JP4743817B2 - Image processing apparatus and image processing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image processing apparatus and an image processing method, and in particular, data of each pixel in a recording apparatus that performs recording by moving a recording head having a plurality of recording elements arranged in a predetermined direction relative to a recording medium. The present invention relates to image processing for converting data into data having a smaller number of gradations than the number of input gradations.
[0002]
[Prior art]
For example, as information output devices in word processors, personal computers, facsimiles, etc., there are various types of recording devices that record information such as desired characters and images on a sheet-like recording medium such as paper or film. However, among them, a method of forming a text or an image on a recording medium by attaching a recording agent to the recording medium has been put into practical use, and a representative example of such a method is an ink jet recording apparatus. In recent years, the performance of ink jet recording apparatuses has improved, and not only text but also images have been recorded.
[0003]
The ink jet recording apparatus uses a nozzle group in which a plurality of ink discharge ports (nozzles) capable of discharging ink of the same color and the same density are arranged in order to improve the recording speed and improve the image quality. Typically, nozzle groups are provided for inks of the same color and different densities and inks of different colors. In addition, there are some ink jets that can be ejected by changing the ejection amount of the same color and the same density in several steps.
[0004]
Then, recording is performed by ejecting ink from the nozzles while moving the recording head provided with these nozzle groups relative to the recording medium.
[0005]
When an image is recorded, a halftone processing method such as a dither method or an error diffusion method is used as a method for faithfully reproducing the gradation of image information. For example, an error diffusion method ("An" by R. Floyd et al.) Is known as a technique for converting multi-valued image data into a binary image (or an image having a binary number or more and a gradation number smaller than the input gradation number). adaptive algorithm for spatial gray scale ", SID International Symposium Digest of Technical Papers, vol4.3, 1975, pp.36-37), by diffusing the binarization error generated in a pixel to the subsequent multiple pixels, This is a pseudo gradation expression.
[0006]
The error diffusion method is widely used in image processing apparatuses such as printers, copying machines, and facsimiles as a pseudo halftone processing method with high gradation reproducibility.
[0007]
[Problems to be solved by the invention]
However, the following problems occur when recording is performed using the error diffusion method as described above.
[0008]
Here, an ink jet printer that forms an image by causing a recording head having a plurality of nozzles arranged in a predetermined direction to scan on the recording medium in a direction intersecting the nozzle arrangement direction and ejecting ink onto the recording medium A case where an image is recorded by a serial printer as described above will be described as an example.
[0009]
Among a plurality of nozzles that eject ink droplets (dots), there are nozzles that cannot eject dots due to some influence (non-ejection), or nozzles whose ejected dot volume is less than a specified value. In particular, when the nozzle row is long and includes a large number of nozzles, there is a high probability that there are nozzles that cannot perform such normal recording.
[0010]
FIG. 6 is a diagram showing a process of forming an image by scanning one line of an image row (raster) using one nozzle row. Reference numeral 60 denotes a nozzle having a good ejection state, 61 denotes a nozzle in a non-recording state where dots cannot be ejected, 62 denotes a binarization result by an error diffusion method, and 63 denotes a dot recording state.
[0011]
As shown in FIG. 6, when an image is formed by a single scan, dots cannot be recorded on a recording medium in rasters corresponding to non-recording nozzles. Therefore, when it is necessary to form dots on the raster corresponding to the non-recording nozzles by the binarization processing using the conventional error diffusion method, the number of dots that must actually be recorded in the vicinity of the dots. An image is formed with a smaller number of dots. That is, the density storage, which is one of the advantages of the error diffusion method, is not sufficiently performed, and the quality of the recorded image is significantly deteriorated.
[0012]
The present invention has been made in view of the above situation, and an image processing apparatus capable of performing high-quality image recording even when recording is performed using a recording head having a recording element that cannot perform normal recording. And an image processing method.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, an image processing apparatus of the present invention is an image processing apparatus of a recording apparatus that performs recording by moving a recording head having a plurality of recording elements arranged in a predetermined direction relative to a recording medium. Because
Determining means for determining whether or not the input pixel data is pixel data recorded by a recording element that cannot perform normal recording;
Quantization means for converting the input multi-gradation data of each pixel into data having a smaller number of gradations than the number of input gradations;
Error diffusion means for diffusing the difference between the input data of the pixel of interest and the data quantized by the quantization means to pixels around the pixel of interest;
Pixel data determined to be recorded by a recording element that cannot perform normal recording by the determination means Is converted to data representing non-recording It is characterized by that.
