JP3797646B2 - Facsimile device capable of color image communication - Google Patents

Description

実際の回路では、以下の順序で処理が行われる。
【００２９】
まず、（３−ａ）１６個のテーブルＴ［ｘ，ｙ］（ｘ＝１〜４，ｙ＝１〜４）における各テーブルの２５６個のセルＴ［ｘ，ｙ］［ｔ］（ｔ＝０〜２５５）に、以下の値を予め書き込んでおく。
【００３０】
ｙ＝１〜３のときＴ［ｘ，ｙ］［ｔ］＝Ａｘｙ×ｔ
ｙ＝４ のときＴ［ｘ，ｙ］［ｔ］＝Ａｘ４×ｔ＋Ａｘ５×ｔ×ｔ÷２５６
そして、（３−ｂ）ＵＣＲ処理部２２の出力Ｃ、Ｍ、Ｙ、Ｋの値をテーブルＴに入力し、その出力Ｔ［ｘ，１］［Ｃ］、Ｔ［ｘ，２］［Ｍ］、Ｔ［ｘ，３］［Ｙ］、Ｔ［ｘ，４］［Ｋ］（ｘ＝１〜４）を得る。
【００３１】
（３−ｃ）、（３−ｂ）で得た４つの値を加算器で足し合わせた後、その結果が０未満になる場合は０にクリップし、２５６以上になる場合は２５５にクリップし、出力Ｃ’、Ｍ’、Ｙ’、Ｋ’を得る。ｘ＝１，２，３，４である場合、クリップ後の出力がそれぞれＣ’、Ｍ’、Ｙ’、Ｋ’になる。
【００３２】
（４）得られたＣ’Ｍ’Ｙ’Ｋ’データに対し、プリンタγ補正処理部２４において、出力プリンタの色再現特性に合うようにγ変換処理を行う。
【００３３】
（５）γ変換を行った後のＣＭＹＫデータに対して、既知の方法で量子化処理を行い、二値化し、これをプリンタ３へ送って出力する。
【００３４】
上記実施例におけるカラーコピー時の上記処理は、基本的には、従来の「カラーコピー可能なファクシミリ」におけるカラーコピー時の動作と同じである。
【００３５】
カラーコピーにおける全ての処理は、本装置内で行われるので、マスキング処理やγ変換のパラメータは、各装置のスキャナの特性に応じたものとすればよい。
【００３６】
しかし、画像の通信処理を行う場合、送信相手のプリンタが自分側の端末と同じ色再現特性を持っているとは限らないので、送信側の端末のスキャナでスキャンしたままで色特性を補正しない画像を送信すると、受信側がそれに合わせて通信ごとにマスキングやγ変換等の画像処理パラメータを変えなければならず、不経済である。
【００３７】
また、送信側の装置に合わせて処理パラメータを変えるという手段も考えられるが、この場合も、上記と同様に送信側がパラメータを通信相手毎に変える必要がある。
【００３８】
以下、ファクシミリ装置１００を構成する各ブロックで行われるカラー画像通信時における処理内容について説明する。まず、送信時の処理について説明する。
【００３９】
（１）カラーコピー時と同じく、画像処理部２の入力を画像読み取り部１にセットし、スキャナ依存の色空間のデジタルＲＧＢ画像データを得る。
【００４０】
（２）スキャナ依存の色空間のＲＧＢデータを、スキャナγ変換部２１とマスキング処理部２３とが標準的な色空間データに変換する。上記実施例では、ＮＴＳＣ−ＲＧＢ色空間に変換するものとする。ある特性を持ったＲＧＢ画像データをＮＴＳＣ−ＲＧＢに変換するのは、γ変換処理（ア）と３×３のマトリクス演算処理（イ）とによって可能であることが既に知られている。
【００４１】
（２−ａ）スキャナγ変換処理部２１で、γ変換処理（ア）を行う。カラーコピー時は、スキャナのＲＧＢ輝度データをＣＭＹ濃度データに変換していたが、送信時にはＲＧＢ輝度データを別のＲ’Ｇ’Ｂ’輝度データに変換するようにテーブルの値をセットする。
【００４２】
（２−ｂ）ＵＣＲ処理部では、スキャナγ変換処理部２１の出力ＲＧＢ輝度データに対し、何もせずそのまま次の処理部へ送る。画素単位にＲ’Ｇ’Ｂ’０の順で画素単位に出力される。
【００４３】
（２−ｃ）マスキング演算処理部２３では、次の式２に示す３×３マトリクス演算処理（イ）を行う。
【００４４】
【数２】

実際の回路では、マスキング演算処理部２３の１６個のテーブルＴ［ｘ，ｙ］（ｘ＝１〜４、ｙ＝１〜４）の各テーブルにおける２５６個のセルＴ［ｘ，ｙ］［ｔ］（ｔ＝０〜２５５）に、以下の値を予め書き込んでおく。
【００４５】
ｘ＝１〜３、ｙ＝１〜３であるときに、Ｔ［ｘ，ｙ］［ｔ］＝Ｄｘｙ×ｔ
ｘ＝４またはｙ＝４であるときに、Ｔ［ｘ，ｙ］［ｔ］＝０
このように、テーブルの各セルの値をセットし、その後はカラーコピー時と同様の処理をすれば、カラーコピー時の４×５マトリクス演算と全く同じ回路で、３×３のマトリクス演算を行うことができる。
【００４６】
出力は画素単位でＲ”Ｇ”Ｂ”０の順になる。このＲ”Ｇ”Ｂ”は、送信側端末のスキャナの色空間からＮＴＳＣ−ＲＧＢ色空間に変換された結果である。
【００４７】
（４）プリンタγ変換部での処理は行わない。テーブルには入力と同じ値をセットする。
【００４８】
（５）量子化処理部での処理は行わない。入力の、画素順にＲ”Ｇ”Ｂ”０の多値データをそのまま、プリンタ３ではなく、メモリ６へ出力する。
【００４９】
（６）ＣＰＵ４は、メモリ６に出力された多値データから０の部分を除いてＲＧＢ画像データとし、その後、データをそのまま、または適当な手段で圧縮し、モデム５経由でファイルとしてＢＦＴ等のプロトコルで通信路へ送信する。このＲＧＢ画像データの色空間は、ＮＴＳＣ−ＲＧＢである。
【００５０】
上記画像データを受信した側の端末では、以下の処理を行う。該受信側端末は、図１に示すファクシミリ装置と同じ構成を持っていることを条件とする。
【００５１】
（１）受信データをモデム５経由でメモリ６に一旦格納する。
【００５２】
（２）受信画像データが圧縮されていれば、適当な手段でこれを伸長して、ＲＧＢ多値カラー画像データを得る。
