JP4280388B2 - Image processing apparatus, method, and storage medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus for printing a color image data in monochrome, relates square Ho及 beauty storage medium.
[0002]
[Prior art]
In recent years, with the improvement of computer hardware, it has become possible to handle complex data such as color images having multiple gradations. In particular, with the widespread use of digital cameras and the like, there are many opportunities to handle color images, and accordingly, colorization is also progressing in print output devices as image output devices.
[0003]
However, color printing output requires that the printing position of pigments of at least three colors or more be accurately aligned, and the cost of the printing mechanism may be more than three times that of the monochrome printing mechanism. Print output devices are generally more expensive than monochrome print output devices.
[0004]
A general-purpose image output device, such as a laser printer, itself has a single computer, communicates with an external device such as a host computer, receives commands and print data, and draws and develops them on a bitmap memory. Printing output is performed. Since this apparatus is a general-purpose machine, it requires some technical knowledge in use and may not be easily used. In addition, the processing of a color image with a large amount of information has many parameters to be set as compared with a monochromatic image, and the processing generally takes time and labor.
[0005]
On the other hand, even when printing color image data, color printing is not necessary depending on the contents and circumstances, and monochrome printing is often sufficient in time.
[0006]
As described above, the color print output device and the monochrome print output device tend to be used properly in consideration of necessity and cost. Ideally, it is desirable to output color images to a color print output device and monochrome images to a monochrome print output device for printing. That is, there is no problem if both color and monochrome print output devices are installed and the print device used in the host computer can be freely switched. In addition, when a monochrome image is output by a color print output device, there is no problem with respect to the output display contents, except that the cost is wasted and the print speed is slow.
[0007]
[Problems to be solved by the invention]
However, in many cases, for example, only a monochrome print output device is installed, or only the monochrome print output device is connected to the host computer. As described above, since handling of color images is generalized on a computer, there are not a few cases where a color image is printed by a monochrome print output device. In such a case, in the conventional image output apparatus, normally, only the density information is stored and the color information is discarded when the color image is converted into monochrome data for printing. As a result, various colors are converted to the same gray value. For example, if the characters and background have the same density but different colors, they are printed as approximately the same gray value, and the characters melt into the background, making it impossible to recognize the characters. .
[0008]
As long as the color information is discarded, this phenomenon is inevitable. In order to avoid this, conventionally, the user has designed the color of the color image in consideration of the density at the time of monochrome printing, which is troublesome.
[0009]
Here, in order to confirm a collision between images converted to the same gray value, it is conceivable to actually develop a color image while maintaining gradation information. However, a large storage capacity is required to hold the entire print output image, and a storage capacity of about 8 Mbytes is required to hold a binary image image of 600 dpi A3 size, for example. If an image of the entire image is to be saved as gradation data, it requires 64 Mbytes, which is 8 times as much as 256 gradations of gray, and further requires several times as much storage capacity as that of color.
[0010]
However, in general, the printing device needs to reduce the amount of expensive temporary storage memory mounted, so the entire image such as the background is saved in the bitmap format directly required by the printing mechanism, and individual drawing requests are made on the entire image. It often takes the form of drawing and developing an image of an object such as individual text. For this reason, it is not realistic in cost to make it possible to confirm on the developed image whether the gray values after color conversion match or do not match.
[0011]
In addition, with the expansion of the user group of computer-related equipment, it is required to make it easier to use even in general-purpose print output devices and to enhance convenience.
[0012]
The present invention has been made in order to solve the above, an object, an image processing apparatus capable of distinguishably monochrome printing color images while maintaining low cost, square Ho及 Beauty storage To provide a medium.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, an image processing apparatus according to claim 1 of the present invention includes a saving means for saving a bitmap image of a background image in a drawing range of an object to be processed , and the processing to the bitmap image of the background image. A drawing means for drawing a bitmap image of the target object; a bitmap image of the background image saved by the saving means; and a bitmap image of the object to be processed in the bitmap image of the background image by the drawing means Bitmap images are compared with each other and bitmap patterns are compared to obtain an exclusive OR, and the number of ON bits, which is the number of pixels having a difference, is added. Detecting means for detecting a density difference based on the area of the drawing range; and Redrawing means for correcting the density information of the object to be processed and redrawing the bitmap image of the object to be processed with the corrected density information when the output density difference is smaller than a threshold; It is characterized by having .
