JP3305013B2 - Image processing apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus having a communication function for inputting and outputting a color image, and an image processing method therefor.

[0002]

2. Description of the Related Art When copying an image using an image processing apparatus that inputs and outputs a color image, the user sets the color and sharpness of the output image according to his / her preference.

Further, an image processing apparatus having a communication function and inputting a color image and outputting a binary image, when binarizing at a transmitting side apparatus, does not grasp color characteristics at a receiving side. Perform binarization and send. Alternatively, when the receiving device has a color processing or gradation correction function, the transmitting device transmits a color multi-level signal.

[0004]

In the above-described image processing apparatus having a communication function for inputting / outputting a color image, if an appropriate mode is set in a receiving side apparatus, an image intended by a transmitting side is received. There is a problem that can not be sent to the side.

In recent years, the input / output function of a color image in an image processing apparatus has been improved, calibration can be performed by the apparatus itself, and variations in image quality among apparatuses with respect to color reproduction and resolution have been reduced. On the other hand, the user often changes the mode in order to intentionally change and output the original image, and when outputting the received image, it is necessary to return the mode to the initial state.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to output color image data received via a communication line without deteriorating the image quality.

[0007]

The present invention has the following arrangement as one means for achieving the above object.

[0008] An image processing apparatus according to the present invention comprises an input unit for inputting color image data, a receiving unit for receiving color image data via a communication line, and a process for image processing the input or received color image data. Means, output means for outputting image-processed color image data, and control means for setting parameters used for the image processing, wherein the control means outputs the color image data received by the receiving means. In this case, parameters set in the processing unit for color image data input by the input unit are initialized. An input unit for inputting color image data; a receiving unit for receiving color image data via a communication line; a processing unit for performing image processing on the input or received color image data; Output means, and control means for setting parameters used for the image processing, wherein the control means is set in the processing means when outputting color image data received by the receiving means. Further, parameters for color image data input by the input means are saved in a memory, other parameters are set in the processing means, and the parameters saved in the memory after the received color image data is output. Is returned.

[0009] An image processing method according to the present invention is an image processing method for performing image processing on color image data input from input means or color image data received via a communication line, and outputting the processed image. When outputting the received color image data, image processing parameters set for the color image data input by the input unit are initialized. Further, an image processing method for performing image processing of color image data input from the input means, or color image data received via a communication line, and outputting the received color image data, The image processing parameters set for the color image data input by the input unit are saved in a memory, other image processing parameters are set, and after the received color image data is output, the image processing parameters are saved in the memory. It is characterized by restoring image processing parameters.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments according to the present invention will be described below in detail with reference to the accompanying drawings.

[0011]

FIG. 1 is a block diagram showing the configuration of a copying machine according to a first embodiment. During the color copying operation, the copying machine shown in FIG.
The image signal of the read document is digitized by A / D conversion in the A / D / shading correction unit 2, and the sensitivity unevenness and illumination unevenness of the color CCD 1 are corrected by shading correction.

Subsequently, the LOG / masking / UCR unit 3 performs LOG conversion, masking processing and UCR (under color removal) to obtain a YMCK (yellow, magenta, cyan, black) signal from the RGB signal. Then, the edge emphasis unit 4 performs edge emphasis based on the edge emphasis amount set by the user, and furthermore, the color balance unit 5 obtains a color balance, and then outputs a color hard copy.

The CPU 7 controls the entire copying machine, and data and parameters necessary for the control are stored in the RAM 8. The protocol conversion / compression / expansion circuit 6 will be described later.

FIG. 2 shows a matrix configuration of the edge enhancement in the edge enhancement section 4. The edge enhancement unit 4 performs an operation of adding a value obtained by multiplying the image signal of 5 × 5 pixels by the coefficient shown in FIG. 2 to the image signal of the target pixel. The value of α can be changed by the user. FIG. 3 shows a gradient function γ in the color balance unit 5, which can be moved independently for each of Y, M, C, and K. In addition, the user can select which inclination is to be set, whereby the color density changes. The initial value is the edge enhancement coefficient α shown in FIG.
Is zero, and the color balance slope function γ shown in FIG.

