JP3063356B2 - Digital image processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital image processing apparatus having a function of enlarging or reducing an original image represented by digital data.

[0002]

2. Description of the Related Art Conventionally, in this type of digital image processing apparatus, enlargement / reduction processing has been performed by a single enlargement / reduction processing method unique to the apparatus.

[0003]

However, with the recent increase in resolution and image quality of input devices, it has become possible to input large-size original images at high resolution.
The amount of data handled by the enlargement / reduction processing increases, causing a reduction in processing speed. In such a situation, in a digital image processing apparatus having only a high-resolution enlargement / reduction method,
Since the processing method requires a large amount of processing time, the processing time increases significantly with an increase in the amount of data of the original image, and a large-capacity original image can be expanded to a desired size within a limited time. Shrinking is a near impossible problem. On the other hand, in a digital image processing apparatus having only a simple enlargement / reduction method, the time required for the enlargement / reduction processing is short, but when the enlargement ratio is large, image quality such as jaggy is deteriorated, and a high-definition output image is not obtained. There is a problem that it cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has an object to provide a digital image processing apparatus capable of executing enlargement and reduction processing while maintaining the best image quality within a limited time. It is intended to provide.

[0005]

In order to achieve this object, a digital image processing apparatus according to the first aspect of the present invention comprises a comparing means for comparing the data amount of original image data with a reference value;
As a result of the comparison by the comparison means, if the data amount of the original image data is equal to or less than the reference value, the first processing method is expanded.
When a reduction method is selected, and the data amount of the original image data is larger than the reference value, a simpler method than the first processing method is used.
Expansion of the second processing method is a pure processing method, and a selection means for selecting a reduction method. Also, it is described in claim 2.
In the digital image processing apparatus according to the present invention, the digital image processing device according to claim 1 is provided.
In addition to the configuration of the third aspect of the present invention, the first processing method may include a third-order processing method.
It is an interpolation processing method using a pline surface.
Configuration. Further, according to the third aspect of the present invention,
The digital image processing apparatus according to claim 1 or 2,
In addition to the above configuration, the second processing method may be a linear interpolation processing.
It is a configuration characterized by a logical method.

[0006]

In the digital image processing apparatus according to the first aspect of the present invention, when receiving the original image data, the comparing means compares the data amount of the original image data with the reference value. When the original image is small and the data amount is equal to or smaller than the reference value, the selecting means selects the enlargement or reduction method of the first processing method . It is a simpler processing method than the processing method
An enlargement or reduction method of the second processing method is selected. Using the selected enlargement / reduction method, enlargement / reduction processing is executed to obtain an output image. Further, the data of the invention according to claim 2 is provided.
In the digital image processing apparatus, the operation of the invention according to claim 1 is achieved.
In addition to the above, the first processing method includes a tertiary splicing method.
Enlargement / reduction processing is executed by interpolation processing using curved surfaces.
To obtain an output image. Further, according to the third aspect of the present invention,
The digital image processing apparatus according to claim 1 or 2,
In addition to the action of Ming, the second processing method includes linear
Enlargement / reduction processing is executed by the interpolation processing method, and the output image is
obtain.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied as a print control apparatus will be described below with reference to the drawings. FIG. 1 is a schematic diagram of an external connection of the print control apparatus according to the present embodiment. An external connector 1 of the computer 100 is provided so that a print command can be transferred between the computer 100 and the print control device 300.
01 and the first interface connector 3 of the print control device
01 is connected by the first cable 501. The second interface connector 302 of the print control device 300 and the interface connector 201 of the inkjet printer 200 are connected by a second cable 502 so that the raster image data can be sent from the print control device 300 to the inkjet printer 200.

Next, referring to FIG.
Will be described in detail. First interface connector 301 to which data from computer 100 is input
Is connected to a first interface circuit 303 that receives the data. Similarly, a second interface circuit 350 is connected to the second interface connector 302 so that data can be transmitted. A first bus 313 is connected to the other ends of both interface circuits so that data can be transferred to and from the first CPU 305.