[0014]
Also, the image processing method of the present invention that achieves the above object provides an image processing method for a recording apparatus that performs recording by moving a recording head having a plurality of recording elements arranged in a predetermined direction relative to the recording medium. Because
A determination step of determining whether the input pixel data is pixel data recorded by a recording element that cannot perform normal recording;
A quantization process for converting the input multi-gradation data of each pixel into data having a smaller number of gradations than the number of input gradations;
An error diffusion step of diffusing the difference between the input data of the pixel of interest and the data quantized by the quantization means to pixels around the pixel of interest,
Data of pixels determined to be recorded by a recording element that cannot perform normal recording in the determination step Is converted to data representing non-recording It is characterized by that.
[0015]
Further, the above object can be achieved by a computer program for causing the image processing method to be executed by a computer and a storage medium storing the program.
[0016]
That is, according to the present invention, in a recording apparatus that performs recording by moving a recording head having a plurality of recording elements arranged in a predetermined direction relative to a recording medium, the input pixel data is recorded normally. It is determined whether or not the pixel data is recorded by a recording element that cannot be used, and the input multi-gradation data of each pixel is converted into data having a smaller number of gradations than the number of input gradations. Data of pixels determined to be recorded by a recording element that cannot perform normal recording in quantization by diffusing a difference between pixel input data and quantized data to pixels around the pixel of interest. On the other hand, a quantization process different from that of other pixel data is performed.
[0017]
In this way, pixel data determined to be recorded by a recording element that cannot perform normal recording is included in processing different from other pixel data, for example, an error given to surrounding pixels. By performing this process, the pixel data can be distributed to surrounding pixels.
[0018]
Therefore, even when recording is performed using a recording head having a recording element that cannot perform normal recording, the total value of pixel data around each pixel of interest is the same as the input data, and the information included in the input image is maintained. Recorded high-quality images.
[0019]
When the quantizing means converts the pixel data determined to be recorded by the recording element that cannot perform normal recording by the determining means into data representing non-recording, all the data of this pixel is the surrounding pixels. Therefore, information included in the input image is accurately maintained.
[0020]
Further, if it is further provided with filter means for performing a predetermined filter process on the input pixel data before input to the quantization means, it is determined that the recording is performed by a recording element that cannot perform normal recording. It is preferable because the data of each pixel can be appropriately distributed by surrounding pixels.
[0021]
In this case, it is preferable that the user selects a predetermined filter process from a plurality of filter processes via the user interface.
[0022]
The filter means may perform a predetermined filter process on pixels around the determined pixel recorded by a recording element that cannot perform normal recording.
[0023]
In addition, if the plurality of filter processes are different from each other in at least one of the range in which the predetermined filter process is performed and the filter characteristics, the effect of each filter is different, and the filter process suitable for the image to be recorded can be selected. Therefore, it is preferable.
[0024]
In this case, it is convenient to further include filter storage means for storing a plurality of filter processing parameters.
[0025]
It is preferable that the image processing apparatus further includes a detection unit that detects a recording element that cannot perform normal recording.
[0026]
In this case, it is preferable that the detection means detect a recording element that cannot perform normal recording based on a driving result of each recording element or a recording result of each recording element onto a recording medium.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0028]
In the embodiment described below, a recording head having a plurality of nozzles arranged in a predetermined direction is scanned on a recording medium in a direction intersecting the nozzle arrangement direction, and ink is ejected onto the recording medium. An image processing apparatus according to a serial type recording apparatus using an inkjet recording method for forming an image will be described as an example.
[0029]
(First embodiment)
FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to the first embodiment of the present invention. Reference numeral 100 denotes an ejection state detection unit, 101 denotes a non-recording raster determination unit, 102 denotes an address input terminal, 103 denotes an input terminal for pixel data, 104 denotes an accumulated error addition unit, 105 denotes a threshold setting terminal for setting a quantization threshold, and 106 denotes Quantization unit 107 is an error calculation unit that calculates a quantization error, 108 is an error diffusion unit that diffuses the quantization error, 109 is an accumulated error memory, and 110 is an output terminal for image data formed by a series of processing. .
