て非線形量子化特性を設定し、入力信号を量子化する。FIG. 1 shows a transmitting/receiving system of a circuit implementing the method according to the present invention. The explanation will mainly be based on the luminance signal Y series, but in the R-Y signal series and the B-Y signal series, elements corresponding to the circuit elements of the Y signal series have R and Y instead of Y after the numerical code, respectively. I gave it a B. In the transmission system A, the adder/subtractor 10Y calculates the difference between the sampled yi and the quantized value (predicted value) yt-+'' of the previous pixel from the predictor 12Y.The quantizer 14Y The quantizer 14Y quantizes the difference value Y! become
符号化器１６Ｙは、量子化器１４Ｙからの量子化信号（
代表値）を二進符号化する。例えば、出現頻度の高い代
表値には短い符号を割り当て、出現−８＝
頻度の低い代表値には長い符号を割り当てる。The encoder 16Y receives the quantized signal (
(representative value) is binary encoded. For example, a short code is assigned to a representative value that appears frequently, and a long code is assigned to a representative value that occurs less frequently (-8=occurrence).
量子化器１４Ｒは、予測器１２Ｙからの予測値Ｖ ｉ−
＋’によってδ、１７゛ による非線形量子化特性を設
定し入力信号を量子化する。もう一つの量子化器１４Ｂ
は、予測器１２Ｙの予測値ｙｉ−１゛によってδＢ７゛
による非線形量子化特性を設定し入力信号を量子化す
る。The quantizer 14R receives the predicted value V i- from the predictor 12Y.
+' sets the nonlinear quantization characteristic of δ, 17゛, and quantizes the input signal. Another quantizer 14B
quantizes the input signal by setting a nonlinear quantization characteristic of δB7' based on the predicted value yi-1' of the predictor 12Y.
量子化器１４Ｙの出力である代表値は、予測器１２Ｙに
も印加され、次の画素の予測に利用される。予測器１４
Ｙ、１４Ｒ，１４Ｂは、一般的に、差分量子化代表値に
前値を加算する加算器と、当該加算器の出力を１画素分
遅延させる遅延回路とからなり、当該遅延回路の出力が
予測器の出力となり、また当該遅延回路の出力は前値と
して当該加算器にも印加され、差分信号の復元に利用さ
れる。The representative value that is the output of the quantizer 14Y is also applied to the predictor 12Y, and is used for predicting the next pixel. Predictor 14
Y, 14R, and 14B generally consist of an adder that adds the previous value to the differential quantization representative value, and a delay circuit that delays the output of the adder by one pixel, and the output of the delay circuit is predicted. The output of the delay circuit is also applied as a previous value to the adder and used to restore the difference signal.
符号化器１６Ｙ、１６Ｒ，１６ＢのＤＰＣＭ出力は、伝
送路２０Ｙ、２０Ｒ，２０Ｂを介して、受信系Ｂに送ら
れる。受信系Ｂでは、復号器３０Ｙ、３０Ｒ，３０Ｂが
、伝送路２０Ｙ、２ＯＲ。The DPCM outputs of encoders 16Y, 16R, and 16B are sent to receiving system B via transmission lines 20Y, 20R, and 20B. In receiving system B, decoders 30Y, 30R, 30B are transmission lines 20Y, 2OR.
２０ＢのＤＰＣＭ信号を復号し、加算器３２Ｙ。The adder 32Y decodes the DPCM signal of 20B.
３２Ｒ，３２Ｂに送る。加算器３２Ｙ、３２Ｒ。Send to 32R and 32B. Adders 32Y, 32R.
３２Ｂは、送信系Ａでの予測器１２Ｙ、１２Ｒ。32B are predictors 12Y and 12R in the transmission system A.
