JP2634049B2 - Text printing quality control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention manages the print quality of character printed matter such as dictionaries and textbooks, centered on characters, printed by a printing machine such as an offset printing machine or letterpress printing machine. The present invention relates to a character print quality control device that performs the following.

(Prior Art) In general, in a character printed matter centering on a character printed by a printing machine such as an offset printing machine or a letterpress printing machine, particularly in encyclopedias, dictionaries, textbooks, etc., all pages of the character printed matter are used. Maintaining uniform density and thickness of characters is strongly required as the quality of character prints. Also, among printing failures that occur during printing, the presence or absence of bleeding, blurring, overprinting, etc. is one of the major factors in evaluating the printing quality of characters. Therefore, conventionally, in order to prevent such deterioration in print quality, the printed character being printed is manually extracted at a certain interval, and the impression of the character (density, thickness), the appearance of the character, Evaluation is performed for blurring and the like, and the printing press is adjusted so that print quality is kept constant.

(Problems to be Solved by the Invention) However, it is impossible due to the characteristics of the printing press to operate one printing press in the same state for a long time and keep the print quality of the character prints constant. Further, since one character printed matter is usually composed of a plurality of signatures, printing is often performed separately by a plurality of printing machines. For this reason, the quality management of the printed matter is greatly influenced by the characteristics of the printing machine and the individual differences in the sense of the evaluator who manages the printing quality of the printing machine operator and the like. On the other hand, even if the same operator evaluates the printed text, even if the physical condition at that time, the environment such as lighting, etc.
Variations occur in the evaluation due to various factors, resulting in variations in print quality. Furthermore, recently, since the number of skilled persons who can evaluate the print quality of a character print has decreased, it has become increasingly difficult to guarantee the print quality of the character print.

Despite the above situation, there is currently no device that automatically manages the print quality of printed text,
The emergence of such devices has been strongly desired.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and evaluates the print quality of a character print such as an encyclopedia, a dictionary, a textbook or the like having a particularly high print quality requirement by various factors. It is an object of the present invention to provide a character print quality management device capable of automatically and easily managing the print quality of a character print without causing a variation, thereby maintaining a stable print quality of a character print.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, in a device for managing the print quality of at least one character printed matter of a dictionary, a dictionary, and a textbook centered on characters, Is divided into a plurality of pixels and taken in as a gradation signal for each pixel, and a gradation signal of a frequently used character portion used over all pages of the character printed matter is extracted and taken in. Input means, storage means for storing a tone signal for each pixel captured by the input means, and (a) density of a paper portion and density of a character portion based on the tone signal stored in the storage means. And (b) detecting an edge portion of the character and calculating a distance between the edge portions to obtain a density distribution between the character print material and the character distribution. Features that indicate print quality A feature quantity extracting means for extracting the quantity, or a feature quantity extracting means for creating a character density histogram and extracting a feature quantity representing the print quality of the character print from the density histogram, and a feature quantity extracted by the feature quantity extracting means The print quality evaluation unit evaluates the print quality of the character print by performing the determination of the print quality or comparison with the reference data, and the output display unit outputs and displays the result evaluated by the print quality evaluation unit.

(Operation) In the above-described character print quality management device, the frequently used character portion used over all pages of the character print material to be managed is scanned using the input unit, and divided into a plurality of pixels. A gradation signal for each pixel is input, and the gradation signal for each pixel is stored in the storage unit. Then, based on the gradation signal, the feature amount extracting means obtains a density distribution between the density of the paper part and the density of the character part, or detects an edge part of the character and obtains a distance between the edge parts. Alternatively, a density histogram of a character is created, and a predetermined characteristic amount representing the print quality of the character print is extracted from the density histogram. The print quality is evaluated by the print quality evaluation means or compared with the reference data to evaluate the print quality, and the evaluation result is output and displayed to the operator of the printing press by the output display means. Therefore, since the operator can adjust the printing press with reference to the displayed contents and manage the printing quality based on objective data, it is possible to suppress the variation in the quality of the printing machine and to ensure that high printing quality is required. In character prints such as textbooks, dictionaries, and textbooks, it is possible to greatly reduce the occurrence of defective prints due to variations in print quality and the like.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an external view showing a basic hardware configuration example of a character print quality management device according to the present invention, and FIG. 2 is a functional block diagram of the character print quality management device.

