JP3430844B2 - Image information compression method, information processing apparatus and printer - 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 information compression method for compressing image information, an information processing apparatus for transmitting image information compressed based on the image information compression method to a printer, and image information. Regarding the printer to print.

[0002]

2. Description of the Related Art In recent years, personal computers and other information terminals have become inexpensive and have become widespread, and printers used for printing characters and images output by these information terminals have also become widespread. In addition, the printing method applicable to such a printer includes an inkjet method, a sublimation type thermal transfer method, a fusion type thermal transfer method, and the like. Especially, regarding the inkjet method, the image quality and hardware of black and white printing are higher than those of other methods. It is applied to many of the printers currently on the market due to its superior cost and running cost. Furthermore, regarding the print quality of color in these printing methods and the adaptability of printing on plain paper, the difference between them is improved by applying various image processing techniques and improving the ink. Is being promoted.

FIG. 10 is a diagram showing a configuration example of a conventional printer and a personal computer to which the printer is connected. In the figure, a personal computer 12
0 is a cable 120c conforming to the Centronics standard
Is connected to the printer 121 via. The personal computer 120 also includes a processor (CPU) 122.
And an R connected to the processor 122 via a bus.
OM123, RAM124, FD interface (FD
INT) 125, HD interface (HDDINT)
126 and Printer Interface (PINT) 12
7, a floppy disk drive 128 connected to the FD interface 125, and an HD interface 12
6, and a printer interface 127 is connected to one end of the cable 120c described above.

Further, the printer 121 includes the processor 1
30, an external interface (EINT) 131 connected to the processor 130 via a bus, a parameter ROM 132, a program ROM 133, and a work RAM
134, the bit map RAM 135, the drive unit 136, the font ROM 137 and the operation unit 138, and the density conversion unit 13 connected in parallel to the input / output terminals of the drive unit 136.
9-C, 139-M, 139-Y, 139-K, connected to the output of these density converters 139-C, 139-M, 139-Y, 139-K and the input / output terminal of the external interface 131. And the engine 140 that has been operated.

In the conventional example having such a configuration, the ROM 123 provided in the personal computer 120 has a BIOS (Basic Input / O) adapted to each function for driving the printer 121 via the printer interface 127.
utput System) is stored in advance. Also, the processor 1
At the time of startup, the 22 loads an operating system (hereinafter, simply referred to as “OS”) from the hard disk drive 129 to the RAM 124 via the HD interface 126 and executes the OS.

Further, the processor 122 manages the HD interface 126 under the resource management performed by the OS.
From the hard disk drive 129 to the RAM 12
When printing the image information generated in the process of loading the application program in 4 and executing the application system, the image information is logically delivered to the OS.

The image information delivered in this way is delivered to the BIOS activated by the OS executed by the processor 122, and the BIOS controls the printer interface 127 which is the hardware based on a predetermined procedure. The cable 120c
Is sent to the printer 121 via the. Note that, hereinafter, a series of processes performed by the processor 122 in this manner is referred to as “sending process”.

On the other hand, in the printer 121, the parameter R
The OM 132 stores in advance a table that gives the arrangement of dots to be printed based on the area gradation method for the gradation values that can be taken by the individual pixels to be printed.
The processor 130 executes the program stored in the program ROM 133 in advance to capture the image information sent from the personal computer 120 via the external interface 131 as described above, and the buffer area provided in the work RAM 134 in advance. This image information is stored in. Further, when the processor 130 analyzes the image information stored in the buffer area in this way and recognizes that the content is information other than characters such as a photograph or a line drawing, each of the individual pieces of image information forming the image information is analyzed. Printing is performed by referring to the above-mentioned table using the gradation value as a key for each pixel (hereinafter, it is assumed that the four primary colors of cyan, magenta, and yellow subtractive color mixture primary colors and black are individually corresponded). Image information in a format corresponding to the layout of the surface is generated and stored in the bitmap RAM 135. In addition, below, a series of processes performed by the processor 130 in this manner is referred to as a “gradation conversion process”.

Further, the processor 130 scans the image information stored in the bit map RAM 135 in units of pixels or dots while associating it with the printing order, and supplies the image information obtained based on the scanning to the drive unit 136. .
The drive unit 136 divides such image information into the above-described four-color components, and the density conversion units 139-C, 139-M, and 139-.
Y, 139-K, and these density conversion units 139-C, 1
The 39-M, 139-Y, and 139-K print by driving the engine for each color. In the following,
A series of processes performed by the processor 130 in this manner subsequent to the gradation conversion process is referred to as “driving process”.

It should be noted that the font ROM 137 has a font table showing fonts individually corresponding to individual codes which can be given from the personal computer 120 in place of the above-mentioned image information when the object to be printed is a character or a symbol. It is stored in advance.

In such a case, the processor 1
30 obtains the array of dots to be printed by referring to the font table instead of the above-mentioned table. Further, the operation unit 138 is composed of a switch, a display, and the like provided for the operation of the printer 121 and the display of the status, and a desired man-machine interface can be realized by linking with a program executed by the processor 130 at a predetermined frequency. Be served.

Further, in the parameter ROM 132, various parameters (for example, the size of the grid in pixel units) to be determined in the process of the processor 130 or referred to in the process of the process as described above are stored in advance. Is stored.

[0013]

By the way, in the above-mentioned conventional example, the amount of image information sent from the personal computer 120 to the printer 121 is larger than that in the case where the printing target is only characters or symbols. However, it may take a long time to transfer from the printer interface 127 to the external interface 131, and the time required for completion of printing from the time when it is sent from the personal computer 120 may be unacceptably long. There were many.