１２Ｂと同様の予測器３４Ｙ、３４Ｒ，３４Ｂからの予
測値”！ ｉ−１’＋ ｒ ｙｉ−、＋ ＋ ｂｙ
ｉ−＋”をそれぞれ復号器３０Ｙ、３０Ｒ，３０Ｂの出
力に加算し、色彩の各成分信号３’！’＋ ｙｉ’＋
ｂ□°を出力する。加算器３２Ｙ、３２Ｒ，３２Ｂの出
力はそれぞれ連係する予測器３４Ｙ、３４Ｒ，３４Ｂに
も印加され、加算器３２Ｙ、３２Ｒ，３２Ｂでの信号復
元に利用される。Predicted values from predictors 34Y, 34R, and 34B similar to 12B "! i-1'+ r yi-, + + by
i-+" to the outputs of the decoders 30Y, 30R, and 30B, respectively, to obtain each color component signal 3'!'+yi'+
Output b□°. The outputs of the adders 32Y, 32R, and 32B are also applied to associated predictors 34Y, 34R, and 34B, respectively, and are used for signal restoration in the adders 32Y, 32R, and 32B.
受信系Ｂの各復号器３０Ｙ、３０Ｒ，３０Ｂの復号特性
は、予測器３４Ｙの出力ｙ、−１”により、送信系Ａの
量子化及び符号化特性に対応するものに選択・設定され
る。The decoding characteristics of each of the decoders 30Y, 30R, and 30B of the receiving system B are selected and set to correspond to the quantization and coding characteristics of the transmitting system A based on the output y, -1'' of the predictor 34Y.
受信側での前値予測値は送信側での前値予測値と同じ値
であるため、このアルゴリズムにより受信系Ｂにおいて
完全な復元を実現出来る。Since the predicted previous value on the receiving side is the same as the predicted previous value on the transmitting side, complete restoration can be achieved in the receiving system B using this algorithm.
Ｙ信号、Ｒ−Ｙ信号及びＢ−Ｙ信号で符号化及び復号の
アルゴリズムは同じであるが、前述の如く、成分毎に許
容量子化誤差が異なるので、量子化器１４Ｙ、１４Ｒ，
１４Ｂ及び復号器３０Ｙ。The encoding and decoding algorithms are the same for the Y signal, R-Y signal, and B-Y signal, but as described above, the allowable quantization error differs for each component, so the quantizers 14Y, 14R,
14B and decoder 30Y.
３０Ｒ，３０Ｂの伝達特性は、当然ながら個々に異なる
。Naturally, the transmission characteristics of 30R and 30B are different from each other.
図示例では、Ｙ信号、Ｒ−Ｙ信号及びＢ−Ｙ信号を別々
の伝送路で伝送するように説明したが、現実の構成では
、Ｙ、Ｒ−Ｙ、Ｂ−Ｙのそれぞれの符号化が行われた後
でこれらをシリアル信号に変換して伝送路に送出し受信
系Ｂでこれを３つに分解して復号する。但し、本発明で
は復号のために輝度情報が必要であるので、先ずＹ信号
の処理を行い、その後Ｒ−Ｙ、Ｂ−Ｙの処理を行う。In the illustrated example, the Y signal, R-Y signal, and B-Y signal are transmitted through separate transmission paths, but in the actual configuration, each of Y, R-Y, and B-Y is encoded. After that, these signals are converted into serial signals and sent out to the transmission line, where the receiving system B divides them into three parts and decodes them. However, since the present invention requires luminance information for decoding, the Y signal is processed first, and then the RY and BY signals are processed.
以上の説明では、Ｙ−Ｒ−Ｙ−Ｂ−Ｙ表色系での例を示
したが、本発明の方法は、他の表色系、例えばＹＩＱ、
Ｌａ＊ｂ＊、Ｌｕ＊ｖ’に表色系では、それぞれＹ、Ｌ
、Ｌが明るさを表現しているので、そのＹ、Ｌ、Ｌの予
測値を用いて最適の量子化特性を設定出来る。また、Ｒ
ＧＢ系ではＧ信号が明るさを近似的に表しているので、
Ｇ信号の予測値で本発明の方式を実現出来る。In the above explanation, an example was given using the Y-R-Y-B-Y color system, but the method of the present invention can also be applied to other color systems, such as YIQ,
In the color system, La*b* and Lu*v' are Y and L, respectively.