First, in FIG. 1, 1 is an encyclopedia to be managed,
Character printed matter such as dictionaries and textbooks, 2 is a flat bed type image scanner as an input means, 3 is a transparent frame on the top of the image scanner 2, 4 is a light shielding door, and 5 is a switch. Reference numeral 6 denotes an image scanner 2 via a cable 7.
A monitor 8, a disk device 9, and a mouse device 10 are connected to the processor 6 as shown in the figure.

Here, the printed character 1 may be printed by a printing machine using an offset printing method, or may be printed by a printing machine using a letterpress printing method. Further, the present invention is not limited to the same printing machine, but may be a character printed matter printed by a plurality of printing machines. On the other hand, as the image scanner 2 as an input means, it is desirable to read the image with a gradation of 8 bits or more and a resolution of about 10 to 30 lines per 1 mm. This is because the resolution of the human eye is about several tens of micrometers, so if the resolution is too low, quality control becomes meaningless.
If the input is too small, the amount of data to be handled increases, and not only does the time required for subsequent arithmetic processing become extremely long, but also the memory and disk capacity for storing the data become quite large. is there. For this reason, in this embodiment, an image scanner using a CCD line sensor having a resolution of 16 lines per mm will be described. The input means is not limited to a flatbed type image scanner, but may be a CCD type camera, a video signal output type camera, a drum type scanner or a flying spot type scanner. Also, the configuration of the system is not limited to that shown in FIG.
Other configurations may be used as long as they have equivalent functions and effects.

Next, in FIG. 2, 11 scans a specific character portion in the character print 1 to be managed, that is, a frequently used character portion used over all pages of the character print 1, and scans a plurality of pixels. Input means (CCD line sensor) 12 for dividing and taking in as an optical grayscale image signal which is a gradation signal for each pixel and converting it to an electric signal and outputting the signal, and 12 for the output signal from this input means 11 A LOG circuit for converting the signal into a density value, a numeral 13 is a digitizing means for converting an analog signal which is an output signal from the LOG circuit 12 into a digital signal, and a numeral 14 is for correcting the output signal from the digitizing means 13. And an image processing means 15 for storing the output signal from the image processing means 14. The reference numeral 51 performs a predetermined operation / process based on the grayscale image signal stored in the storage means 15 and obtains a predetermined characteristic amount (character density, thickness, blur, blurring) representing the print quality of the character print 1. And the like, and the characteristic quantity extracted by the characteristic quantity extracting means or the comparison with reference data stored in advance in the reference memory 52 to determine the print quality of the character print 1. This is a processing unit including a print quality evaluation unit to be evaluated. Reference numeral 53 denotes an auxiliary storage unit composed of a disk for storing the evaluation result of the processing unit 51, and reference numeral 54 denotes an output display unit composed of a monitor for outputting and displaying the evaluation result of the processing unit 51.

Here, when the LOG circuit 12 inputs a grayscale image signal as a gradation signal by the CCD line sensor, the portion having a high print density is an important factor in the character quality.
This is used for the purpose of digitizing the gradation of a high density portion with high precision and high resolution before performing D conversion. However, the same effect can be obtained by increasing the number of A / D conversion bits by using a linear amplifier or by using another nonlinear amplifier. Further, the image processing means 14 may use a calibration curve in advance because the signal digitized by the digitizing means 13 may include information errors due to optical distortion of the CCD line sensor and variations in photoelectric conversion characteristics. And the like, and the data is stored in the storage means 15, and the data of the calibration curve is appropriately called up and used for the purpose of correcting the signal value. In this case, as a calibration method, linear (one-dimensional) correction may be performed when a flatbed image scanner is used as the input unit 11, but when a TV camera or the like is used, the correction may be performed in consideration of the illumination. A planar (two-dimensional) correction is performed.

