JPH07273982A - Image forming device - Google Patents

Abstract

PURPOSE:To improve the picture quality of an image picture without deteriorating the picture quality of a font graphic picture by performing conversion into similar multi-valued data and printing the image picture with gradations only when the image picture is discriminated. CONSTITUTION:Input picture data stored in a storage means 6 are outputted sequentially and a picture discrimination means 7 discriminates a bit map picture to be outputted whether it is a font graphic image or an image picture as to pixels in. Only when the image picture is decided, a picture processing means 8 performs similar binary-tomulti-valued conversion processing and sends the result to a picture recording means 3, so that gradational print processing is performed. The picture discrimination is performed by comparing the number of successive black-and-white components with a specific threshold value. Thus, the font graphic picture is printed in binary mode and the image picture is printed in multi-valued mode, so that the picture quality of the image picture can be improved without lowering the picture quality of the font graphic picture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for recording an image using image data of a digital copying machine or the like.

[0002]

2. Description of the Related Art Conventionally, printers of various principles have been proposed as output terminals for personal computers, workstations, etc., but in recent years, laser beam printers used in electrophotographic processes and laser exposure technology have been particularly effective in recording speed and printing. It is superior in terms of quality and is rapidly becoming popular. Hereinafter, a conventional image forming apparatus will be described.

FIG. 10 is a block diagram of a conventional image forming apparatus. The image forming apparatus 1 comprises a controller unit 2 and an image recording means 3. The image forming apparatus 1 receives the image information transferred from the host computer 4 via the cable 9, and the image developing means 5 develops the binary bit map image to be actually printed in the image information storing means 6. When the storage in the image information storage unit 6 is completed, the image recording unit 3 starts to be activated, and the image recording unit 3 is started.
Printing is performed by outputting pulses corresponding to binary bit map image information.

[0004]

However, in the above-mentioned conventional configuration, since the binary image information is printed as it is, the image quality of the image is poor, and the similar multi-value processing is performed. However, since the entire image is processed, the font / graphics image is blurred and the image quality is deteriorated.

An object of the present invention is to solve such a problem, and an object thereof is to provide an image forming apparatus capable of improving the image quality of an image without lowering the image quality of a font / graphics image. To do.

[0006]

To this end, according to the present invention, image information storage means for storing sequentially input image data and image data stored in the image information storage means are sequentially printed. An image forming apparatus comprising an image recording unit for recording an image, the image data determining unit for determining black and white of image data stored in the image information storage unit, and the connection determination for determining black and white connection of image data. Means and image identifying means for identifying whether a font / graphics image or an image image based on whether the number of predetermined black / white connected components according to the black / white determination result of the image data is equal to or more than a predetermined threshold value. Image processing means for performing multi-value similarity on an image image is provided.

Further, the image identification means is provided with a threshold value changing means for changing the threshold value for distinguishing between the font / graphics image and the image image at a predetermined ratio when the image data is discriminated as an image image. is there.

[0008]

In the above structure, the image information accumulating means accumulates sequentially input image data, the accumulated image data is sequentially output to the image recording means, and printing is performed based on the image data to form an image. The image data output from the image information storage means is recorded by the image recording means based on the image data by normal printing in the font / graphics image and by gradation printing in the image image. As described above, the image identification means identifies the output target pixel in the bitmap image as an image image or a font / graphics image, and the image data subjected to the identification processing is given to the image processing means, and the image identified by the image processing means. Similar multi-value conversion processing from binary to multi-value is performed only on the image, and the image data subjected to the similarity multi-value conversion processing is recorded by the image recorder. The image quality of the font / graphics image is set so that the printing based on the image data by the image recording means is performed by the normal printing in the font / graphics image and the gradation printing in the image image. It is possible to obtain a high-quality image in the image without deteriorating the image quality.