【００５３】
このデータの色空間は、ＮＴＣＳ−ＲＧＢである。
【００５４】
（３）ＣＰＵ４は、このＲＧＢ画像データを、ラスタ順で、画素毎にＲＧＢの順で画像処理部２へ入力する。
【００５５】
（４）以降、プリントアウトするまでの処理は、カラーコピー時と同じである。ただし、スキャナγ変換、マスキングに関する各処理部のパラメータ（テーブルの内容）は、該受信側端末のスキャナの色再現特性からではなく、ＮＴＳＣ−ＲＧＢ色空間から該受信側端末のプリンタの色再現特性に合わせて変換できる値をセットする。
【００５６】
上記実施例によれば、現在ある「カラーコピー可能なファクシミリ」とほぼ同じ回路コストで、カラー画像を送受信することができる。また、送信側で色変換パラメータを相手毎に変えなくても、受信側は送信側と同じ色の画像を得ることができる。
【００５７】
つまり、送信側のカラースキャナの機種に関わらず、受信側では標準的な色空間で表現されたカラー画像データから印字データに変換するパラメータを持つだけで、送信側のカラー画像と同じ発色の印字画像を得ることができる。しかも、上記従来のカラーコピー可能なファクシミリが有する回路を多く流用するので、装置コストは上記従来のカラーコピー可能なファクシミリとほとんど変わらない。
【００５８】
【発明の効果】
本願発明によれば、色空間変換に使用するパラメータを変更することによって、カラースキャナから入力したカラースキャナに依存する色空間のカラー画像データを、カラープリンタに対応した色空間へ変換するとともに、電話回線と上記モデムとを介して受信しメモリに格納されている標準的な色空間のカラー画像データを、カラープリンタに対応した色空間へ変換する画像処理部と、画像処理部へ入力するカラー画像データとして、上記カラースキャナが読み取ったカラースキャナに依存する色空間のカラー画像データ、または、メモリから読み出した標準的な色空間のカラー画像データを選択する選択手段とを設けたので、単機におけるカラーコピー時、カラー画像受信時のそれぞれにおいて色空間変換に使用するパラメータを変えることによって、カラー画像の色空間変換が出来、送信側と受信側とで画像の色が大きく異ならないようにするためのコストが低いファクシミリ装置を提供できる。
また、カラー画像送信時においても、色空間変換に使用するパラメータを変えることによって、カラー画像の色空間変換が出来、送信側と受信側で画像の色が大きく異ならないようにするためのコストが低いファクシミリ装置を提供できる。
【図面の簡単な説明】
【図１】 本発明の一実施例であるファクシミリ装置１００を示すブロック図である。
【図２】 上記実施例におけるマスキング処理部２３の構成を示す図である。
【符号の説明】
１００…ファクシミリ装置、
１…画像読み取り部、
２…画像処理部、
３…プリンタ装置、
４…ＣＰＵ、
５…モデム、
６…メモリ、
２１…スキャナγ変換部、
２２…ＵＣＲ処理部、
２３…マスキング処理部、
２４…プリンタγ変換部、
２５…量子化処理部。[0001]
BACKGROUND OF THE INVENTION
The present invention scans an image with a color scanner and converts it into electronic color image data, transmits the data to another terminal having the same capability using a communication line such as a telephone line, and prints the data. It relates to a device that can.
[0002]
[Prior art]
A facsimile machine capable of color copying is conventionally known, but this conventional facsimile machine does not have a function of transferring a color image. That is, the conventional facsimile machine alone cannot transmit a color image via a telephone line.
[0003]
Therefore, when a color image is to be transmitted via a telephone line, the color image is read by a color scanner, and a personal computer creates a color image file based on the read color image and transmits it using a modem or the like.
[0004]
[Problems to be solved by the invention]
In the conventional example, when a color image is transmitted, it is necessary to install a personal computer and a color scanner only for image communication, which causes a cost problem.
[0005]