In order to achieve the above object, an image processing method according to claim 2 of the present invention includes a saving step of saving a bitmap image of a background image in a drawing range of an object to be processed, and the processing to the bitmap image of the background image. A drawing step of drawing a bitmap image of the target object; a bitmap image of the background image saved by the saving step; and a bitmap image of the object to be processed in the bitmap image of the background image by the drawing step Bitmap images are compared with each other and bitmap patterns are compared to obtain an exclusive OR, and the number of ON bits, which is the number of pixels having a difference, is added. A detection step for detecting a density difference based on the area of the drawing range; When the density difference detected by the detection step is smaller than a threshold value, the density information of the object to be processed is corrected, and the bitmap image of the object to be processed is redrawn with the corrected density information. And a drawing step.
In order to achieve the above object, a storage medium according to a third aspect of the present invention is a computer-readable storage medium storing a program for causing a computer to execute the image processing method, and the image processing method includes: Saved by saving the bitmap image of the background image in the drawing range of the target object, drawing step for drawing the bitmap image of the object to be processed in the bitmap image of the background image, and saved by the saving step In addition, the bitmap image is compared with the bitmap image of the background image and the bitmap image in which the bitmap image of the object to be processed is drawn on the bitmap image of the background image by the drawing step. Take the sum and have a difference A detection step of integrating the number of ON bits, which is the number of cells, and detecting a density difference based on the integrated number of ON bits and the area of the drawing range; and the density difference detected by the detection step is a threshold value If smaller, the density information of the object to be processed is corrected, and a redrawing step of redrawing the bitmap image of the object to be processed with the corrected density information is provided.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0040]
(First embodiment)
The first embodiment exemplifies a case where the image processing apparatus is configured as a monochrome printing apparatus that can be connected to an external device such as a host computer.
[0041]
FIG. 1 is a block diagram showing the configuration of the image processing apparatus according to this embodiment. This apparatus includes a CPU 201 (first development means, second development means, correction means, re-deployment means), ROM 202, RAM 203, print interface 204, external device interface 205 (reception means), and comparison unit 206 (density detection means). ) Are connected to each other via a bus line 300.
[0042]
The CPU 201 controls the entire apparatus, and performs various image processing, input / output control, and the like. The ROM 202 stores a control program executed by the CPU 201 and various data. The ROM 202 also stores a color conversion table 212 described later. The RAM 203 temporarily stores print commands and print data sent from the outside, and is also used as an operation work area of the CPU 201. In the RAM 203, a first expansion area 211 (a part of the first expansion means) and a second expansion area 210 (a part of the second expansion means) described later are secured.
[0043]
The printing interface 204 is an interface with a printing mechanism (printing means, not shown). The external device interface 205 is an interface with an external device such as a host computer. A print command, print data, and the like are received from an external device via the external device interface 205, converted to a print image, output from the print interface 204, and printed.
[0044]
The comparison unit 206 compares the bitmap images stored in the first development area 211 and the second development area 210 as will be described later.
[0045]
The color image data handled by this device includes drawing objects such as text, image images, and graphic images. Images of individual drawing objects (other image data) are drawn and expanded on the entire image that is the background image. Is output.
[0046]
The first development area 211 stores a bitmap image of a background image (specific image data) (not including a drawing object) in a drawing object area of the drawing object. The second development area 210 stores a bitmap image obtained by developing a drawing object and a background image.
[0047]
FIG. 2 is a diagram showing a flowchart of the drawing process in the present embodiment.
[0048]
There may be a plurality of drawing objects, but in this process, each one is processed. First, a drawing object waiting for drawing processing is taken out from the RAM 203 (step S201), and it is determined whether or not the drawn drawing object is a drawing object to be processed in this processing (step S202). That is, when performing gray value adjustment processing, it is not possible to simply execute this processing for all drawing objects. For example, in the case of an image image or a graphics image with a filled area, if this process is performed, there is a high possibility that the color output will be improperly changed, so it is excluded from the processing target in this embodiment. However, these can be processed. In the present embodiment, a drawing object such as text data is a processing target.
[0049]
If it is determined in step S202 that the extracted drawing object is not a drawing object to be processed in this process, the drawing object is drawn as it is (step S203), and whether or not a drawing object waiting to be processed remains. Is determined (step S204). If the result of the determination is that there are still drawing objects waiting to be processed, the process returns to step S202. On the other hand, if there are no drawing objects waiting to be processed, this process is terminated.
[0050]
On the other hand, if it is determined in step S202 that the extracted drawing object is a drawing object to be processed in this process, a bitmap image of the background image in the drawing range (drawing target area SP) of the drawing object. Is saved in the first development area 211 (step S205).
