Method of non-destructive quality inspection of materials and videomonitor realizing this method

A method of non-destructive quality inspection of materials wherein a data transmitter and a material to be inspected are positioned very near to each other and set in motion in relation to each other. Information fed by the data transmitter is converted into a black-white or color image indicative of the quality of the material being inspected. Information fed by the data transmitter is kept in a memory and, as it is converted into a black-and-white or color image, it is periodically read out. The address of a memory location in the memory from which the readout cycle is to begin is assigned prior to the start of each readout cycle. A videomonitor realizing this method including a data transmitter mounted on a scanning device, a display unit connected to a control unit and an address unit including a recording counter series connected to a switch, as well as a readout counter connected to another input of the switch. An address code rewrite unit is inserted between the output of the recording counter and the input of the readout counter.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to control and measuring instruments and, in 
particular, to methods and videomonitors for non-destructive quality 
inspection of materials. 
The invention can be used in the oil and gas industry for pipe weld quality 
testing, in machine building for detecting flaws in rolled products, in 
ship building for quality testing of welded ship hulls and tanks, and in 
other fields where products have to be tested for continuity defects. It 
can also be employed in medicine and biology for storage, processing, and 
visualization of information on biological objects. 
2. Description of the Prior Art 
Known in the art is a method for non-destructive quality inspection of 
materials (U.S. Pat. No. 3,341,771; Cl. 324-213), comprising the steps of 
magnetizing the material to be inspected, a magnetic recording medium 
being placed on the surface on this material, then removing said magnetic 
medium which through the action of the magnetizing field had recorded a 
magnetogram which contains information on the quality of the material 
being tested, and placing the magnetic medium into a device for recording 
said magnetogram, in which the pick-up is positioned near the surface of 
the magnetic medium and their relative motion is ensured. Information 
sensed by the pick-up is converted into electrical signals which are used 
to assess the quality of the material. 
The apparatus realizing this method comprises a magnetic pick-up capable of 
reciprocating motion above the surface of the magnetic medium, an 
amplifier, and an indicator. The indicator is a cathode-ray tube 
displaying a pulse signal whose shape is used to assess the quality of the 
material being inspected. 
However, this method and apparatus realizing the method are deficient in 
that they can only be used to detect a flaw in the material being 
inspected. They cannot furnish any 3-D characteristics of this flaw, such 
as the depth, shape, length, relative position. 
Also known in the art is an ultrasonic flaw detector USDl manufactured by 
KRAUTKRAMER in the Federal Republic of Germany "(Booklet of Krautkramer, 
Production Program for 1984-1985, p.7)". In this device a data transmitter 
is an ultrasonic transducer placed on the surface of the material to be 
tested and their relative motion is ensured. Information fed by the 
transmitter is processed in the built-in microcomputer and displayed on 
the screen of the cathode-ray tube as an image of echo signals and as 
digital data on the depth of the flaw and the distance from the transducer 
to the projection of the flaw on the surface of the tested product. 
But the aforementioned device is deficient in that it cannot provide a 
shadow-color image indicative of the quality of the material being tested. 
It also cannot provide prompt information on the amount and relative 
position of flaws in the material, their length and configuration. 
The closest prior art is a method for non-destructive testing (cf., for 
example, U.S.S.R. Inventor's Certificate No. 456,572; 1974) whereby 
information fed by a pick-up, which is indicative of the quality of the 
material being tested, is subjected to scale and time conversion by 
entering this information to a storage unit in synchronism with the motion 
of the pick-up relative to the tested material, and then displayed on the 
screen of a cathode-ray tube, while the recording is simultaneously read 
from the memory. 
There is known a videomonitor realizing this method (cf., for example, G. 
R. Kreps, Forming Television Signals in Flaw Detectors Using Automatic 
Mechanical Scanning, Defektoskopiya, 1979, No. 6, pp. 106-109) which 
comprises several series-connected components: a data transmitter mounted 
on a device which scans this transmitter in relation to the tested 
material, an analog-digital converter, a memory, a digital-analog 
converter, and a display which is a color electron beam tube; a recording 
counter connected in series to a switch whose output is connected to the 
memory, a readout counter whose output is connected to a second input of 
the switch, a control unit connected to the synchronization input of the 
data transmitter and to inputs of the recording counter, the readout 
counter, the analog-digital converter, the memory, the switch, and the 
digital-analog converter, a synchronization output of the scanning device 
being connected to the other input of the recording counter. 
However, the aforementioned device is deficient in that it cannot provide 
continuous display of information on the quality of the tested material 
when the pick-up is transported in relation to this tested material for a 
long distance. This device also cannot provide a prompt increase in the 
resolution of the color picture for the detailed analysis of the material 
quality. It also cannot help determine precisely the coordinates and 
length of a defect. 
The term "data transmitter" used here and henceforth in this description 
means a flaw detector equipped with a pickup. It is evident that the 
pickup is placed near the surface of the tested material on a scanning 
device, while information and timing signals are fed from the outputs of 
the flaw detector. 
SUMMARY OF THE INVENTION 
The primary object of this invention is to provide a method of 
non-destructive quality inspection of materials, which can make this 
inspection more reliable and increase its information content. 
Another object of this invention is to provide a method of non-destructive 
quality inspection of materials, which can ensure prompt access to 
information on the quality of a material having great length by rapidly 
defining the number of defects, their shape, and arrangement throughout 
the length of the material. 
One more object of this invention is to provide a method of non-destructive 
quality inspection of materials, which can be used for detailed quality 
testing by increasing the resolution of the black-and-white or color 
image. 
Yet another object of the invention is to provide a method of 
non-destructive quality inspection of materials, which can make this 
inspection more reliable by setting the system of coordinates of the 
black-and-white or color image in univocal correspondence with that of the 
material being inspected. 