Regarding the time required for the above-mentioned transfer, for example, there is a technique in which the processor 122 compresses the amount of information by performing gradation conversion processing on image information prior to transmission in the above-described transmission processing. When applied, it was shortened, and some BIOSes and printers actually applied such a technology. However, in such a conventional example, an image showing a photograph having low adaptability to a compression encoding method such as an MH encoding method or an MMR encoding method, a table or a figure having low adaptability to the PMEG encoding method, and the like. Like information, depending on the combination with the compression processing method, the calculation required time of the compression processing and the achieved compression rate vary greatly. The transfer time could be rather long.

Further, the information amount of the image information binarized based on the similar compression technique is not surely shortened due to the large fluctuation of the compression rate described above, but rather than the original information amount. There was a possibility of increase. Therefore, in the personal computer 120 and the printer 121, the R
A large-sized storage area had to be secured in the AM 124 and the work RAM 134 although the possibility of access was extremely low.

It is an object of the present invention to provide an image information compression method, an information processing apparatus and a printer which can surely improve the printing efficiency regardless of the image information to be printed.

[0017]

According to a first aspect of the present invention, there is provided image information indicating an image represented based on a gradation expression method of both or one of an area gradation method and a density gradation method. To generate a plurality of partial image information by dividing the image information into a unit of a lattice composed of a plurality of adjacent pixels, and to generate a gradation representation method for each of the generated plurality of partial image information. It is characterized in that a sequence of code words is obtained by performing an arithmetic operation for rounding the ratio of the total sum of the gradation values based on the gradation value and the maximum value that the gradation value can take.

In the image information compression method according to the first aspect of the present invention, image information indicating an image represented based on a gradation expression method of both or one of an area gradation method and a density gradation method. Is taken in and the image information is divided into units of a lattice consisting of a plurality of adjacent pixels to generate a plurality of partial image information. Further, an arithmetic operation for rounding the ratio between the sum of the gradation values based on the gradation expression method and the maximum value that the gradation value can take is performed on each of the plurality of partial image information generated in this way. By doing so, a sequence of code words is obtained.

That is, since the image information is converted into a sequence of code words by summing up the gradation values for each grid by the maximum value of the gradation values, the arrangement of such gradation values is performed. Regardless of the above, the amount of information can be surely compressed. According to a second aspect of the present invention, image information indicating an image represented based on either or both of the area gradation method and the density gradation method is taken in, and the image information is adjacent. A plurality of partial image information is generated by dividing into a unit of a grid composed of a plurality of pixels, and the sum of the gradation values based on the gradation representation method and the image are generated for each of the generated plurality of partial image information. The sequence of code words is calculated by rounding the ratio between the product of the maximum value of the density gradation value based on the density gradation method that should be applied to the expression and the maximum value that the gradation value can take. It is characterized in that it has an encoding means 21 for obtaining.

In the image information compression method according to the second aspect of the present invention, image information indicating an image represented based on the gradation expression method of either or both of the area gradation method and the density gradation method. Is taken in and the image information is divided into units of a lattice consisting of a plurality of adjacent pixels to generate a plurality of partial image information. Furthermore, the sum of the gradation values based on the gradation expression method described above and the density gradation value based on the density gradation method that should be applied to the image expression are individually added to the plurality of partial image information thus generated. The product of the maximum of and
A string of code words is obtained by performing an arithmetic operation that rounds the ratio of the gradation value to the maximum possible value.

That is, in the image information, the product of the sum of the gradation values for each grid and the maximum value of the density gradation values based on the density gradation method to be applied to the expression of the corresponding image is the gradation value. Since it is converted into a code word string by being normalized with the maximum value, the amount of information can be surely compressed regardless of the arrangement of the gradation values. A third aspect of the present invention is the image information compression method according to the second aspect, wherein the encoding unit 21 includes a predetermined number of lower bits and remaining upper bits for each of the obtained codewords. Is separated.

According to the image information compression method of the third aspect of the present invention, in the image information compression method of the second aspect, for each of the obtained codewords, a predetermined number of lower bits and remaining bits are used. The upper bits are separated. Such upper bits give the approximate value of the gradation value indicated by each code word, and the error component of the approximate value is indicated by the remaining lower bits. Therefore, the arrangement of dots to be indicated by all these bits. It is possible to significantly reduce the amount of information as compared with the conventional example in which the combination of and the gradation value is individually encoded.

FIG. 1 is a block diagram showing the principle of the invention described in claim 4. According to a fourth aspect of the present invention, image information representing an image to be printed is processed based on the image information compression method according to any one of the first to third aspects,
Image information processing means 31 for generating a sequence of code words indicating the image information, and printer interface means 33 for transmitting the sequence of code words generated by the image information processing means 31 to the printer are provided. .

In the information processing apparatus according to the fourth aspect of the present invention, the image information processing means 31 provides image information representing an image to be printed according to any one of the first to third aspects. Processing is performed based on the image information compression method, and a sequence of code words indicating the image information is generated. Further, the printer interface unit 33 sends the sequence of code words thus generated to the printer based on the interface system applied to the printer.

That is, it is possible to request the printer adapted to the image information compression method according to any one of claims 1 to 3 to print a desired image while surely compressing the amount of information. Therefore, the transmission efficiency of the interface formed between the printer and the printer can be improved, the tasks can be efficiently shared by a plurality of tasks and users, and the efficiency of printing can be improved.

FIG. 2 is a block diagram showing the principle of the invention described in claim 5. According to a fifth aspect of the invention, with respect to the dots to be printed for each grid based on the area gradation method and / or the density gradation method corresponding to the code word, the arrangement and the gradation value are set. The storage means 41, which is stored in advance in association with the possible combinations of values of the codewords, and the sequence of codewords transmitted by the information processing apparatus according to claim 4, fetches each of these codewords. With respect to the above, based on the gradation conversion means 43 for obtaining the combination of the arrangement and the gradation value stored in association with the storage means 41, and the combination of the arrangement and the gradation value obtained by the gradation conversion means 43. A printing unit 45 that prints for each grid is provided.

