RU1807311C - Flaw detection method for finished and coated cylindrical parts - Google Patents

Abstract

FIELD OF THE INVENTION An object of the invention is to increase productivity and accuracy. The method consists in illuminating the surface of a rotatable pipe with a illuminator and obtaining data on the continuity of the primer layer. The illumination is carried out to obtain the illuminated surface of the screen light reflector located behind it by means of a television camera directed to the tube with the orientation of the lines of the latter along the generatrix of the pipe, while the control line signal is analyzed in the comparator in amplitude in comparison with a given threshold with the issuance of an impulse to control the blocking device in case of exceeding threshold signal. 3 e.p. f l, 2 ill. ё

Description

The invention relates to a measurement technique and can be used to detect defects, for example, a primer coating on surfaces of a cylindrical and spherical shape.

An object of the invention is to increase productivity.

In FIG. 1 shows an arrangement of elements of a device for carrying out a method; in FIG. 2 is a block diagram of a specific device for implementing the method.

In FIG. 1 shows a pipe 1, coated with a primer and illuminated by a light source 2. Behind the pipe 1, with respect to the light source 2, a screen light reflector 3 is arranged with strips calibrated by reflectivity 4. The camera 5 is located at an angle to the light source 2 in one horizontal or vertical plane (not shown in the figures) with its orientation along forming pipe 1. The camera 5 has two outputs, one of which is connected to the clock selector 6, and the other video signal output to the detector 7. Selector 6 has two outputs, one of which is connected to the counting input of the 8 register of D-flip-flop 9 and trehvhodrvy AND gate 10, and the other - with the reset input of the register 8 via a D-flip-flop 11 and inverter 12, through the dynamic RC-chain. The inverting output of the D-trigger 11 is connected to the second input of the three-input element And 10. The non-inverting output of the D-trigger 11 is connected to one of the inputs of the three-input element And 13, the output of which is connected to the counting input of the register 14.

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The reset inputs of the registers 8 and 14 are connected to the output of the logical element And 12. The outputs of the registers 8 and 14 are connected to the detector 15 coincidence, the output of the latter is connected to one of the input of the two-input element And 16, the other input of which is connected to the line output of the selector 6, and the output is with the control inlet of the switch 17. The output of the detector 7 is connected to the inverter 18, the output of which is simultaneously connected to the second input of the element And 13, the first input of which is connected to the line output of the selector 6. In addition, the output of the detector 7 is connected to the control m the input of the switch 19. The signal input of the switch 19 is connected to the video signal output of the camera 5. The input of the detector 7 is connected to the adjustment resistor 20 through the storage capacitor 21 and the detector 22. The video output of the camera 5 is connected to the signal input of the switch 17, the signal output of which is connected to the inverting input of the comparator 23, and the inverting input of the latter is connected to the slider of the adjustment resistor 20. The output of the comparator 23 is connected to the control of the actuator 24. You are connected to a two-input element And 16 is connected n with the control input of the switch 17 through an expander 25 pulses.

The detection of primer defects occurs as follows.

A light source 2 illuminates the surface of the pipe 1 against the background of a screen light reflector 3 with bands calibrated by reflectivity. Light rays reflected from the surface of the tube 1 and reflector 3 enter the camera 5 in the field of view of the cathode ray tube (not shown in the figures). A signal appears on the video output of camera 5, which at the beginning of the frame contains information in the form of rectangular pulses (such as a meander), the presence of which is explained by the passage of lines depicting the surface of the screen reflector 3. These signals are fed to detector 7 at the output which, during the passage of the signal, the meander is set to logic level 1, when the atom is turned on, the switch 19 is turned on and connects the video signal output of the camera 5 to the input of the amplitude detector 22. At the output of the detector 22, the voltage level nor proportional to the amplitude of the signal meander and proportional to the sensitivity of the television camera 5. A part of this voltage, taken from the variable resistor 20, is a reference for the comparator 24. The integration circuit formed by the internal resistance of the detector 22 and the capacitor 21, keeps the amplitude of the reference voltage in flow

whole frame. When the beam passes from the screen floor to the surface of the pipe, logical 1 from the detector goes to the zero state and enters inverter 18, the output of which is set to logic 1. This

0 the signal goes to one of the inputs of the three-input logic element And 13.