Next, a processing procedure for hard-copying an image signal sent using the communication function in the copying machine of the present embodiment will be described.

FIG. 4 is a flowchart showing a hard copy processing procedure according to this embodiment.

When an image signal is sent to the copying machine via the communication line 15 shown in FIG. 1, the protocol conversion / compression / expansion circuit 6 converts the image signal into RGB image data (step S1). At this time, if necessary, the RGB image data is stored in a buffer memory (not shown).

In step S2, the CPU 7 saves the coefficient α (for YMCK) of the edge emphasizing unit 4 and the value of the gradient function γ (for YMCK) of the color balance unit 5 in the RAM 8, and in step S3, executes edge emphasis. The coefficient α and the gradient function γ of the unit 4 and the color balance unit 5 are initialized (reset). That is, as described above, α = 0 in the edge enhancement unit 4 and γ = 1 in the color balance unit 5.
Is set.

Thereafter, in step S4, the transmitted image data is added to the LOG / masking / UCR unit 3 and the edge enhancement unit 4
The image processing of the color balance unit 5 is performed. And
In step S5, it is determined whether the color hard copy has been completed. If the determination result is NO, the process returns to step S4 to continue the image processing.

If the decision result in the step S5 is YES, the CPU
In step S7, the process proceeds to step S6, extracts the parameters α and γ saved in step S2 from the RAM 8, sets them in the edge emphasizing unit 4 and the color balance unit 5, and ends the process.

As described above, according to this embodiment,
When an image is transmitted via a communication line, the parameters set by the user for normal copying are temporarily saved in a memory, and after the transmitted image is hard copied,
The parameter set by the user is restored. Therefore, the image transmitted via the communication line can be hard copied without being affected by the parameters set by the user and without deteriorating the image quality.

As the color balance, the CPU 7 may load one of the characteristic straight lines shown in FIG. 3 from the RAM 8 to the color balance unit 5 instead of setting the inclination function γ. May be calculated and set in the color balance unit 5.

The parameters to be saved are, in addition to edge enhancement and color balance, for example, a smoothing process such as smoothing, and a mode for moving both α and γ of YMCK for edge enhancement and color balance together. Magnification or the like may be used, as long as the user can move them to change the image performance.

The communication function may be a telephone line, a dedicated line, a LAN (local area network), an ISDN, or the like as a line or a protocol.
Anything that electrically connects remote places, such as G3 and G4 facsimile and Ethernet, may be used.

[0025]

Second Embodiment Hereinafter, a second embodiment according to the present invention will be described.

FIG. 5 is a block diagram showing a configuration of a color image input / output device according to the second embodiment. FIG. 1 shows a color image input / output device 21 on the image receiving side (hereinafter, referred to as a receiving device) and a color image input / output device 41 on the image transmitting side.
(Hereinafter, referred to as a transmitting device), and both devices are connected to each other via a communication line 60.

In the transmitting side apparatus 21 and the receiving side apparatus 41, 22 and 42 read an image from a document, and
The color CCDs 23 and 43 output as signals are A / D and shading sections that perform A / D conversion and shading correction of image signals read from the original, and 24 and 44 perform LOG conversion of RGB data and CMY data. This is the LOG conversion circuit to generate.

Reference numerals 25 and 45 denote masking / UCR circuits for performing masking and UCR by matrix operation and generating YMCK data, and reference numerals 26 and 46 denote gamma correction units for performing gamma conversion. Reference numerals 27 and 47 denote tone correction units for each nozzle, which will be described later. The YMCK data corrected here is processed by the binarization processing units 28 and 48, and then input to the nozzle driving units 32 and 52.

Next, the operation of the receiving device 21 and the transmitting device 41 will be described with reference to the flowchart shown in FIG.