[0051]
FIG. 3 is a diagram illustrating an example of a bitmap pattern. FIG. 4A shows a bitmap image of the background image stored in the second development area 210. In FIG. 9A, the drawing target area SP corresponds to the drawing range of the drawing object to be processed. FIG. 4B shows a bitmap image of the background image in the drawing target area SP, and this image is saved in the first development area 211. FIG. 4C shows a bitmap image when the drawing object is developed and drawn as it is on the background image, and the image is stored in the second development area 210. FIG. 4D is a diagram showing a comparison result (density difference K) described later between the bitmap image shown in FIG. 4B and the bitmap image shown in FIG.
[0052]
Returning to FIG. 2, in step S <b> 205, a bitmap image as shown in FIG. 3B is stored in the first development area 211.
[0053]
Next, the target drawing object is developed and drawn (step S206). That is, the drawing object is drawn on the background image, and a bitmap image as shown in FIG. 3C is stored in the second development area 210. Next, the threshold value P is read (step S207). This threshold value P is obtained from the color conversion table 212 stored in the ROM 202.
[0054]
FIG. 4 is a diagram illustrating an example of the contents of the color conversion table 212 stored in the ROM 202. In the color conversion table 212, a threshold value P and a correction amount Q (offset amount) are set in advance according to the density (color) value. Since the density (color) value is difficult to distinguish from the background image and the degree of density change due to correction differs, appropriate density comparison and density correction are performed according to each color.
[0055]
Returning to FIG. 2, the bitmap image of the background image in the drawing target area SP saved and saved in the first development area 211, and the bit in the drawing target area SP of the background image and drawing object saved in the second development area 210 are returned. Pixels in the map image are compared (step S208). In FIG. 3, the bitmap pattern shown in FIG. 3B is compared with the bitmap pattern in the drawing target area SP shown in FIG.
[0056]
Next, as a result of pixel comparison, a density difference K between the two is detected (step S209). In the present embodiment, as the density difference K, the coincidence rate of both pieces of pixel information per area in the drawing target region SP is employed. Since comparison between binary bitmap images is possible by taking an exclusive OR, it depends on how many integrated values of the number of ON bits (ON pixels) obtained by taking the exclusive OR are. A density difference K is detected. That is, a pixel having a difference between both bitmap patterns becomes the ON bit, and the density difference K is calculated by the density difference K = (ON bit) / (area of the drawing target area SP).
[0057]
Next, it is determined whether or not the threshold value P is greater than the density difference K (step S210). If the result of the determination is that the threshold value P ≦ the density difference K, the drawing target area saved in the first development area 211 is saved. There is a sufficient difference between the bitmap image of the background image in the SP and the background image stored in the second development area 210 and the bitmap image in the drawing target area SP of the drawing object, and the drawing object appears to melt into the background image. Since it is determined that there is no absence, the process proceeds to step S204. Accordingly, the density correction is not performed on the drawing object, and the drawing object is output with the density as it is. Referring to FIG. 3, the comparison result between the bitmap pattern shown in FIG. 3B and the bitmap pattern in the drawing target area SP shown in FIG. 3C is different as shown in FIG. Therefore, after the output, the difference can be identified by the drawing object.
[0058]
On the other hand, if the threshold value P> the density difference K as a result of the determination in step S210, there is a possibility that the drawing object will melt into the background image and not be identified if it is output as it is. I do. The correction amount Q at this time can be obtained from the color conversion table 212. The correction is performed, for example, by adding the correction amount Q to the density information.
[0059]
Next, the drawing object is drawn again with the density information after correction (step S212). As a result, the image defined by the drawing object can be identified from the background image. The re-developed bitmap image is written in the second development area 210. Thereafter, the process proceeds to step S204. Note that the bitmap image written in the second development area 210 is output from the print interface 204 and printed.
[0060]
According to the present embodiment, when the density of the drawing object is the image data of a color that approximates the density of the background image, the density information of the drawing object is corrected and the drawing is performed. It is possible to avoid being indistinguishable by melting into an image. In addition, since it is not necessary to increase the mounting memory for developing and saving a color image holding gradation information, the printing mechanism does not increase the cost and the printing mechanism holds only a bitmap image. Even if it exists, it is feasible. Therefore, it is possible to perform monochrome printing so that a color image can be identified while maintaining low cost.
