JPS6356639A - Magnification distribution measuring method for copy image - Google Patents

Abstract

PURPOSE:To easily find a magnification distribution by measuring edge intervals which are different between forward and backward scans plural times at both ends in both longitudinal and lateral directions and at center positions in a step wherein the intervals of respective lines of a sample are measured while scanning positions are made different. CONSTITUTION:The edge intervals which are different between forward and backward scans are measured at six positions, i.e., both ends R-R, L-L, U-U, and D-D in the (x) and (y) directions and at center positions V-V and H-H. Further, the measurement is performed three times at each position while scanning positions are made different and mean values data are calculated and parts where no measurement is taken are decided and only effective data are left. Then measurement data of a used original are read out and compared with the measurement data on the sample to find the magnification distribution of each part. Thus, the magnification is accurately measured while the whole image is fractionized finely and the magnification distribution of the image is easily and speedily found without using any complex measuring instrument.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for measuring the magnification of a copied image obtained by an electrophotographic copying machine or the like.

(Prior Art) Conventionally, it has been carried out to measure whether such a copied image is formed at a full-screen magnification, and to examine and evaluate the accuracy of the optical system and drive system of a copying machine or the like based on the results. There is.

The following methods are known as this conventional measurement method.

■ Copy a manuscript with a scale of JIS grade 1, measure both ends of the image using the original scale, and find the magnification. This is done in both the vertical and horizontal directions.

- Put marks such as "+" or "ma" on the test chart in advance, measure the distance between the marks in the copied image, and calculate the magnification from the distance between the marks on the test chart.

However, in such a conventional method, the distance between the front edge and the rear edge of the copied image is measured, and the magnification can only be calculated as an average value of a partial image.

For this reason, it has been impossible to measure and evaluate the appearance of an image whose magnification is mechanically determined, as well as the stability of the drive unit, from the image plane. Here, the direction orthogonal to the traveling direction of copying is determined by the distortion of the lens of the optical system, and the traveling direction is determined by the start-up characteristics of the drive system. Further, although it is possible to measure the stability of the drive system electrically, it is time-consuming and cannot be easily performed.

(Objective of the Invention) The present invention addresses the conventional technical problems, and uses a specific image to determine the magnification distribution of the entire copied image without using a complicated measuring device, and evaluates and drives the image. It is an object of the present invention to provide a method for measuring the magnification distribution of copied images that allows easy evaluation of the system.

(Structure of the Invention) The present invention reads an image of an original drawn in a grid pattern with a predetermined line width and a predetermined spacing, and a number consisting of a copied image of this original, and measures the magnification distribution of the copied image. The method includes inputting sample creation conditions, measuring the set state of the sample, its inclination and positional deviation, roughly measuring the copying magnification of the sample, measuring the distance between each line of the sample, and comparing the measured data of the original and the sample to determine the magnification. The process of calculating the distribution and the output display of the magnification distribution are sequentially performed, and the step of measuring the interval between each line of the sample involves scanning different edge intervals in a round trip at both ends and in the center in both the vertical and horizontal directions. It consists in measuring multiple times using different positions.

With this measurement method, it is possible to measure the magnification while dividing the entire image into fine sections, and its distribution can be known.

(Example) FIG. 1 shows an example of a manuscript (test chart) used in the measuring method of the present invention. In other words, WL A is A4, for example.
Lines B with a width of 1jlIl are drawn in a grid pattern at intervals of 10M on a sheet of paper of the same size.As will be described later, in the present invention, this manuscript and a copy of this manuscript II! (Sample) The distance between each line in the vertical direction is at both ends (R-R, L-L) and at the center (V-V).

Lateral ends (U-U, D-D) and center (H-H)
The coordinates of a total of six locations are measured by image reading using optical scanning, and the magnification distribution of the image is determined based on this.

Figure 2 shows the measurement flow of the magnification distribution by the 1st measurement.
The figure shows the measurement flow, and FIG. 4 shows the processing flow. Hereinafter, an explanation will be given based on these. In FIG. 2, in step S1, sample preparation conditions are input to a coordinate measuring device (not shown). In other words, the original 1 used
(test chart) type (registration number, etc.), original size, sample size, copy magnification (specified magnification), copy direction, etc. Next, in step S5, the sample set state is checked. This check measures the distance from the first scanning coordinate, that is, the coordinate axis x-y of the measuring device to the outermost line as shown in Figure 5, at 2 to 30 locations (d1 to d3) according to the input conditions, Measure the tilt and positional deviation in the X and y directions.

Next, in step S3, the copy magnification is measured as a preliminary measurement. That is, the length of the ten upper right portions of the sample is scanned in the X direction, and a rough coordinate calculation magnification (copy magnification) is determined from the cumulative distance. Subsequent coordinate calculations are performed using the results obtained here.