A first bus 313 has a first dynamic memory 306 for storing data, a third interface circuit 307 for interfacing with a hard disk drive 309, and a second CPU 311 to be described later.
A first port of a dual-port memory 308 having two ports for communicating with the first and the second memory and capable of accessing the same memory cell from both ports, and a DMAC 314 for performing direct memory transfer between the devices.
Is connected.

The hard disk drive 309 stores in advance the procedures of a plurality of enlargement / reduction processing methods and the procedures of the method of selecting and switching the enlargement / reduction processing method.
Since these processing methods are stored in the hard disk 309, it is possible to easily add or change the enlargement / reduction processing method. On the other hand, the second bus of the second CPU 310 has the second port of the aforementioned dual port memory 308 and the second dynamic memory 311 for storing data.
Is connected. It should be noted that various control signals such as an address bus and a chip select signal are not shown in FIG.

Next, the configuration of the second interface circuit 350 will be described in detail with reference to FIG. First CPU 305
A data input terminal of a first-in first-out memory device (hereinafter, referred to as FIFO) 351 is connected to the first bus 313 so that data can be written from the first bus 313. The data output terminal of the FIFO 351 has the second
A driver 352 for outputting data to the interface connector 302 is connected. A receiver 353 is provided to receive a ready signal from the second interface connector 302 and to input the ready signal to the control circuit 354.

A control circuit 354 is provided for generating a read signal 359 of the FIFO 351 and a data clock signal 356 output to the second interface connector via the driver 352, and controls the timing of the control circuit 354. In order to generate the clock signal 360 for controlling, the clock generation circuit 35
5 are provided. The empty flag 357 of the FIFO 351 is input to the control circuit 354.

Next, the configuration of the ink jet printer 200 will be described in detail with reference to FIG. The interface connector 201 is connected to a receiver 202 for inputting the input data and the data clock signal 221 to the data input terminal of the FIFO 205 and the interface control circuit 204. To the interface connector 201, a driver 203 for outputting a ready signal 220 generated by the interface control circuit 204 is connected. Also FIF
FIFO2 to prevent O205 overflow
05 is connected to the interface control circuit 204. Further data FI
To write to the FO 205, a write signal 222 from the interface control circuit 204 is connected.

The data output terminal of the FIFO 205 has a CPU
A bus 230 is connected so that the data can be read from the bus 206, and a dynamic memory 2 for storing data is connected to the bus 230 so that data can be exchanged with each other.
07, a first data memory 209 for storing print data to be described later, a second data memory 210, and a third data memory 2
11 and the fourth data memory 212 are connected to each other. The data output terminal of the first data memory is connected to the first head control circuit 213 so that the print data 224 can be sent out. In order to control the reading, the read signal 228 of the data read control circuit 208 is changed to the first data. It is connected to the memory 209.

On the other hand, the first head control circuit 213 has a head control signal 229 connected to the ink jet head 251 so that the amount of ink ejected from the nozzle 256 can be controlled. A pipe 260 is connected so that ink can be supplied from the pump. Also in the case of the second to fourth data memories 210, 211, 212, the first data memory 20
9 are connected in the same way as in the case of FIG. Each of the ink jet heads 251 to 254 has a pipe 260 to 26
Through 3, for example, black, yellow, magenta,
Four cyan inks are supplied.

Four ink jet heads 251 to 2
A drum 269 wound with paper 264 is rotatably disposed around the shaft 265 so as to face the shaft 265.
Is supplied with a rotation timing signal.
The encoder 266 which can be transmitted to the STA is attached.
Further, a belt 268 is wound around the shaft 265 to transmit the rotation of the motor 267. The four inkjet heads 251 to 254 are mounted on one bed (not shown), and are configured to be integrally movable in the axial direction of the drum 267.

The print control device 30 configured as described above
A series of printing operations of "0" will be described with reference to FIGS. When receiving the command group to be printed from the computer 100, the first CPU 305 first stores the command group in the hard disk drive 309. At this time, since the command group is received without interpretation, the computer 1
00 can be quickly released from the communication and stored in the hard disk drive 309, so that the capacity of the dynamic memory 306 for storing the command group can be reduced. When all commands from the computer 100 are input, the first CPU 305
In order to interpret this command group, the second CPU 310
Write the command to instruct.