[0061]
Further, since the density difference K is detected only in the drawing target area SP, which is an area where there is a difference in pixels, and is performed based on the pixel information coincidence rate, the detection accuracy of the density difference K can be improved. .
[0062]
Furthermore, since the density correction is performed only when the density difference K is smaller than the threshold value P, the density correction can be performed only when identification is assumed to be difficult, and wasteful processing can be reduced.
[0063]
Further, since the threshold value P and the correction amount Q are set based on the density information before the density correction of the drawing object, it is possible to appropriately determine the necessity of correction for every color of the drawing object and to determine the optimal amount. Correction can be performed.
[0064]
Furthermore, since this apparatus is configured as a printing apparatus that can be connected to an external device, it is possible to perform monochrome printing so that a color image received from a host computer or the like can be identified, and the versatility is high.
[0065]
In the present embodiment, the correction amount Q of the density information of the drawing object is obtained by referring to the color conversion table 212. Depending on the nature of the printing process, the number of pixels drawn per area and density do not necessarily correspond linearly. Therefore, the threshold value for performing the redrawing process according to the density value must be changed, and the amount of change in gradation must also be adjusted. Further, the density value can be configured to include color information. Since the density value and the correction amount are vectorized instead of a single numerical value, the size of the table becomes large, but it is possible to change the direction of the offset to be adjusted depending on the hue. In the case of such a configuration, it is changed brightly or darkly depending on the color.
[0066]
The density correction is performed only on the drawing object. However, even if it is performed on the background image or both of the drawing object and the background image, the identification can be made if the relationship between the two is limited. is there. However, in order to identify each drawing object from the background image when there are a plurality of drawing objects, it is preferable to perform density correction processing on each drawing object as in the above example.
[0067]
In addition, although demonstrated from the viewpoint of making identification with a background image and a drawing object easy, it is not restricted to these. For example, on the basis of specific image data or color, density correction may be performed on the image data or color so that the contents of other image data or color can be identified.
[0068]
The density difference K is detected in the drawing target area SP in order to increase detection accuracy. However, the present invention is not limited to this, and the density difference K may be detected in the entire area or a part of the drawing target area SP.
[0069]
(Second Embodiment)
The second embodiment of the present invention exemplifies a case where the image processing apparatus is configured as a host computer to which a monochrome printing apparatus is connected. Accordingly, processing corresponding to the above-described drawing processing (FIG. 2) is performed on the printer driver on the host computer side.
[0070]
Depending on the configuration and operation mode of the printing mechanism, the host computer may generate a complete bitmap image before sending it to the printing apparatus. In this case, it is necessary to perform image processing with a printer driver. In general, the host computer has more capacity in the main storage device and the secondary storage device than the printer. However, in practice, since the print output program is usually started as a subprocess of another application, it cannot monopolize so many resources. Further, although the secondary storage device has a large storage capacity, it is desirable to provide a page memory that is frequently rewritten in the main storage device. Therefore, the host computer also executes processing corresponding to the drawing processing (FIG. 2) on the main storage device.
[0071]
FIG. 5 is a block diagram showing the main configuration of the image processing apparatus according to this embodiment.
[0072]
This apparatus is configured by connecting a CPU 201 ′ to a printer interface 205 ′ (output means) and a main storage device 203 ′ via a bus 300 ′. The main storage device 203 ′ includes a ROM 202 ′, a RAM, and the like, and a first development area 211 ′ and a second development area 210 ′ are secured. In addition to the control program executed by the CPU 201 ′, the ROM 202 ′ stores a comparison program 206 ′ and a color conversion table 212 ′.
[0073]
The first development area 211 ′, the second development area 210 ′, and the color conversion table 212 ′ have the same functions and configurations as the first development area 211, the second development area 210, and the color conversion table 212 in the first embodiment. Have The comparison program 206 ′ is a program for executing a process corresponding to the drawing process (FIG. 2), and serves to perform the same function as the comparison unit 206 in the first embodiment.
[0074]
In this apparatus, the drawing process is executed by the CPU 201 ′, and the process is the same as the drawing process of FIG. The processed bitmap image is transferred to a printing apparatus (not shown) connected to the apparatus via the printer interface 205 and printed out by the printing apparatus.
[0075]
According to the present embodiment, the same effect as that of the first embodiment can be obtained in that the color image can be identified and printed on the printing apparatus in monochrome. In addition, since the density correction processing is performed on the host computer side, any connected monochrome printing apparatus can perform identifiable monochrome printing.