The CPU 29 includes a LOG conversion circuit 24, a masking / UCR
Masking coefficients, UCR (under color removal) coefficients, and coefficients for binarization processing (for example, coefficients of an error diffusion matrix shown in FIG. 9) from the circuit 25, the gamma correction unit 26, the gradation correction unit 27, and the binarization processing unit 28 Read parameters such as (Step S1
1). These parameters are used for protocol conversion / compression processing.
/ After the protocol conversion in the memory unit 31, the data is sent to the transmitting device 41 via the communication line 60 (step S1).
2).

On the other hand, the transmitting side device 41 has a parameter for determining a preset image performance, that is, a masking coefficient or
Parameters such as a UCR (under color removal) coefficient and a coefficient for binarization processing are stored in the RAM 50. Then, the above parameters sent from the receiving device 21 are set in the LOG conversion circuit 44, the masking / UCR circuit 45, the gamma correction unit 46, the gradation correction unit 47, and the binarization processing unit 48 (step S13). .

In step S14, a color image is read by the transmitting device 41, and in step S15, the color C is read.
A / D conversion and shading correction are applied to the color image signal read from the color original by the CD 42 in the A / D / shading unit 43, and the LOG conversion in which the parameters sent from the receiving apparatus 21 are set. The image signal processing of the circuit 44, the masking / UCR circuit 45, the gamma correction unit 46, the gradation correction unit 47, and the binarization processing unit 48 generates binary signals of Y, M, C, and K.

The image signal obtained in the above processing is
The data is sent to the protocol conversion / compression processing / memory unit 51, where it is taken into a buffer (not shown), if necessary, to take timing, and signal compression such as run-length compression is performed. Then, protocol conversion / compression / compression / memory unit 51
The protocol conversion is performed by the
(Step S16).

The receiving device 21 converts the data transmitted from the transmitting device 41 into a protocol by the protocol conversion / compression processing / memory unit 31 and, if necessary, takes it into a buffer and then performs decompression processing. The signal is returned to the binary signal of Y, M, C, and K (step S17). Then, in step S18, the YMCK binary signal is sent to the nozzle driver 32, and a color hard copy is generated.

When the transmission process is completed, the transmission-side device 41 again stores the parameters saved in the RAM 50 into the LOG conversion circuit.
44, masking / UCR circuit 45, gamma correction unit 46, gradation correction unit 47, and binarization processing unit 48, and return to the initial state.

Here, parameters for determining image performance will be described.

In the processing of the LOG conversion circuit 24 (44), the input signal is
j (j = R, G, B, I R is red, I _G is green, I _B represents the signals of blue), and if the output signal and Oj, wherein
It is represented by (1). Oj = (-255 / △ D) log (Ij / 255)… (1)

In the equation (1), ΔD is a density range and usually takes a value of 1 ≦ ΔD ≦ 2.5, which is a parameter of the LOG conversion circuit 24 (44). When the LOG conversion circuit 24 (44) is in the LUT (look-up table) format, it is possible to use a group of numerical values stored in the LUT as a parameter.

The masking / UCR circuit 25 (45)
Is the signal after LOG conversion, the K signal is created from equation (2),
The matrix operation of equation (3) is performed to obtain Y ′, M ′, C ′, and K ′. Therefore, 4 × 4 = 16 coefficients of the matrix are parameters of the masking / UCR circuit 45. The masking process and the UCR may include a non-linear term such as quadratic. K = min (YMC)… (2)

The gamma correction unit 26 (46) calculates I _L (L = Y, M, C, K)
The relationship between the input signal and the density of the color hard copy is linearized, for example, according to a correction curve having characteristics as shown in FIG. These characteristic curves are stored in the LUT,
The numerical value group of this LUT is a parameter.

Further, the tone correction unit 27 (47) for each nozzle
This is necessary when a plurality of nozzle heads are provided as in an ink jet printer, and each nozzle follows a gradation correction characteristic as shown in FIG. 8 (one nozzle corresponds to one correction curve).

As described above, according to this embodiment,
A parameter for determining the image performance of the receiving side is transmitted from the receiving side to the transmitting side. The transmitting side transmits a YMCK binary signal obtained by performing image processing on the multi-valued color image data according to the parameters to the receiving side, and the receiving side outputs a color hard copy using the YMCK binary signal. Accordingly, the amount of image data to be transmitted can be reduced while maintaining color reproducibility and image uniformity, and as a result, communication time and communication cost can be reduced. For example, if 8-bit (24 bits / pixel) data for each RGB pixel is converted to 1-bit (4 bits / pixel) data for each YMCK pixel, the transmission data amount can be reduced to 1/6.