A further object of the invention is to provide a method of non-destructive 
quality inspection of materials, which makes this inspection reliable and 
increases its information content by furnishing a capability for prompt 
and accurate determination of coordinates and length of a defect. 
The primary object of this invention is also to provide a videomonitor 
realizing the method of non-destructive quality inspection of materials, 
which is capable of continuous and prompt quality control of materials 
having great length, and ensures high reliability and information content 
of inspection. 
Another object of the invention is to provide a videomonitor having 
improved resolution of the black-and-white or color image of defects in 
the material being inspected and, consequently, a higher information 
content of quality inspection. 
Yet another object of the invention is to provide a videomonitor capable of 
making quality inspection more reliable by setting the coordinate system 
of the portion of the tested material being inspected. 
Still another object of the invention is to provide a videomonitor which 
makes it possible to determine the length of a defect, its location on the 
portion of the material being inspected in relation to the reference 
point, including extended portions. 
A further object of the invention is to provide a videomonitor which makes 
it possible to separate in time the process of picking up information on 
the quality of the extended material and the process of analyzing this 
information in order to detect defects. 
These and other objects of the invention are achieved in a method of 
non-destructive quality inspection which comprises the steps of placing at 
least one transmitter of information on the quality of the material in the 
immediate vicinity of the surface of the material being inspected, setting 
the transmitter and material in motion in relation to each other, sampling 
information on the material quality fed by the transmitter, entering this 
information to the memory synchronously with the cycles of data 
transmitter displacement in relation to the tested material, reading this 
information from the memory by cycles, and converting it into a 
black-and-white or color picture which is used to assess the quality of 
the material being inspected, the address of the memory to start the next 
reading cycle being assigned prior to the beginning of this cycle. 
It becomes possible, therefore, to display on the videomonitor screen any 
portion of the black-and-white or color image, to change the frames of the 
image if the capacity of the memory permits storage of information whose 
content exceeds one frame. It also becomes possible to separate in time 
the process of picking up information on the quality of the material being 
inspected and the process of information displaying for visual monitoring. 
The information content and reliability of the material quality inspection 
can be greatly improved in this manner. 
Advisably, the address of the working memory location which is to start the 
reading cycle, while information is being converted into a black-and-white 
or color picture, should be the address of the memory location to which 
the last recording had been made. 
It becomes possible to display a sliding image on the screen so that 
continuous quality control of extended materials, such as long welds, can 
be effected. The information content and promptness of quality inspection 
are thus improved. 
Advisably, information recording to the working memory should be gated by a 
pulse and, when the duration of the sampling pulse changes, the sampling 
frequency of information signals should be changed. 
It becomes possible to improve the resolution of the black-and-white or 
color picture, to determine the distance to the defect from the data 
transmitter during acoustic non-destructive inspection and, consequently, 
to increase the information content of inspection. 
Advisably, the location of the data transmitter and the direction of its 
displacement should be recorded with respect to a reference point on the 
material being inspected so that univocal correspondence is established 
between the coordinate systems of the black-and-white or color image and 
the material being inspected. 
It becomes possible to set a scale of the image, to eliminate distortion of 
the image in relation to the real picture of the material being inspected 
and, consequently, to make non-destructive inspection more thrustworthy. 
Advantageously, a marker line should be provided on the image, whose 
coordinates should be determined in advance in accordance with the 
location of the data transmitter in relation to the reference point on the 
material being inspected, and this marker line should be moved along the 
black-and-white or color picture in order to determine the location and 
length of any portion of the material. 
It becomes possible to accurately determine the place of a defect in the 
material being inspected and its length. The information content and 
reliability of quality inspection is significantly improved in this way. 
These objects are also achieved by a videomonitor realizing the method of 
non-destructive quality inspection of materials, comprising a data 
transmitter mounted on a device for scanning said data transmitter in 
relation to the material being inspected and a display unit connected in 
series to said data transmitter, as well as a control unit connected in 
series to an address unit, said control unit and address unit being 
connected, respectively, to synchronization outputs of the data 
transmitter and scanning device and to inputs of the display unit which 
comprises, connected in series, an analog-digital converter coupled to the 
output of the data transmitter, a memory, a digital-analog converter, and 
a display, while the address unit comprises a series-connected chain 
including a recording counter whose inputs are connected, respectively, to 
the synchronization output of the scanning device and to the control unit, 
and a switching circuit whose output is connected to the address input of 
the memory, and a readout counter inserted between the output of the 
control unit and the switching circuit. According to the invention the 
video monitor, also comprises a memory address code rewrite unit inserted 
between the output of the recording counter and the second input of the 
readout counter, while the other input of the code rewrite unit is 
connected to the output of the control unit. 
It becomes possible to preset a working memory address of each subsequent 
readout cycle prior to the beginning of this cycle, and, in particular, 
the address of the memory location to which the last recording had been 
made, which shifts the image of the display screen, the former image being 
replaced by incoming information, and thus obtain a sliding image. It 
becomes possible to make quality inspection of extended material 
continuous, thus contributing to the expansion of the information content 
of inspection and expediting the process of testing. 
Advisably, the address unit should comprise an image element counter whose 
output is connected to the switching circuit, and the control unit should 
comprise a variable frequency pulse generator connected to the input of 
the picture element counter and to the analog-digital converter, a 
sampling pulse generator whose input is connected to the data transmitter 
and whose output is connected to the recording counter, to the reset input 
of the image element counter, to the control input of the switching 
circuit, and to the input of the working memory, and a synchronizing 
generator whose outputs are connected, respectively, to the readout 
counter, the rewrite unit, and the digital-analog converter. 
