JP6344617B2 - Image processing device - Google Patents

Description

  The present invention relates to an image processing apparatus.

  An image processing apparatus such as an image forming apparatus adds attribute information to each pixel in an image, and performs processing corresponding to the attribute information on the pixel (see, for example, Patent Document 1).

JP 2011-4277 A

  In the image processing apparatus, when image data is transferred from the first device to the second device and the second device performs processing according to the attribute information as described above, in addition to the image data indicating the image, Attribute information needs to be transferred from the first device to the second device.

  Therefore, when image data is transferred by parallel communication, a signal line for transferring attribute information is usually used in addition to a signal line for transferring image data. For example, when the image data is 4-bit data, four signal lines are used for transferring the image data, and when the attribute information is 1-bit data, another signal line is used for transferring the attribute information. used. In this way, when attribute information is transferred between devices, a signal line different from the image data transfer signal line is required, which increases the cost of the apparatus.

  Even when image data is transferred by serial communication, the attribute information is transferred in addition to the image data, which increases the amount of data to be transferred.

  The present invention has been made in view of the above problems, and an object thereof is to obtain an image processing apparatus that suppresses an increase in apparatus cost due to transfer of attribute information between devices.

  An image processing apparatus according to the present invention includes a transmitting device that transmits image data and a receiving device that receives the image data. The transmitting device includes a first image processing unit that performs screen processing on a halftone area in the image data, and a plurality of pixels including a target pixel to which the attribute information is to be added in the image data after the screen processing An attribute information adding unit that changes the density pattern to a specific density pattern and adds the attribute information, and an image data transmitting unit that transmits the image data after the attribute information is added. The receiving device includes: an image data receiving unit that receives the image data after the attribute information is added; an attribute information detecting unit that detects a plurality of pixels having the specific density pattern in the received image data; A second image processing unit that performs predetermined image processing on the target pixel in the plurality of pixels detected by the attribute information detection unit. The specific density pattern is a density pattern other than all density patterns that appear in a plurality of pixels by the screen processing.

  According to the present invention, it is possible to obtain an image processing apparatus that suppresses an increase in apparatus cost due to transfer of attribute information between devices.

  These and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of screen growth. FIG. 3 is a diagram illustrating an example of the specific density pattern. FIG. 4 is a diagram for explaining processing executed by the image processing apparatus shown in FIG. 1 (1/2). FIG. 5 is a diagram for explaining processing executed by the image processing apparatus shown in FIG. 1 (2/2).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to an embodiment of the present invention. The image processing apparatus shown in FIG. 1 is built in an image forming apparatus such as a printer or a multifunction peripheral, and includes a transmission side device 1 and a reception side device 2.

  Here, the transmission side device 1 is a controller ASIC (Application Specific Integrated Circuit), and is an integrated circuit that executes predetermined image processing such as screen processing. The receiving device 2 is an engine ASIC, and is an integrated circuit that controls an electrophotographic development process such as a photosensitive drum and an exposure device. The transmission side device 1 and the reception side device 2 are connected to each other by a signal line 3, and image data after screen processing is supplied from the transmission side device 1 to the reception side device 2 via the signal line 3. The number of signal lines 3 is the same as the number of bits (for example, 4 bits) of the image data after screen processing, and the image data after screen processing is transferred via the signal line 3 by parallel communication.

  The transmission side device 1 includes an image processing unit 11, an attribute information addition unit 12, and an image transmission unit 13.

  The image processing unit 11 performs image processing necessary for printing such as color conversion and screen processing on the image data. In particular, the image processing unit 11 extracts a halftone area (for example, a gradation area such as a photographic area) in an image based on the image data, and performs screen processing on the extracted halftone area.

  The attribute information adding unit 12 changes the density pattern of a plurality of pixels including the target pixel to which the attribute information should be added in the image data after the screen processing described above to a specific density pattern, and adds the attribute information to the image data.

  Here, the specific density pattern is a density pattern other than all density patterns appearing in a plurality of pixels by screen processing.

  FIG. 2 is a diagram illustrating an example of screen growth. In the screen processing, for example, as shown in FIG. 2, each pixel in the image data is converted into a screen pattern corresponding to the pixel value (that is, density). Since the screen pattern is set in advance, a density pattern that does not appear as a screen pattern can be specified in advance. FIG. 3 is a diagram illustrating an example of the specific density pattern. One density pattern that does not appear as a screen pattern is used as a specific density pattern used to add attribute information. For example, in the case of the screen pattern shown in FIG. 2, for example, the density pattern shown in FIG. 3 is used as the specific density pattern. In the specific density pattern shown in FIG. 3, the density is arranged in the order of density zero, intermediate density, and maximum density in three pixels along the main scanning direction.