Further, as described above, when a personal computer and a color scanner are installed, the color space of the color image becomes an RGB space specific to the scanner. Therefore, when the color printer on the reception side prints the reception image, the transmission side There is a problem that the color of the image may be greatly different between the receiving side and the receiving side.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a facsimile apparatus capable of color image communication at a lower cost than the cost when a personal computer and a color scanner are added to a conventional facsimile apparatus "color can only be copied". [0007]
[Means for Solving the Problems]
The present invention enables color image communication via a telephone line by providing a conventional facsimile apparatus capable of color copying with a file transmission / reception function and a function capable of inputting a multi-value image from the CPU to the image processing unit. Moreover, the facsimile apparatus transmits the image data after converting the color space of the color scanner of the facsimile apparatus to a predetermined standard color space by using a circuit used at the time of color copying.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram showing a facsimile apparatus 100 according to an embodiment of the present invention.
[0009]
The facsimile apparatus 100 includes an image reading unit (color scanner) 1, an image processing unit 2, a printer device 3, a CPU 4, a modem 5, and a memory 6.
[0010]
An image reading unit (color scanner) 1 is an image reading unit that scans an original image with a CCD or CS (contact sensor) to obtain a digital RGB image. The R, G, and B data are each composed of 8 bits (256 gradations), and each pixel is output in the order of R, G, and B in the raster order of the image. The color space of this image data is unique to the CCD and CS.
[0011]
The image processing unit 2 is an image processing unit that applies digital calculation processing to the input digital RGB image and creates print data for printing by the printer device 3. However, when inputting a signal to the image processing unit 2, either the input from the image reading unit 1 or the input from the CPU 4 can be selected by the designation of the CPU 4.
[0012]
The image processing unit 2 includes a scanner γ conversion unit 21, a UCR processing unit 22, a masking processing unit 23, a printer γ conversion unit 24, and a quantization processing unit 25.
