PRINT CONTROL DEVICE EXECUTING ERROR DIFFUSION PROCESS IN WHICH CONDITION IS DETERMINED BY PROBABILITY

• US 20130335781A1
• Filed: 03/14/2013
• Published: 12/19/2013
• Est. Priority Date: 06/13/2012
• Status: Active Grant

• Current Assignee: Brother Kogyo Kabushiki Kaisha (Brother Industries Limited)
• Original Assignee: Brother Kogyo Kabushiki Kaisha (Brother Industries Limited)
• Inventors: KUNO, Masashi
• Granted Patent: US 8,810,858 B2
• Time in Patent Office: Days
• US Class Current: 358/3.03
• CPC Class Codes: H04N 1/4052 by error diffusion, i.e. transferring the binarising error to neighbouring dot decisions
• CPC Class Codes: H04N 1/4057 the pattern being a mixture of differently sized sub-patterns, e.g. spots having only a few different diameters multi-toning H04N1/40087

Abstract

In a print control device, an executing unit executes an error diffusion process in which one of a first and second setting processes is executed. In the first setting process, the executing unit determines whether a first condition is satisfied. The first condition includes that the corrected value of the pixel data is larger than the first threshold value and that the first allowance condition determined by a first probability is satisfied. After the executing unit determines that the first condition is not satisfied, the executing unit determines whether a second condition is satisfied. The second condition includes that the corrected value of the pixel data is larger than the second threshold value. In the second setting process, the executing unit determines whether the second condition is satisfied. After the executing unit determines that the second condition is not satisfied, the executing unit determines whether the first condition is satisfied.

Claims

1. A print control device comprising:

a processor; and

a memory that stores a computer program that, when executed by the processor, causes the control device to function as;

an acquiring unit configured to acquire image data representing an image including a plurality of pixels, the image data including a plurality of pixel data corresponding to the plurality of pixels, each of the plurality of pixel data including a gradation value;

an executing unit configured to execute an error diffusion process on each of the plurality of pixel data, the executing unit including;

a target pixel setting unit configured to set target pixel data from among the plurality of pixel data;

a correcting unit configured to correct a gradation value of the target pixel data by using a distribution error, the distribution error being set by at least one error value of at least one pixel data on which the error diffusion process has been executed;

a first determining unit configured to determine whether a corrected value of the target pixel data is larger than a first threshold value, and determine whether the corrected value of the target pixel data is larger than a second threshold value different from the first threshold value;

a second determining unit configured to determine whether a first allowance condition is satisfied, the first allowance condition being determined by a first probability, the first probability depending on the gradation value of the target pixel data;

a dot value setting unit configured to set a dot value of the target pixel data to one of a first dot value and a second dot value different from the first dot value, the dot value indicating a size of a dot; and

an error value setting unit configured to set an error value of the target pixel data based on both concentration value corresponding to the dot value of the target pixel data and the corrected value of the target pixel data; and

an output unit configured to output print data determined by the dot value for each of the plurality of pixel data,

wherein the executing unit executes one of a first setting process and a second setting process,

wherein in the first setting process, the executing unit determines whether a first condition is satisfied, the first condition including that the corrected value of the target pixel data is larger than the first threshold value and that the first allowance condition is satisfied,

wherein in the first setting process, after the executing unit determines that the first condition is satisfied, the dot value setting unit sets the dot value of the target pixel data to the first dot value,

wherein in the first setting process, after the executing unit determines that the first condition is not satisfied, the executing unit determines whether a second condition is satisfied, the second condition including that the corrected value of the target pixel data is larger than the second threshold value,

wherein in the second setting process, the executing unit determines whether the second condition is satisfied,

wherein in the second setting process, after the executing unit determines that the second condition is satisfied, the dot value setting unit sets the dot value of the target pixel data to the second dot value,

wherein in the second setting process, after the executing unit determines that the second condition is not satisfied, the executing unit determines whether the first condition is satisfied.