  As shown in FIGS. 2 and 3, the screen pattern and the specific density pattern are expressed by an array of densities having a predetermined number of gradations (for example, 16) (including density zero, intermediate density, and maximum density). In FIG. 2 and FIG. 3, pixels with zero density are expressed in white, pixels with maximum density are expressed in black, and pixels with intermediate density are expressed in hatches.

  The image transmission unit 13 transmits the image data to which the attribute information has been added to the reception-side device 2 via the signal line 3 for each pixel along the scanning direction. The transmission side device 1 transmits the image data to which the attribute information has been added to the reception side device 2 through the same number of signal lines 3 as the number of bits of the image data.

  The receiving device 2 includes an image data receiving unit 21, an attribute information detecting unit 22, and an image processing unit 23.

  The image data receiving unit 21 receives the image data to which the attribute information has been added from the transmitting device 1 via the signal line 3.

  The attribute information detection unit 22 detects a plurality of pixels having the specific density pattern described above in the received image data.

  The image processing unit 23 performs predetermined image processing on a target pixel (at a predetermined position) in a plurality of pixels detected by the attribute information detection unit 22.

  Further, in the transmission side device 1, the attribute information adding unit 12 selects a specific density pattern corresponding to the attribute information to be added from a plurality of specific density patterns, adds the attribute information with the selected specific density pattern, and receives it. In the side device 2, the image processing unit 23 selects the image processing corresponding to the detected specific density pattern (that is, selected by the attribute information adding unit 12) with respect to the target pixel in the plurality of pixels having the detected specific density pattern. Image processing corresponding to the specific density pattern) may be executed.

  Further, the image processing unit 23 returns the density changed when the attribute information adding unit 12 changes the density pattern of the plurality of pixels to the specific density pattern to the original density.

  The receiving device 2 controls the electrophotographic development process based on the image data after the image processing by the image processing unit 12.

  In this embodiment, the pixel of interest (that is, a pixel to which attribute information is added) is, for example, a pixel in a line drawing such as a character, and the image processing unit 23 performs attention in a plurality of pixels having the detected specific density pattern. Thinning processing is performed on the pixel. The thinning process is executed, for example, to reduce toner consumption. For example, among the plurality of pixels having the specific density pattern, the pixel having the maximum density is set as the target pixel, and the density of the target pixel is lowered in the thinning process. For example, by using a specific density pattern extending in the main scanning direction as shown in FIG. 3, the width of the line extending in the main scanning direction is narrowed by the thinning process. Further, by using the specific density pattern extending in the sub-scanning direction, the width of the line extending in the sub-scanning direction is narrowed by the thinning process.

  Next, the operation of the image processing apparatus will be described.

  In the transmission-side device 1, the image processing unit 11 outputs the image data after the halftone area is screen-processed. The attribute information adding unit 12 converts the density pattern of a plurality of predetermined pixels around the target pixel into a specific density pattern corresponding to the attribute information, for example, using the edge of the line drawing as the target pixel in the image data, and thus the attribute Output image data with added information. The image data transmission unit 13 transmits the image data to which the attribute information is added via the signal line 3.

  On the other hand, in the receiving device 2, the image data receiving unit 21 receives and outputs image data transmitted via the signal line 3. The attribute information detection unit 22 detects a specific density pattern in the received image data, and notifies the image processing unit 23 of the positions of a plurality of pixels where the specific density pattern is detected.

  The image processing unit 23 specifies the position of the target pixel in the received image data based on the detected positions of the plurality of pixels, and executes predetermined image processing on the target pixel. At this time, since the specific density pattern is not detected from the halftone area subjected to the screen processing, this image processing is not executed for such a halftone area.

  Here, as an example, a case will be described in which the image processing unit 23 executes the thinning process on the target pixel in the receiving device 2.

  4 and 5 are diagrams for explaining processing executed by the image processing apparatus shown in FIG.

  In the transmission-side device 1, as shown in FIG. 4, the pixel value of a pixel belonging to a line drawing that is a solid image included in the original image after the screen processing is 15 (maximum value). Here, the pixel density is represented by 4 bits. Then, the density of pixels adjacent to the edge (here, the target pixel) is changed from zero to 1 so that the density pattern of the plurality of pixels around the edge of the original image becomes the specific density pattern shown in FIG. To intermediate density). In this way, the image data with the specific density pattern added around the edge is transmitted to the receiving device 2.