On the other hand, when the second CPU 310 receives this command, the second CPU 310
9 and instructs the first CPU 305 to write to the dual port memory 308 in the same manner. When the command group is written to the dual port memory 308, the second CPU 3
10 starts the interpretation and stores the result in the second dynamic memory 311. The procedure of the interpretation will be described in detail with reference to FIGS.

First, the flow of the enlargement / reduction processing will be described with reference to FIG. The second CPU 310 learns from the command written in the dual port memory 308 that the processing to be executed is enlargement / reduction processing,
Further, the enlargement factor is known (Step S1, hereinafter simply referred to as S1). Next, a command requesting that the procedure of the method of selecting and switching the enlargement / reduction processing method be read from the hard disk 309 is written in the dual port memory 308 (S2). 1st C
The PU 305 reads the instruction of the dual port memory 308, reads the procedure of the method of selecting and switching the enlargement / reduction processing method from the hard disk 309, and writes the procedure to the dual port memory 308 (S3). 2nd CPU3
10 reads the procedure of the method of selecting and switching the enlargement / reduction processing method written in the dual port memory 308 and writes it in the second dynamic memory 311 (S4).

The second CPU 310 sequentially interprets the procedure written in the second dynamic memory 311 and selects an enlargement / reduction processing method according to the data amount of the original image (S
5). Next, a command requesting that the selected procedure of the enlargement / reduction processing method be read from the hard disk 309 is written in the dual port memory 308 (S6). First
The CPU 305 reads the instruction from the dual port memory 308 and selects the enlarged /
The procedure of the reduction processing method is read and written in the dual port memory 308 (S7). The second CPU 310 reads the procedure of the enlargement / reduction processing method written in the dual port memory 308 and reads the second dynamic memory 31.
1 is written (S8).

Next, a procedure (S5) for selecting an enlargement / reduction processing method according to the data amount of the original image will be described with reference to FIG. In this embodiment, a case where two types of enlargement / reduction processing methods are prepared will be described. Here, the reference value N written in the second dynamic memory 311 is referred to simultaneously with the procedure for selecting the enlargement / reduction processing method.

The reference value N is a reference value for classifying the enlargement / reduction processing. In this embodiment, the number of bytes of the original image data is adopted as the reference value, and the reference value N = 3.6 (megabytes). ). The value of N can be calculated using a photo service format (110 mm x 80 mm) using an image scanner or the like.
It is almost equal to the amount of data read at 0 dpi ((8 bits / color) × 3 colors). The reference value N is not limited to this value, and a plurality of reference values can be set when a plurality of enlargement / reduction processing methods are prepared.

The data amount of the original image is compared with the reference value N. If the data amount of the original image is equal to or smaller than N, it is determined that the processing time does not increase significantly even if a high-resolution enlargement / reduction processing method is performed. For example, a high-definition enlargement / reduction processing method M2 such as enlargement / reduction processing using a cubic spline is selected. If the data amount of the original image is larger than N,
It is determined that the processing time significantly increases when the reduction processing method is performed, and a simple enlargement / reduction processing method M1 such as enlargement / reduction processing by linear interpolation is selected.

Here, the simple enlargement / reduction processing method is as follows.
This is a processing method in which the arithmetic processing is relatively simple, for example, a method in which new pixels are generated by interpolating between pixels of an original image by linear interpolation.

Here, the linear interpolation will be described with reference to FIG. Four pixels Qi, adjacent in the horizontal and vertical directions of the original image
7, j, Qi + 1, j, Qi, j + 1, and Qi + 1, j + 1 are set as control points 401, and a square surface Pi, j hatched by hatching in FIG.
402 is represented by the following equation.

[0026]

(Equation 1)

Since the elements of the coefficient matrix NL appearing in this equation are composed of only 0, 1, and -1, Pi, j
There is no burden on the CPU in the calculation of. By substituting arbitrary real numbers in the range of 0 ≦ u ≦ 1 and 0 ≦ v ≦ 1 for u and v in this equation, the value of a new pixel on the surface Pi, j 402 is obtained. For example, to enlarge the original image 7 times in the horizontal and vertical directions, the values of u and v are set to 0.0, 0.143, and 0.28, respectively.
By substituting into the above equation as 6, 0.429, 0.571, 0.714, and 0.857 for calculation, a total of 49 pixel values can be obtained.
If this process is performed for the entire range of the original image, image data enlarged seven times can be obtained.

