JPH06268865A - Picture communications equipment - Google Patents

Abstract

PURPOSE:To reduce the quantity of a circuit and a cost by selecting an input source to a gamma correction means and an output destination of a gamma correction coefficient after gamma correction depending on each operation and sharing with the common gamma correction means for the gamma correction at the time of each operation such as transmission, reception and copying. CONSTITUTION:First - third selectors 30, 31, 37 switch an input source, an output destination and each gamma correction coefficient of a gamma correction section 32 based on a control signal in each operation such as transmission, reception and copying of the equipment. Thus, a correction section 32 before each operation inputs and writes one of read/display/copying use gamma correction coefficients 34-36 depending on each operation kind from a correction coefficient memory 33. That is, according to a control signal from an input terminal 38, a reception system 24 or an image sensor 21 and a display device 25 or a transmission system 22 and furthermore a corresponding coefficient are selected respectively and the density is corrected and each operation is executed. Thus, the common use correction section 32 is used to reduce a circuit quantity and a cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image communication apparatus, and more particularly to an image communication apparatus capable of performing density correction on both a read image and a display image by a single correction means.

[0002]

2. Description of the Related Art In an image communication apparatus such as a facsimile or a personal computer having a communication function, an original is read and the read image data is transmitted through a communication line or displayed as an image on a display. Some have functions. A conventional example of such an image communication device is shown in FIG.

In FIG. 4, reference numeral 1 is a reading system for reading an original in an image communication apparatus, 2 is a transmission system for sending the image data read by the reading system 1 onto a communication line 3, and 4 is a line from the communication line 3. A receiving system 5 for receiving a signal is a display system for displaying the image data input from the reading system 1 or the received image data. The reading system 1 includes an image sensor 6, a reading gamma correction unit 7 that corrects the density of an image read by the image sensor 6, and a reading gamma that stores a correction coefficient that regulates the correction operation of the reading gamma correction unit 7. It is composed of a correction coefficient storage unit 8. The transmission system 2 includes an encoding unit 9 that encodes the image data read by the image sensor 6 and a transmission unit 10 that sends the encoded image data to the communication line 3. The receiving system 4 includes a receiving unit 11 that receives a signal input from the communication line 3 and a decoding unit 12 that decodes the received image data. Also, display system 5
Stores the display gamma correction unit 13 that corrects the density of the display image and the correction coefficient that controls the correction operation in the display gamma correction unit 13 for the image data sent from the reading system 1 or the receiving system 4. Display gamma correction coefficient storage unit 1
4 and a display 15 for displaying an image based on the image data after gamma correction. A selector 16 is provided between the reading system 1, the receiving system 4, and the display system 5. The selector 16 inputs the read image data and the received image data, selects one of the two image data according to the control signal from the control signal input unit 17, and outputs the selected image data to the display system 5. ing.

In such a configuration, the reading system 1 reads a still image such as an original by the image sensor 6, but the correction coefficient is input from the reading gamma correction coefficient storage unit 8 to the reading gamma correction unit 7 prior to the reading of the original. . The image data after gamma correction is input to the encoding unit 9 and the selector 16 of the transmission system 2, and when the image communication apparatus is operating in the transmission mode, the image data is encoded and transmitted by the operation of the transmission system 2. It is sent out on the communication line 3 by the section. On the other hand, in the image display operation, the correction coefficient is input from the display gamma correction coefficient storage unit 14 to the display gamma correction unit 13 prior to this display, and the control signal for determining the output source of the image data to be displayed is the control signal. It is input from the input unit 17 to the selector 16. As a result, the selector 16
Selects the image data from the reading system 1 or the receiving system 4 and outputs it to the display gamma correction unit 13. The image data is gamma-corrected and then sent to the display 15 for display.

[0005]

However, in such a conventional image communication apparatus, the reading gamma correction coefficient storage for storing the reading gamma correction section 7 and the correction data for its operation in the reading system 1 is used. Since the display gamma correction unit 13 and the display gamma correction coefficient storage unit 14 that stores the correction data for the operation are provided in the display system 5 separately from the unit 8, the entire image communication apparatus is provided. In view of the configuration, there is a problem that the circuit amount is increased and the production cost is increased. Further, when performing a copy operation with this image communication device, there is a waste of operation in that two gamma corrections of reading and display must be adjusted in order to adjust the gamma correction.

The present invention has been made in view of the above problems, and an object thereof is to provide an image communication apparatus having a simple structure and capable of performing density correction of an image without performing unnecessary operation. .