Further, when the image discriminating means discriminates the image data to be processed as an image image, in the subsequent discrimination, the threshold value for discriminating the font / graphics image from the image image is changed at a predetermined ratio. By including the means, the identification result of the processing target dot influences the next identification, the image identification means easily distinguishes from the image image, and the identification accuracy of the region where the image images are connected can be improved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention, FIG. 2 is a schematic configuration diagram of image identifying means of the image forming apparatus, and FIG. 3 is a link identifying principle by the image identifying means of the image forming apparatus. FIG. 3 is a principle diagram showing a discrimination processing target dot and a surrounding thereof.

In FIG. 1, the image forming apparatus 1 is composed of a controller unit 2 and an image recording means 3. The image forming apparatus 1 converts the printer code transferred from the host computer 4 via the cable 9 into binary data by the image expansion means 5 in the controller unit 2, and the converted image data is stored in the image information storage means. Accumulate in 6.

Further, in the case of this embodiment, the image identifying means 7 is provided on the output line from the image information storage means 6 to the image recording means 3.
Also, the image processing means 8 is provided. When the multi-value gradation mode is set, the image identifying means 7 identifies the image image of the image data output from the image information accumulating means 6 and the font / graphics image, and then causes the image processing means 8 to operate. Forward. The image processing means 8 performs multi-value gradation processing only on the image image portion of the image data output from the image identification means 7, then transfers it to the image recording means 3, and image formation in the multi-value gradation mode is performed. . If the multi-value gradation mode is not set, the image identification means 7 and the image processing means 8 directly transfer the image data output from the image information storage means 6 to the image recording means 3 without processing, and in the normal mode. Allow image formation.

The use of the multi-value gradation mode can be executed by including a command for performing the multi-value gradation mode in the printer code transferred from the host computer 4 to the image forming apparatus 1. Alternatively, it can be executed by an input from a key on the side of the image forming apparatus 1.

The image identifying means 7 has a multi-value gradation mode identifying means 10 as shown in FIG. The multi-value gradation mode identifying means 10 determines whether or not there is a command or signal for using the multi-value gradation mode, and when it is not the multi-value gradation mode, the image data accumulated in the image information accumulating means 6 Then, the image is output to the engine I / F 16 without any processing, and the image recording means 3 forms an image based on the data stored in the image information storage means 6. In the unprocessed image formed in this case, all the image dots forming the image are printed with single-level data.

The multi-value gradation mode identifying means 10 multi-value gradation processing means 14 multi-value gradations the image data stored in the image information storage means 6 in the multi-value gradation mode. , Image data discrimination means 11, connection discrimination means 1
2. Through the processing of the identification processing means 13, the identification processing means 13
On the basis of the result of the discrimination between the image image and the font / graphics image by the above, the data discriminated as the image image is processed by the multi-value gradation processing means 14 by the engine I /
The data which is output to F16 and is identified as a font / graphics image is the image data stored in the image information storage means 6 is output to the engine I / F16, and the image is recorded by the image recording means 3 based on the processed image signal. Allow the formation to take place.

The image data discriminating means 11 detects black and white of the image in the image data, the connection discriminating means 12 detects the array of the image data of each pixel, and the discrimination processing means 13 detects the image data of each pixel. Based on the array, the font / graphics image or the image image is discriminated based on whether or not the number of predetermined black and white connected components according to the black and white determination result of the pixel to be processed is a predetermined threshold value or more. It should be noted that the image dots and the print dots are explained as corresponding one to one, but the signal processing method is not limited to this, and one image dot may be printed by a plurality of print dots. it can.

The image processing means 8 has a multi-value gradation processing means 14, a selection means 15, and an engine I / F 16 as shown in FIG.
have. The multi-value gradation processing means 14 converts the image data into a plurality of levels of data. The conversion to multi-valued conversion is performed with 9 gradations, and the 1-dot pulse output width to the image recording means 3 is 0, 1/8, 2/8, 3/8, 4/8, 5 /
Multi-value conversion is performed by converting the pulse width into 8, 6/8, 7/8, and 1.