2. The print control device according to claim 1, wherein the second dot value indicates a size of the dot larger than a size of the dot indicated by the first dot value, and the second threshold value is larger than the first threshold value,

wherein the executing unit executes the first setting process,

wherein the dot value setting unit does not set the dot value of the target pixel data to the first dot value when the first allowance condition is not satisfied, even when the corrected value of the target pixel data is larger than the first threshold value and smaller than the second threshold value.

3. The print control device according to claim 2, wherein the second determining unit further determines whether a second allowance condition is satisfied, the second allowance condition being determined by a second probability,

wherein when the second condition further includes that the second allowance condition is satisfied, the dot value setting unit sets the dot value of the target pixel data to the second dot value.

4. The print control device according to claim 3, wherein the first probability is smaller than the second probability when the gradation value is in a prescribed first range including a value smaller than the second threshold value.

5. The print control device according to claim 1, wherein the first probability decreases continuously when the gradation value is in a prescribed second range including a value smaller than the second threshold value.

6. The print control device according to claim 3, wherein the first determining unit further determines whether the corrected value of the target pixel data is larger than a third threshold value larger than the second threshold value,

wherein when the corrected value of the target pixel data is larger than the third threshold value, the dot value setting unit sets the dot value of the target pixel data to a third dot value from among the plurality of dot values, the third dot value indicating a size of the dot larger than the size of the dot indicated by the second dot value,

wherein the second probability decreases continuously when the gradation value is in a prescribed third range including a value smaller than the third threshold value.

7. The print control device according to claim 6, wherein the first probability increases continuously when the gradation value is in a fourth range including a value larger than the third threshold value.

8. The print control device according to claim 1, wherein the second dot value indicating a size of the dot smaller than a size of the dot indicated by the first dot value, and the second threshold value is smaller than the first threshold value.

9. The print control device according to claim 1, wherein the dot value setting unit sets the dot value of the target pixel based on a determination result of the first determining unit and a determination result of the second determining unit.

10. A non-transitory computer-readable storage medium storing computer-readable instructions that, when executed by a processor, causes an image processing device to perform:

acquiring image data representing an image including a plurality of pixels, the image data including a plurality of pixel data corresponding to the plurality of pixels, each of the plurality of pixel data including a gradation value;

executing an error diffusion process on each of the plurality of pixel data, the executing including;

setting target pixel data from among the plurality of pixel data;

correcting a gradation value of the target pixel data by using a distribution error, the distribution error being set by at least one error value of at least one pixel data on which the error diffusion process has been executed;

determining whether a corrected value of the target pixel data is larger than a first threshold value;

determining whether the corrected value of the target pixel data is larger than a second threshold value different from the first threshold value;

determining whether a first allowance condition is satisfied, the first allowance condition being determined by a first probability, the first probability depending on the gradation value of the target pixel data;

setting a dot value of the target pixel data to one of a first dot value and a second dot value different from the first dot value, the dot value indicating a size of a dot; and

setting an error value of the target pixel data based on both concentration value corresponding to the dot value of the target pixel data and the corrected value of the target pixel data; and

outputting print data determined by the dot value for each of the plurality of pixel data,

wherein the executing executes one of a first setting process and a second setting process,

wherein in the first setting process, the executing determines whether a first condition is satisfied, the first condition including that the corrected value of the target pixel data is larger than the first threshold value and that the first allowance condition is satisfied,

wherein in the first setting process, after the executing determines that the first condition is satisfied, the setting of the dot value sets the dot value of the target pixel data to the first dot value,

wherein in the first setting process, after the executing determines that the first condition is not satisfied, the executing determines whether a second condition is satisfied, the second condition including that the corrected value of the target pixel data is larger than the second threshold value,

wherein in the second setting process, the executing determines whether the second condition is satisfied,

wherein in the second setting process, after the executing determines that the second condition is satisfied, the setting of the dot value sets the dot value of the target pixel data to the second dot value,

wherein in the second setting process, after the executing determines that the second condition is not satisfied, the executing determines whether the first condition is satisfied.