[0030]
Hereinafter, the operation of the image processing apparatus of FIG. 1 will be described with reference to the flowchart of FIG.
[0031]
First, the discharge state detection unit detects the discharge state of each nozzle (step S200). Here, a nozzle in a non-recording state in which the ejection amount of ink droplets at each nozzle is less than a specified value is detected. Next, the input image is sequentially scanned by an image scanning unit (not shown), and each pixel data is input from the input terminal 103 (step S201).
[0032]
FIG. 3 is a diagram showing how the input image is scanned. Reference numeral 300 denotes an upper left pixel of the input image, and reference numeral 301 denotes a lower right pixel of the input image. The scanning of the image starts from the pixel 300 at the upper left corner of the image area and proceeds in the right direction for each pixel. When the right end of the image data sequence is reached, the process proceeds to the left end pixel of the image data sequence one pixel below. When the process is repeated in this manner and the pixel reaches the lower right pixel 301, the image scanning process is completed.
[0033]
Next, the accumulated error value corresponding to the pixel position of the accumulated error memory is added to the pixel data input by the accumulated error adding unit 104 (step S202). The cumulative error memory has one storage area E0 and the same number of storage areas E (x) as the number of horizontal pixels W of the input image, and stores quantization errors by a method described later. It is assumed that the accumulated error memory has been initialized with an initial value of 0 before starting the processing.
[0034]
FIG. 4 is a diagram showing details of the contents stored in the cumulative error memory. In the accumulated error adding unit 104, the value of the error memory E (x) corresponding to the horizontal pixel position x of the input pixel data is added. That is, with respect to the input pixel data I, the pixel data after addition of the accumulated error has a value of I ′
I ′ = I + E (x)
It becomes.
[0035]
Next, the non-recording raster determination unit 101 refers to the raster number of the input image input from the address input terminal 102 to determine whether or not the raster of interest is a raster capable of image formation (step S203). Here, when the raster number of the raster of interest is L, the number of nozzles provided in the nozzle row is N, and the nozzle number in the non-printing state is Pi,
L% N = Pi
A raster that satisfies the condition is determined not to perform image formation. Note that% is an operator representing modulo (remainder).
[0036]
FIG. 5 is a diagram showing an image forming process in the case where a nozzle row in which the number of nozzles N = 16, the number of nozzles in a non-printing state is P0 = 3, and P1 = 11 is used. As shown in FIG. 5, it is determined that the raster of the output image with the raster number L = 3, 11, 19,...
[0037]
Next, if it is determined that the raster of interest is a raster capable of image formation, the quantization unit 106 performs the first quantization process A (step S204), and the raster is a raster that does not perform image formation. If determined, the quantization unit 106 performs the second quantization process B (step S205).
[0038]
Here, each quantization process will be described in detail. First, in the first quantization process A, the pixel data I ′ after the cumulative error addition is compared with the threshold value determined by the threshold value setting terminal 105 to determine the output pixel value. In the present embodiment, the output value after quantization is binary, and the output pixel value is determined by comparing one threshold value with the pixel data I ′ after adding the cumulative error. That is, if the input pixel value is an integer value in the range of 0 to 255, the output gradation value O is an expression:
O = 0 (I ′ <128)
O = 255 (I ′ ≧ 128)
Determined by.
[0039]
On the other hand, in the second quantization process B, the output gradation value O is not recorded for any input pixel value.
O = 255
And In this embodiment, dots are recorded at pixel positions where the output value is 0, and dots are not recorded at pixel positions where the output value is 255.
[0040]
Next, in the error calculation unit 107, the difference between the pixel data I ′ after the cumulative error addition and the output pixel value O, that is, the quantization error Err is
Err = I'-O
(Step S206).
[0041]
Next, in the error diffusion unit 108, according to the horizontal position x of the pixel of interest,
E (x + 1) ← E (x + 1) + E × 7/16 (x <W)
E (x-1) ← E (x-1) + E × 3/16 (x> 1)
E (x) ← E0 + E × 5/16 (1 <x <W)
E (x) ← E0 + E × 8/16 (x = 1)
E (x) ← E0 + E × 13/16 (x = W)
E0 ← E × 1/16 (x <W)
E0 ← 0 (x = W)
An error diffusion process is performed so as to satisfy (Step S207).