The selecting means 15 is based on the information from the image identifying means 7 when the multi-value gradation mode is not set.
When the multi-value gradation mode is set and the processing result of the identification processing means 13 is a font / graphics image, no processing is added to the image data of the image information storage means 6 and the engine I / F 16 is processed. When the multi-value gradation mode is set and the processing result of the identification processing means 13 is an image image, the data of the multi-value gradation processing means 14 is output to the engine I / F 16. The image data obtained by the above-described signal identification and conversion is the engine I /
The image recording means 3 outputs the image data to F16, and the image recording means 3 forms an image based on the converted image data.

In the processed image formed in this case, of the image data, only the image data discriminated as an image image is converted into a plurality of levels of data and printed, and the font
The binary image information of the image data discriminated as a graphics image is printed as it is. As a result, the image quality of the image can be improved without lowering the image quality of the font / graphics image, and an image that is visually easy to see can be provided.

The image identification processing and the multi-value gradation processing are basically realized by hardware. Since both the image identification processing and the multi-value gradation processing are performed by referring to the peripheral dots of the processing target dot, the data of the peripheral dots must be read. Next, it is necessary to identify the dots to be processed on the basis of the read data and then apply the process to output the processed data to the image recording means 3. This process is divided into the following three processes, and the processes are performed in parallel. That is, the data read in the process A is latched, the target dot is subjected to the predetermined process performed by the image identifying means 7, the process target dot is subjected to the process performed by the multi-value gradation processing means 14, and the process C is performed.
Then, based on the result of the image identification means 7, a process of selecting whether the data is multi-value gradation processed data or the image data stored in the image information storage means 6 is added and output to the image recording means 3. With this method, it is possible to deal with complicated processing such that multi-value gradation processing is not completed within one video clock.

Here, the principle of the image identification processing in the image identification means 7 will be described with reference to FIG. With respect to the original image of binary data, a 5 × 5 window centering on a pixel to be subjected to the image identification processing is set, the image identification determination target dot is w22, and the upper, lower, left and right dots of the image identification processing target dot are from w00 to w.
As shown in FIG. 3, the connection A, B, C, D, E, F, G, H of the windows in eight directions is obtained. Connection A,
B, C, D, E, F, G and H are A = w00 → w11,
B = w02 → w12, C = w04 → w13, D = w24
→ w23, E = w44 → w33, F = w42 → w32,
The image data is arranged in the direction of G = w40 → w31 and H = w20 → w21. It is possible to take in information in a range close to the target dot by checking the connection with respect to the dots in the vicinity of the target dot to be subjected to the image identification process.

Based on the image data of the dots for image identification,
Switches the connection used for image identification processing. As a determination method, if the image identification processing target dot is white, a black and white concatenation number is adopted. If it is black, the number of black and white connections is adopted. If the image discrimination processing target dot is white, the discrimination processing means 13 obtains the number of black and white couplings among the couplings A, B, C, D, E, F, G, and H, which is equal to or more than a predetermined threshold value. For example, the dot for identification processing is discriminated as an image image, and if it is below the threshold value, it is discriminated as a font / graphics image. By performing this process, it is possible to identify whether the output target pixel in the bitmap image is an image image or a font / graphics image.

FIG. 4 is a schematic configuration diagram of the image identifying means of the image forming apparatus of the second embodiment of the present invention. Since only the image identifying means 7 is different from the first embodiment, this point will be described in detail and duplicated description will be omitted. The image discriminating means 7 has a multi-value gradation mode discriminating means 10, an image data discriminating means 11, a connection discriminating means 12, a discriminating processing means 13 and a threshold value changing means 17, and discriminating processing in the multi-value gradation mode. This is different from the first embodiment in that a threshold value changing means 17 is provided corresponding to the previous discrimination result of the means 13 and changing the image discrimination threshold value by a predetermined ratio according to the previous discrimination result.

Here, in the threshold value changing processing by the threshold value changing means 17, the threshold value for discriminating the font / graphics image and the image image is the previous discrimination result is the font / graphics image. Sometimes set to 3,
When it is an image image, it is set to 2. Image images have a high probability of appearing relatively continuously, so
By once determining the image image by such a process, it is easy to determine the image in the subsequent process, and thus it becomes easy to correspond to a continuous region of the image image, and the accuracy of the image identification can be improved.

