SU1599730A1 - Roentgenotelevision flaw detector - Google Patents

Abstract

The invention relates to a technique for non-destructive testing of materials and products, specifically to an X-ray television flaw detector, and can be used in diagnosing the quality of welded joints. The purpose of the invention is to increase the reliability of control of welded joints. A device containing a series-connected X-ray source, a controlled object, an X-ray light converter and a transmitting television camera on a CCD array (devices with charge coupling), as well as an adder, a delay line, a coincidence circuit, and a defect classifier, additionally introduced an analog a digital converter, four buffer circuits, a quad, two accumulators, a subtraction unit, a square root extraction unit, a memory register, a comparison circuit, two NOT elements, a counter, and a one-shot. 4 il.

Description

The invention relates to non-destructive testing of materials and products, more specifically to radiation flaw detectors, and can be used in flaw detection of welds.

The aim of the invention is to increase the reliability of the control.

Fig. 1 shows the block diagram of the proposed X-ray focal flaw detector; in fig. 2 is a functional circuit diagram of a camera on a three-phase array of devices with charge-coupled connection (CCD) with a control unit; in fig. 3 - block diagram of the defect classifier; in fig. 4 shows the results of calculating the probability of a correct diagnosis for three values of the probability o.

The X-ray flaw detector will clamp the X-ray source 1, the object to be monitored 2, the X-ray converter 3 light transmitting the television camera 4 on the array of devices with charge coupling, control unit 5, one-shot 6, ADC 7, buffer circuit 8, HE element 9, buffer circuit 10, quadrant II, accumulator 12, counter 13, accumulator 14, buffer circuit 15, coincidence circuit 16, buffer circuit 17, subtraction unit 18, extraction unit 19, square root (BICC), delay line 20, HE element 21, adder 22, classifier 23 defects, register 24 n m minute, comparing circuit 25, electrical input 26 of the flaw detector, the output

27 control units, formers

28-30 phase voltages, block 31 delisl

with

s

with

frequency generator, generator 32 transfer pulses, generator 33 readout pulses, section FOR accumulation, section 35 of memory, video amplifier 36, output register 37, output device ctBO 38.

X-ray radiation source 1, passed through a controlled object. 2, is converted in the converter 3 into optical radiation projected onto the transmitting television camera 4 on the CCD array; the electrical input 26 of the flaw detector is connected to the inputs of the control unit 5 and the one-oscillator 6; The output of the television camera 4 is connected to the input A | 11 7 and the input of the classifier 23 defects, the input of which is connected to the input: ohm of the delay line 20 and one output 27 of the control unit 5, the other to the output of which is connected to the control input of the television camera 4, and: the output is combined with the installation input of the counter 13, the input of the classifier | ikator 23 the gate inputs of accumulator 12 the accumulator 14, the buffer circuit 15, the buffer circuit 17 and the register 24 a memory. The output of the A / D converter 7 is connected to the information inputs of the buffer circuit 8 and the buffer circuit 10, the control input of which is connected to the 1st input of the coincidence circuit 16, the input is connected to the output of the HE element 9o by the input of the classifier 23 and Through the element NOT 21 to the input of the circuit 16 matches. The output of the buffer 110 is combined with the input of the Quad 1 and the information input of the accumulator 14, the output of which is connected to the information input of the buffer circuit 17 whose output is combined with the information inputs of the 18-subtraction unit and the adder 22, The output of the quad squadron 11 is connected to the information input of the accumulator 12, the output of which is connected to the information input of the buffer circuit 15, the output of which is connected to the information input of the bln.a 18 subtraction, the output of which through the BICC 19 is connected to the information input of the adder 22 whose output is connected , To the data input of the register memory 24, whose output is connected to the data input of the comparison circuit 25, an information input of which is connected to the output buffer circuit 8. The output line

five

0

five

0

five

0

five

0

20 delay connected to the input of the circuit 16 matches, the output of which is connected to the counting input of the counter 13, the output of which is connected to the input of the element HE 9.

The proposed X-ray flaw detector works as follows.

The X-ray radiation from source 1, after passing through the controlled object 2, creates on the converter 3 shadows; the image of the internal macrostructure of the site of object 2. After the transformation, the optical image is projected onto the matrix in the transmitting television camera 4 (Fig. 1).