[0013]
The scanner γ conversion unit 21 is a scanner γ conversion unit that converts RGB (luminance) image data obtained by the image reading unit 1 into CMY (density) data. Corresponding to 256 types of input data of R, G, and B, each table is configured as three tables that output 8-bit data of C, M, and Y, respectively. As with the input, the pixels C, M, and Y are output in raster order.
[0014]
The UCR processing unit 22 is a UCR processing unit that performs UCR (Under Color Removal) processing from the 8-bit CMY data obtained by the scanner γ conversion unit 21 to generate 8-bit K (black) data. Since the UCR algorithm is known, its description is omitted. However, according to the setting of the CPU 4, this circuit does not generate K from the CMY data and can pass the CMY data as it is to the next processing unit without processing. In this case, K is output as 0. Output in the order of each pixel C, M, Y, K in raster order.
[0015]
The masking processing unit 23 is a masking processing unit that converts the CMYK multivalued image data obtained up to the UCR processing unit 22 into CMYK data in a color space corresponding to the printer 3 by performing a matrix operation.
[0016]
FIG. 2 is a diagram showing the configuration of the masking processing unit 23 in the above embodiment.
[0017]
Each table is composed of 16 tables with 256 cells ((4 CMYK colors) × 4 (CMYK colors)), an adder that adds the outputs thereof, and a clipper that clips the outputs from 0 to 255. CMYK data for one pixel is stored in a register for data input in pixel order in CMYK order, and four tables are simultaneously accessed for each color, and the output of the table is added by an adder. Output what is clipped to the range of. By setting appropriate values shown later in this table, 4 × 5 or 3 × 3 matrix calculation processing can be performed.
[0018]
The printer γ conversion unit 24 is a printer γ conversion unit that performs gamma correction on “multi-valued CMYK data in a color space corresponding to the printer device 3” obtained by the masking processing unit 23. Similar to the scanner γ conversion unit 21, it is configured as a table that outputs 8-bit data of C, M, Y, or K for 256 types of input data of C, M, Y, and K, respectively.
[0019]
The quantization processing unit 25 is a quantization processing unit that binarizes the 8-bit CMYK data obtained by the printer γ conversion unit 24 and converts the data into print data that can be output by the printer 3. However, according to the setting of the CPU 4, no processing is performed on the output CMYK data of the printer γ correction processing unit 24, and the multivalued CMYK data can be output to the bus and output to the memory 6.
[0020]
The printer 3 is a printer that prints out the print data generated by the image processing unit 2.
[0021]
The CPU 4 is a CPU that controls the entire facsimile apparatus 100.
[0022]
The modem 5 is a modem that is connected to a telephone line and transmits / receives data.
[0023]
The memory 6 is a memory that temporarily stores the received data sent from the telephone line via the modem 5 and the result read by the image reading unit 1 and quantized by the image processing unit 2.
[0024]
The image processing unit 2, the printer device 3, the CPU 4, the modem 5, and the memory 6 are connected to each other by a bus.
[0025]
Next, the operation of the above embodiment will be described.
[0026]
There are six ways of using the above embodiment: 1, monochrome copy processing 2, monochrome facsimile transmission processing 3, monochrome facsimile reception processing 4, color copy processing 5, color image transmission processing 6, and color image reception processing. Among these, operations 1 to 3 are the same as those of the conventional facsimile, and thus the description thereof is omitted.
[0027]
First, the operation of each block during color copy processing will be described.
(1) The input of the image processing unit 2 is set in the image reading unit 1, and based on the RGB data of each dot in the digital RGB image of the scanner-dependent color space obtained therefrom, the scanner γ conversion unit 21 performs CMY Obtain concentration data.
(2) The UCR processing unit 22 generates K from the obtained CMY density data.
(3) The obtained CMYK data is subjected to a 4 × 5 matrix operation shown in the following expression 1 by the masking processing unit 23 to obtain CMYK (C′M′Y′K ′) that matches the output characteristics of the printer. Generate data.
[0028]
[Expression 1]

In an actual circuit, processing is performed in the following order.
[0029]
First, (3-a) 256 cells T [x, y] [t] (t = t in each table in 16 tables T [x, y] (x = 1 to 4, y = 1 to 4). 0 to 255), the following values are written in advance.