[0042]
This completes the error diffusion processing for one pixel of the input image. It is determined whether or not this error diffusion processing has been performed on all the pixels of the input image (step S208), and if it is determined that the above processing has been performed on all the pixels, the pseudo halftone processing of the input image Is completed.
[0043]
In the first embodiment, the ejection state detection unit detects the ejection amount of the ink droplets at each nozzle to detect the non-recording nozzles. However, the ejection state detection unit detects the ink droplets ejected from each nozzle. The non-recording nozzles may be detected by paying attention to the recording area on the recording medium.
[0044]
As described above, according to the first embodiment, the error diffusion method is performed by forcibly non-printing dots with respect to a raster that cannot perform image formation due to the influence of nozzles in a non-printing state. It is possible to provide a high-quality output image without impairing the density storage characteristics of the input image data, which is an advantage of the above.
[0045]
(Second Embodiment)
Hereinafter, a second embodiment of the image processing apparatus according to the present invention will be described. In the following description, description of the same parts as those in the first embodiment will be omitted, and description will be made focusing on characteristic parts of the present embodiment.
[0046]
FIG. 7 is a block diagram showing the configuration of the second embodiment of the image processing apparatus of the present invention. In contrast to the configuration of the first embodiment illustrated in FIG. 1, a filtering setting unit 701 that performs filtering setting by a user, a filtering unit 702 that performs filtering processing on an input image according to the filtering setting, and a filter used for filtering are stored. A filter storage memory 703 and a monitor 704 for performing filtering settings are added, and an input image 700 having 8-bit gradation information per pixel is input as an input image.
[0047]
Hereinafter, the operation of the image processing apparatus of FIG. 7 will be described with reference to the flowchart of FIG.
[0048]
First, the discharge state detection unit detects the discharge state of each nozzle (step S800). Here, a nozzle in a non-recording state in which the ejection amount of ink droplets at each nozzle is less than a specified value is detected. Next, the strength of the filtering process performed on the input image in the filtering setting unit 701, the size of the target region, and the filter characteristics are specified by the user (step S801).
[0049]
FIG. 11 shows an example of a user interface screen when designating these setting parameters. This user interface screen is displayed on the monitor 704. Reference numeral 1100 denotes a filter strength designation unit, 1101 denotes a filtering process area designation unit, 1102 denotes a filter characteristic designation unit, 1103 denotes a filtering setting determination unit, and 1104 denotes a filtering setting re-execution determination unit. A filter to be used is determined from the filter storage memory in accordance with the filtering strength and filter characteristics specified by the user through such a user interface screen.
[0050]
Next, the filtering process is performed only on the filtering process area designated by the user in the neighboring raster of the image sequence not subjected to the image recording designated by the non-recording raster determination unit described later (step S802).
[0051]
FIG. 9 shows an example of filters corresponding to various strengths exemplified in the user interface screen of FIG. In both cases, the center corresponds to the pixel position to be processed, and the value entered in each square is the correction coefficient. 900 is a 1 × 1 pixel intensity 1 filter, 901 is a 1 × 3 pixel intensity 2 filter, 902 is a 1 × 5 pixel intensity 3 filter, and 903 is a filter size. A 3 × 3 pixel strength 3 filter 904 is a filter size of 5 × 5 pixel strength 4 filter. The filter 900 has the weakest filtering action (no action), and the filtering action increases in the order of 901 to 904.
[0052]
For example, when the filter 903 having the correction intensity 3 is selected and the filtering method is an average value of the eight pixels around the processing target pixel and the processing target pixel, the pixel value at the pixel position (x, y) is set to G (x , Y), the pixel value G ′ (i, j) after the filter correction for the processing target pixel position (i, j) is
G ′ (i, j) =
{G (i-1, j-1) + G (i, j-1) + G (i + 1, j-1)
+ G (i-1, j) + G (i, j) + G (i + 1, j)
+ G (i-1, j + 1) + G (i, j + 1) + G (i + 1, j + 1)} / 9
Given in.