On the other hand, the high-resolution enlargement / reduction processing method is as follows.
This is a processing method having relatively complicated arithmetic processing, for example, a method of generating new pixels by interpolating between pixels of an original image by cubic spline surface interpolation.

Here, the cubic spline interpolation will be described with reference to FIG. 16 pixels Qi, j, Qi + 1, j, Qi + 2, j, Qi + 3, j, Qi, j + adjacent to the original image in the horizontal and vertical directions
1, Qi + 1, j + 1, Qi + 2, j + 1, Qi + 3, j + 1, Qi, j + 2, Qi +
1, j + 2, Qi + 2, j + 2, Qi + 3, j + 2, Qi, j + 3, Qi + 1, j + 3,
Using Qi + 2, j + 3 and Qi + 3, j + 3 as control points 403, a square surface Pi, j404 hatched by oblique lines in FIG. 8 is expressed by the following equation.

[0030]

(Equation 2)

The elements of the coefficient matrix NR appearing in this equation are composed of real numbers, and the size of the matrix is large. Therefore, it takes more processing time to calculate Pi, j than linear interpolation, but higher definition interpolation is possible. is there. As in the case of the linear interpolation, a new pixel value on the plane Pi, j 404 can be obtained by substituting arbitrary real numbers in the range of 0 ≦ u ≦ 1 and 0 ≦ v ≦ 1 for u and v in this equation. For example, to enlarge the original image by 8 times in the horizontal and vertical directions, the values of u and v are set to 0.0, respectively.
By substituting into the above equation as 0.125, 0.250, 0.375, 0.50, 0.625, 0.750, and 0.875 for calculation, a total of 64 pixel values can be obtained. If this process is performed for the entire range of the original image, image data enlarged eight times can be obtained.

When the interpretation described above is performed and the preparation for the enlargement / reduction processing is completed, the second CPU 310 issues a command to the dual port memory 308 to notify the start of printing. Upon receiving the command, the first CPU 305 writes a start command of the inkjet printer 200 in the second interface circuit 350. If the ready signal 358 is true, the second interface circuit 350 reads the command from the FIFO 351 one byte at a time, and sends out the data clock signal 356 one pulse at a time. The interface control circuit 204 in the inkjet printer 200 fetches the command into the FIFO 205 in synchronization with the data clock signal 356.

The above operation is performed by the FIF in the print controller 300.
There is no interruption until O351 becomes empty or the FIFO 205 in the inkjet printer 200 becomes full. Further, the interface control circuit 204 notifies the CPU 206 that data has been input to the FIFO 205. The CPU 206 sequentially reads out the data and, when recognizing that it is a start command, starts the motor 267 by means of a mechanism control circuit (not shown) and rotates the drum 269.

Subsequently, the second CPU 310 enlarges and expands the original image raster data on the hard disk 309 while sequentially executing the procedure of the second dynamic memory 311.
By executing the reduction process, the output data for one raster is developed and written to the dual port memory 308.

The first CPU 305 has a dual port 30
8 is stored in the dynamic memory 306, and the DMAC 314 is instructed to write the expanded data to the second interface circuit 350. At this time, the required capacity of the dynamic memory is at least the data amount of one raster, and may be significantly smaller than the case where one page of expanded data is provided. DMAC 314 is F
When the FIFO 351 becomes full, the writing is interrupted and the FIFO
When O351 becomes empty, writing is started again. While the direct memory transfer is suspended, the first CPU 305 transmits the next original image raster data to the second C
The data can be transferred from the hard disk drive 309 to the PU 310 side, and the developed data can be stored in another area of the first dynamic memory 306. Further, the second CPU 310 can continue the enlargement / reduction process regardless of whether or not the bus 230 is in use, so that high-speed processing is possible.

When the expansion data is written into the FIFO 351 by the DMAC 314, the data is sent to the ink jet printer 200, as described in the section of sending the start command, and the CPU 206 temporarily stores the data in the dynamic memory 207. I do.