In the printer according to the fifth aspect of the invention, the storage unit 41 prints for each grid based on the area gradation method and / or the density gradation method corresponding to the code word. For dots to be formed, combinations of arrangement and gradation values are stored in advance in association with possible values of the codeword. The gradation conversion unit 43 takes in the sequence of codewords sent by the information processing apparatus according to claim 4, and stores the arrangement and gradation stored in association with the storage unit 41 for each of these codewords. Get the combination with the value. Further, the printing unit 45 prints for each grid based on the combination of the arrangement and the gradation value obtained in this way.

That is, since the printing is surely performed under the application of the image information compression method according to any one of claims 1 to 3 in cooperation with the information processing apparatus according to claim 4, it is given as image information. Regardless of the arrangement and combination of the gradation values that are set, a desired image is efficiently printed based on the simple gradation conversion performed by the gradation conversion unit 43.
FIG. 3 is a principle block diagram of the invention described in claims 6-9.

According to a sixth aspect of the present invention, image information indicating an image represented based on either or both of the area gradation method and the density gradation method is fetched, and the image information is acquired. Of the plurality of partial image information by dividing each of the plurality of adjacent image units into a unit of a lattice composed of a plurality of adjacent pixels, and the plurality of partial image information generated by the division processing unit 11 individually expresses gradation. Encoding means 1 for obtaining a sequence of code words by performing an arithmetic operation for rounding the ratio of the sum of gradation values based on the modulus and the maximum value that the gradation values can take.
3 and the storage means 5 in which the combination of the arrangement and the gradation value of the dots to be printed for each grid based on the gradation expression method is stored in advance in association with the possible value of the code word.
1 and the sequence of codewords obtained by the encoding means 13, and the storage means 51 for each of these codewords.
The gradation conversion unit 53 that obtains a combination of the arrangement and the gradation value that are stored in association with each other, and print for each grid based on the combination of the arrangement and the gradation value that is obtained by the gradation conversion unit 53. And a printing unit 55 for performing the printing.

In the printer according to the sixth aspect of the invention, the division processing means 11 produces an image represented based on the gradation expression method of the area gradation method and / or the density gradation method. A plurality of partial image information is generated by taking in the image information shown and dividing the image information into a unit of a lattice composed of a plurality of adjacent pixels. Further, the encoding unit 13 rounds the ratio of the sum of the gradation values based on the gradation representation method and the maximum value that the gradation value can take to each of the plurality of pieces of partial image information thus generated. A sequence of codewords is obtained by performing an arithmetic operation.

Further, in the storage means 51, with respect to the dots to be printed for each grid based on the gradation representation method, the combination of the arrangement and the gradation value is associated with the possible value of the above code word. It is stored in advance. The gradation conversion means 53
For each of the code words obtained by the encoding means 13, a combination of the arrangement and the gradation value stored in the storage means 51 in association with each other is obtained. Further, the printing unit 55 prints for each grid based on the combination of the arrangement and the gradation value obtained in this way.

Therefore, even if the division processing means 11 and the encoding means 13 are not provided in the information processing apparatus for generating the image information indicating the image to be printed,
In the same manner as when the information processing apparatus according to claim 4 and the printer according to claim 5 are linked, the amount of image information is compressed and the efficiency of printing is improved, and in this way. The amount of information is compressed and the scale of hardware is significantly reduced.

According to a seventh aspect of the present invention, image information indicating an image represented based on either or both of the area gradation method and the density gradation method is fetched, and the image information is acquired. Of the plurality of partial image information by dividing each of the plurality of adjacent image units into a unit of a lattice composed of a plurality of adjacent pixels, and the plurality of partial image information generated by the division processing unit 11 individually expresses gradation. Arithmetic that rounds the ratio between the product of the sum of the gradation values based on the method and the maximum value of the density gradation values based on the density gradation method that should be applied to the image representation, and the maximum value that the gradation values can take. Encoding means 21 that obtains a sequence of code words by performing an operation, and for the dots to be printed for each grid based on the gradation representation method, a combination of the arrangement and the gradation value is a value that the code word can take Pre-stored memory associated with Gradation for taking in the stage 61 and the sequence of code words obtained by the encoding means 21, and obtaining for each of these code words the combination of the arrangement and the gradation value stored in association with the storage means 61. Conversion means 63,
The present invention is characterized by including a printing unit 65 that prints for each grid based on the combination of the arrangement and the gradation value obtained by the gradation conversion unit 63.

In the printer according to the seventh aspect of the invention, the division processing means 11 produces an image represented based on the gradation expression method of either or both of the area gradation method and the density gradation method. A plurality of partial image information is generated by taking in the image information shown and dividing the image information into a unit of a lattice composed of a plurality of adjacent pixels. Further, the encoding means 21 is based on the sum of the gradation values based on the gradation expression method and the density gradation method to be applied to the image expression, for each of the plurality of partial image information thus generated. A sequence of code words is obtained by performing an arithmetic operation that rounds the ratio of the product of the density gradation value and the maximum value and the maximum value that the gradation value can take.

Further, in the storage means 61, for the dots to be printed for each grid based on the gradation representation method, the combination of the arrangement and the gradation value is stored in advance in association with the possible values of the code word. To be done. The gradation conversion unit 63 obtains, for each of the code words obtained by the encoding unit 21, a combination of the arrangement and the gradation value stored in the storage unit 61 in association with each grid. Further, the printing unit 65 prints for each grid based on the combination of the arrangement and the gradation value obtained in this way.

Therefore, even when the information processing apparatus for generating the image information showing the image to be printed is not provided with the division processing means 11 and the encoding means 13,
Similarly to the case where the information processing apparatus according to claim 4 and the printer according to claim 5 are linked, the information amount of multi-valued image information is compressed, and the efficiency of printing is improved, and By compressing the amount of information in this way, the scale of hardware is greatly reduced.