Next, the operation of the character print quality management device configured as described above will be described.

First, the worker sets the character print 1 to be measured on the transparent base 3 above the flatbed type image scanner 2 such that the inspection surface of the character print 1 is in contact with the base 3. Next, the worker closes the light shielding door 4 for shielding external light and turns on the switch 5, so that the data from the image scanner 2 is transferred to the processor 6 via the cable 7. This data is obtained by inputting a specific character in the character print 1, that is, a frequently used character used over all pages of the character print 1 by the input means 11 as a grayscale image signal. It is digitized through the digitizing means 13 and further corrected by the image processing means 14 for signal errors due to optical distortion and variation in photoelectric conversion characteristics, and stored in the storage means 15. The characteristic amount extracting means of the processing means 51 performs a predetermined calculation and processing based on the grayscale image signal stored in the storage means 15 to extract a predetermined characteristic amount representing the print quality of the character print 1. You. Further, the extracted feature amount is determined and evaluated by the print quality evaluation unit of the processing unit 51.
Alternatively, the print quality is evaluated by comparing with reference data stored in the reference memory 52. The evaluation result of the print quality is output and displayed to the operator of the printing press by the output display means 54, that is, the monitor 8, and is stored in the auxiliary storage means 53.

Next, a method for extracting a characteristic amount representing the print quality of the character print 1 from the grayscale image signal captured by the image scanner 2 and a method for evaluating and evaluating the print quality by determining and comparing the characteristic amounts are described. Will be described.

First, the operator transfers image data including the density of a character print as a reference from the image scanner 2 to the processor 6 by the above-described method. At this time, the image data may be stored in the memory of the processor 6 or may be stored in the disk device 9 serving as the auxiliary storage unit 53. Next, the operator selects a character whose characteristic amount of a specific character quality is to be obtained from the image of the character printed matter displayed on the monitor 8.
In this case, a specific character may be selected by scanning the cross-shaped or square-shaped cursor displayed on the monitor 8 with the mouse device 10, or may be selected using a digitizer, a keyboard, or the like. However, this operation may not be performed manually, but may be performed automatically by adding a means for automatically selecting a specific character in the processor 6.

In addition, in the case of Japanese, the character for which the characteristic amount is to be obtained is “.”, “,”, “”, “”, “”, “”, Or “1”. By selecting a character with a high character, it is possible to compare the quality of the same character between pages or between signatures if it has the same series and character style. We use the fact that the same character series and font are often used between pages and between signatures. Is more effective because the probability that the character to be compared is present on the page to be compared is high, and it is less likely that comparison cannot be performed. In addition, it is possible to reduce the effect of this on text printed materials using languages other than Japanese. Be selected frequent letters and symbols are of use in character prints, it is similar to that of Japanese.

Hereinafter, a method of selecting a frequently used character "" as shown in FIG. 4 as an example from a textbook such as a text print as shown in FIG. 3 and obtaining a feature amount obtained from the selected character will be described.

First, in order to obtain a density distribution of a contour portion of a character, a density cross-sectional view 19 of one cross section 18 at a ““ ”portion in FIG.
In this case, if the density distribution is as shown in FIG.
If an ideal step is formed at the boundary between the image and the character portion 17, the intermediate value of the density (here, the intermediate value
It is a density value between the density of 16 and the density of the character part 17,
(Not an intermediate value), and the printing state is ideal. On the other hand, when the density cross-sectional view slowly changes at the boundary between the paper white portion 16 and the character portion 17 as shown in FIG. 4A, as shown in FIG. It is possible to determine that there are a plurality of intermediate values having different density values, and that "blur" has occurred in the printing state of the outline portion of the character. When the density cross-sectional view has two density peaks and spreads at the boundary between the paper white portion 16 and the character portion 17 as shown in FIG. ), It is possible to determine that there is a flat portion of the density value, and that a "burst" has occurred in the printing state of the outline portion of the character.