FIG. 5 is a schematic block diagram of the image identifying means of the image forming apparatus of the third embodiment, and FIGS. 6, 7, 8 and 9 are flowcharts of the same operation. The image identifying means 7 is different from the first and second embodiments. First, a threshold value is set according to the relationship between the number of black pixels and the number of boundaries between black pixels and white pixels as to whether the identification processing target pixel in the image information storage means 6 is an image image or a font / graphics image, and the threshold value is set. The image discriminating means 18 for discriminating based on the reference will be described below. The image discriminating means 18 discriminates an image image from a font / graphics image by utilizing the relationship between the number of black pixels in a 7 × 7 window and the number of boundaries between black pixels and white pixels. The threshold value takes an intermediate value between the image min69 and the font / graphics ma × 71, and y =
(-0.048) * p * p + 2.35 * p. Here, p is the number of black pixels, and y is a threshold value corresponding to the number of black pixels.

Next, the operation of the above configuration will be described. As shown in FIGS. 6 to 9, the image expansion means 5 expands the bitmap image in the image information storage means 6 (step 1). The window is set so that the upper left pixel of the bitmap image in the image information storage means 6 becomes the center of the 7 × 7 window (step 2), and it is determined whether or not there is a portion where no actual pixel exists in the window. If there is no nonexistent portion, the number of black pixels in the window (step 5) and the number of boundaries between black pixels and white pixels in the window (step 6) are counted. If it is determined in step 3 that there is a portion that does not exist, the portion where no actual pixel exists in the window is a black pixel (step 4).
As a result, step 5 and step 6 are performed. Further, it is judged whether the number of boundaries between black pixels and white pixels with respect to the number of black pixels exceeds a threshold value (step 7). If the threshold is not exceeded, it is determined that the target pixel is a part of the font or graphics, and no processing is performed and the image recording means 3 is executed.
The pulse is output to (step 8). If it exceeds the threshold value, the number of black pixels in the 5 × 5 smoothing processing area 66 centered on the output target pixel is obtained (step 9). The pulse width corresponding to the number of black pixels in the smoothing area 66 is selected from the relationship of the pulse width to the number of black pixels in the smoothing processing area (step 10), and the corresponding pulse is output to the image recording means 3 (step). 11). Next, it is determined whether the bitmap image output has been completed to the end (step 12). If not completed, the window is shifted by one pixel (step 13) and the process returns to step 2. If it is finished, printing is finished.

However, the above-mentioned configuration has a problem that the image discrimination means 18 discriminates the pixel data to be processed, which is a part of the image image, from the font / graphics image. This problem is as follows. To solve.

An image information storage means 6 for storing sequentially input image data, an image recording means 3 for sequentially printing and recording an image using the image data stored in the image information storage means 6, and an image. The output target pixel is an image based on a threshold value determined based on the relationship between the number of black pixels in a predetermined processing target window in the image data stored in the information storage unit 6 and the number of boundaries between black pixels and white pixels. Image discrimination means 18 for discriminating between an image and a font / graphics image
And an image processing unit 8 for performing similar multi-valued processing on the identified image image, the image identifying unit 7 is provided, and the image identifying unit 18 sets the processing target image data to the font / graphics image. When it is determined that
Further, the image identification means 7 is used to display an image or a font.
Make sure that it is a graphics image.

More specifically, when the discrimination result of the image discriminating means 18 is an image image, the image discriminating processing determines that the image is an image regardless of the output of the discriminating processing means 13. On the other hand, when the image discrimination unit 18 discriminates the font / graphics image, the discrimination processing unit 13 further performs the processing and outputs the result. The image identification processing in this case is shown in (Table 1).

[0030]

[Table 1]

[0031]

According to the image forming apparatus of the present invention, when the image is formed by printing based on the image data, the output target pixel in the bitmap image is an image image or a font / graphics image by the image identifying means. It is possible to perform a conversion process from a binary value to a similar multi-valued value only in the image image, and without causing deterioration in the image quality of the font / graphics image, it is possible to obtain a high gradation image in the image image. A high quality image can be obtained.

