JP2801628B2 - Position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention is applied to a test object having a linear measurement target portion having different contrast between a contour portion and a central portion, for example, an aqueous magnetic fluid for magnetic domain observation is applied. The present invention relates to an improvement in a position detecting device capable of detecting a position of a magnetic recording pattern of a magnetic recording pattern of a VTR magnetic tape with high accuracy.

(Prior Art) Conventionally, for example, a VTR magnetic tape 1 as shown in FIG. 22 has been known, but a magnetic recording format as shown in FIG. The inspection is performed to determine whether the magnetic recording pattern is within a predetermined standard.

Conventionally, this inspection was performed on a VTR magnetic tape 1 after recording was completed.
A magnetic domain observation aqueous magnetic fluid 2 is applied to the VTR, and the VTR magnetic tape 1 coated with the magnetic domain observation aqueous magnetic fluid 2 is developed to form a control pulse, a contour of a magnetic recording portion such as a video track, and a central portion. The linear measurement target portions having different contrasts are exposed on the magnetic tape 1 for VTR, and the magnetic domains are visually observed by setting the magnetic tape 1 for VTR on a tool microscope for precision measurement and the like as a measurement target portion. Detect the position such as the magnetic recording position of the control pulse, etc.
The standard is being measured.

(Problems to be Solved by the Invention) However, the conventional method of measuring the standard by detecting the position by visual observation relies on visual measurement, so the work efficiency is low, and the measurement has large dispersion and low accuracy. There is a problem that.

Further, there is a position detecting device which performs measurement of a standard of a test object having a measurement target portion having a contrast different between a contour portion and a central portion by image processing. If the obtained image is unclear and not good, there is a problem that accurate position detection cannot be performed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a position detecting device capable of greatly improving work efficiency and performing high-accuracy and quick measurement even when an image is unclear and unsatisfactory.

(Means for Solving the Problems) According to the first invention of the present application, contrast is different between two contours and a central portion existing between the two contours, and brightness of the central portion is different on both sides thereof. An image forming optical system that forms an image of the test object having a linear measurement target portion lower than the contour portion, a television camera that electrically detects the image, and the image data obtained by the television camera. An image rotation processing unit that positions the measurement target unit in the reference axis direction; a multilevel quantization level integration processing unit that integrates image data processed by the image rotation processing unit at a multilevel quantization level for each same address; A position detection unit for obtaining the position of the measurement target unit from the extreme value of the central part obtained by the binarization level integration processing unit.

According to a second aspect of the present invention, there is provided a linear measurement method in which contrast is different between two contour portions and a central portion existing between the two contour portions, and the brightness of the central portion is lower than the contour portions on both sides thereof. An image forming optical system that forms an image of the test object having the target portion, a television camera that electrically detects the image, and a tilt of the measurement target portion with respect to a reference axis line from image data obtained by the television camera. A tilt detection unit for detecting, a multi-level quantization level integration processing unit that integrates image data obtained by the television camera in a tilt direction of the measurement target unit detected by the tilt detection unit at a multi-level quantization level; A position detection unit for obtaining a position of the center of the measurement target unit from an extreme value of an output obtained by the quantification level integration processing unit.

(Operation) According to the position detecting device of the present invention, since the image data obtained for each scanning line is multi-valued and integrated to extract feature points, even if the obtained image is not good, ,
The feature points can be clearly extracted, and high-accuracy measurement can be performed quickly.

(Embodiment) Hereinafter, an embodiment of a position detecting device according to the present invention will be described with reference to the drawings.

FIG. 20 is a perspective view showing the entire configuration of the position detecting device according to the present invention. In FIG. 20, 3 is an operation table, 4 is a tool microscope installation table, 5 is a monitor, and 6 is a monitor.
CRT, 7 is an XY plotter, 8 is a keyboard, 9 is a joystick (operation console), 10 is a mouse, 11 is a tool microscope having an image forming optical system in part, and 12 is a contrast between a contour and a center. Is a set table for setting a magnetic tape for VTR as a test object having a different linear measurement target portion, 13 is a TV camera for electrically detecting an image, 14 'is an eyepiece, and each electrical component Is as shown in Figure 21
It has a predetermined connection relationship with the CPU 14, the control unit 15, the image processing unit 16, the pulse converter 17, and the motor driver unit 18.

This position detection device is capable of automatically measuring and calculating the same type of tape after specifying the location and conditions to be measured in advance.
Alternatively, the data is output to the XY plotter 7 and can be saved in a data file.

In this position detecting device, four types of software, teaching, automatic measurement, data processing, and utility, are prepared, and each software is executed by a menu designation method.