It becomes possible to sample information entered to the working memory, to 
change the length of the sampling pulse and its arrival time, to change 
the sampling frequency, and thus increase the resolution of the 
black-and-white or color image in order to obtain information on the 
distance to the defect from the data transmitter by applying acoustic 
non-destructive test methods. The information content of quality 
inspection is increased in this way. 
Possibly, the address unit should comprise a rewrite signal generator 
inserted between the synchronizing generator and the memory address code 
rewrite unit, while the recording counter should be reversible, two inputs 
thereof being connected, respectively, to the second and third inputs of 
the rewrite signal generator and to two synchronization outputs of the 
scanning device. 
It becomes possible to establish a univocal correspondence between the 
coordinate systems of the inspected zone and its image on the display and 
thus improve the trustworthiness of quality inspection. 
Advisably, the videomonitor should comprise an image coordinate display 
unit connected to the address unit and to the control unit. 
It becomes possible to determine the location and length of defects in the 
material being inspected and, consequently, to expand the information 
content of quality inspection. 
Advisably, the coordinate display unit should comprise a reversible counter 
of marker line coordinates, whose two inputs are connected, respectively, 
to outputs of the synchronizing generator, a comparison unit connected in 
series to the up-down counter and having its second input connected to the 
second output of the readout counter, two OR elements having some inputs 
connected, respectively, to the second and third outputs of the up-down 
counter of marker line coordinates and other inputs connected, 
respectively, to the second and third outputs of the reversible recording 
counter, a reversible frame counter whose inputs are connected to outputs 
of the first and second OR elements, and a digital display unit connected 
in series to the reversible frame counter and having the second input 
thereof connected to the output of the marker line coordinate reversible 
counter. 
It becomes possible to define the location and length of a defect much more 
accurately and, consequently, improve the reliability and trustworthiness 
of the material quality inspection. 
Advisably, the address unit of the videomonitor should additionally 
comprise two OR elements inserted between the synchronization outputs of 
the scanning device and two inputs of the reversible recording counter, 
respectively, the second inputs of the OR elements being connected to 
respective outputs of the synchronizing generator. 
It becomes possible to display on the screen any part of the material being 
inspected, because information concerning this part had been recorded in 
the working memory while the data transmitter had been passing this part 
earlier. In this case, the amount of information stored in the working 
memory may exceed the capacity of one frame. The desired part of the image 
can be selected for display by shifting the image on the screen without 
using the scanning device. 
Rapid readout of information on the quality of material can be realized 
even with such methods of non-destructive quality inspection where the 
operational time of the data transmitter is restricted. The shadow color 
picture of the material being inspected can be analyzed afterwards, making 
the quality inspection still more reliable.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
It should be pointed out at the outset that the claimed method of 
non-destructive quality inspection of materials may be an ultrasonic, 
magnetic-tape, or electromagnetic method. The data transmitter, 
accordingly, may comprise an ultrasonic transducer, or a magnetosensitive 
transducer, or an eddy-current transducer, or any other transducer 
depending on the method employed. 
For simplicity the method of non-destructive quality inspection described 
below will be referred to a specific type of material testing, namely 
ultrasonic inspection of welded joints. 
The proposed method of non-destructive quality inspection of materials 
comprises the following operations or steps. 
A signal is obtained containing information on the quality of the material 
being inspected. This signal is converted into a black-and-white or color 
image, which is referred to as "image" hereinafter. To this end, a data 
transmitter 1 (FIG. 1) is applied on a portion 2 of the material and they 
are set into relative motion. The source information signal received by 
the data transmitter 1, e.g. acoustic, magnetic, or any other signal, is 
converted into an electrical signal which is sampled and digitized. The 
sequence of digital codes thus obtained is converted into a signal 
containing information on the quality of the portion 2 of the material 
being inspected. This signal is stored and kept for a required period. To 
produce an image, this information is periodically read, put through a 
digital-to-analog converter to produce line and frame synchronization 
signals and a video signal required to obtain a black-and-white or color 
image. 
A sliding image is produced when moving the data transmitter 1 a long 
distance in relation to the portion 2 of the material being inspected. 
Thus, it can be transported along an extended weld 3. When, for example, 
the data transmitter 1 is transported along the weld 3 to the left, the 
image 4 of the defect is shifted down on a screen 5. The direction of the 
shift is indicated by an arrow on the screen. When the data transmitter 1 
is shifted to the right, the color image 4 of the defect is shifted 
upwards. In this manner continuous inspection of an extended weld 3 can be 
performed interactively, on a real time basis, when signals of the data 
transmitter 1 are immediately displayed on the screen. 
To this end, readout cycles should be started from those information 
signals which had been obtained last from the data transmitter 1 in order 
to convert the stored information into a black-and-white or color image. 
The information content and promptness of testing can be improved in this 
way. 
Direct quality testing may be impracticable during the movement of the data 
transmitter 1 in relation to the tested material because the operational 
time of the data transmitter 1 is restricted and the amount of information 
fed thereto is too large due to the great length of the tested portion 2. 
In this case quality inspection is separated into two stages. At first, 
information on the quality of the tested material is stored during the 
period when the data transmitter 1 is operational. When the data 
transmitter 1 completes its working cycle, stored information is read and 
converted into a black-and-white or color image. The sliding image can be 
obtained by artificially assigning a sequence of signals starting the 
readout cycles while these signals are being converted into a color shadow 
image. In this way any portion of the image can be selected and analyzed 
in detail. The reliability and information content of quality inspection 
is greatly improved in this manner. 
The resolution of the image can be controlled, if required. 
To this end, the signal "a" (FIG. 2) is gated by a pulse "b" and sampled 
with a specific frequency f.sub.1 (cf., pulse sequence "c"). 