According to an eighth aspect of the present invention, in the printer according to the sixth or seventh aspect, the printing means has an arrangement of combinations of arrangements and gradation values obtained for each grid by the gradation converting means. Prior to printing, is divided into units of a large grid larger than the grid, and has means for averaging both or one of the deviation of the arrangement and the variation of the gradation value for each large grid. To do.

According to an eighth aspect of the present invention, in the printer according to the sixth or seventh aspect, the printing means includes the arrangement and the gradation value obtained for each grid by the gradation conversion means. Prior to printing, the arrangement of the combination is divided into units of a large grid larger than the grid, and the deviation of the arrangement and / or the variation of the gradation values are averaged for each large grid.

That is, since the reduction in resolution is alleviated for each large grid, under the application of the image information compression method of claims 1 to 3, the larger the sum of the gradation values for each grid is, the more the image information is compressed. The resolution, which is likely to be lowered in exchange for the rate, is increased as compared with the printer according to claims 6 and 7. According to a ninth aspect of the present invention, in the printer according to any one of the fifth to eighth aspects, the combination of the dot arrangement for each grid and the gradation value is stored and these are targets of printing. Is provided and a memory 71 shared by the gradation converting means and the printing means is provided for storing the arrangement and the row of gradation values.

In the printer according to the ninth aspect of the present invention, the memory 71 stores the combination of the dot arrangement and the gradation value for each grid, and the arrangement and the gradation value to be printed. And the storage of the columns are shared by the gradation converting means and the printing means, respectively. That is, the scale of hardware can be reduced as compared with a printer in which a storage area or a memory is individually provided as a storage destination of the above-described storage.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 4 shows claims 1 to 9.
It is a figure which shows the embodiment corresponding to the invention of statement. In the figure, parts having the same functions and configurations as those shown in FIG. 10 are designated by the same reference numerals, and the description thereof will be omitted here.

The difference between the present embodiment and the conventional example shown in FIG. 10 lies in that processor 12 is replaced by processor 12.
2a, and ROM123a instead of ROM123
Is provided in place of the personal computer 120, has a processor 130a in place of the processor 130, and has a parameter ROM 1 in place of the parameter ROM 132.
A printer 12 having 32a and having a program ROM 133a instead of the program ROM 133.
1a is provided in place of the printer 121.

The correspondence between the present embodiment and the block diagrams shown in FIGS.
(Processor 130a and external interface 13
1) corresponds to the separation processing means 11, and is a processor 122a.
Corresponds to the encoding means 13 and 21 and the image information processing means 31, the processor 122a and the printer interface 127 correspond to the printer interface means 33, the parameter ROM 132a and the bitmap RA.
M135 corresponds to the storage means 41, 51, 61, the processor 130a and the work RAM 134 correspond to the gradation conversion means 43, 53, 63, and the processor 130a, the drive section 136, the density conversion sections 139-C, 139-M, 139-Y,
139-K and engine 140 are printing means 45, 55,
The bit map RAM 135 corresponds to the memory 71.
Corresponding to.

FIG. 5 is an operation flowchart of this embodiment corresponding to the inventions described in claims 1 to 4. Figure 6
It is an operation | movement flowchart of this embodiment corresponding to invention of Claims 5-9. FIG. 7 is a diagram for explaining the operation of this embodiment corresponding to the invention described in claims 5, 6, and 9.

Hereinafter, referring to FIGS. 4 to 7, claims 4 to 7 will be described.
The operation of this embodiment corresponding to the invention described in 1) will be described.
The feature of this embodiment is that the personal computer 120a is used.
In the procedure, there are a sending process performed by the processor 122a and a tone conversion process and a drive process performed by the processor 130a in the printer 121a.

In the personal computer 120a, R
In the OM 123a, the same program as the program stored in advance in the ROM 123 shown in FIG. 10 is stored in advance together with the BIOS that implements the following processing. Also, RA
In M124, an arrangement of dots to be actually printed based on the area gradation method with respect to a gradation value that can be taken by each pixel to be printed (hereinafter, referred to as “pixel gradation value”),
A table that gives an array of gradation values (hereinafter, referred to as “dot gradation values”) that each dot should have is stored in advance.

When printing the image information generated during the execution of the application system, the processor 122a delivers the image information to the above-mentioned BIOS via the OS.

The image information transferred in this way is under the BIOS executed by the processor 122a, and the pixel level corresponding to each of the four color components (hereinafter, for simplicity, it is assumed that there are only three primary colors). It is converted into a string of key values (Fig. 5 (1)). Further, the processor 12
2a continues the execution of the same BIOS, and in the process, for each pixel gradation value obtained as the above-mentioned row while being associated with each primary color, the pixel gradation value is used as a key for the above-mentioned operation. By referring to the table
For example, as shown in FIGS. 8A to 8C, the corresponding dot arrangement (here, for simplicity, it is assumed that each dot is given by a square matrix of 4 dots × 4 dots). , The dot gradation value of these dots (here,
For the sake of simplicity, an array of "0" to "255 (= 2 ⁸ -1) is assumed to be taken." (FIG. 5).
(2)).

The processor 122a also sums up the dot gradation values ΣC (= 1946), ΣM (= 2697), ΣY (= 243) for each of such dot gradation value arrays.
(FIG. 5 (3)), and by rounding off the ratio between the sum of these values and the maximum value (= 255) of the above-mentioned dot gradation values, the values individually corresponding to the three primary colors (hereinafter referred to as “gradation A code value ") is calculated (FIG. 5 (4)).