, L express brightness, so the optimal quantization characteristics can be set using the predicted values of Y, L, and L. Also, R
In the GB system, the G signal approximately represents brightness, so
The method of the present invention can be implemented using the predicted value of the G signal.
以上、説明したように、本発明によれば、簡単な回路構
成でカラー画像信号を表現している表色系の各成分に対
する人間の視覚特性の許容量子化誤差に応じて適応的に
差分符号化を行うので、カラー画像信号に対して、画質
劣化の少ない差分符号化を行うことができ、カラー画像
信号の圧縮効率を高くすることができる適応形差分符号
化方式を提示することができる。As described above, according to the present invention, a differential code is adaptively applied according to the permissible quantization error of human visual characteristics for each component of a color system expressing a color image signal using a simple circuit configuration. Therefore, it is possible to perform differential encoding on color image signals with less image quality deterioration, and it is possible to present an adaptive differential encoding method that can improve the compression efficiency of color image signals.
第１図は、本発明に係る適応形予測符号化方式を実施す
るための送受信回路構成例、第２図はＹ。
Ｒ−Ｙ、Ｂ−Ｙ表色系における各成分信号の許容量子化
誤差と輝度信号Ｙとの関係を示す図、第３図は、連続時
点ｉ−１，ｉの各色彩成分の説明図、第４図は第３図の
時点ｉのカラー画像信号を差分量子化する際の各成分の
許容量子化誤差を示す図、第５Ａ図、第５Ｂ図、第６Ａ
図及び第６Ｂ図は第４図の特性により決定される非線形
量子化特性を例示する図である。FIG. 1 shows a configuration example of a transmitting/receiving circuit for implementing the adaptive predictive coding method according to the present invention, and FIG. A diagram showing the relationship between the permissible quantization error of each component signal and the luminance signal Y in the R-Y, B-Y color system, FIG. 3 is an explanatory diagram of each color component at consecutive time points i-1, i, FIG. 4 is a diagram showing the allowable quantization error of each component when differentially quantizing the color image signal at time i in FIG. 3, FIG. 5A, FIG. 5B, and FIG. 6A.
6B and 6B are diagrams illustrating nonlinear quantization characteristics determined by the characteristics shown in FIG. 4.
Claims (1)
本化信号から差分信号を形成し、前記差分信号を量子化
して符号化する方式であって、カラー画像を表現する各
成分毎の許容量子化誤差を色彩の明るさを表す成分の予
測値に従い設定し、設定された前記許容量子化誤差の大
きさに応じて適応的に各成分の差分信号の量子化特性を
調定することを特徴とする適応形差分符号化方式。A method in which a color image signal is sampled to obtain a sampled signal, a difference signal is formed from the sampled signal, and the difference signal is quantized and encoded, and the tolerance for each component representing the color image is determined. A quantization error is set according to a predicted value of a component representing the brightness of a color, and a quantization characteristic of a difference signal of each component is adaptively adjusted according to a size of the set allowable quantization error. Features an adaptive differential encoding method.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61221639A JPS6376686A (en) | 1986-09-19 | 1986-09-19 | Adaptation type difference encoding system |
| US07/413,954 US5072290A (en) | 1986-09-19 | 1989-09-28 | Color image signal encoding device |
| US08/132,687 US5428394A (en) | 1986-09-19 | 1993-10-07 | Adaptive type differential encoding method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61221639A JPS6376686A (en) | 1986-09-19 | 1986-09-19 | Adaptation type difference encoding system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6376686A true JPS6376686A (en) | 1988-04-06 |
Family
ID=16769926
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61221639A Pending JPS6376686A (en) | 1986-09-19 | 1986-09-19 | Adaptation type difference encoding system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6376686A (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6033789A (en) * | 1983-08-03 | 1985-02-21 | Matsushita Electric Ind Co Ltd | Method for transmitting picture to be coded |
-
1986
- 1986-09-19 JP JP61221639A patent/JPS6376686A/en active Pending
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6033789A (en) * | 1983-08-03 | 1985-02-21 | Matsushita Electric Ind Co Ltd | Method for transmitting picture to be coded |
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