When performing automatic measurement, first, a measurement location and the like are specified in advance by teaching, registered as a list of measurable files as a list, and automatic measurement is performed based on the list. The CRT6 normally displays an in-menu before starting measurement.This main menu consists of teaching, automatic measurement mode, data processing mode, and utilities.
When the automatic measurement mode of the main menu is designated by the cursor or the mouse 10 displayed on the CRT 6, the automatic measurement mode is intended.

Before operating the measurement start key of the keyboard 8 or the mouse 10, the VTR magnetic tape 1 is set in advance on the set table 12.
Is to be set.

Next, a file that can be automatically measured is created by teaching. An operator can arbitrarily assign a name to this file, a list thereof is displayed on the CRT, and measurement is started by the keyboard 8 or the mouse 10. Information such as measurement date, lot number, branch number, etc. can be input before this start.

Here, teaching refers to designating the position of a coordinate axis, the position of a control pulse, the position of a video track, and the like in advance. This teaching mode has editing functions such as insertion and deletion, and is also saved as a teaching file. You can also.

This teaching is performed, for example, as shown in FIG. 19. In FIG. 19, reference numeral 19 denotes a reference side of a VTR magnetic tape, reference numeral 20 denotes a control track, reference numeral 21 denotes a video track, and reference numeral 22 denotes a control pulse. In this control track 20, a white magnetic magnetic fluid for magnetic domain observation adheres to the control track 20 for each recording location 22. The magnetic magnetic fluid for magnetic domain observation tends to adhere to the contour of the magnetic recording portion in a large amount, and the central portion has a relatively small amount of adhesion. Therefore, the contrast differs between the central portion and the separated portion.

A temporary coordinate point is designated by the teaching, and a reference side (edge) 20 is detected as a light-dark boundary by searching from the start point A to the start point B with an arrow 23 as shown in an enlarged manner in FIG. . For example, when the line width center M of the video track is designated as a provisional coordinate point, as shown in an enlarged view in FIG. To determine the intersection of the center line LO of the straight lines Z and Z 'and the reference straight line Lx of the reference axis Y. In FIG. 18, the shaded area indicates the area where the amount of the magnetic magnetic fluid for magnetic domain observation adhered to the video track is relatively large, and the central area between the shaded areas is the magnetic domain observation area. 2 shows a region where the amount of the attached aqueous magnetic fluid is relatively small.

The image capturing is performed using the point designated by the teaching as the temporary coordinates. The CPU 14 measures the control pulse position at the location designated by the teaching while performing image processing to be described later, and performs processing for obtaining the average pitch. Further, the CPU 14 detects a correction amount with respect to the standard value of the video track, and also obtains a logical value.

Further, the CPU 14 performs a process of obtaining a distance from the line width center M specified by the teaching to the video tape reference side based on the provisional coordinates specified by the teaching while performing image processing, and displays the result on the CRT 6.

An embodiment of the image processing of such a position detecting device will be described below.

1 to 6 show a first embodiment of the position detecting device according to the present invention.
FIG. 1 shows an embodiment, and illustrates image processing in the case where the inclination of an image is known. FIGS. 1 to 3 schematically show an image displayed on a CRT 6. In FIGS. 1 to 3, reference numeral 24 denotes a box for designating a processing region, a hatched region 25 represents a dark portion where the amount of the magnetic domain observation aqueous magnetic fluid is small, and white line regions 26 and 27 represent magnetic domain observation aqueous magnetic fluids. These figures show, for example, a magnetic recording portion of the control track 20.

When an image is input (see step S1 in FIG. 6), the CP
U14 functions as an image rotation processing unit, performs affine transformation of the image displayed on the screen at a known angle, and rotates the image as shown in FIG. The straight line which is the edge of 26, 27 is Y as the reference axis.
The image is displayed so as to be parallel to the value (step in FIG. 6).
S2). Next, the CPU 14 removes noise from the image data by a spatial filtering process, and emphasizes the edges (see step S3 in FIG. 6). Then, scanning is performed at predetermined intervals in the horizontal direction (X-axis direction) as shown by arrows as shown in FIG. 3 to obtain a plurality of concentration distribution curves Ni as shown in FIG. 4 (FIG. 6). Step S4). In the density distribution curve Ni, the X-axis direction corresponds to the pixel address in the horizontal direction, and the vertical direction corresponds to the brightness. The CPU 14 performs the multi-level integration by performing the multi-level integration, thereby obtaining an integration curve Ns as shown in FIG. 5 by performing the multi-level integration in correspondence with each of these pixel addresses. (See step S5 in FIG. 6). That is, the degree of brightness at the same pixel address for each scanning line is cumulatively integrated to obtain an integral curve Ns.

Then, feature points are extracted based on the integral curve Ns, and the position of the measurement target portion is specified as an evaluation point by the set parameters (see step S6 in FIG. 6). The evaluation point is, for example, position information from the position of the provisional coordinates of the control pulse 20 to the center of the magnetic recording location. By calculating the evaluation point between adjacent controller pulses, the average pitch of the control pulse 20 is obtained. Will be.