[0053]
In the present embodiment, according to the processing area size specified by the filtering setting unit 701, the correction processing is performed only for ± 3 rasters before and after the image sequence on which image recording is not performed. Filtering processing is not performed for image sequences not corresponding to this.
[0054]
Next, the accumulated error value corresponding to the pixel position of the accumulated error memory is added to the pixel data input in the accumulated error adding unit 104 (step S803). The cumulative error memory has one storage area E0 and the same number of storage areas E (x) as the number of horizontal pixels W of the input image, and stores quantization errors by a method described later. The details of the contents stored in the accumulated error memory are the same as those in the first embodiment described with reference to FIG. 4, and the accumulated error memory is all initialized to the initial value 0 before the processing is started. .
[0055]
In the accumulated error adding unit 104, the value of the error memory E (x) corresponding to the horizontal pixel position x of the input pixel data is added. That is, the input pixel data I is defined as I ′ after the cumulative error addition.
I ′ = I + E (x)
It becomes.
[0056]
Next, the non-recording raster determination unit 101 refers to the raster number of the input image input from the address input terminal 102 to determine whether or not the raster of interest is a raster capable of image formation (step S804). When the raster number of the raster of interest is L, the number of nozzles provided in the nozzle row is N, and the nozzle number in the non-printing state is Pi,
L% N = Pi
A raster that satisfies the condition is determined as a raster that does not perform image formation. Note that% is an operator representing modulo (remainder). An example of the image forming process is the same as that in FIG. 5 described with respect to the first embodiment.
[0057]
Next, when it is determined that the raster of interest is a raster capable of image formation, the quantization unit 106 performs the first quantization processing A (step S805), and the raster is a raster that does not perform image formation. If determined, the quantization unit 106 performs the second quantization process B (step S806). The contents of the processes performed in the first quantization process A and the second quantization process B are the same as those in the first embodiment, and therefore will not be described in detail here.
[0058]
Next, the error calculation unit 107 calculates the difference between the pixel data I ′ after the accumulated error addition and the output pixel value O, that is, the quantization error Err (step S807). The process performed here is the same as the process performed in step S206 of the first embodiment.
[0059]
Next, the error diffusion unit 108 performs error diffusion processing according to the horizontal position x of the pixel of interest (step S808). The process performed here is the same as the process performed in step SS207 of the first embodiment.
[0060]
As described above, the error diffusion process for one pixel of the input image is completed. It is determined whether or not such error diffusion processing has been performed for all the pixels of the input image (step S809), and if it is determined that the above processing has been performed for all the pixels, the pseudo intermediate of the input image The key processing is completed.
[0061]
In this embodiment, the ejection state detection unit detects the ejection amount of the ink droplets at each nozzle to detect the non-recording nozzles, but the ejection state detection unit records the ink droplets ejected from each nozzle. You may detect the nozzle of a non-recording state paying attention to the recording area on a medium.
[0062]
Further, in the present embodiment, the filtering process is performed with the average value of the eight pixels around the processing target pixel and the processing target pixel, but this may be a weighted average value around the processing target pixel. As the weighting filter, for example, values as shown in FIG. 10 can be used. In both cases, the center pixel corresponds to the processing target pixel, and the value entered in each square is the correction coefficient. 1000 is a filter having a filter size of 1 × 3 pixels, 1001 is a filter having a filter size of 1 × 5 pixels, 1002 is a filter having a filter size of 3 × 3 pixels, and 1003 is a filter having a filter size of 5 × 5 pixels.
[0063]
As described above, according to the second embodiment, the filtering process specified by the user can be performed on the vicinity of the raster where the image is not recorded in the input image, and the output image quality in the vicinity of the raster where the image cannot be recorded is obtained. It can be changed according to the user's preference.
[0064]
(Other embodiments)
In the embodiment described above, an image is formed by causing a recording head having a plurality of nozzles arranged in a predetermined direction to scan on the recording medium in a direction intersecting the nozzle arrangement direction and ejecting ink onto the recording medium. The image processing apparatus according to the recording apparatus using the ink jet recording system has been described as an example, but the present invention can also be applied to a recording apparatus that performs recording according to a system other than the ink jet system. In this case, the nozzle that ejects ink droplets corresponds to a recording element that records dots.