[0076]
Note that the image processing system can be configured by connecting the monochrome printing apparatus as the image processing apparatus in the first embodiment to an external device such as a host computer. An image processing system can also be configured by connecting a monochrome printing apparatus to a host computer as an image processing apparatus in the second embodiment of the invention.
[0077]
Note that a storage medium in which a program code of software that realizes the functions of the above-described embodiments is recorded is supplied to the image processing apparatus, and a computer (or CPU or MPU) of the image processing apparatus is stored in the storage medium. It goes without saying that the object of the present invention can also be achieved by reading and executing the code.
[0078]
In this case, the program code itself read from the storage medium realizes the novel function of the present invention, and the storage medium storing the program code constitutes the present invention.
[0079]
As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, or the like can be used.
[0080]
In addition, the functions of the above-described embodiments are realized by executing the program code read by the computer, and an OS or the like running on the computer is actually processed based on an instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the above and the processing thereof is included.
[0081]
Furthermore, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function is determined based on the instruction of the program code. It goes without saying that the CPU or the like provided in the expansion board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.
[0082]
【The invention's effect】
As described above, according to this onset bright, it is possible to distinguishably monochrome printing color images while maintaining low cost.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a flowchart of a drawing process in the same form.
FIG. 3 is a diagram showing an example of a bitmap pattern in the same form.
FIG. 4 is a diagram showing an example of contents of a color conversion table stored in a ROM in the same form.
FIG. 5 is a block diagram showing a main configuration of an image processing apparatus according to a second embodiment of the present invention.
[Explanation of symbols]
201 CPU (first expansion means, second expansion means, correction means, re-expansion means)
202 ROM
203 RAM
204 Printing interface 205 External device interface (reception means)
206 Comparison part (concentration detection means)
210 Second development area (part of second development means)
211 1st expansion | deployment area | region (a part of 1st expansion | deployment means)
212 color conversion table 201 ′ CPU (first developing means, second developing means, density detecting means, correcting means, re-developing means)
205 'Printer interface (output means)
203 ′ main storage device 211 ′ first expansion area (part of first expansion means)
210 ′ second expansion region (part of second expansion means)
206 'comparison program 212' color conversion table

Claims (3)

Saving means for saving a bitmap image of a background image in a drawing range of an object to be processed;
Drawing means for drawing the bitmap image of the object to be processed on the bitmap image of the background image;
Bitmap patterns between the bitmap image of the background image saved by the saving unit and the bitmap image in which the bitmap image of the object to be processed is drawn on the bitmap image of the background image by the drawing unit. Detection means for taking an exclusive OR for comparison, integrating the number of ON bits, which is the number of pixels having a difference, and detecting a density difference based on the integrated number of ON bits and the area of the drawing range When,
When the density difference detected by the detection means is smaller than the threshold value, the density information of the object to be processed is corrected, and the bitmap image of the object to be processed is redrawn with the corrected density information. An image processing apparatus comprising: a drawing unit . A saving step for saving a bitmap image of the background image in the drawing range of the object to be processed;
A drawing step of drawing a bitmap image of the object to be processed on the bitmap image of the background image;
Bitmap patterns between the bitmap image of the background image saved by the saving step and the bitmap image in which the bitmap image of the object to be processed is drawn on the bitmap image of the background image by the drawing step. Detection step of comparing and taking exclusive OR, integrating the number of ON bits that are the number of pixels having a difference, and detecting a density difference based on the number of ON bits integrated and the area of the drawing range When,
When the density difference detected by the detection step is smaller than a threshold value, the density information of the object to be processed is corrected, and the bitmap image of the object to be processed is redrawn with the corrected density information. An image processing method comprising: a drawing step. A computer-readable storage medium storing a program for causing a computer to execute an image processing method,
The image processing method includes:
A saving step for saving a bitmap image of the background image in the drawing range of the object to be processed;
A drawing step of drawing a bitmap image of the object to be processed on the bitmap image of the background image;
Bitmap patterns between the bitmap image of the background image saved by the saving step and the bitmap image in which the bitmap image of the object to be processed is drawn on the bitmap image of the background image by the drawing step. Detection step of comparing and taking exclusive OR, integrating the number of ON bits that are the number of pixels having a difference, and detecting a density difference based on the number of ON bits integrated and the area of the drawing range When,
When the density difference detected by the detection step is smaller than a threshold value, the density information of the object to be processed is corrected, and the bitmap image of the object to be processed is redrawn with the corrected density information. And a drawing step.

Images