JP2002279406A - Linewidth uniformity evaluation method, and record medium recording linewidth uniformity evaluating program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a line width uniformity evaluating method for evaluating line width uniformity with proper balance to the perception of a person independent from a reference setting method for the width of a segment to be measured, and vertical/lateral segments in evaluating the quality of an image outputted by an image output device, etc. SOLUTION: The image outputted by the image output device is read, the widths of the segments printed inside the image and across the images are measured, a line width uniformity evaluation quality is calculated by the line width uniformity evaluation quantity=N×(maximum linewidth-minimum linewidth)/average line width and the uniformity of the linewidth is evaluated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is printers and copiers, and other relates to the quality evaluation of the output image by the image output apparatus, in particular evaluate the uniformity of the line segment is printed between the image or image The present invention relates to a method and a recording medium on which the program is recorded.

[0002]

2. Description of the Related Art An image output from an image output device is
If the line width fluctuates greatly within a page or between pages, it is often the case that a user makes a complaint. In particular, when a drawing is output, the demand for uniformity of line width is severe. For this reason, in the process of inspecting the performance of the image output apparatus, the manufacturer generally measures and evaluates the uniformity of the line width within a page and between pages, and performs quality control.

Conventionally, the evaluation of the uniformity of the line width is based on the standard deviation of the measured line width and the PP value (= maximum line width−minimum line width).
It was common to use such as an evaluation amount. For example, Japanese Patent Application Laid-Open No. 3-188357 discloses a technique for measuring and evaluating a line width and a line pitch. However, it is possible to output an average value, a maximum value, a minimum value, a standard deviation, and the like as an evaluation result. Has been described.

[0004]

In the production process, when managing the uniformity of the line width of a printing result, it is needless to say that some tolerance is set for an evaluation amount such as a standard deviation or a PP value. A decision is made as to pass or reject. The tolerance must be set by the person who will ultimately evaluate the image, based on the degree of perceived change in line width. If this is not the case, an unnecessarily strict tolerance is set and adjustment costs and reject costs increase, which can result in an increase in product costs. In other words, it can be said that it is desirable that the evaluation amount used when evaluating the uniformity of the line width is an evaluation amount linear to human perception.

However, when the standard deviation is used as the evaluation amount, for example, even when the standard deviation is the same 50 μm, when the average line width is 100 μm and 1 mm, the degree of perceived change in the line width is greatly different. In the case of, the change in the line width is remarkably perceived. In other words, if the line width to be measured is fixed, there is a correlation between the perceived line uniformity and the standard deviation of the line width, but a certain tolerance is set for different line widths. Can not do it. The same applies to the PP value. That is, neither the standard deviation nor the PP value is an evaluation amount that is linear to human perception of the line width variation.

Therefore, the standard deviation and the PP
When managing line width fluctuations with values, it is necessary to set different allowable values for each line pattern width to be measured, and when measuring line width fluctuations using line patterns with different thicknesses, , Because the allowable value was set for each line width, the process management became complicated, which could cause an increase in process management costs or a management error. .

[0007] Next, even when the line width is generally changed, it is easy to compare the case of a line segment that does not intersect with the line segment and the case of a line segment that intersects one another. And the sensitivity to the intersecting line segments is naturally high. In addition, differences in line width between vertical and horizontal lines are likely to occur in the process, and complaints are likely to occur, so the uniformity of the line width of intersecting lines is independent of the fluctuation of line width of non-intersecting lines. In many cases, allowable values are set and managed as the evaluated items.

In this case, it is common to manage a difference value or a ratio between the vertical line width and the horizontal line width as a uniformity evaluation amount. When using the ratio, although it does not depend on the line width, the evaluation value differs depending on the vertical or horizontal line width, so that the other is thicker and thinner than the reference line, There is a problem that an allowable value must be set. For example, when two orthogonal line widths are 2: 3, the line width ratio is 1.5 based on the former, and 0.666 based on the latter, and the line widths are equal. It can be seen that the difference from the line width ratio of 1.0 in the case differs depending on how to take the standard. Further, since the evaluation amount for any of the line width fluctuations described above does not have a linear relationship with the amount of human perception that the line width change is perceived, it is desired to make the line width fluctuation twice as severe at the level of human perception. If you think, the corresponding tolerance cannot be simply determined. That is, with the conventionally used evaluation amount for the line width fluctuation, it is not possible to easily set an appropriate allowable value corresponding to the human perception with respect to the change in the required accuracy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a first object of the present invention is to provide a method for measuring the width of a line segment to be measured and the width and length of a line without depending on a standard. The object of the present invention is to realize an evaluation of the line width uniformity that is compatible with the perception of. A second object of the present invention is to realize evaluation of line width uniformity without being affected by an abnormal value even when a part of the line width measurement has an abnormal value. A third object of the present invention is to realize uniformity evaluation in which a difference in human perceptual sensitivity between a case where lines intersect and a case where lines do not intersect is corrected.