[0030]
When y = 1 to 3 T [x, y] [t] = Axy × t
When y = 4, T [x, y] [t] = Ax4 × t + Ax5 × t × t ÷ 256
Then, (3-b) the values of the outputs C, M, Y, and K of the UCR processing unit 22 are input to the table T, and the outputs T [x, 1] [C], T [x, 2] [M] , T [x, 3] [Y], T [x, 4] [K] (x = 1 to 4).
[0031]
After adding the four values obtained in (3-c) and (3-b) with an adder, if the result is less than 0, it is clipped to 0, and if it is 256 or more, it is clipped to 255. , Outputs C ′, M ′, Y ′, K ′. When x = 1, 2, 3, and 4, the output after clipping is C ′, M ′, Y ′, and K ′, respectively.
[0032]
(4) The printer γ correction processing unit 24 performs γ conversion processing on the obtained C′M′Y′K ′ data so as to match the color reproduction characteristics of the output printer.
[0033]
(5) The CMYK data after the γ conversion is quantized by a known method, binarized, and sent to the printer 3 for output.
[0034]
The above-described processing at the time of color copying in the above embodiment is basically the same as the operation at the time of color copying in the conventional “color copy capable facsimile”.
[0035]
Since all processes in color copying are performed in this apparatus, the masking process and γ conversion parameters may be in accordance with the characteristics of the scanner of each apparatus.
[0036]
However, when performing image communication processing, the printer at the other end of the transmission does not necessarily have the same color reproduction characteristics as the terminal on the own side, so the color characteristics are not corrected while being scanned with the scanner at the terminal on the sending side. When an image is transmitted, the receiving side must change image processing parameters such as masking and γ conversion for each communication accordingly, which is uneconomical.
[0037]
In addition, it is possible to change the processing parameter according to the apparatus on the transmission side, but in this case as well, it is necessary for the transmission side to change the parameter for each communication partner as described above.
[0038]
Hereinafter, processing contents at the time of color image communication performed in each block constituting the facsimile apparatus 100 will be described. First, processing during transmission will be described.
[0039]
(1) As in color copying, the input of the image processing unit 2 is set in the image reading unit 1 to obtain digital RGB image data in a scanner-dependent color space.
[0040]
(2) The RGB data in the scanner-dependent color space is converted into standard color space data by the scanner γ conversion unit 21 and the masking processing unit 23. In the above embodiment, conversion to the NTSC-RGB color space is assumed. It is already known that RGB image data having certain characteristics can be converted to NTSC-RGB by γ conversion processing (A) and 3 × 3 matrix operation processing (A).
[0041]
(2-a) The scanner γ conversion processing unit 21 performs γ conversion processing (a). At the time of color copying, the RGB luminance data of the scanner is converted into CMY density data, but at the time of transmission, a table value is set so that the RGB luminance data is converted into another R′G′B ′ luminance data.
[0042]
(2-b) The UCR processing unit sends the output RGB luminance data of the scanner γ conversion processing unit 21 to the next processing unit as it is without doing anything. The data is output in pixel units in the order of R′G′B′0 in pixel units.
[0043]
(2-c) The masking calculation processing unit 23 performs 3 × 3 matrix calculation processing (A) shown in the following Expression 2.
[0044]
[Expression 2]

In an actual circuit, 256 cells T [x, y] [t in each table of 16 tables T [x, y] (x = 1 to 4, y = 1 to 4) of the masking arithmetic processing unit 23. ] (T = 0 to 255), the following values are written in advance.
[0045]
When x = 1 to 3 and y = 1 to 3, T [x, y] [t] = Dxy × t
T [x, y] [t] = 0 when x = 4 or y = 4
In this way, if the value of each cell in the table is set and then the same processing as in color copying is performed, 3 × 3 matrix calculation is performed with the same circuit as the 4 × 5 matrix calculation in color copying. be able to.
[0046]
The output is in the order of R "G" B "0 in pixel units, where R" G "B" is the result of conversion from the scanner color space of the transmitting terminal to the NTSC-RGB color space.
[0047]
(4) No processing is performed in the printer γ conversion unit. Set the same value as the input to the table.
[0048]
(5) Processing in the quantization processing unit is not performed. The input multi-value data of R "G" B "0 in pixel order is output to the memory 6 instead of the printer 3.