From the second output of the camera 5, clock pulses pass, which in the selector 6 are divided into horizontal and frame pulses. Line pulses of positive polarity are simultaneously fed to the input of the three-input logic element And 1.0 and to the input of the three-input element And 13. At the same time, the frame pulses of the selector 6

0 (also of positive polarity) are fed to Ottrigger 11, which is connected via its inverting and non-inverting outputs, alternately allowing the passage of horizontal pulses through

5, the logical elements And 13 and 10, provided that the output of the inverter 18 is also logical G, i.e. Lines with information corresponding only to the reflection from the pipe surface pass through.

0 from the output of the element And 10 line pulses fall on the p-trigger 9, which divides the number of line pulses by two. In the process of running the tube with a beam from the upper to the lower edge, only even (or odd) line pulses enter register 8 and 5, which are added up and stored in register 8. In the next, second half-cycle, D-trigger 11 switches to a new position and horizontal pulses, also reflecting the state of the pipe surface, they arrive at the counting input of the register 14. Information about the number of lines stored in the register 8 is received, together with the information from the register 14, into the match detector 15 for comparison. If the numbers in both registers 8 and 14 are equal, the logical 1 appears at the output of the coincidence detector 15 and arrives at the And16 element. The horizontal sync pulse passes through the And 16 element only if logical G came into it from the match detector 15, and then this sync pulse determines the reference line corresponding to the center of the pipe 1. This pulse is transmitted to the 25 pulse expander, which at the moment when the signal ends, it connects through the switch 17 for a time equal to the line travel (about 60 μs) the inverting input of the comparator 23 to the video output of the camera 5. In

When the reference line passes through the comparator, the signal level is compared with the reference signal throughout the entire line. In case there is no primer on the pipe surface. At the output of the comparator 23, O appears and the actuator 24 rejects the pipe.

At the end of the second half-frame, the next frame pulse transfers the O-flip-flop 11 to its initial state, while the inputs of the registers 8 and 14 are connected, connected to the output of the logical element And 12.

The leading edge of the pulse at the non-inverting output of the D-flip-flop 11 through a dynamic RC-circuit and the inverter 12 produces the operation of registers 8 and 14 on O.

If there are no primer defects on the pipe surface, 1 will appear at the output of the comparator 23 and no signals will be sent to the actuator 24, while the process of monitoring the pipe surface continues.

The described method allows to automatically detect defects in the primer coating and to automatically reject them, eliminates errors in the rejection of products due to pollution of the optical systems of the illuminator and the camera. In addition, the method allows to increase the monitoring performance due to its continuity, providing high reliability and reliability of defect detection.

Claims (4)

1. A method for detecting defects in processing and coatings of cylindrical products, which consists in illuminating the side surface of the product and analyzing the review data, including that, in order to increase productivity, images of a reflecting background and image are formed in the plane of analysis products in the position when its axis is parallel to the scan lines in the analysis plane, at Scanning the image, analyzing the received video signal and generating a threshold signal proportional to the amplitude of the video signal of the background axis, select a control line 5 that matches the image of the generatrix of the product lying in the plane of its diametrical cross section, perpendicular to the analysis plane, analyze the video signal from the control line, and oh A defect is judged by the deviation of the amplitude of the control line signal from the threshold signal. 2. The method according to claim 1, characterized in that, in order to increase accuracy, the background is formed in the form of bands calibrated by reflectivity, the direction of which is perpendicular to the scan lines. and the video signal from them is used as a threshold signal. 0 3. The method of pops 1 and 2, in which, in order to improve accuracy with periodic transverse movement of the product, a reference line corresponding to the upper image-forming image of the product is extracted from the video signal and the line number is fixed, and the control line number is determined by counting from the reference number. a row fixed for each diameter product of the number of rows. 0 4. The method according to claims 1 and 2, characterized in that, in order to increase accuracy with periodic transverse displacement of the product and increase productivity by automatically detecting and counting 5 a fixed number of lines, a light and the receiver is placed in the plane of the diametrical section of the product, the reference line number is extracted, then the line number defining from the same frame 0 the lower image generator of the article, and the control line number is determined as half the difference between the line numbers, and the control line itself is selected according to the received number in the next 5 frame. Fie. { Ziyeo / Mal Simrombe s (and Eeeasigp || ILU4 Ј 1 CHH tonut 4ntt