[0007]

In order to achieve the above object, the present invention provides a gamma correction coefficient storage means for storing gamma correction coefficients corresponding to a transmission operation, a reception operation and a copy operation, and this gamma correction coefficient storage means. Gamma correction means for performing a correction operation based on the gamma correction coefficient of the means, gamma correction coefficient means for selecting a gamma correction coefficient according to each operation and outputting it to the gamma correction means, and a transmission operation or a reception operation. The present invention is characterized by comprising first switching means for switching an input source of the gamma correction means and second switching means for switching an output destination of the gamma correction means during a transmission operation or a display operation.

[0008]

With the above construction, when the image communication apparatus is operating, the input source of image data to the gamma correction means, the input source of gamma correction coefficients, and the output destination of the image data after gamma correction are switched according to the type of operation. . Then, since the common gamma correction means performs the gamma correction operation at each of the transmission, reception, and copy operations, the gamma correction section can also be used to perform different gamma corrections.

[0009]

1 to 3 are views for explaining an embodiment of an image communication apparatus according to the present invention. Of these, FIG. 1 is a block diagram showing the overall configuration of the image communication apparatus according to the embodiment. In this figure, reference numeral 21 is an image sensor for reading a document in the image communication apparatus, 22 is a transmission system for sending the image data read by the image sensor 21 onto the communication line 23, and 24 is a signal from the communication line 23. In the receiving system, these transmitting system 22 and receiving system 24 have the same configurations and functions as the transmitting system 2 and the receiving system 4 in the above-mentioned conventional example. Reference numeral 25 is a display as a means for displaying image data input from the image sensor 21 or received image data. The transmission system 22 is
An encoding unit 26 that encodes the image data read by the image sensor 21 and a transmitting unit 27 that sends the encoded image data to the communication line 23.
The receiving system 24 includes a receiving unit 28 that receives a signal input from the communication line 23 and a decoding unit 29 that decodes the received image data. Image sensor 21,
First and second selectors 30 and 31 are provided between the transmission system 22, the reception system 24, and the display 25, and a gamma correction unit 32 is provided between the first and second selectors 30 and 31. Has been. The first selector 30 inputs the read image data and the received image data, selects one of these two image data, and outputs it to the gamma correction unit 32. The gamma correction section 32 receives the image data from the first selector 30, corrects the density of the image using a predetermined correction coefficient, and outputs the resulting data to the second selector 31. ing. The second selector 31 receives the correction data from the gamma correction unit 32 and selectively outputs the image data to the transmission system 22 or the display 25 according to the operation mode at that time.

A correction coefficient memory 3 as a gamma correction coefficient storage means for inputting to the gamma correction section 32 necessary gamma correction coefficients according to the correction operation of the gamma correction section 32.
3 is connected. The correction coefficient memory 33 includes a read gamma correction coefficient storage unit 34 used to perform density correction of a read image, a display gamma correction coefficient storage unit 35 used to correct density of a display image, and a soft copy. Copy gamma correction coefficient storage unit 36 used to perform image density correction, and correction data from the read gamma correction coefficient storage unit 34, display gamma correction coefficient storage unit 35, and copy gamma correction coefficient storage unit 36. And a third selector 37 that switches the output according to the operation mode. Then, the operation mode signal is input to the first selector 30, the second selector 31, and the third selector 37 from the control signal input terminal 38.

Here, FIG. 2 shows a specific example of the configuration of the gamma correction unit 32. In the figure, reference numeral 39 is a rewritable memory (RAM) that performs gamma correction processing, and a gamma correction coefficient is input to its I terminal,
The data after gamma correction is output from the O terminal to the second selector 3
It is output to 1. Reference numeral 40 is a write address generator for writing correction data to the RAM 39, 41 is a selector for selecting an address to the RAM 39, 42 is an address selection signal generator for selecting an address signal for writing or reading to the RAM 39, Reference numeral 43 is a write pulse generation unit when writing the correction coefficient data into the RAM 39.
The address data from the write address generator 40 and the image data selected by the first selector 30 are input to the selector 41. 44 is the third selector 3
A correction coefficient input terminal to which the gamma correction coefficient selected by 7 is input, 45 is an image input terminal to the gamma correction unit 33, and 46 is an image output terminal to which the image data after gamma correction is sent to the second selector. The operation of the image communication apparatus having such a configuration will be described below. The image sensor 21 reads a still image such as an original, but the gamma correction unit 3 is read from the correction coefficient memory 33 prior to the reading of the original.
The correction coefficient is input to 2. The first selector 30 provided on the image data input side of the gamma correction unit 32 is of the type of operation of this device (transmission operation, reception operation, copy operation).
The input source of the image data to the gamma correction unit 32 is switched according to The second selector 31 provided on the image data output side of the gamma correction unit 32 switches the output destination of the image data after the density correction by the gamma correction unit 32 according to the type of operation of the apparatus. Also, the third selector 3
Similarly, 7 switches the input source of the gamma correction coefficient to the gamma correction unit 32 in accordance with the type of operation of this apparatus.