In other words, when “blurring” or “blurring” has occurred, there are a plurality of intermediate values between the paper white portion 16 and the point of the highest density in the character portion 17, and the number of intermediate values By determining whether or not the character is included, it is possible to quantify the sharpness of the outline of the character as objective information.

Next, a method for determining the thickness of a character will be described. Note that the method referred to here is a method of measuring the thickness of a character with high accuracy, and does not calculate the thickness itself (a method of measuring a length equal to or less than a pixel width).

A method for determining the thickness of a character is performed by detecting an edge portion of the character and determining a distance (hereinafter, referred to as an edge distance) as follows. That is, the sixth
The figure shows one pixel of the resolving power in the line direction of the input means 11 and a density graph for the one pixel. In FIG. 6, when the density of the paper white portion is A, the density of the character portion is B, the intermediate density value of the pixel of the edge portion is C, and the distance (resolution) of one pixel is P, The edge distance x is obtained as follows.

C = A (P−x) + Bx / P Therefore, x = P (A−C) / (A−B) + the number of pixels in the character part Therefore, it is compared whether or not this character thickness is within the reference value. By doing so, the thickness of the character can be evaluated.

 Next, a method of determining the density value of a character will be described.

As a method of determining the density value of a character, the maximum density of the above-described density cross section may be used as the character density, or a density histogram of the selected character is created as shown in FIG. The value at the time of 34 may be used as the character density, or the average value of the density of the character portion may be obtained and used as the character density.

On the other hand, to calculate the average value of the density of the character portion, a density histogram of the selected character is obtained as shown in FIG. 7, and the density of the paper white portion 30 and the density of the character portion 31 are divided by a certain threshold value. A character portion is extracted, and arithmetic calculation is performed on the density in a portion where the density is higher than the threshold. In this case, the threshold value may be simply an intermediate density between the white level and the black level, or an intermediate density which divides the highest frequency value 33 of the white level portion 30 and the highest frequency value 34 of the black level portion 31 into two. May be used.

Therefore, the density of the character portion can be evaluated by comparing whether or not the character density value is equal to the reference density value.

The evaluation results of the various characteristic amounts of the printed character obtained as described above are displayed on the monitor 8 to notify the operator of the printing press. At this time, the feature amount may be displayed numerically, or may be graphically displayed using a bar graph or the like. The operator adjusts the printing press based on the evaluation results of the various characteristic amounts of the character prints displayed on the monitor 8, thereby making it possible to suppress variations in the print quality of the characters, and to print the entire character prints. The quality can be improved. In addition, by sequentially storing and storing the extracted feature amounts in the disk device 9 and managing them, it is possible to prevent variations in print quality due to aging. As a result, it is also possible to manage the print quality of the published print by the revision or edition.

As described above, in the character print quality management apparatus of the present embodiment, the evaluation result of the characteristic amount relating to the print quality such as the character density, character thickness, buzz, blur, and the like is transmitted to the operator of the printing press by the monitor 8. Since the display is made to notify the operator, not only can the variation in the evaluation of the character print quality of the operator due to individual differences and aging (fatigue) be suppressed, but also the quality control of the character print can be performed by a non-expert. A great advantage, such as extremely easy operation, can be obtained, and as a result, the occurrence of defective character prints can be greatly reduced.

(Effects of the Invention) As described above, according to the present invention, the print quality of character prints, especially characters such as encyclopedias, dictionaries, and textbooks, for which print quality requirements are particularly high, can be used to reduce variations in evaluation due to various factors. It is possible to provide a character print quality management device that can automatically and easily manage the print quality without causing any trouble, and thus can always keep the print quality of the character prints stable.