Further, the CPU 206 sequentially stores only the cyan data component for one raster in the data memory 212, and issues an instruction to cause the data reading control circuit 208 to perform printing for one raster when the storing is completed. Upon receiving the instruction, the data read control circuit 208 causes the contents of the fourth data memory 212 to be sent to the fourth head control circuit 216 in synchronization with the output signal of the encoder 266. The fourth head control circuit 216 determines the drive amount based on the data and drives the head 254. Head 2
Numeral 54 ejects an ink amount corresponding to the driving amount onto the paper 264.
As a result, one raster image of cyan is printed on the paper 264 on the drum 269.

Next, the CPU 206 moves the head in the axial direction by one raster, and repeats the above operation for the next cyan raster image. And head 2
When 53 comes to the first cyan raster position, the same is repeated from the next on magenta and cyan data. If the necessary data is not on the dynamic memory 207, the process waits until data is input.

The above operation is repeated for yellow and black, and at the end of the print data, the printing of the raster is sequentially stopped from cyan for printing.
4 can be printed in full color. At this time, the capacity required for the dynamic memory 207 in the ink jet printer 200 is the product of the data amount for at most one raster and the maximum number of offset rasters of the head. As a result, the same printed matter can be obtained with an extremely small amount of memory for the raster image memory for one page.

As described above, if the operation of printing while rasterizing the output data for one raster is executed for all the raster data of the original image, an enlarged / reduced image printed in full color can be finally obtained. .

As is clear from the above description, according to the print control apparatus 300 of the present embodiment, it is possible to obtain an enlarged or reduced image having the best image quality within a limited time.

The present invention is not limited to the embodiment described in detail above, and can be modified without departing from the scope of the invention. For example, the printing apparatus may be of a sublimation type thermal transfer type, or a magneto-optical disk device or a tape drive device may be used instead of the hard disk drive.

The enlargement / reduction processing method includes linear interpolation,
The interpolation is not limited to the spline interpolation, but may be simple interpolation, interpolation using low-order or high-order polynomial surfaces, interpolation using rational surfaces, or the like. . Furthermore, by setting a limit value of the processing time, estimating each execution time in the prepared enlargement / reduction processing method from the data amount of the original image, and selecting the best processing method within the processing time limit value, In addition, it is possible to guarantee the output of the enlarged / reduced image within a limited time.

[0044]

As apparent from the above description,
According to the digital image processing device of the present invention, it is possible to obtain an enlarged or reduced image having the best image quality within a limited time.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an external connection of a print control apparatus according to an embodiment.

FIG. 2 is a block diagram of a print control device.

FIG. 3 is a block diagram of an interface control circuit.

FIG. 4 is an internal block diagram of the ink jet printer.

FIG. 5 is a flowchart showing a procedure of enlargement and reduction processing.

FIG. 6 is a flowchart showing a procedure for selecting an enlargement / reduction processing method.

FIG. 7 is an explanatory diagram of linear interpolation among enlargement and reduction methods in the embodiment.

FIG. 8 is an explanatory diagram of cubic spline interpolation among the enlargement and reduction methods in the present embodiment.

[Explanation of symbols]

 300 print control device 305 first CPU 310 second CPU

Claims (3)

(57) [Claims] 1. A digital image processing apparatus for enlarging or reducing an original image represented by said original image data based on original image data defining densities of a large number of pixels arranged in a matrix. A comparison unit that compares the data amount of the data with a reference value, and as a result of comparison by the comparison unit, if the data amount of the original image data is equal to or less than the reference value, the first processing method is expanded;
When a reduction method is selected, and the data amount of the original image data is larger than the reference value, a simpler method than the first processing method is used.
A digital image processing apparatus comprising: a selection unit that selects an enlargement or reduction method of the second processing method that is a pure processing method . 2. The method according to claim 1, wherein the first processing method includes a cubic spline.
An interpolation processing method using a curved surface.
2. The digital image processing device according to 1. 3. The method according to claim 2, wherein the second processing method is a linear interpolation processing method.
3. The digital device according to claim 1, wherein
Tal image processing device.