Further, the processor 122a individually converts the gradation code values calculated in this way into hexadecimal codes (for example, "8", "B", "1") (FIG. 5 (5)). ),
By arranging these hexadecimal codes in order of cyan, magenta, and yellow, the codeword (= 8B
1) is generated (FIG. 5 (6)), and these code words are sent to the printer 121a via the printer interface 127.
"Sending process" by sending to the target (Fig. 5 (7))
I do.

On the other hand, in the printer 121, the parameter R
In the OM 132a, a gradation code-dot arrangement conversion table that actually gives "arrangement of dots to be printed based on the area gradation method" for the "gradation code value" of each pixel to be printed (Hereinafter, simply referred to as “table”) is stored in advance.

The processor 130a is a program ROM
By executing the program stored in the 133a in advance, the sequence of code words sent from the personal computer 120a as described above is fetched via the external interface 131, and these are stored in the buffer area provided in the work RAM 134 in advance. The sequence of code words is stored (FIG. 6 (1)).

Further, the processor 130a analyzes the sequence of code words thus stored in the buffer area (FIG. 6 (2)), and the content indicates information other than characters such as a photograph or a line drawing. Is recognized, the above-mentioned table is set for each pixel of the image information indicated by the sequence of the codeword (hereinafter, it is assumed that the three primary colors are individually corresponded in the same manner as in the conventional example) using the gradation code value as a key. By referring to (FIG. 6 (3), FIG. 7 (1), and (2)), image information in a format corresponding to the arrangement of the printing surface is generated (FIG. 6 (4), FIG. 7 (3)), and the image information is generated. The "gradation conversion process" is performed by storing the image information in the bitmap RAM 135 (FIG. 6 (5)).

The processor 130a is driven by the drive unit 136.
And density converters 139-C, 139-M, 139-Y, 13
Drive processing for driving the engine 140 via 9-K (see FIG. 6).
Since (6)) is the same as the conventional example, its description is omitted here. As described above, according to the present embodiment, the image information is converted into the shortest code indicating the number of dots to be filled based on the area gradation method for each pixel giving the image information, and then the personal computer 120a outputs the image information. The data is sent to the printer 121a.

Therefore, the personal computer 12
At 0a, the amount of image information to be printed is reliably compressed, and the image information is efficiently sent to the printer 121a. Further, in the printer 121a, in place of the table provided in the parameter ROM 132 in the conventional example, a gradation code-dot arrangement conversion table having a size significantly smaller than that table is provided, and the procedure of the gradation conversion processing is greatly changed. Printing is efficiently performed without causing any significant changes.

Hereinafter, referring to FIG. 4 to FIG.
The operation of this embodiment corresponding to the invention described in 1) will be described.
The difference between the present embodiment and the embodiment corresponding to the invention described in claims 1, 5, and 6 is that the personal computer 120
The procedure is a sending process performed by the processor 122a in a and a gradation conversion process performed by the processor 130a in the printer 121a.

In the personal computer 120a, R
In the OM 123a, the same program as the program stored in advance in the ROM 123 shown in FIG. 10 is stored in advance together with the BIOS that implements the following processing. Also, RA
In M124, the arrangement of dots to be printed based on the combination of the area gradation method and the density gradation method with respect to the pixel gradation value that can be taken by each pixel to be printed,
A table that gives an array of dot density gradation values to be taken by each dot is stored in advance.

When printing the image information generated during the execution of the application system, the processor 122a delivers the image information to the above-mentioned BIOS via the OS. The image information delivered in this way is stored in the BIOS executed by the processor 122a.
Is converted into a column of pixel gradation values corresponding to each of the four color components (hereinafter, for simplicity, it is assumed that there are only three primary colors) (FIG. 5 (1)).

Further, the processor 122a has the same B
The execution of IOS is continued, and in the process, for each pixel gradation value obtained as the above-mentioned column while being associated with each primary color, the table described above is referred to by using the pixel gradation value as a key. By doing so, the arrangement of the corresponding dots and the array of dot gradation values of these dots are acquired (FIG. 5 (2)).

The processor 122a also sums up the dot gradation values ΣC (= 1946), ΣM (= 2697), ΣY (= 243) for each of such dot gradation value arrays.
And the product of the sum of these and the maximum value of the density gradation for each dot to which the printer 121a applies and the ratio of the maximum value (= 255) of the above-mentioned dot gradation value are rounded off to obtain the three primary colors. A value (hereinafter, referred to as “multi-value gradation code value”) individually corresponding to is calculated (FIG. 5A).

Further, the processor 122a individually converts the multi-value gradation code values calculated in this way into hexadecimal codes (for example, "17", "20", "3") (see FIG. 5)), these hexadecimal codes are arranged in order of cyan, magenta, and yellow in order to generate codewords (= 17203) (FIG. 5 (6)), and these are also transmitted via the printer interface 127. By sending out the code word of the above to the printer 121a (FIG. 5 (7)), the "sending process" is performed.

On the other hand, in the printer 121, the parameter R
In the OM 132a, a multi-value gradation code-dot arrangement conversion table that gives the arrangement of dots to be actually printed based on the area gradation method for the multi-value gradation code value of each pixel to be printed. (Hereinafter, simply referred to as “table”) is stored in advance. The processor 130a uses the program R
By executing the program stored in advance in the OM 133a, the sequence of code words sent from the personal computer 120 as described above is fetched via the external interface 131, and these are stored in the buffer area provided in the work RAM 134 in advance. The sequence of code words is stored (FIG. 6 (1)).

Further, the processor 130a analyzes the sequence of code words thus stored in the buffer area (FIG. 6 (2)), and the content indicates information other than characters such as a photograph or a line drawing. Is recognized, the above-mentioned table is referred to for each pixel (hereinafter, it is assumed to correspond to the three primary colors individually) of the image information indicated by the sequence of the code word, using the multi-value gradation code value as a key ( (Fig. 6 (3))
As a result, image information in a format corresponding to the layout of the printing surface is generated (FIG. 6 (4)), and the image information is stored in the bitmap RAM1.
"Gradation conversion process" by storing in 35 (Fig. 6 (5))
I do.