Next, measurement is performed in step S4. This is the first
What is shown in the figure < Edge spacing U1 that differs in the round trip as shown in Figure 6 at both ends and in the center in both x and y directions
．． Q2.・, ml, m2゜... are measured. moreover,
Measurements are made three times at different scanning positions at each location, the average value of the data is calculated, and areas that could not be measured due to breaks in lines are determined and only valid data is retained. Note that the detailed flow of this step S4 will be described later.

Next, processing is performed in step S5. This reads the measurement data of the document used, compares it with the measurement data of the sample, and calculates the magnification distribution for each part. This step S
The detailed flow of step 5 will be described later.

Next, the magnification distribution obtained in step S6 is output, that is, displayed on an external terminal device such as a display or printer.
The measurement is completed by printing and recording on a storage device such as a disk.

FIG. 3 shows the flow of the measurement in step S4. To explain this, the first line is detected in step S11, the distance is counted based on the edge passing through the line in step S12, the next line is detected in step St3, and the next line is detected in step S14. Compare the counted distance with the pitch MIN (minimum 1ll). This pitch MIN
is 0.8X (span of 1 square)X (designated magnification). If the counted distance is greater than the pitch MIN,
Proceeding to step S15, the pitch is compared with pitch MAX (maximum value).

This pitch MAX is 1.2X (span of 1 square) x (
specified magnification). If the counted distance is smaller than the pitch MAX, the process moves to step S16 and data is written in the array.

If the comparison result at step S% is NO, the process returns to step St+. Also, the comparison result in step S15 is N
If o, dummy data O(
0). This means that the line could not be detected.

Thereafter, in step 818, the distance counter is reset and the data Nα is updated by subtracting 1. This data Nα is the number of squares to be measured. Subsequently, in step S19, it is checked whether the data is Nα-(zero), and if the determination is negative (No), the process returns to step S13 and the steps are repeated in the same manner, and if the determination is YES, the process ends.

FIG. 4 shows the flow of the process in step S5. To explain this, in step $21, each line is measured three times with a slightly shifted position, and the average of the three pieces of data is calculated and used as the measured data for that line. next,
In step 322, correction is performed in the case where one or two data out of the three data are O(", that is, a line cannot be detected.

Here, if the data is 0 (zero) all three times,
Excludes data when calculating the average of one line or all lines.

Next, in step S23, measurement data of a document (chart) for comparison is read from the disk.

Further, in step 824, the data in the corresponding boxes of the sample (copy) and original (chart) are compared to determine the magnification. Subsequently, in step 825, 1
The average magnification of the lines and the data with the largest difference from the designated magnification are determined, and in step 826 the average of the magnifications of all lines is determined, and then the process ends.

Figure 7 shows an example of the magnification distribution actually measured. In this example, the magnification of the original and the sample (copied image) is 1 (10
0%). Right (R), vertical (■), left (C), upper (U), horizontal (H), and lower (D) correspond to the scanning directions indicated by the dashed lines in FIG. 1, respectively. From this measurement result, it is possible to determine at which position the magnification is not normal, and it is possible to easily evaluate the image and the optical system and drive system of the copying machine.

(Effects of the Invention) As described above, according to the measuring method of the present invention, in the step of measuring the interval between each line of the sample, both ends in both the vertical and horizontal directions,
Because measurements were taken multiple times at 6!5 locations in the center, with different edge spacings in the reciprocating direction and in different scanning directions,
The magnification can be measured accurately by dividing the entire image into small sections, and the magnification distribution of the image can be easily and quickly determined without using complicated measuring equipment. Comprehensive evaluation of the optical system and drive system of a copying machine can be easily and highly accurately performed.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of a document used in the measurement method of the present invention, FIG. 2 is a flowchart of the measurement method of the present invention, FIG. 3 is a flowchart of measurement steps, FIG. 4 is a flowchart of processing steps, and FIG. Figures 5 and 6 are explanatory diagrams of the measurement method.
FIG. 7 is a diagram showing an example of measurement results. A... Original m (chart), B... Line. Patent applicant Agent: Sanda Kogyo Co., Ltd.
Patent Attorney Etsushi Kotani Patent Attorney Nagou1 Masamukai Patent Attorney Yasuo Itaya Figure 1 Figure 2

Claims (1)

[Claims] 1. A method for measuring the magnification distribution of a copied image by reading the image of an original drawn in a grid pattern with a predetermined line width and at a predetermined interval, and a sample consisting of a copied image of this original. Input conditions, measure sample set state, tilt and positional deviation, approximate sample copy magnification,
The steps of measuring the distance between each line of the sample, calculating the magnification distribution by comparing the measurement data of the original and the sample, and displaying the output of the magnification distribution are sequentially performed. A method for measuring magnification distribution of a copied image, characterized by measuring different edge intervals multiple times at different scanning positions at both ends and in the center in both horizontal directions.