The color shadow image 4 of the defect is obtained on the screen 5 (FIG. 
3). Information on the defect is contained in the electrical signal a 
(FIG. 2) fed from the data transmitter 1. When the length of the gating 
pulse "d" becomes shorter, the sampling frequency f.sub.2 (pulse sequence 
"e") should be increased to produce an image 4 (FIG. 4) of the defect, 
which has a higher resolution. 
The next step is to establish a univocal correspondence between the 
coordinate systems of the tested material and the image 4 (FIG. 1). 
To this end, a digital code 6 should be generated, which indicates a 
coordinate of an image part. Sync signals are produced as the data 
transmitter 1 covers a specific distance in relation to the tested 
material, this distance being constant throughout the path of the data 
transmitter 1. By counting the number of sync signals the distance covered 
by the data transmitter 1 can be determined in relation to some initial 
reference point. Further on, each sync signal indicative of a distance 
covered by the data transmitter 1 relative to the tested material is put 
into correspondence to a group of signals fed to storage from the data 
transmitter 1. Each group of information signals is, therefore, associated 
with a specific portion of the image on the screen 5 after the stored 
information if read and converted into a color shadow image. A reverse 
problem is to be solved, in other words, the image part of interest should 
be associated with a group of signals and, consequently, with the number 
of the sync signal in the sequence of these signals fed while the data 
transmitter 1 moves from the reference point. Then the distance from the 
portion 2 of the tested material, which corresponds to the selected image 
part, to the reference point is determined and a digital code 6 of the 
image part is generated. 
Moreover, when the direction of movement of the data transmitter 1 in 
relation to the portion 2 of the tested material is reversed, the image 
shift is inhibited until the data transmitter 1 reaches that portion 2 of 
the tested material, whose image is not displayed on the screen 5. This 
eliminates distortions of the image on the screen 5 and improves the 
information content of reliability of testing. 
The method of non-destructive quality inspection will be dealt with in more 
detail below when operation of the videomonitor realizing this method is 
described for a specific application--testing of welds. 
An embodiment (FIG. 6) of a videomonitor realizing the method of 
non-destructive quality inspection of materials comprises a data 
transmitter 1 installed on a device 7 for scanning this transmitter 1 in 
relation to the portion 2 of the inspected material and connected in 
series with a display unit 8. The videomonitor also comprises, connected 
in series, a control unit 9 coupled to a synchronization output of the 
data transmitter 1 and to the display unit 8, and an address unit 10 
connected to a synchronization output of the scanning device 7 and to the 
input of the display unit 5. 
The display unit 8 may comprise an analog-digital converter 11 coupled to 
the data transmitter 1, a memory 12, a digital-analog converter 13, and a 
display 14, all these units being connected in series. The above mentioned 
units are well known to those skilled in the art and are used here for 
their primary purpose. 
The display 14 may be a conventional black-and-white or color TV set. The 
address unit 10 may comprise series-connected units: a recording counter 
15 connected to the synchronization output of the scanning device 7 and to 
the control unit 9, and a switching circuit 16 whose output is connected 
to the address input of the memory 12. The address unit 10 may also 
comprise a readout counter 17 inserted between the output of the control 
unit 9 and a respective input of the switch 16. According to the 
invention, an address code rewrite unit 18 inserted between the output of 
the recording counter 15 and the second input of the readout counter 17. 
The outputs of the control unit 9 are connected, respectively, to the 
analog-digital converter 11, the memory 12, the digital-analog converter 
13, and to control inputs of the rewrite unit 18 and the switch 16. 
The address code rewrite unit 18 is a conventional circuit connecting the 
information output of the recording counter 15 to the setting input of the 
readout counter 17, which provides a capability for controlling rewriting 
of information. The control unit 9 performs, in this case, the function of 
generating vertical and horizontal scan signals for the CRT display 14, 
synchronizing the operation of all units, and controlling recording and 
readout of information kept in the memory. Such units are commonly used in 
conventional TV games and raster displays. It is usually manufactured as a 
display controller. All other units of the videomonitor are conventional 
and, therefore, well known to those skilled in the art. 
The rewrite unit 18 provides the videomonitor with a capability to form a 
sliding image, which substantially expands the information content of the 
device. The address unit 10 (FIG. 7) of the videomonitor may, according to 
the invention, comprise an image element counter 19 connected to a 
respective input of the switch 16. The control unit 9 may comprise a 
gating pulse generator 20 connected to control inputs of the image element 
counter 19, the switch 16, and the working storage 12, the input of the 
gating pulse generator 20 being connected to the synchronization output of 
the data transmitter 1. Besides, the control unit 9 may comprise a 
variable frequency pulse generator 21 connected to the input of the image 
element counter 19 and to the timing input of the analog-digital converter 
11, and a synchronizing generator 22 whose outputs are connected, 
respectively, to the rewrite unit 18, to the readout counter 17, and to 
the digital-analog converter 13. In this case, the input of the recording 
counter 15 is connected to the synchronization output of the scanning 
device 7. All these units are well known to those skilled in the art. They 
are included in the device in order to provide a capability to control the 
resolution of the videomonitor, increasing or decreasing it as the case 
might be. The videomonitor is also capable of promptly determing the depth 
of defects or their position in relation to the weld limits, thus 
improving the information content of testing. 