[0065]
The present invention also provides a serial line such as a so-called full-line type recording apparatus that has a recording head having a length corresponding to the recording width of the recording medium and performs recording by moving the recording medium relative to the recording head. The present invention can also be applied to a recording apparatus that performs recording by moving a recording head relative to a recording medium, other than the type of recording apparatus (printer).
[0066]
Furthermore, in the above-described embodiment, the image processing apparatus has been described as including a discharge state detection unit that detects the discharge state of each nozzle of the recording head. However, the detection of the discharge state is performed for nozzles that cannot perform normal recording. If the position (number) is recognized by the image processing apparatus, it may be performed by another apparatus. In this case, the nozzle position and number data for which normal recording cannot be performed is transmitted to the image processing apparatus from another apparatus that has detected the ejection state, and stored in a predetermined memory location in the image processing apparatus. It becomes.
[0067]
In the above-described embodiment, a configuration having a recording head having one nozzle row will be described. However, in a configuration in which the number of nozzle rows corresponding to the type of ink is used to perform color printing, each nozzle row The processing described in each embodiment is performed on the data recorded in each.
[0068]
Note that the present invention can be applied to a system (for example, a copier, a facsimile machine, etc.) consisting of a single device even when applied to a system composed of a plurality of devices (for example, a host computer, interface device, reader, printer, etc.). You may apply.
Another object of the present invention is to supply a storage medium storing software program codes for implementing the functions of the above-described embodiments to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium. Needless to say, this can also be achieved by reading and executing the program code stored in the.
[0069]
In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.
[0070]
As a storage medium for supplying the program code, for example, a floppy disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.
[0071]
Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the 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 actual processing and the processing is included.
[0072]
Further, 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 expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.
[0073]
When the present invention is applied to the above-described storage medium, the storage medium stores program codes corresponding to the flowcharts described above (shown in FIG. 2 and / or FIG. 8).
[0074]
【The invention's effect】
As described above, according to the present invention, the pixel data determined to be recorded by a recording element that cannot perform normal recording is processed differently from other pixel data, for example, surrounding pixels. By performing such processing as to be included in the error given to the pixel data, the pixel data can be distributed to surrounding pixels.
[0075]
Therefore, even when recording is performed using a recording head having a recording element that cannot perform normal recording, the total value of pixel data around each pixel of interest is the same as the input data, and the information included in the input image is maintained. Recorded high-quality images.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an image processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing processing in the image processing apparatus of FIG. 1;
FIG. 3 is a diagram illustrating a state of scanning an input image.
FIG. 4 is a diagram showing details of contents stored in an accumulated error memory.
FIG. 5 is a diagram illustrating an image forming process when a nozzle row including nozzles in a non-recording state is used.
FIG. 6 is a diagram illustrating a process of forming an image by scanning one line of an image row using one nozzle row.
FIG. 7 is a block diagram showing a configuration of a second embodiment of the image processing apparatus of the present invention.
8 is a flowchart showing processing in the image processing apparatus of FIG.
FIG. 9 is a diagram illustrating an example of a filter for performing filtering.
FIG. 10 is a diagram illustrating an example of another filter for performing filtering.
FIG. 11 is a diagram showing a user interface screen for performing filtering setting.