The processor 130a is driven by the drive unit 136.
And density converters 139-C, 139-M, 139-Y, 13
Drive processing for driving the engine 140 via 9-K (see FIG. 6).
Since (6)) is the same as the conventional example, its description is omitted here. As described above, according to the present embodiment, the image information is the sum of the gradation values to be filled with multi-valued densities based on the combination of the area gradation method and the density gradation method for each pixel giving the image information. Is converted into the shortest code indicating
It is sent from a to the printer 121a.

Therefore, the personal computer 12
At 0a, the amount of image information to be printed is reliably compressed, and the image information is efficiently sent to the printer 121a. Further, in the printer 121a, in place of the table provided in the parameter ROM 132 in the conventional example, a multi-value gradation code-dot arrangement conversion table whose size is significantly smaller than that table is provided, and the gradation conversion processing procedure is also provided. Printing can be performed efficiently without significant changes.

Hereinafter, referring to FIG. 4 to FIG.
The operation of the present embodiment corresponding to will be described. The difference between this embodiment and the embodiments corresponding to the inventions described in claims 2, 5, and 6 is that the sending process performed by the processor 122a in the personal computer 120a and the printer 121a.
In the procedure with the gradation conversion processing performed by the processor 130a.

The processor 122a uses the image information generated in the process of executing the application system as the OS.
When it is delivered via the OS, the B is delivered via the OS in the same manner as the embodiment corresponding to the invention described in claims 2, 5, and 6.
By executing IOS, the image information is converted into a column of pixel gradation values corresponding to each of the components of four colors (hereinafter, for simplicity, it is assumed that there are only three primary colors) (see FIG. 1)), in this way, for each pixel tone value obtained as the above-mentioned row while being associated with each primary color,
The corresponding dot arrangement and the array of dot gradation values of these dots are acquired (FIG. 5 (2)).

Further, the processor 122a obtains the sum ΣC, ΣM, ΣY of the dot gradation values for each of the arrays of such dot gradation values, and the sum of these ΣC, ΣM, and ΣY, and the density for each dot to which the printer 121a applies. By rounding off the ratio of the product of the maximum value of the gradation and the maximum value of the dot gradation value described above, the multi-value gradation code value individually corresponding to the three primary colors is calculated (FIG. 5 (a)). .

Further, the processor 122a, for each multi-value gradation code value calculated in this way, selects the lower two bits and these two bits of the binary code indicating the multi-value gradation code value. Cyan for all consecutive high-order bits,
Code words are sequentially generated by packing while associating magenta and yellow in this order (FIG. 5B), and these code words are sent to the printer 121a through the printer interface 127 (FIG. 5 (7)). )), The "sending process" is performed.

Regarding the operation of each part of the printer 121 which receives such a code word, when the contents of the multi-value gradation code-dot arrangement conversion table are given in advance in a format adapted to the above-mentioned code word, Since it is the same as the embodiment corresponding to the invention described in claims 2, 5 and 6, the description thereof is omitted here. As described above, according to the present embodiment, the image information is processed in the same manner as in the embodiments corresponding to the inventions according to claims 2, 5, and 6 by the area gradation method and the density scale for each pixel to which the image information is given. It is converted into the shortest code indicating the total of gradation values to be filled with multi-valued density based on the combination with the toning. Further, such image information is added with multivalued information (or binary information) indicating the density (including whether or not it should be filled) for each primary color and each pixel, and the personal computer 12 is added.
Compared with the conventional example in which the data is sent from 0 to the printer 121, the required amount of both and the transmission efficiency between them are surely increased.

Therefore, in this embodiment, high-quality printing based on the multi-value gradation method can be performed inexpensively and quickly. FIG. 9 is a diagram for explaining the operation of this embodiment corresponding to the invention described in claim 8. The present embodiment and claims 1 to 1.
The difference from the embodiment corresponding to the invention described in 7 is the procedure of gradation conversion processing performed by the processor 130a in the printer 121a.

In the printer 121a, the parameter ROM
Reference numeral 132a denotes a multi-value gradation code-dot arrangement conversion table that gives the arrangement of dots to be actually printed based on the area gradation method for the multi-value gradation code value of each pixel to be printed. (Hereinafter, simply referred to as “table”) is stored in advance. The processor 130a is a program ROM
By executing the program stored in the 133a in advance, the sequence of code words sent from the personal computer 120 as described above is fetched via the external interface 131, and these are stored in the buffer area provided in the work RAM 134 in advance. The sequence of code words is stored (FIG. 6 (1)).

Further, the processor 130a analyzes the sequence of codewords thus stored in the buffer area (FIG. 6 (2)), and the content indicates information other than characters such as a photograph or a line drawing. , The individual pixels that make up the image information represented by the sequence of codewords (below,
It is assumed that the three primary colors are individually supported. ), The above-mentioned table is referred to by using the multi-value gradation code value as a key (FIG. 6 (3)) to generate image information in a format corresponding to the arrangement of the printing surface (FIG. 6 (4)).

Further, the processor 130a stores the image information in units of a grid (hereinafter, "large grid") larger than a grid (hereinafter, "small grid") in which the dots shown in the above table are arranged. Virtually divide (Fig. 9
(a)), and the "gradation conversion process" is performed by performing the process of averaging the physical arrangement of dots in units of such a large grid (Figs. 6 (a) and 9 (b)). Complete.

Thus, according to this embodiment,
In the embodiments corresponding to the inventions described in 7 to 7, the larger the number of dots to be filled for each unit area, the lower the resolution that is reduced in exchange for the compression ratio of the image information is reduced by the internal processing performed by the processor 130a. It is surely improved compared with the embodiment of. Hereinafter, the operation of the embodiment corresponding to the invention described in claim 9 will be described with reference to FIGS. 4 and 7.