An image coordinate display unit 23 (FIG. 8) is provided, according to the 
invention, in the videomonitor in order to establish a univocal 
correspondence between the coordinate systems of the image and a specific 
portion of the tested material and, also, to precisely determine the 
position of any portion of the image in relation to the reference point 
and the length thereof. The image coordinate display unit 23 is connected 
to outputs of the control unit 9 and the address unit 10 and to the input 
of the display unit 8. Besides, the address unit 10 may comprise a rewrite 
signal generator 24 and the address code rewrite unit 18. The recording 
counter 15 may be reversible, two inputs thereof being connected, 
respectively, to two inputs of the rewrite signal generator 24 and to two 
synchronization outputs of the scanning device 7. The address unit 10 
designed as described above can form a sliding image in two directions 
which correspond to the forward or reverse movement of the data 
transmitter 1 effected by the scanning device 7. The address unit 10 can 
also eliminate distortions of the image when the direction of the data 
transmitter 1 is reversed, thus improving the trustworthiness of testing. 
The rewrite signal generator 24 is a conventional logic circuit built 
around known logic elements. A specific embodiment of such circuit is 
described below. 
The image coordinate display unit 23 may comprise a reversible counter 25 
of marker line coordinates, whose two inputs are connected, respectively, 
to outputs of the synchronizing generator 22 and which is coupled in 
series to a comparison circuit 26 whose second input is connected to the 
second output of the readout counter 17; a first and a second OR elements 
27 and 28 whose first inputs are connected, respectively, to the second 
and third outputs of the marker line coordinate reversible counter 25, 
while the second inputs thereof are connected, respectively, to the third 
and fourth outputs (carry and borrow outputs) of the reversible recording 
counter 15. In addition, the image coordinate display unit 23 comprises a 
reversible counter 29 of image frames, whose inputs are connected to 
outputs of the first and second OR elements 27 and 28 and which is coupled 
in series to a digital indication unit 30 whose second input is connected 
to the output of the marker line coordinate reversible counter 25. This 
electrical connection of units in the image coordinate display unit 23 
permits a substantial increase in the information content of the quality 
inspection. It becomes possible to precisely determine the position of 
length of defects 31 in the material 2 (FIG. 1) being inspected. The above 
mentioned units are known to all those skilled in the art. 
Besides, the address unit 10 of the videomonitor may, according to the 
invention, comprise two OR elements 32 and 33 inserted between the 
synchronization outputs of the scanning device 7 and two inputs of the 
reversible recording counter 15, respectively. The second inputs of the 
third and fourth OR elements 32 and 33 are connected to respective outputs 
of the synchronizing generator 22. This arrangement of the address unit 10 
permits prompt testing and increases the information content of tests. 
This is particularly true for non-destructive methods where information on 
the inspected material is to be picked up expeditiously. 
An embodiment of the rewrite signal generator 24 is shown in FIG. 10. 
The rewrite signal generator 24 comprises a series-connected chain 
including a first AND element 34 whose input is connected to the first 
synchronization output of the scanning device 7, a reversible counter 35, 
a decoder 36, and a second AND element 37; a third AND element 38 whose 
input is connected to the second synchronization output of the scanning 
device 7, while the output thereof is connected to the second input of the 
reversible counter 35, a series-connected chain including a first trigger 
39 whose two inputs are connected to two respective outputs of the 
reversible counter 35, a fourth AND element 40, and an OR element 41 whose 
output is connected to the gating input of the decoder 36, a fifth AND 
element 42 whose input is connected to the second output of the first 
trigger 39, while the output thereof is connected to the second input of 
the OR element 41, and a second trigger 43 whose two setting inputs are 
connected, respectively, to the first and second outputs of the scanning 
device 7, while the inverting and non-inverting outputs are connected, 
respectively, to the second inputs of the fourth and fifth AND elements 40 
and 42. 
The second input of the second AND element 37 and the output thereof are 
connected, respectively, to the output of the synchronizing generator 22 
and to the control input of the address code rewrite unit 18. 
The videomonitor realizing the new method of non-destructive quality 
inspection of materials operates, according to the invention, as follows. 
The data transmitter 1 (FIG. 1) mounted on the scanning device 7 is 
transported along the portion 2 of the material being inspected, 
specifically along the weld 3. The analog signal produced by the data 
transmitter 1 (FIG. 6) is converted in the analog-digital converter 11 
into a digital code and supplied to the memory 12. Using the signal fed 
from the synchronization output of the scanning device 7 and timing 
signals fed from the output of the control unit 9, the recording counter 
15 forming the code of the memory address location whereto the recording 
is made. 
A signal of the control unit 9 makes the switch 16 disconnect the outputs 
of the readout counter and connects the outputs of the recording counter 
to the address inputs of the memory. The control unit 9 generates a 
recording instruction fed to the memory 12. In this manner, the incoming 
information is recorded into the memory 12. During readout and display, 
the control unit 9 uses the switch 16 to supply the address of the storage 
location to be read to the address inputs of the memory 12. Then the 
control unit 9 generates a signal for the digital-analog converter 13 
which converts the digital code into an analog signal fed to the display 
14 where it is transformed into a color shadow image. 
The complete counting cycle of the counters 15 and 17 is sufficient to 
address all memory locations in the memory 12, which corresponds to full 
recording and readout cycles. 
In this particular example explaining the operation of the device the 
recording counter 15 is assumed to count down and goes through the states 
n, n-1, . . . , n+1 during the complete counting cycle, while the counter 
17 counts forward and goes through the states n, n+1, . . . , n-1. The 
readout counter 17 completes one full counting cycle within a period 
required for displaying one field on the screen 5 of the display 15. This 
means that a complete frame is displayed on the screen 5 during two full 
cycles of the readout counter 17. 
A signal enabling rewriting of the current code of a storage address from 
the outputs of the recording counter 15 to the readout counter 17 is 
supplied from the control unit 9 to the address code rewrite unit 18 at 
the end of every other counting cycle of the counter 17. This means that 
at the beginning of every other counting cycle the output of the readout 
counter 17 is the code of the storage address to which the last recording 
had been made, and, consequently, each new frame displays new information. 