[0010]

SUMMARY OF THE INVENTION In order to achieve the first object, the present invention provides an image output by an image output device or the like in which the line width of a line segment printed within an image or between images is uniform. The following equation (1): Line width uniformity evaluation amount = N × (maximum line width−minimum line width) / average line width (1) N is evaluated by an evaluation amount expressed by a proportional constant. I do.

Further, in order to achieve the second object, the present invention is to improve the uniformity of the line width of a line segment printed within an image or between images of an image output by an image output device or the like. of (2) line width uniformity evaluation quantity = N × line standard deviation / average line width of (2) N is and evaluating the evaluation amount represented by the proportionality constant.

In order to achieve the third object, the present invention evaluates the uniformity of the line width between lines intersecting with each other, and evaluates the uniformity of the line width between lines not intersecting with each other. It is characterized in that the proportionality constant (coefficient) N of the equations (1) and (2) differs between the cases.

[0013] Evaluation value calculation formula (1), since with linear evaluation amount of human perceptual characteristics as the uniformity evaluation amount, in the development and production process, can set an appropriate allowable amount based on the perceptual characteristics , Efficient product development becomes possible. Also,
Since the evaluation amount calculation formula (2) uses a standard deviation of the line width or a value proportional thereto instead of (maximum line width−minimum line width) in the expression (1), a measurement error or the like in the measurement of the line width is used. Therefore, even when an abnormal value occurs, the evaluation document can be properly evaluated without being greatly affected.

Further, the coefficient N of the evaluation amount calculation formulas (1) and (2) is made different between the uniformity evaluation amount of the intersecting line segment and the uniformity evaluation amount of the line width of the non-intersecting line segment. In either case, it is possible to evaluate as a human perceived amount with respect to a common variation in line width. Therefore,
At the stage of setting the quality regulation of the image output device or the like, the uniformity of the line width for the case where the line segments intersect and the case where the line segments do not intersect has conventionally been set with different allowable values as different evaluation items. Image quality can be managed in a unified manner, and efficient product development and production process management can be performed.

The proportionality constant N in the evaluation amount calculation formulas (1) and (2)
For example, N = 1.38 when deriving a subjective evaluation value for uniformity when line segments do not intersect, and N = when deriving a subjective evaluation value for uniformity when line segments intersect. 2.11 and N = 1 may be used to evaluate only the relative good or bad.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be specifically described with reference to the drawings. FIG. 1 is a block diagram of one embodiment of a hardware configuration for realizing the line width uniformity evaluation method of the present invention. In FIG. 1, an image input unit 100 is, for example, a CCD camera or a scanner, and reads a line to be evaluated from an image output by an image output device. The line width measuring unit 110 binarizes the read line image with a predetermined threshold to calculate a line width (line width). In general, any method may be used for measuring the line width. The line width storage unit 120 stores, for example, a plurality of line width data of an image output from the image output device, which is measured within a page or across pages. Statistics calculation means 13
0 calculates a statistic (an average value, a maximum value and a minimum value, or a standard deviation) from the line width data stored in the line width storage unit 120, and passes the calculated value to the line width uniformity calculation unit 140. The line width uniformity calculation means 140 evaluates the line width uniformity according to the equation (1) or (2) based on the statistic from the statistic calculation means 130 and the coefficient N stored in the coefficient storage means 150 in advance. Calculate the amount. The display unit 160 is a CRT or other display, and displays the line width uniformity evaluation result obtained by the line width uniformity calculation unit 140. This line width uniformity evaluation result may be output to a printer or the like.