The difference in operation between this embodiment and the embodiment corresponding to the invention described in claims 1 to 7 is that the printer 121
In the procedure of the gradation conversion processing performed by the processor 130a. In the printer 121, the processor 130a
A code word string sent from the personal computer 120 is fetched via the external interface 131, and a bit is used instead of the buffer area provided in advance in the work RAM 134 in the embodiment corresponding to the invention of claims 1 to 8. The sequence of these codewords is stored in the empty area of the map RAM 135.

Further, the processor 130a executes the program stored in advance in the program ROM 133a, and in this way, the bitmap RAM 13 is executed.
When the code word sequence stored in 5 is analyzed and it is recognized that the content indicates information other than characters such as a photograph or a line drawing,
Corresponding to the layout of the printing surface by referring to the above-mentioned table using the gradation code value as a key for each pixel that constitutes the image information indicated by the code word sequence (FIGS. 7 (1) and (2)). Image information in the specified format is generated (Fig. 7 (3)),
The "gradation conversion process" is performed by storing the image information in the bitmap RAM 135 again.

The processor 130a is driven by the drive unit 136.
And density converters 139-C, 139-M, 139-Y, 13
The driving process for driving the engine 140 via 9-K is the same as that of the conventional example, and therefore its description is omitted here. Thus, according to the present embodiment, the work RAM
The method according to claim 1, wherein the buffer area is not provided in 134.
Since gradation conversion processing is performed in the same manner as the embodiment corresponding to the invention described in 8, the scale of hardware and power consumption can be reduced, and the storage area of the work RAM 134 has various added values. It can be effectively used to realize it.

In the embodiments corresponding to the inventions described in claims 2 to 5, multi-value gradation expression is performed based on the area gradation method. There is no limitation, and the density gradation method may be applied alone or these gradation methods may be used in combination. In addition, in each of the embodiments described above,
The personal computer 120a compresses and sends the image information, and the printer 121a receives the image information and prints it. However, the present invention is not limited to such a configuration and is provided in the printer 121a, for example. If the processor 130a similarly compresses the image information given through the external interface 131, the printer 121a can be reduced in size by reducing the size of the table or the like used for printing.

Further, in each of the above-described embodiments, the size of the grid to be applied is given to the processor 122a and the processor 130a in advance, but the present invention is not limited to such a configuration, and for example, the personal computer 120a and the printer 121a. The processor 130a notifies the processor 122a based on a predetermined interface procedure between the
It may be stored in advance in 2a.

Further, in each of the above-described embodiments, the processor 122a has the BIOS stored in the ROM 123a in advance.
However, the present invention is not limited to such a configuration, and may be performed by executing software stored in the ROM 123a or the RAM 124a as an OS or an application system, for example.

Further, in each of the above-described embodiments, the dots to be filled are obtained by referring to the (multi-valued) gradation code-dot arrangement conversion table, but the present invention is not limited to such a configuration and, for example, The order and number of dots to be filled for each grid may be given instead of such a (multi-valued) gradation code-dot arrangement conversion table.

Further, in each of the above-mentioned embodiments, the image information is given as a set of gradation values based on the subtractive color mixture system, but the present invention is not limited to such image information and, for example, a monochrome or additive color mixture system is used. It may be given as a set of gradation values.

[0084]

As described above, according to the first and second aspects of the invention, the sum of the gradation values for each grid is normalized by the maximum value that the gradation values can take, so that the sequence of code words Since the data is converted, the amount of information can be surely compressed regardless of the arrangement of the gradation values.

According to the third aspect of the invention, the amount of information can be significantly reduced compared to the conventional example. According to the fourth aspect of the present invention, the transmission efficiency of the image information with the printer is improved, effective sharing by a plurality of tasks and users is possible, and the efficiency of printing is improved. Claim 5
In the invention described in (3), a desired image is efficiently printed based on simple gradation conversion regardless of the arrangement and combination of gradation values given as image information.

In the inventions according to claims 6 and 7, even when the information processing apparatus is not provided with the division processing means and the encoding means, the information processing apparatus according to claim 4 and the invention according to claim 5 The amount of image information is compressed in the same manner as when the printer described in 1) is linked, the efficiency of printing is improved, and the scale of hardware is significantly reduced as compared with the conventional printer. .

According to the invention described in claim 8, under the application of the image information compression method of claims 1 to 3, the larger the sum of the gradation values for each grid is, the lower the exchange rate is for the compression rate of the image information. The possible resolution is increased compared to the printer according to claims 6 and 7. In the invention described in claim 9, the scale of hardware can be reduced.

Therefore, in the information processing system to which these inventions are applied, it is possible to improve the reliability and reduce the running cost, and it is possible to flexibly adapt to various image information and operating modes. Become.

[Brief description of drawings]

FIG. 1 is a block diagram showing the principle of the invention described in claim 4.

FIG. 2 is a principle block diagram of the invention according to claim 5;

FIG. 3 is a principle block diagram of the invention described in claims 6 to 9.

FIG. 4 is a diagram showing an embodiment corresponding to the invention described in claims 1 to 9.

FIG. 5 is an operation flowchart of the present embodiment corresponding to the invention described in claims 1 to 4.

FIG. 6 is an operation flowchart of the present embodiment corresponding to the invention described in claims 5-9.

FIG. 7 is a diagram for explaining the operation of the present embodiment corresponding to the invention described in claims 5, 6, and 9.

FIG. 8 is a diagram illustrating the assumption of compression processing.

FIG. 9 is a diagram for explaining the operation of this embodiment corresponding to the invention described in claim 8;

FIG. 10 is a diagram showing a configuration example of a conventional printer and a personal computer connected to the printer.