Further, in the image discrimination processing, when the image data to be processed is discriminated as an image image, a threshold value for discriminating a font / graphics image from an image image is changed at a predetermined ratio in the subsequent discrimination. As a result, the image identifying means can easily distinguish the image from the image, so that it is easy to correspond to the area where the image appears continuously, and the accuracy of the image identification can be improved.

Further, the threshold value determined based on the relationship between the number of black pixels in a predetermined window to be processed in the image data stored in the image information storage means and the number of boundaries between black pixels and white pixels is output as a reference. The target pixel is an image image or font
In an image forming apparatus provided with an image discriminating means for discriminating whether the image is a graphics image, when the image discriminating means discriminates the image data to be processed as an image image, the output result of the image discriminating apparatus is When the output result of the image discrimination means is a font / graphics image, the discrimination processing means further discriminates and outputs the result so that the image discrimination means is an image image. The problem that some of the target data is determined to be a font / graphics image can be solved, and the accuracy of image identification can be further improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an image identifying unit of the image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a principle diagram showing an identification processing target dot and its surroundings showing a connection identification principle by the image identification means of the image forming apparatus of the first embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of an image identifying means of an image forming apparatus according to a second embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of image identifying means of an image forming apparatus according to a third embodiment of the present invention.

FIG. 6 is a flowchart of the operation of the image identifying means of the image forming apparatus according to the third embodiment of the present invention.

FIG. 7 is a flowchart of the operation of the image identifying means of the image forming apparatus according to the third embodiment of the present invention.

FIG. 8 is a flowchart of the operation of the image identifying means of the image forming apparatus of the third embodiment of the present invention.

FIG. 9 is a flowchart of the operation of the image identifying means of the image forming apparatus according to the third embodiment of the present invention.

FIG. 10 is a configuration diagram of a conventional image forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 image forming apparatus 2 controller unit 3 image recording means 5 image expansion means 6 image information storage means 7 image identification means 8 image processing means 10 multi-value gradation mode identification means 11 image data determination means 12 connection determination means 13 identification processing means 14 Multi-value gradation processing means 15 selection means 17 threshold value changing means 18 image discrimination means

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Claims (3)

[Claims] 1. An image information storage means for storing sequentially input image data, and an image recording means for sequentially printing and recording an image using the image data stored in the image information storage means. An image forming apparatus, comprising: an image data discriminating means for discriminating black and white of discrimination target pixels of image data accumulated in the image information accumulating means; a coupling discriminating means for discriminating black and white coupling of image data; Image discrimination means for discriminating whether the pixel to be discriminated is a font / graphics image or an image image depending on whether or not the number of predetermined black and white connected components corresponding to the black and white determination result is equal to or more than a predetermined threshold value,
An image forming apparatus comprising: an image processing unit that performs similarity multi-value conversion on the identified image image. 2. The threshold value changing means for changing the threshold value for distinguishing between the font / graphics image and the image image at a predetermined ratio when the image identifying means discriminates the image data as the image image. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. 3. Image information storage means for storing sequentially input image data, image recording means for sequentially printing and recording images using the image data stored in the image information storage means, and the image. The output target pixel is an image pixel based on a threshold value determined by the relationship between the number of black pixels in a predetermined processing target window in the image data stored in the information storage means and the number of boundaries between black pixels and white pixels. Or font
An image forming apparatus, comprising: an image determination unit for identifying whether it is a graphics image and an image processing unit for performing similarity multi-value conversion on the identified image image. Image discrimination means for discriminating whether the pixel to be discriminated is a font / graphics image or an image image based on whether or not the number of black and white connected components is equal to or more than a predetermined threshold value is provided, and the image discrimination means fonts the image data to be processed. An image forming apparatus characterized in that, when the image is determined to be a graphics image, the image identification means determines whether it is an image image or a font / graphics image.