[Brief description of the drawings]

FIG. 1 is a hardware configuration diagram showing one embodiment of a character print quality management device according to the present invention, FIG. 2 is a functional block diagram showing one embodiment of a character print quality management device according to the present invention, and FIG. FIG. 4 is a view for explaining the relationship between a place where one character of a character printed matter is enlarged and a density sectional view at one place, and FIGS. 5 (a) and 5 (b) show the same embodiment. FIG. 6 is a diagram for explaining a method of evaluating “blur” and “blurring” in the example, and FIG. 6 is a diagram for explaining a method of evaluating the resolving power of the input means and “character thickness” in the embodiment. FIG. 7 is a diagram showing a density histogram for explaining a method of evaluating “character density” in the embodiment. DESCRIPTION OF SYMBOLS 1 ... Character printed matter, 2 ... Image scanner, 3 ... Transparent stand, 4 ... Light shielding door, 5 ... Switch, 6 ... Processing machine, 7 ... Cable, 8 ... Monitor, 9 ... Disk device , 10 ... mouse device, 11 ... input means, 12 ... LOG
Circuit 13, Numericalizing means 14, Image processing means 15, 15
Storage means, 51 processing means, 52 reference memory, 53
Auxiliary storage means, 54 ... output display means, 16 ... paper white part,
17 ... Character part, 18 ... Position of density cross section, 19 ... Ideal density cross section, 20 ... Density density cross section, 21 ... Dense density cross section, 30 ... Paper white part of density histogram , 31
…… Character part of density histogram, 32 …… Threshold, 33…
... mode density in paper white part, 34 mode density in character part.

Claims (3)

(57) [Claims] At least a dictionary centering on characters, a dictionary,
In a device for managing the print quality of a single text print of a textbook, the print subject to be managed is divided into a plurality of pixels and fetched as a gradation signal for each pixel, and used over all pages of the text print. Input means for extracting and taking in the gradation signal of a frequently used character portion, storage means for storing a gradation signal for each pixel taken in by the input means, and A feature amount extracting means for obtaining a density distribution between the density of the paper portion and the density of the character portion based on the stored tone signal, and extracting a feature amount representing the print quality of the character print; A print quality evaluation unit for evaluating the print quality of the character print by judging the feature amount extracted by the unit or comparing with the reference data; and outputting a result evaluated by the print quality evaluation unit. Text printing quality control apparatus characterized by comprising and an output display unit for displaying. 2. At least a dictionary, a dictionary, and the like centered on characters.
In a device for managing the print quality of a single text print of a textbook, the print subject to be managed is divided into a plurality of pixels and fetched as a gradation signal for each pixel, and used over all pages of the text print. Input means for extracting and taking in the gradation signal of a frequently used character portion, storage means for storing a gradation signal for each pixel taken in by the input means, and A feature amount extracting unit that detects an edge portion of the character based on the stored gradation signal, obtains a distance between the edge portions, and extracts a feature amount representing a print quality of the character printed matter; and the feature amount extracting unit. A print quality evaluation unit that evaluates the print quality of the character print by performing determination of the extracted feature amount or comparison with reference data, and a result evaluated by the print quality evaluation unit. Text printing quality control apparatus characterized by comprising and an output display unit for outputting display. 3. At least a dictionary, dictionary, centered on characters.
In a device for managing the print quality of a single text print of a textbook, the print subject to be managed is divided into a plurality of pixels and fetched as a gradation signal for each pixel, and used over all pages of the text print. Input means for extracting and taking in the gradation signal of a frequently used character portion, storage means for storing a gradation signal for each pixel taken in by the input means, and A feature amount extracting unit that creates a character density histogram based on the stored tone signal, and extracts a feature amount representing the print quality of the character print from the density histogram; and a feature extracted by the feature amount extracting unit. A print quality evaluation unit that evaluates the print quality of the character print by performing the determination of the amount or comparison with the reference data, and the print quality evaluation unit evaluates the print quality. Text printing quality control apparatus characterized in that it comprises an output display means displays and outputs result, a.