The coefficient N stored in the coefficient storage means 150
As described above, for example, when deriving a subjective evaluation of unity when line segments do not intersect, N = 1.3.
8. N = 2.11 when deriving a subjective evaluation value for uniformity when line segments intersect, and N = 1 when evaluating only relative good or bad. In addition,
Which of equation (1) and equation (2) is to be applied may be specified in advance.

FIG. 2 is a flowchart in the case where the equation (1) is applied to the evaluation of the evaluation of the line width uniformity. FIG. 3 is a flowchart when the equation (2) is applied. FIG.
3 is a program that can be executed by a computer as a computer-readable recording medium (floppy (registered trademark), CD-
ROM, etc.). Figure 1
Is actually realized in a computer environment such as a CPU, a memory, and an input / output device. By loading a program described in a recording medium, the line width measuring unit 120 and the statistic calculating unit 130 are loaded. The desired functions such as the line width uniformity calculation means 140 and the like are achieved.

Hereinafter, specific experimental results will be shown. First, 2
When book segments were presented, a psychological experiment was performed on the perception of the difference between the line widths. FIG. 4 shows the preconditions and questions asked to the subject, and FIG. 5 shows the arrangement of the samples. In this experiment, the basic sample on the left was fixed to a line segment with a predetermined line width,
An experiment was conducted by randomly presenting samples having several types of line widths as evaluation samples on the right side. The line segments fixed on the right side had line widths of 77 μm and 133 μm.

FIG. 5 shows the results obtained by plotting the evaluation points obtained by the experiment on the vertical axis and the absolute value of the difference value of the line width of each sample pair on the horizontal axis. However, the subjective evaluation points are standardized from 0 to 1. The two lines in the figure are regression lines corresponding to the experimental results obtained by changing the line width of the left sample. From FIG. 5, when the difference value of the line width is used as the evaluation value of the line width variation,
It can be seen that the evaluation amount giving the same subjective evaluation value point differs depending on the line width of the sample.

On the other hand, FIG. 7 shows a case where the abscissa axis represents the evaluation amount expressed by the equation (3). Line width uniformity evaluation amount = (absolute value of line width difference value) / average line width (3) As can be seen from FIG. 7, regression lines for two experimental results having different line widths are almost parallel and close to each other. The contribution rate of the result of linear regression of the experimental results is also 0.8
It is as high as 65. The regression equation at this time is shown in equation (4). Subjective evaluation point = 1.38 × Evaluation amount of line width uniformity (4) The term of the y-intercept is 0 because the 95% confidence limit extends over positive and negative, and the statistical test result is 5% and not significant.

That is, the evaluation amount represented by the expression (3), that is, the expression (1), does not depend on the line width of the reference sample, as compared with the subjective evaluation for the difference in the line width of the pair of line segments. It can be said that the evaluation amount is linear in the subjective evaluation result. Also,
By using the equation (4), it is possible to predict a subjective evaluation point.

In the above-described experiment, as a matter of course, when the difference between the line segments to be compared becomes larger than a certain value, the evaluation result is saturated (nobody is satisfied at all), but the saturated result is obtained. Is not shown in FIG. In the experiment, the saturation saturates at 0.65 or more in the evaluation by the equation (3). When the saturated portion is also taken into consideration, a linear relationship is not obtained, but there is no practical problem because an allowable value is not set in a line width variation region where the evaluation is saturated.

Just as in the above-described experiment, subjective evaluation was performed using a pattern in which vertical and horizontal lines intersect. In the experiment,
The average line width in the vertical and horizontal directions is A (100 μm center), B (200 μm).
m center) and C (300 μm center) were set.
FIG. 8 shows the result.

As can be seen from FIG. 8, it is understood that the evaluation independent of the line width can be performed by using the evaluation amount of the expression (3) even in the intersection pattern. The straight line in FIG.
This is the result of regression of evaluation results at different levels collectively.
The regression equation is shown in equation (5). The contribution ratio was as high as 0.886. Subjective evaluation point = 2.11 × line width uniformity evaluation amount (5) Comparing Expressions (4) and (5), the line width of the pattern where line segments intersect due to the large inclination of Expression (5) is obtained. It is sensitive to changes in, and is consistent with general trends. From the expressions (3) and (5), the allowable value for the line width variation of the line intersecting with the line width variation of the line segment discretely placed within the page or between the pages, for example, "Although the difference is known, A subjective evaluation value corresponding to an evaluation term such as "satisfactory level" can be set uniformly. In addition, the meaning of the allowable value is clarified, and it is easy to set an appropriate allowable value even when improving accuracy.