Since the recording counter 15 counts down, the address code of the memory 
location which starts the display of a frame coincides with or precedes 
the address code of the memory location which started the display of the 
preceding frame. In consequence, the image on the videomonitor screen is 
successively shifted and replaced by new information fed from the data 
transmitter transported along the material 2. In this manner a sliding 
image is produced. This offers the advantage of continuous quality 
inspection of an extended material, particularly a long weld 3, on a real 
time basis. 
The block diagram of FIG. 7 shows the videomonitor which, in addition to 
the above positive effect, also offers the advantage of changing the 
resolution of the image. The gating pulse generator 20 is activated by 
pulses fed from the data transmitter 1. The duration and position of the 
gating pulse which is the output pulse of the generator 20 can be varied 
in order to make the gating pulse coincide in time with the information 
signal or an arbitrary portion of this signal applied to the input of the 
analog-digital converter 11. 
The gating pulse is supplied to the control input of the memory 12 and sets 
it to the recording mode. The gating pulse is supplied to the switch 16 
and sets it to the position in which the address code fed from the outputs 
of the recording counter 15 and the image element counter 19 is supplied 
to the address inputs of the working storage 12. Information fed from the 
output of the analog-digital converter 11 to the memory 12 is recorded in 
the memory location having this address. Timing pulses whose frequency can 
be adjusted are supplied from the output of the variable frequency pulse 
generator 21 to the counting input of the image element counter 19. The 
frequency of timing pulses is selected so that the length of the gating 
pulse is equal to 2.sup.n -1 periods of timing pulses, where n is the 
number of digits of the image element counter 19. 
In this manner signals are sampled and recorded, each signal being 
represented as a sequence of digital codes in the memory 12 which is a 
table memory. The number of a line in the table is provided by the 
recording counter 15, while the number of the memory location in the line 
is provided by the image element counter 19. The number of memory 
locations in a line is equal to 2.sup.n -1. 
With no gating pulse applied, the image element counter 19 is reset and the 
memory 12 starts the readout, the outputs of the readout counter 17 being 
connected via the switch 16 to the address inputs of the memory 12. The 
readout counter 17 interrogates all memory locations and the lower-order 
digits produce the code of the memory location in a line, while the higher 
order digits produce the line number code. During the readout information 
is displayed on the screen 5 of the display 14 line by line. Signals are 
converted into colored or black-and-white stripes and their totality forms 
a colored or black-and-white image of the portion of the material being 
inspected. 
When the gating pulse becomes longer, the duration 2.sup.n -1 of the timing 
pulse periods becomes less than the length of this gating pulse. In this 
case some information is lost since the image element counter 19 starts a 
new counting cycle when it completes the former one. As a result, some 
elements of information recorded in the memory 12 are erased. In order to 
avoid the distortion, the frequency of timing pulses has to be decreased 
by shortening the output pulses of the variable frequency pulse generator 
21. 
When the gating pulse decreases, the duration 2.sup.n -1 of timing pulse 
periods becomes longer than the length of the gating pulse. In this case, 
each memory line is supplied with less information than it is capable of 
accomodating and, consequently, the remaining memory locations retain 
former information which is the cause of distortions during readout. In 
order to eliminate the distortion, the frequency of timing pulses will 
have to be increased. 
Shorter gating pulses and respective adjustment of the frequency of timing 
pulses permit control of sufficiently short portions of the information 
signal and higher resolution of the image. Higher resolution of the 
videomonitor means greater information content can be displayed thereon. 
The frequency of the variable frequency pulse generator 21 may be adjusted 
by any known methods in order to change the length of the gating pulse. 
Referring to FIG. 2, the time charts show information signal "a", the 
gating pulse "b", the timing pulse sequence "c" having the frequency 
f.sub.1, the gating pulse "d" which is half as long as the gating pulse 
"b", the timing pulse sequence "c" whose frequency f.sub.2 is twice as 
high as the frequency f.sub.1. 
FIG. 3 shows a colored shadow image of a portion of the material being 
inspected when the information signal "a" is gated by the pulse "b" and 
timed by the sequence of pulses "c" with the frequency f.sub.1. 
FIG. 4 shows a colored shadow image of a portion of the material being 
inspected when the information signal "a" is gated by the gating pulse "d" 
and timed by the sequence of pulses "c". 
Comparison of the images of FIGS. 3 and 4 demonstrates that the resolution 
of the image in FIG. 4 is twice as high as that of FIG. 3. 
It can also be demonstrated that by changing the position of the gating 
signal in time the position of the image 4 of the defect changes in 
relation to the boundaries of the screen 5. Thus, for example, when the 
gating pulse is shifted to the right on the time axis of the chart shown 
in FIG. 2, the respective image on the screen 5 (FIGS. 3 or 4) moves down 
and, when the gating pulse is shifted to the left, the image on the screen 
5 moves to the right. 
This offers a new advantage when using acoustic non-destructive testing 
techniques. The depth of a defect can be determined during vertical 
sounding by watching the position of the image 4 of this defect on the 
screen 5 or the position of the defect in relation to the boundaries of 
the weld 3 (FIG. 1). For this purpose, several parameters have to be set 
in advance, such as the length of the gating pulse, its position in time, 
and the frequency of sampling of the generator 21. 
The above described operations permit a substantial increase in the 
information content of testing. 
FIG. 8 shows a block diagram of a videomonitor which, in addition to the 
above described positive effect, offers the advantage of higher 
reliability and greater information content of testing. 
In this embodiment, the recording counter 15 is reversible and the scanning 
device 7 can produce, in addition to synchronization signals, a signal 
indicating the direction of movement of the data transmitter 1 in relation 
to the material 2 being inspected. 