Therefore, when an operation mode signal is input from the control signal input terminal 38, one of the read gamma correction coefficient storage unit 34, the display gamma correction coefficient storage unit 35, and the copy gamma correction coefficient storage unit 36 is activated. The gamma correction coefficient storage units 34, 3 selected and selected by the third selector 37 according to the type of operation of the apparatus.
One type of gamma correction coefficient of a plurality of gamma correction coefficient sequences of 5 or 36 (for example, light, dark, normal, etc.) is written in the gamma correction unit 32. FIG. 3 shows an example of the gamma correction coefficient sequence as described above. Figure 3 (a)
Represents a correction coefficient for performing "light" gamma correction on the input image data. Hereinafter, FIG. 3B shows "dark" the input image data, and FIG. 3C shows "normal" gamma correction on the input image data. Represents a correction coefficient for These "pale, dark,
The "normal" gamma correction coefficient sequence is different for transmission, reception, and copying. This gamma correction unit 3
At the same time when the gamma correction coefficient is written into the second selector 2, the input source of the image data is selected by the first selector 30 according to the operation mode signal, and the second selector 3 is selected.
The output destination of the image data is selected by 1. That is, when the apparatus is in the reception mode, the first selector 30 selects the reception system 24, the second selector selects the display 25, and the third selector 37 selects the display gamma correction coefficient storage unit 35. It

Next, the operation of the gamma correction unit 32 will be described. As described above, prior to the transmission, reception, and copy operations, the correction coefficient corresponding to each operation is written in the gamma correction unit 32 in advance. The write address is generated by the write address generator 40, and the address selection signal generator 4
2 selects the write state, the selector 41
A write address is input to the A terminal of the RAM 39 via. The write pulse is generated by the write pulse generator 43 and input to the WE terminal of the RAM 39. The correction coefficient is input from the correction coefficient input terminal 44 and input to the I terminal of the RAM 39. With the above operation, the correction coefficient is written. Gamma correction is performed by the correction coefficient written in the RAM 39 during transmission, reception, and copy operations.
The image data is input from the image input terminal 45, and the read state is selected by the output of the address selection signal generator 42, whereby the read address is input to the A terminal of the RAM 39 via the selector 41. The corrected image data is output from the O terminal of the RAM 39 via the image output terminal 46.

Assuming that the operation mode of the apparatus is the transmission operation, the image data after gamma correction is the second selector 31.
The output destination is selected by and is input to the encoding unit 26 of the transmission system 22, where the image data is encoded and the transmission unit 2
7 is transmitted to the communication line 23. On the other hand, in the image display operation mode, the output destination is selected by the second selector 31, is input to the display 25, and is displayed on the display 25.

[0015]

As described above, according to the present invention,
The input source to the gamma correction means, the gamma correction coefficient, and the output destination after gamma correction are switched according to the type of operation, and the common gamma correction means is also used for gamma correction during each operation of transmission, reception, and copying. Therefore, the circuit amount and cost related to the gamma correction can be reduced. Further, various effects can be obtained such that the gamma correction during the copy operation can be adjusted by only one gamma correction unit.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an image communication device according to the present invention.

FIG. 2 is a block diagram showing a specific configuration example of a gamma correction unit used in the above embodiment.

FIG. 3 is a diagram showing an example of a correction coefficient for performing “light”, “dark” or “normal” gamma correction on input image data.

FIG. 4 is a block diagram showing an example of a conventional image communication device.

[Explanation of symbols]

 21 image sensor (image reading means) 22 transmission system 23 communication line 24 reception system 25 display (display means) 30 first selector 31 second selector 32 gamma correction section 33 correction coefficient memory 34 read gamma correction coefficient storage section 35 display Gamma correction coefficient storage unit 36 Gamma correction coefficient storage unit for copying 37 Third selector 38 Control signal input terminal

Claims (1)

[Claims] 1. A gamma correction coefficient storage means for storing gamma correction coefficients corresponding to a transmission operation, a reception operation and a copy operation, and a gamma correction means for performing a correction operation based on the gamma correction coefficient of the gamma correction coefficient storage means. A gamma correction coefficient selection means for selecting a gamma correction coefficient according to each operation and outputting it to the gamma correction means, and a first source for switching the input source of the gamma correction means during a transmission operation or a reception operation.
And a second switching means for switching the output destination of the gamma correction means during the transmission operation or the display operation.