  In the receiving device 2, a specific density pattern is detected in the image data, and among the plurality of pixels of the specific density pattern, the density of the edge pixel (that is, the target pixel) is reduced from 15 to 8, and the adjacent pixel of the edge The concentration of is returned from 1 to zero.

  In this way, thinning is performed in the receiving device 2 with respect to the pixel designated in the transmitting device 1.

  As shown in FIG. 5, when the pixel adjacent to the edge has an intermediate density (5 in FIG. 5), the image data is transmitted to the receiving device 2 without changing the pixel density in the transmitting device 1. Then, the thinning process is performed on the edge as in the case of FIG.

  As described above, according to the above-described embodiment, in the transmission-side device 1, the image processing unit 11 performs screen processing on the halftone area in the image data, and the attribute information adding unit 12 performs processing after the screen processing. In the image data, the density pattern of a plurality of pixels including the target pixel to which the attribute information is to be added is changed to a specific density pattern, the attribute information is added, and the image data transmitting unit 13 receives the image data after the attribute information is added Is transmitted to the receiving device 2. In the receiving device 2, the image data receiving unit 21 receives the image data, the attribute information detecting unit 22 detects a plurality of pixels having a specific density pattern in the received image data, and the image processing unit 23 Predetermined image processing is executed on the target pixel in the plurality of pixels detected by the attribute information detection unit 22. The above-described specific density pattern is a density pattern other than all density patterns that appear in a plurality of pixels by the above-described screen processing.

  As a result, it is not necessary to install a separate signal line for transferring attribute information, so that an increase in apparatus cost due to transfer of attribute information between the devices 1 and 2 can be suppressed.

  Various changes and modifications to the above-described embodiment will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing its intended advantages. That is, such changes and modifications are intended to be included within the scope of the claims.

  For example, in the above embodiment, as shown in FIG. 3, the density pattern arranged in the order of zero density, intermediate density, and maximum density along the main scanning direction does not appear in the screen pattern. For example, when a density pattern arranged in the order of maximum density, intermediate density, and density zero along the main scanning direction does not appear in the screen pattern, such a density pattern is What is necessary is just to use as a specific density pattern.

  The present invention is applicable to, for example, an image processing apparatus in an image forming apparatus.

DESCRIPTION OF SYMBOLS 1 Transmission side device 2 Reception side device 11 Image processing part (an example of 1st image processing part)
DESCRIPTION OF SYMBOLS 12 Attribute information addition part 13 Image data transmission part 21 Image data reception part 22 Attribute information detection part 23 Image processing part (an example of a 2nd image processing part)

Claims (6)

A sending device that sends image data;
A receiving device for receiving the image data,
The transmitting device is:
A first image processing unit that performs screen processing on a halftone area in the image data;
By changing the density pattern of a plurality of pixels including a target pixel to be added with attribute information Te the image data smell after the screen processing to a specific concentration pattern, the attribute information adding unit that adds the attribute information,
An image data transmission unit that transmits the image data after the attribute information is added,
The receiving device is
An image data receiving unit for receiving the image data after the attribute information is added;
An attribute information detection unit for detecting a plurality of pixels having the specific density pattern in the received image data;
A second image processing unit that performs predetermined image processing on a target pixel in the plurality of pixels detected by the attribute information detection unit;
The specific density pattern is a density pattern other than all density patterns appearing in a plurality of pixels by the screen processing;
An image processing apparatus.



  The said 2nd image process part performs the image process corresponding to the said specific density pattern detected with respect to the attention pixel in the said several pixel detected by the said attribute information detection part. The image processing apparatus described.   The said 2nd image process part returns the density | concentration changed when changing the density pattern of the said several pixel to a specific density pattern by the said attribute information addition part, The original density | concentration is characterized by the above-mentioned. 2. The image processing apparatus according to 2.   4. The receiving device according to claim 1, wherein the receiving device is an integrated circuit that controls an electrophotographic development process based on the image data after the image processing of the second image processing unit. The image processing apparatus of any one of them.   The transmission side device transmits the image data to which the attribute information has been added to the reception side device through the same number of signal lines as the number of bits of the image data. The image processing device according to claim 1. The target pixel is a pixel in a line drawing,
The second image processing unit performs a thinning process on a target pixel in a plurality of pixels having the detected specific density pattern;
The image processing apparatus according to claim 1, wherein:

Images