[Explanation of symbols]
100 Discharge state detector
101 Non-recording raster determination unit
102 Address input terminal
103 Image data input terminal
104 Cumulative error adder
105 Threshold setting terminal
106 Quantization unit
107 Error calculator
108 Error diffusion section
109 Cumulative error memory
110 Image data output terminal

Claims (19)

An image processing apparatus of a recording apparatus that performs recording by moving a recording head having a plurality of recording elements arranged in a predetermined direction relative to a recording medium,
Determining means for determining whether or not the input pixel data is pixel data recorded by a recording element that cannot perform normal recording;
Quantization means for converting the input multi-gradation data of each pixel into data having a smaller number of gradations than the number of input gradations;
Error diffusion means for diffusing the difference between the input data of the pixel of interest and the data quantized by the quantization means to pixels around the pixel of interest ;
The image processing apparatus characterized by converting the data of pixels determined to be recorded by the recording element which does not perform the normal recording, the data representing the non-recorded by the pre-Symbol judging means. The image processing apparatus according to claim 1, further comprising a filter unit that performs a predetermined filter process on the input pixel data before input to the quantization unit. The image processing apparatus according to claim 2 , further comprising a user interface for a user to select the predetermined filter process from a plurality of filter processes. The filter means of claim 2 or 3, characterized by applying predetermined filtering process on pixels around the pixels which are determined to be recorded by a recording element in which the normal recording can not be performed Image processing device. Wherein the plurality of filter processing, the image processing apparatus according to claim 3 or 4 at least one of the ranges and the filter characteristic is subjected to the predetermined filtering process is characterized in different possible. The image processing apparatus according to claim 3 , further comprising a filter storage unit that stores parameters of the plurality of filter processes. The image processing apparatus according to any one of 6 claim 1, characterized by further comprising a detection means for detecting a recording element in which the normal recording can not be performed. The image processing apparatus according to claim 7 , wherein the detection unit detects a recording element that cannot perform the normal recording based on a driving result of each recording element. The image processing apparatus according to claim 7 , wherein the detection unit detects a recording element that cannot perform the normal recording based on a recording result of each recording element on a recording medium. The recording apparatus, in any one of claims 1 to 9, wherein said that the recording head in a direction intersecting the array direction of the recording element is a printing apparatus for printing by scanning on the recording medium The image processing apparatus described. The recording head, an image processing apparatus according to any one of claims 1 to 10, characterized in that the ink jet recording head for recording by discharging ink. An image processing method of a recording apparatus that performs recording by moving a recording head having a plurality of recording elements arranged in a predetermined direction relative to a recording medium,
A determination step of determining whether the input pixel data is pixel data recorded by a recording element that cannot perform normal recording;
A quantization process for converting the input multi-gradation data of each pixel into data having a smaller number of gradations than the number of input gradations;
An error diffusion step of diffusing the difference between the input data of the pixel of interest and the data quantized by the quantization means to pixels around the pixel of interest ,
An image processing method characterized by the pre-conversion Symbol data of pixels determined to be recorded by a recording element in which the normal recording can not be performed in the determination step, the data representing the non-recording. The image processing method according to claim 12 , further comprising a filtering step of performing a predetermined filtering process on the input pixel data before the quantization step. The image processing method according to claim 13 , further comprising a selection step in which the user selects the predetermined filtering process from a plurality of filtering processes via a user interface. In the filter process, as claimed in claim 13 or 14, characterized by applying predetermined filtering process on pixels around the pixels which are determined to be recorded by a recording element in which the normal recording can not be performed Image processing method. Wherein the plurality of filter processing, image processing method according to claim 14 or 15, at least one of the ranges and the filter characteristic is subjected to the predetermined filtering process are different from each other, respectively. The image processing method according to any one of claims 12 to 16, characterized in that it comprises further a detection step of detecting a recording element in which the normal recording can not be performed. A computer program that causes a computer to execute an image processing method of a recording apparatus that performs recording by moving a recording head having a plurality of recording elements arranged in a predetermined direction relative to a recording medium,
The image processing method includes:
A determination step of determining whether the input pixel data is pixel data recorded by a recording element that cannot perform normal recording;
A quantization process for converting the input multi-gradation data of each pixel into data having a smaller number of gradations than the number of input gradations;
An error diffusion step of diffusing the difference between the input data of the pixel of interest and the data quantized by the quantization means to pixels around the pixel of interest ;
Before SL determination data of pixels determined to be recorded by a recording element in which the normal recording can not be performed in the step, a computer program and converting the data representing the non-recording. A storage medium for storing a computer program that causes a computer to execute an image processing method of a recording apparatus that performs recording by moving a recording head having a plurality of recording elements arranged in a predetermined direction relative to the recording medium. ,
The image processing method includes:
A determination step of determining whether the input pixel data is pixel data recorded by a recording element that cannot perform normal recording;
A quantization process for converting the input multi-gradation data of each pixel into data having a smaller number of gradations than the number of input gradations;
An error diffusion step of diffusing the difference between the input data of the pixel of interest and the data quantized by the quantization means to pixels around the pixel of interest ;
Before SL determination data of pixels determined to be recorded by a recording element in which the normal recording can not be performed in the process, storage medium and converting the data representing the non-recording.

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