In the above experiment, since a pair of line segments was evaluated, the value obtained by dividing (absolute value of line width difference value) by (average line width) was used in equation (3). It was an evaluation amount.

FIG. 7 shows an example of an evaluation chart for evaluating the uniformity of the line width.
Cross lines having the same line width are arranged at the four corners and the center of the page.

In order to evaluate the uniformity of the line width, first, the line widths of all vertical and horizontal lines are measured within a page or across pages. When evaluating the uniformity for crossed line segment, using a crossed pair of line width, (3) to calculate the line width uniformity evaluation quantity by equation (5) below, obtains the subjective evaluation points . Next, when evaluating the uniformity of the line width within a page that does not intersect (strictly, not limited to the line segment that intersects) or across the pages, the easiest is to use the expression (3) (Absolute value) may be (absolute value of difference value between maximum line width and minimum line width). However, in this case, the evaluation is based on the worst value, so it is a severe evaluation,
When an abnormal value occurs in the measured line width due to the influence of dirt or the like, there is a possibility that the uniformity of the line width may be evaluated worse than actual.

In order to prevent such an evaluation error, the standard deviation σ of the line width or N times the standard deviation σ (generally, σ
Is used three times).

[0030]

(1) Since a linear evaluation amount is used for the human perception characteristic as the uniformity evaluation amount, an appropriate allowable value based on the perception characteristic can be set in the development and production processes.
Efficient product development becomes possible. (2) Even if an abnormal value occurs due to a measurement error or the like in the measurement of the line width, the evaluation document can be appropriately evaluated without being greatly affected. (3) By making the coefficient value different between the uniformity evaluation amount of the line width of the intersecting line segment and the uniformity evaluation amount of the line width of the line segment that does not intersect, the fluctuation of the common line width in both cases Can be evaluated as the amount of human perception of

[Brief description of the drawings]

1 is a block diagram of one embodiment of a hardware configuration for implementing the present invention method.

FIG. 2 is a flowchart of one embodiment of the method of the present invention.

FIG. 3 is a flowchart of another embodiment of the method of the present invention.

FIG. 4 is an evaluation procedure manual presented to a subject in a subjective evaluation experiment.

FIG. 5 is an arrangement of samples in an experiment.

FIG. 6 is a graph showing a relationship between a line width uniformity evaluation result of a line segment that does not intersect and a line width difference.

FIG. 7 is a graph showing a relationship between a uniformity evaluation result of a line width that does not intersect and a uniformity evaluation amount.

FIG. 8 is a graph showing a uniformity evaluation result with respect to a line width of an orthogonal line segment and a line width uniformity evaluation amount.

FIG. 9 is an example of a line width uniformity evaluation chart.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 image input means 110 line width measurement means 120 line width storage means 130 statistic calculation means 140 line width uniformity calculation means 150 coefficient storage means 160 display means

Claims (4)

[Claims] 1. A method for evaluating line width uniformity of a line segment printed by an output device, comprising: reading a line segment printed by an output device, measuring the line width, and evaluating the line width uniformity. Line width uniformity evaluation amount = N × (maximum line width−minimum line width) / average line width N is calculated by a proportionality constant, and the line width uniformity is evaluated. Evaluation method. 2. A method for evaluating the uniformity of the line width of a line printed by an output device, comprising: reading a line printed by an output device, measuring the line width, and evaluating the line width uniformity. Line width uniformity evaluation amount = N × standard deviation of line width / average line width N is calculated by a proportionality constant, and the line width uniformity is evaluated. 3. The line width uniformity evaluation method according to claim 1, wherein the line width uniformity between lines intersecting with each other is evaluated, and the line width uniformity between lines not intersecting with each other is evaluated. A method for evaluating the uniformity of line width, wherein the value of the proportionality constant (coefficient) N is made different between the two cases. 4. A computer-readable recording medium storing a line width uniformity evaluation program for causing a computer to execute the line width uniformity evaluation method according to claim 1.