Image processing starts from the moment a pulse is applied to the electrical input 26 of the instrument. During the time interval t ocynie, the accumulation of charges in the photosensitive cells of the CCDs takes place. During the personnel extinguishing pulse, the accumulated charge packets are transferred to the memory section of the matrix, from where they are written to the output register with the line frequency. During the direct move by. In the string, the charge packets by element-by-wire, the TC from the output register and in the output device are converted into a video signal received at the analog input of the A / D converter 7, the luminance video signal Uj. from the output of the television camera 4, is converted into .ADP 7 into a binary code. arriving at the information inputs of the buffer circuits 8 and 10,

The comparison circuit 25 compares the digital code of the charge packet from the analyzed photocell coming from the output of the buffer circuit 8 to its. input, digitally with the code of the threshold level. At the other input, stored during the time of retrieving information from the photo cells of the matrix row in memory register 24.

The level threshold value during the analysis of the (j + 1) th row of photocells is set equal to

M - (V-4z) G, ..

55, where X, represents the percentage of a normal random vein of causality;

Oy is the likelihood of jioKHbix alarms;

z

.; /

2 g

(ZU ;; - zr) / (z-i) - co j, j j

Responsibly assess the mean and variance obtained during the analysis of Z photo element 2 -

Z- led sig 10 pores

l With

Р (SlU - 2: U -) / Z; 1-1

1599730

TO CCD CCD in the jth row preceding the analyzed one.

Consider that Z 1, take Z-1 ftZ, Z / (Z-1) l 1 and estimate the variance of the samples of the video signal of the television camera U and the threshold level k j., Using the formulas

(one)

z z

k TI-

 L j

+

i

at the moment of transition to the review of the new (j + 1) -th line, the line quenching high logic level pulse from the output of the control unit 5 is fed to the control inputs of the accumulators 12 and 14, the buffer circuits 15 and 17 and the memory register 24, has wrapped the contents last one. Accumulated in accumulators 12 and 14 information about ve

g 2

: I

.Uj; in the form of digital codes through open buffer circuits 15 and 17 enters the information-. Cirn inputs of subtraction unit 18, at the output of which a digit 22 is generated

the prime code of the number U ;; - U :; .

i: .i

in order to simplify the design of the flaw detector, it is necessary to choose the value of X multiple of two, i.e. X 2. Then the multiplication on the right side of the expression () is realized by shifting D bits towards the higher bits of the code from the output of BICC 19 relative to the bit inputs of the adder 22. To do this, it is enough to apply the voltage O for D younger bits of the adder 22

At the output of adder 22, a digital code of the number appears.

ZU-; .

X

fti

and, the condition Vi and j I of the presence of a defect in the analyzed photocell of the matrix will be represented as

V - ZU-; implemented in the invention.

(2)

X

ci

 I- ui J, jj

I.ri select Z 2

25

thirty

multiplication in the right-hand side of inequality (2) realizes 2Q with a shift by N bits towards the higher bits of the code from the output of the buffer circuit 8 relative to the bit inputs of the comparison circuit 25. To do this, it suffices to apply the voltage of logical 0 for the N low-order bits of the input of the comparison circuit 25.

The rows of the matrix are located parallel to the weld; the latter makes it possible to consider the first analyzed row of photocells as completely defective. During the analysis of its photocells, the digit outputs of the memory register 24 are set to a digital code corresponding to zero, and the control input of the buffer circuit 35 8 is affected by a low logic level voltage from the output of the one-oscillator 6, thus, during the analysis of all elements The first line on the bit outputs of the buffer circuit 8 40 is set to a digital code corresponding to zero. Therefore, condition (2) will not be fulfilled.

The control of the operation of the flaw detector circuit and the transmitting television camera 45 is organized by the block 5. The explosive circuit diagram of the chamber on a three-phase I matrix with a control unit is shown in FIG. 2. From the output of the control unit 5 to the installation input of the counter 5013, a sequence of pulses with a frequency of lines is applied. The output of control unit 5 is the output of the counting pulse generator. Counter g 13 counts the number of first Z 2 55 defect-free decomposition elements per line. Moreover, the selected number Z does not exceed the number of photocells in the row of the CCD Z matrix and is a multiple of two, that is, Z. Zg.

: An exception to the consideration during the formation of the threshold level of defective photocells is provided by the inclusion of a circuit of 16 coincidences, the input of which through the element-HE 21 is connected to the output of the comparison circuit 25. After counting the Z-ro photocell, a voltage appears at the output of the counter:: corresponding to 1, and a voltage at the input of the circuit 16, I In this case, the input voltage O of the buffer circuit I10, prevents the transfer digital code with: defective item at the output of the buffer: Noah. schemes 10.