[0049]
(6) The CPU 4 removes the zero part from the multivalued data output to the memory 6 to obtain RGB image data, and then compresses the data as it is or by a suitable means, as a file via the modem 5 such as BFT. Send to the communication path using the protocol. The color space of the RGB image data is NTSC-RGB.
[0050]
The terminal that receives the image data performs the following processing. The receiving terminal is required to have the same configuration as the facsimile apparatus shown in FIG.
[0051]
(1) The received data is temporarily stored in the memory 6 via the modem 5.
[0052]
(2) If the received image data is compressed, it is decompressed by an appropriate means to obtain RGB multivalued color image data.
[0053]
The color space of this data is NTCS-RGB.
[0054]
(3) The CPU 4 inputs the RGB image data to the image processing unit 2 in raster order and in RGB order for each pixel.
[0055]
(4) Subsequent processing until printing is the same as in color copying. However, the parameters (table contents) of each processing unit relating to scanner γ conversion and masking are not from the color reproduction characteristics of the scanner of the receiving terminal, but from the NTSC-RGB color space to the color reproduction characteristics of the printer of the receiving terminal. Set a value that can be converted according to.
[0056]
According to the above-described embodiment, a color image can be transmitted and received at substantially the same circuit cost as the existing “color copy capable facsimile”. Further, the receiving side can obtain an image of the same color as the transmitting side without changing the color conversion parameter for each partner on the transmitting side.
[0057]
In other words, regardless of the color scanner model on the sending side, the receiving side only has a parameter to convert color image data expressed in a standard color space into print data, and prints the same color as the color image on the sending side. An image can be obtained. In addition, since many circuits of the conventional color copy capable facsimile are used, the apparatus cost is almost the same as that of the conventional color copy capable facsimile.
[0058]
【The invention's effect】
According to the present invention, by changing the parameters used for color space conversion, the color image data of the color space depending on the color scanner input from the color scanner is converted into the color space corresponding to the color printer, and the telephone. An image processing unit for converting color image data in a standard color space received via a line and the modem and stored in the memory into a color space corresponding to the color printer, and a color image input to the image processing unit Since the color image data in the color space depending on the color scanner read by the color scanner or the selection means for selecting the color image data in the standard color space read from the memory is provided as the data, Change the parameters used for color space conversion when copying and when receiving color images And by, it is the color space conversion of the color image, it is possible to provide a low cost facsimile apparatus so that the color of the image is not largely different between the transmission side and the reception side.
Also, when sending a color image, the color space can be converted by changing the parameters used for color space conversion, and there is a cost to prevent the color of the image from differing significantly between the sending side and the receiving side. A low facsimile machine can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a facsimile apparatus 100 according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a masking processing unit 23 in the embodiment.
[Explanation of symbols]
100: facsimile machine,
1 ... Image reading unit,
2 ... Image processing unit,
3. Printer device,
4 ... CPU,
5. Modem,
6 ... Memory,
21: Scanner γ converter,
22 ... UCR processing unit,
23 ... Masking processing part,
24. Printer γ conversion unit,
25: Quantization processing unit.

Claims (2)

A facsimile machine equipped with a color scanner and a CPU,
A modem that transmits color image data over a telephone line;
A memory for storing color image data received via a telephone line and the modem;
By changing parameters used for color space conversion, color image data in a color space depending on the color scanner input from the color scanner is converted into a color space corresponding to a color printer, and the telephone line and the An image processing unit for converting color image data of a standard color space received via a modem and stored in the memory into a color space corresponding to a color printer ;
A color printer for printing out based on the data converted by the image processing unit;
As color image data to be input to the image processing unit, color image data of a color space depending on the color scanner read by the color scanner or color image data of a standard color space read from the memory is selected. A selection means;
A facsimile apparatus capable of color image communication. In claim 1,
The image processing unit further converts color image data of a color space depending on the color scanner obtained from the color scanner into a standard color space,
In a first case of converting color image data in a color space depending on the color scanner obtained from the color scanner into a color space corresponding to a color printer ,
In the second case of converting color image data in a color space depending on the color scanner obtained from the color scanner into a standard color space ,
In a third case of converting color image data in a standard color space read from the memory into a color space corresponding to a color printer ,
In each of the above, a facsimile apparatus capable of color image communication, wherein a parameter used for color space conversion is changed .

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