Note that the boundaries between the hatched region 25 and the white line regions 26 and 27 are not actually clear, and the boundaries are not represented by geometric straight lines. Integral curve obtained as corresponding to the enlarged view
Ns also has a complicated shape as shown in FIGS.

FIGS. 11 to 16 show a second embodiment of the image processing of the position detecting device according to the present invention, and are used to explain the processing when the inclination is unknown.

In this case, as shown in FIG.
After performing noise removal processing (see steps S1 and S2) on the image displayed at T6 (see FIG. 11), the image is scanned in the horizontal direction as indicated by the arrow in FIG. 12, and the density distribution curve shown in FIG. Ni
(See step S3), and each concentration distribution curve Ni
, A straight line Y 'connecting the peaks Pi is obtained (see step S4), and an inclination θ with respect to the reference axis Y is obtained (see step S5).

Then, each density distribution curve Ni is integrated by adding image data of each pixel address on the straight line Y ', and an integration curve Ns (see step S6) shown in FIG. Is specified (see step S7).

(Effect) Since the position detecting device according to the present invention is configured as described above, it is possible to greatly improve work efficiency and to perform measurement with high accuracy even when an image is unclear and not good. It works.

[Brief description of the drawings]

1 to 10 are views showing a first embodiment of the image processing of the position detecting device according to the present invention, wherein FIG. 1 is a schematic view showing a display state of an image before an image rotation processing; The figure is a schematic diagram showing the image display state after the image rotation processing, FIG. 3 is an explanatory diagram for obtaining the density distribution curve shown in FIG. 4, and FIG. 4 is the density distribution obtained by the scanning shown in FIG. FIG. 5 is a diagram showing an example of a curve, FIG. 5 is a diagram showing an integration curve obtained by multi-value integration of the density distribution curve shown in FIG. 4, and FIG. 6 is a diagram for explaining image processing of the first embodiment. 7 and 8 are enlarged views showing a more general image display state, and FIGS. 9 and 10 are obtained by processing the image data shown in FIGS. 7 and 8. FIGS. 11 to 16 show a second embodiment of the image processing of the position detecting device according to the present invention. FIG. 11 is a schematic diagram showing an image display state before image rotation, FIG. 12 is an explanatory diagram for explaining scanning of the image shown in FIG. 11, and FIG. 13 is FIG. FIG. 14 is a diagram showing an example of a density distribution curve obtained by the scanning shown in FIG. 14, FIG. 14 is an explanatory diagram for obtaining a straight line connecting peaks of the density distribution curve shown in FIG. 13, and FIG. 15 is a density diagram shown in FIG. FIG. 16 is a diagram showing an integration curve obtained by multi-value integration of a distribution curve. FIG. 16 is a flowchart for explaining image processing of the second embodiment. FIGS. 17 to 19 are diagrams for explaining an example of teaching. FIG. 20 is a perspective view showing the overall configuration of the position detecting device according to the present invention, FIG. 21 is a conceptual diagram showing the connection relation of the position detecting device shown in FIG. 20, and FIG. 22 is a VTR. FIG. 23 is a diagram showing a recording format of the magnetic tape for VTR shown in FIG. 22, and FIG. . 1 ... VTR magnetic tape (test object) 2 ... Magnetic fluid for magnetic domain observation 11 ... Tool microscope, 13 ... TV camera 14 ... CPU, 20 ... Control track Ns ... Integral curve, Pi ... Peak (extreme value) Y: Reference axis

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01B 11/00-11/30

Claims (2)

(57) [Claims] 1. A linear measuring object part whose contrast is different between two contour parts and a central part existing between the two contour parts and whose brightness at the central part is lower than the contour parts on both sides thereof. An image forming optical system for forming an image of a test object having the same; a television camera for electrically detecting the image; and image rotation for positioning the measurement target portion in a reference axis direction from image data obtained by the television camera. A processing unit; a multilevel level integration processing unit that integrates the image data processed by the image rotation processing unit at a multilevel level for each same address; and a central unit obtained by the multilevel level integration processing unit And a position detection unit that obtains the position of the measurement target unit from an extreme value of the position detection unit. 2. A linear measuring object part whose contrast is different between two contour parts and a central part existing between the two contour parts and whose brightness at the central part is lower than the contour parts on both sides thereof. An image forming optical system for forming an image of a test object having the same; a television camera for electrically detecting the image; and a tilt for detecting a tilt of the measurement target portion with respect to a reference axis from image data obtained by the television camera. A detection unit; a multilevel quantization level integration processing unit that integrates image data obtained by the television camera in a tilt direction of the measurement target unit detected by the tilt detection unit at a multilevel quantization level; and the multilevel quantization level. A position detection unit that obtains the position of the center of the measurement target unit from the extreme value of the output obtained by the integration processing unit.