At first, the system of coordinates of the portion of the material to be 
inspected is entered. In the example of FIG. 1 this is the axis OY 
extending along the weld 3 with a scale rule 44 marked thereon. 
The system of coordinates of the image is the axis OY' arranged, in this 
case, in the plane of the videomonitor screen. 
The coordinate axis OY of the material portion being inspected can be 
divided into sections each having "m" equal portions. In this case, the 
number "m" is equal to the number of lines in the working storage 12 and, 
consequently, to the number of lines of the image, which are the 
structural components of the image. 
It is clear from the foregoing that each number of a line of the memory 
locations in the memory 12 corresponds to the number of a line of the 
image on the screen 5. When the scanning device 7 passes each said 
portion, a synchronization signal is produced at the output thereof and 
supplied to the counting input of the reversible counter 15 and changes 
its state. When the scanning device 7 passes a section having "m" equal 
portions, "m" synchronization signals are taken from the output thereof 
and the reversible recording counter 15 completes a full counting cycle. 
Addresses are assigned to all lines of memory locations in the memory 12, 
which correspond to all lines of image elements in one frame of the image 
4. 
When the scanning device 7 moves in the positive direction in relation to 
the OY axis (to the right in FIG. 1), the reversible recording counter 15 
counts forward and the image on the screen 5 moves up. When the scanning 
device moves in the opposite direction, the image on the screen 5 is 
shifted down. This means that the positive direction of the OY axis on the 
tested material corresponds to the positive direction of the OY' axis of 
coordinates of the colored shadow image on the screen 5. 
The image element counter 19 is responsible for recording information to 
the memory locations of each line. Since a memory location can be filled 
only when a sync pulse is supplied by the scanning device 7 and each line 
of memory locations corresponds to the image line on the screen 5, each 
section of the path of the scanning device 7 can be assigned to a specific 
portion of the OY' axis, which is equal to the width of the image line. 
The reversible counter 25 of the marker line coordinates and the comparison 
unit 26 are used to form a marker line which is used to indicate any image 
element on the screen 5 (FIG. 1). By feeding pulses from the synchronizing 
generator 22 to the up or down input of the reversible counter 25 of the 
marker line coordinates, any code ranging from 0 to m-1 can be obtained at 
the output of the reversible counter 25, where "m" is the number of image 
element lines on the screen 5. The binary code from the output of the 
reversible counter 25 of the marker line coordinates is supplied to the 
input of the unit 30 for digital indication of coordinates and to the 
input of the comparison unit where it is compared with the binary code fed 
from the higher-order digits of the readout counter 17. At the moment of 
comparison of the two codes, a signal is supplied to the input of the 
digital-analog converter 13 to produce an image of the marker line on the 
screen 5. 
In this manner a marker line is produced on the colored shadow image in the 
line whose number is assigned by the reversible counter 25 of the marker 
line coordinates. The coordinate of the marker line is displayed on the 
digital display of the digital indication unit 30 as referred to the 
system of coordinates of the image. 
Since each coordinate on the OY' axis is associated with a specific section 
of the path along the OY axis on the tested material, the length of any 
image portion on the screen 5 can be determined by shifting the marker 
line along the axis OY' of the image in order to determine the length of a 
respective portion of the tested material. 
This offers the advantage of improved accuracy of measurements of the 
length of defects in the portion 2 of the tested material. It also makes 
testing more reliable and increases its information content. 
If the zero coordinate of the marker line is set when the scanning device 7 
is in the initial position (the reference point), the distance from this 
reference point to any portion of the inspected material, whose image on 
the screen 5 is indicated by the marker line, can be easily determined as 
the scanning device 7 is transported along the material. 
The reversible counter 29 of image frames is provided in the videomonitor 
in order to expand the range of the coordinate system of the image. 
The carry signal is supplied from the output of the reversible counter 25 
of the marker line coordinates to the input of the first OR element 27 
and, further on, from the output of the OR element 27 to the up input of 
the reversible counter 29 of image frames and sets it to a higher level. 
The binary code is further supplied from the output of the reversible 
counter 29 of image frames to the second input of the digital indication 
unit 30 where the coordinate of the image is displayed as the frame 
number. The borrow signal is supplied from the output of the reversible 
counter 25 of the marker line coordinate to the input of the second OR 
element 28 and, from the output thereof, to the down input of the 
reversible counter 29 of image frames, setting it to a lower level. Carry 
and borrow signals from the outputs of the reversible recording counter 
are supplied to the second inputs of the OR elements 27 and 28 and, from 
the outputs thereof, to the up or down inputs of the reversible image 
frame counter 29 setting it to a higher or lower level. 
No matter how long is the path of the scanning device 7 along the weld 3, 
the coordinate of any portion of this weld 3 can be determined as the 
number of an image frame, since the length of the frame, as has been 
described above, corresponds to the sum of "m" sections along the OY axis 
and as a coordinate of the marker line. 
The rewrite signal generator 24 whose block diagram is shown in FIG. 10 is 
intended to eliminate image distortions when the direction of the movement 
of the scanning device 7 is reversed. When the scanning device 7 (FIG. 1) 
moves in the positive direction, the image on the screen 5 moves down. 
This means that new information is displayed in the lower part of the 
screen pushing the old information upwards out of the frame. When the 
scanning device 7 moves in the negative direction, the image moves 
downward. 
To keep new information within the frame (when it is pushed out, it appears 
at the opposite end of the screen) during the reversal of the direction of 
movement of the scanning device 7 and maintain an undistorted image, it is 
necessary to temporarily discontinue the image shift, that is to inhibit 
the operation of the address code rewrite unit 18 until information fed 
after the direction reversal fills all "m" lines of the image. This 
function is performed by the rewrite signal generator 24. 