 For temporal combination. Pulse; ow from the output 27 of the control block 5 from the output of the circuit. 25 comparisons in the de- fection test, a delay line 20 is entered; ki. The defect classifier 23 may i be similar to that described in the prototype. The structural scheme of the classifier: the defect torch (Fig. 3) includes: a video monitor 39, a mixer 40, a coincidence circuit 41, a block 42 for the monitored section, a recorder 43, a generator 44 and a pulse illumination pulse. The signals of defects from the output 45 of the classifier: arrive at the first input of the circuit 41 matches. At the same time, to the other; the input of the coincidence circuit 41 is supplied; pulses from the generator 44 of the light pulses, whose frequency is a few Hertz. As a result, at the output of the matching circuit 41, the defect illumination pulses appear with the frequency of the i generator 44 and, passing through the mixer 40, are mixed with the video signal of the transmitting television camera arriving at the input, with the result that on the screen of the video monitoring device 39 . No defect, a periodically flickering color appears, which greatly improves the visibility of the defect for the operator. The input from the mixer 40 is supplied with a signal from a block 42 for the selection of the monitored area, and on the screen of the video monitoring device 39 there appears a cohort of the image selected for analysis.

By limiting the defect area to counter, the operator then determines the area to be analyzed. Defect signals supplied to the input of block 42 of the monitored section,

pass through it and from the output of the mentioned block is fed to the input of the registrar 43, which records defects by value, according to the selected classification.

When the video signal is captured in the form of digital codes from the output of ACCH1 7, it is possible to process images in a computer according to a predetermined program. In this case, a classifier is used.

The accuracy of diagnosing defects in welded joints P is related to the signal-to-noise ratio

q (-) / С

ROBN (q - X), (3)

where (p (x) is the distribution function

normalized and central normal distribution;

9 (X) (l4) J exp (-tV2) dt,

-00

where f (j is the estimated average value and the variance of the samples from the defective area of the object under study. During the processing of the photoelectric samples The rows of the CCD matrix give an estimate of the average value and the variance G of the normal distribution of the video samples with Z zero-defect photoelectric cells. Let the trust factor J be the probability fit | x} Y because the absolute value of the normalized error of the mean value estimate

- (Mr.

five

not. greater than a given value of t y. Then the confidence interval for the open parameter C is represented by the inequality

BUT

but

if fc 5

one

J5

In tab. I shows the values of the coefficient a J. for a number of values of J and Z.

In tab. 2 shows the boundaries of the confidence interval.

The confidence interval for the dispersion of the normal sl, the untrue value corresponding to the trust coefficient LP, is determined by the inequalities bn j., G is the lower b .c and

The upper bg of the confidence interval can be found from Table. 2

For a CCD 1200CM1 matrix with 232 photocells in each of the 144 rows, the choice of probabilities ci 3, 2-1 О guarantees less than one false response of the flaw detector for analyzing the entire matrix. At the same time, the provision of q 5.3 allows detection of defects with a BOR of 0.9.

The use of 2 64 faultless photovoltaic cells in a row for estimating the parameters of a random process will allow, as follows from the table. i and 2, to provide confidence intervals at confidence coefficients at ep 0.95.

r-VUo, 25G- 0,

1.44

for estimating the mean and variance of the sample of the luminous video signal. In the case of Z 128, the confidence intervals for estimating the parameters of a random variable can be additionally reduced by almost F, 5 times. The present invention provides a high adaptation of the flaw detector to changes in the parameters of the observed video signals, which guarantees an increase in the reliability of control.

F o

rmula of invention

An X-ray inspection flaw detector containing an X-ray source and successively arranged X-ray light converter and a transmitting television camera, the input of which is connected to the first output of the control unit, as well as an adder, delay line, coincidence circuit and defect classifier J, that, in order to improve the reliability of the P: ONT-roll, an analog-to-digital converter, four buffer circuits, a quad, two accumulators, a subtractor