[Explanation of symbols]

11 Separation processing means 13, 21 Encoding means 31 Image information processing means 33 Printer interface means 41, 51, 61 Storage means 43, 53, 63 Gradation conversion means 45, 55, 65 Printing means 71 Memory 120, 120a Personal computer 120c Cable 121, 121a Printer 122, 122a, 130, 130a Processor (C
PU) 123, 123a ROM 124 RAM 125 FD interface (FDINT) 126 HD interface (HDDINT) 127 Printer interface (PINT) 128 Floppy disk drive 129 Hard disk drive 131 External interface (EINT) 132, 132a Parameter ROM 133, 133a Program ROM 134 Work RAM 135 Bitmap RAM 136 Drive unit 137 Font ROM 138 Operation unit 139 Density conversion unit 140 Engine

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Claims (10)

(57) [Claims] 1. An image information indicating an image represented based on the gradation expression method of both or either of the area gradation method and the density gradation method is fetched, and the image information is read by a plurality of adjacent dots. A plurality of partial image information is generated by dividing into a unit of a grid consisting of an array, and each of the generated plurality of partial image information is converted into a gradation value of each of the plurality of dots based on the gradation representation method. A method for compressing image information, characterized in that a sequence of code words is obtained by performing an arithmetic operation for rounding a ratio between a total sum and a maximum value that a gradation value can take. 2. Image information representing an image represented based on the gradation expression method of both or either of the area gradation method and the density gradation method is fetched, and the image information is read by a plurality of adjacent dots. A plurality of partial image information is generated by dividing into a unit of a grid consisting of an array, and each of the generated plurality of partial image information is converted into a gradation value By performing a mathematical operation for rounding the ratio of the product of the total sum and the maximum value of the density gradation value based on the density gradation method to be applied to the expression of the image, and the maximum value that the gradation value can take, An image information compression method characterized by obtaining a sequence of code words. 3. The image information compression method according to claim 2, wherein for each of the obtained codewords, a predetermined number of lower bits and the remaining upper bits are separated. Compression method. 4. The image information representing an image to be printed is processed by processing the plurality of partial image information based on the image information compression method according to claim 1. Information processing, comprising: image information processing means for generating the sequence of the code words indicating the image information; and printer interface means for transmitting the sequence of the code words generated by the image information processing means to the printer. apparatus. 5. A combination of an arrangement and a gradation value of a dot to be printed for each grid based on an area gradation method and / or a density gradation method corresponding to a code word. A storage unit preliminarily stored in association with a possible value of the codeword, and a sequence of codewords transmitted by the information processing apparatus according to claim 4, and the storage unit for each of these codewords. And a gradation conversion unit that obtains a combination of the arrangement and the gradation value stored in association with each other, and printing for each grid based on the combination of the arrangement and the gradation value obtained by the gradation conversion unit. A printer comprising: a printing unit that performs printing. 6. Image information representing an image represented based on the gradation expression method of both or either of the area gradation method and the density gradation method is fetched, and the image information is read by a plurality of adjacent dots. Division processing means for generating a plurality of partial image information by dividing into a unit of a grid made of an array; and each of the plurality of partial image information generated by the division processing means, based on the gradation representation method. Encoding means for obtaining a sequence of code words by rounding the ratio between the sum of each gradation value of the dots and the maximum value that the gradation value can take; With respect to the dots to be printed for each grid, a storage unit in which a combination of the arrangement and the gradation value is stored in advance in association with the possible values of the codeword, and the codeword obtained by the encoding unit Grab columns , A gradation conversion unit that obtains a combination of an arrangement and a gradation value stored in association with the storage unit for each of these code words, and an arrangement and a gradation value obtained by the gradation conversion unit And a printing unit that prints for each grid based on a combination of 7. An image information indicating an image represented based on both or one of the area gradation method and the density gradation method is fetched, and the image information is read by a plurality of adjacent dots. Division processing means for generating a plurality of partial image information by dividing into a unit of a grid made of an array; and each of the plurality of partial image information generated by the division processing means, based on the gradation representation method. Rounds the ratio of the product of the sum of the gradation values of each dot and the maximum value of the density gradation values based on the density gradation method to be applied to the expression of the image, and the maximum value that the gradation value can take. Coding means for obtaining a sequence of code words by performing arithmetic operation, and for dots to be printed for each of the grids based on the gradation representation method, the combination of the arrangement and the gradation value is the code word. Associated with possible values Storage means stored for this purpose, and a sequence of code words obtained by the encoding means is fetched, and for each of these code words, a combination of the arrangement and the gradation value stored in association with the storage means. A printer comprising: a gradation conversion unit that obtains the above; and a printing unit that performs printing for each grid based on the combination of the arrangement and the gradation value obtained by the gradation conversion unit. 8. The printer according to claim 6 or 7, wherein the printing unit precedes printing an array of a combination of the arrangement and the gradation value obtained for each grid by the gradation conversion unit. A printer having means for averaging the deviation of the arrangement and / or the variation of the gradation value for each large grid, and dividing the unit into large grid units larger than the grid. 9. The printer according to claim 5, wherein the combination of the dot arrangement and the gradation value of each grid is stored, and these arrangements to be printed are stored. A printer comprising a memory shared by the gradation converting unit and the printing unit for storing a column of gradation values. 10. Image information indicating an image represented based on the gradation expression method of both or either of the area gradation method and the density gradation method is fetched, and the image information is read by a plurality of adjacent dots. Division processing means for generating a plurality of partial image information by dividing into a unit of a grid made of an array; and each of the plurality of partial image information generated by the division processing means, based on the gradation representation method. The gradation code value is obtained by performing an arithmetic operation that rounds the ratio of the sum of each gradation value of the dots and the maximum value that the gradation value can take,
An information processing apparatus comprising: an encoding unit that converts the obtained gradation code value into a code of a predetermined base number to obtain a code word.