In the second embodiment, when the apparatus on the receiving side and the apparatus on the transmitting side are of the same model, and the coefficients of the error diffusion matrix of the LOG conversion circuit 24, the masking / UCR circuit 25, and the binarization processing unit 28 are the same, Alternatively, only the parameters of the parts handling different parameters for each device, such as the gamma correction unit 26 and the gradation correction unit 27, may be transmitted from the receiving side to the transmitting side.

The communication function may be a telephone line, a dedicated line, a LAN (local area network), or a digital network such as ISDN as a line or protocol. Regarding the protocol, any protocol that connects telecommunications to remote locations, such as a G3 or G4 facsimile or Ethernet, may be used. Furthermore, the compression and decompression processes may be sequential processes such as run-length compression, or may be a system such as JBIG that performs compression while changing the resolution progressively.

The receiving device may not have an image input unit such as a CCD, and the transmitting device may not have an image output unit. The printer is not limited to an ink jet printer, but may be an electrophotographic type, a sublimation type or a mature transfer type.

The present invention may be applied to a system constituted by a plurality of devices or to an apparatus constituted by a single device. Further, it goes without saying that the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus.

[0047]

As described above, according to the present invention,
When the color image data is received, the received color image data is subjected to image processing using, for example, an initial value of the image processing parameter, so that the received color image data can be output without deteriorating the image quality.

After outputting the received color image data and restoring the saved image processing parameters,
An easy-to-use image processing device can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a copying machine according to a first embodiment;

FIG. 2 is a diagram illustrating a configuration of an edge enhancement matrix of an edge enhancement unit.

FIG. 3 is a diagram showing characteristics of a slope function γ of a color balance unit;

FIG. 4 is a flowchart showing a hard copy processing procedure;

FIG. 5 is a block diagram showing a configuration of a color image input / output device according to a second embodiment.

FIG. 6 is a flowchart showing the operation of the receiving device and the transmitting device;

FIG. 7 is a diagram showing a correction curve of a density characteristic of a gamma correction unit;

FIG. 8 is a diagram showing tone correction characteristics for each nozzle of a tone correction unit;

FIG. 9 is a diagram showing an error diffusion matrix.

Claims (6)

(57) [Claims] An input unit for inputting color image data; a receiving unit for receiving color image data via a communication line; a processing unit for performing image processing on the input or received color image data; Output means for outputting color image data, and control means for setting parameters used for the image processing, wherein the control means, when outputting color image data received by the receiving means, by the input means An image processing apparatus for initializing parameters set in the processing means for input color image data. 2. An input means for inputting color image data; a receiving means for receiving color image data via a communication line; a processing means for performing image processing on the input or received color image data; Output means for outputting color image data, and control means for setting parameters used for the image processing, wherein the control means, when outputting color image data received by the receiving means, the processing means The parameters for the color image data set by the input unit are saved in the memory, and the other parameters are set in the processing unit.After the received color image data is output, the parameters are stored in the memory. An image processing apparatus for restoring saved parameters. 3. The image processing apparatus according to claim 1, wherein the parameters are related to color density, edge enhancement, and magnification. 4. An image processing method for performing image processing on color image data input from an input means or color image data received via a communication line, and outputting the received color image data. In the case, an image processing method is characterized in that image processing parameters set for color image data input by the input unit are initialized. 5. An image processing method for performing image processing on color image data input from input means or color image data received via a communication line, and outputting the received color image data. In the case, the image processing parameters set for the color image data input by the input means are saved in a memory, other image processing parameters are set, and after the received color image data is output, the memory An image processing method for restoring the image processing parameters saved in the image processing. 6. The image processing parameter includes a color density,
6. The image processing method according to claim 4, wherein the method relates to edge enhancement and magnification.