ten

15

0

five

0

five

0

five

0

square root, memory register, comparison circuit, two NOT elements, counter, one-shot, the television camera output is connected to the first input of the defect classifier and the analog-to-digital converter input, the output of which is connected to the information input of the first and second buffer circuits, the last connected to the information inputs of the quadrant and the second storage device, the output of which through the third buffer circuit is connected to the first information inputs of the subtraction unit and the cyNimator, the output of the quadrant through the first storage device and the fourth buffer circuit is connected to the second info ;; the action input of the subtraction unit, the output of which is connected via the square root extraction unit to the second at the information input of the adder, the output of which through the memory register is connected to the second comparison input, the first information input of which is connected with the output of the first buffer circuit, the control input of which is connected to the output of the one-shot, the input of which is combined with the input of the control unit and is the electrical input of the flaw detector, with the second output of the control unit connected to the second input of the defect classifier and through delays to the first input of the coincidence circuit, the INPUT of which is connected to the control input of the second buffer circuit and through the counter connected to the input of the first element NOT, the output of which is connected to the second input of the coincidence circuit, the third input of which is connected to the output the second element NOT, the input of which is combined with the third input of the defect classifier and the output of the comparison circuit, the third output of the control unit is connected to the installation input of the counter, the fourth input of the classifier d defects and the control inputs of the first and second storage devices, the memory register, a third-fourth buffer circuits.

Table 1

26

/ 2

3

FIG.

Fig.Z

Claims (1)

Claim An X-ray television flaw detector containing an X-ray source and a sequentially located X-ray-light converter and a transmitting television camera, the input of which is connected to the first output of the control unit, as well as an adder, a delay line, an coincidence circuit, and a defect classifier I mean that, in order to increase the reliability of control, an analog-to-digital converter, four buffer circuits, a quadrator, two drives, a subtraction unit, a square root extraction unit, a memory register are introduced into it , a comparison circuit, two elements NOT, a counter, a one-shot, and the output of the television camera is connected to the first input of the defect classifier and the input of an analog-to-digital converter, the output of which is connected to the information input of the first and second buffer circuit, the output of the latter is connected to the information inputs of the quad and the second drive, the output of which through the third buffer circuit is connected to the first information inputs of the subtraction unit and the adder, the quad output through the first drive and the fourth buffer circuit is connected and with the second information input of the subtraction unit, the output of which through the square root extraction unit is connected to the second information input of the adder, the output of which through the memory register is connected to the second comparison input, the first information input of which is connected to the output of the first buffer circuit, the control input of which is connected to the output of the one-shot, the input of which is combined with the input of the control unit and is the electrical input of the flaw detector, and the second output of the control unit is connected to the second input of the classifier and defects through the delay line with the first input of the coincidence circuit, the output of which is connected to the control input of the second buffer circuit and through the counter connected to the input of the first element NOT, the output of which is connected to the second input of the coincidence circuit, the third input of which is connected to the output of the second element NOT, the input of which is combined with the third input of the defect classifier and the output of the comparison circuit, the third output of the control unit is connected to the installation input of the counter, the fourth input of the defect classifier and the control inputs of the first and a second drive, the memory register, a third ν (fourth buffer circuits. Table 1 z Coefficient a y for 0.8 0.9 0.95 0.98 0.99 2 1, 33 2.06 3.04 4.92 7.01 4 '0.92 1, 07 1, 39 1, 88 2,30 8 0.49 0.66 0.82 1,03 . 1.19 16 0.34 0.44 0.55 0.65 0.73 32 0.23 0.30 0.36 0.43 0.48 64 0.16 0.21 0.25 0.30 0.33 128 0.11 0.15 0.18 0.21 0.23 Τ 'a blitz 2 Z Interval b _H / b _B for 0.8 0.9 0.95 0.98 0.99 2 0.22 0.17 0.14 0.11 0.09 476 9.71 19.76 fifty 100 4 2x39 θχ32. 0 _± 27 0.23 0 _χ 20 2.82 4.22 6.20 10.10 14.49 8 0.52 .0.45 0.40 0.35 0.32 2.00 2,56 3.21 4-, 25 5.22 16 0.64 0.57 0.52 0.47 0.44 1, 61 1, β8 2.17 2,58 2.92 32 0.73 0.67 0.63 0.58 0.55 1.39 1,54 1,69 1, 89  -2.05 64 0 _λ 80 0.75 • 0.72 0.68 0.65 1.26 1.35. 1.44 1, * 55 1, 63 Fiyo1 FIG. 2 Fig.Z FIG. 9 Compiled by V. Skorobogatov Redactor T = Parfenova Tehred L. Serdyukova Proofreaders. Maksimishinets - Order 3137 Circulation 497 Subscription VNIIIPI State 113035, committee on inventions and discoveries at the State Committee for Science and Technology of the USSR Moscow, Zh-35, Raushskaya nab., d. 4/5 · . Production and Publishing Plant Patent, Uzhhorod, st. Gagarina, 101