The rewrite signal generator 24 operates as follows. 
When the scanning device 7 (FIG. 1) moves in the positive direction in 
relation to the OY coordinate axis, sync pulses are supplied from the 
first output thereof to the first input of the first AND element 34 (FIG. 
10) and to the set input of the second trigger 43. No signals are supplied 
in this case from the second synchronization output of the scanning device 
7. When the scanning device 7 moves in the negative direction the 
processes are reversed. The reversible counter 35 counts forward when 
pulses from the output of the first AND element 34 are applied to the 
first input of the counter 35. This is possible when an enable signal is 
supplied from the output of the decoder 36 to the second input of the 
first AND element 34 and the scanning device moves in the positive 
direction. 
The output signal of the decoder 36 is enabling for the first and third AND 
elements 34 and 38 and prohibiting for the second AND element 37, and visa 
versa. 
The decoder 36 detects the zero state of the reversible counter 35 and, if 
an active signal level is available at the gating input thereof, generates 
the enabling signal applied to the first input of the second AND element 
37 and, consequently, inhibiting signals for the first and third AND 
elements 34 and 38. 
Initially, the two triggers 39 and 43 and the reversible counter 35 are in 
the zero state. No active level signal is supplied from the outputs of the 
fourth and fifth AND elements 40 and 42 to the inputs of the OR element 
41. The active level signal is therefore supplied from the output of the 
OR element 41 to the gating input of the decoder 36. 
When the scanning device 7 moves in the positive direction, the very first 
signal fed from the synchronizing output thereof sets the trigger 43. As a 
result, the active signal level appears at the gating input of the decoder 
36, and an enabling potential is applied to the second input of the first 
AND element 34. 
No rewrite signal is produced at the output of the second AND element 37 
since an inhibiting signal is applied to the first input thereof. This 
means that at this stage of movement of the scanning device 7 the image 4 
on the screen 5 is not shifted. 
A sync pulse supplied from the first output of the scanning device 7 via 
the first AND element 34 to the up input of the reversible counter 35 sets 
this counter 35 to a state other than zero and thus confirms the 
inhibiting signal at the input of the second AND element 37. The scaling 
factor of the reversible counter 35 is equal to "m" which is the number of 
lines of an image in a frame. The carry signal fed from the output of the 
reversible counter 39 sets the trigger 39 and an active signal level again 
appears at the gating input of the decoder 36. Since zero code is set at 
the output of the reversible counter 35, the output of the decoder 36 is a 
potential applied to the input of the first AND element 34. The operation 
of this AND element 34 is thus inhibited and, consequently, no pulses are 
fed to the input of the reversible counter 35 which retains its former 
state. 
An enabling potential being applied to the input of the second AND element 
37, timing pulses fed from the output of the synchronizing generator 22 
produce, at the output thereof, rewrite signals supplied to the control 
input of the address code rewrite unit 18. The image 4 on the screen 5 is 
shifted in the positive direction with respect to the OY' axis. This goes 
on until the scanning device 7 moves in the positive direction with 
respect to the OY axis. 
When the direction of movement of the scanning device 7 is reversed, shift 
synchronizing pulses are generated at the second output thereof. The very 
first sync pulse resets the trigger 43 and, consequently, an active signal 
level is set at the output of the fourth AND element 40 while it is 
removed from the gating input of the decoder 36. An enabling potential is 
supplied to the second input of the third AND element 38 and pulses start 
arriving to the down input of the reversible counter 35. Since this 
reversible counter 35 had been in the zero state, the first pulse applied 
to the down input thereof generates a borrow signal at the output of the 
counter 35, which resets the trigger 39. An active signal level is 
restored at the gating input of the decoder 36. But since the binary code 
at the output of the reversible counter 35 had changed and is not zero, 
the output of the decoder 36 is restored to become a signal level active 
for the third AND element, which inhibits the operation of the second AND 
element 37. The shift of the image 4 on the screen 5 is discontinued, and 
the reversible counter 35 starts counting sync pulses fed from the 
scanning device 7 until a zero binary code is set at the information 
output thereof. Since an active signal level is kept at the gating input 
of the reversible counter 35, the output of the decoder 36 is a signal 
enabling the operation of the second AND element 37 and inhibiting the 
operation of the third AND element 38. As a result, the reversible counter 
35 stops counting and remains in the zero state, while the image 4 on the 
screen 5 starts shifting in the negative direction with respect to the 
coordinate axis OY' as the scanning device 7 moves in the negative 
direction in relation to the axis OY. 
This offers the advantage of making the quality inspection more reliable. 
To separate in time the processes of recording data in the memory 12 and 
analyzing these data by visual inspection, the videomonitor of FIG. 9 is 
provided with the third and fourth more OR elements 32 and 33. They permit 
feeding signals to the up and down inputs of the reversible recording 
counter 15 both from the synchronizing outputs of the scanning device 7 
and from the outputs of the synchronizing generator 22. When signals are 
supplied from the synchronizing generator 22, the gating pulse generator 
20 is disabled and the memory 12 starts reading. The codes of memory 
location addresses from which readout cycles are started are generated by 
the reversible recording counter 15. They are rewritten, after each 
readout cycle, to the readout counter 17. A colored or black-and-white 
image kept in the memory 12 can thus be recalled, the capacity of the 
memory 12 being in excess of the information volume required to display 
one frame on the screen 5. In this case, the number of states of the 
counters participating in the entering information to the memory 12 and 
its readout should correspond to the number of memory locations of the 
memory 12. The readout counter 17 should pass, during readout cycles, the 
number of states which corresponds to the number of memory locations 
required to obtain a complete frame of colored or black-and-white image. 
This offers the advantage of making the quality inspection more reliable, 
thrustworthy, and rapid. 
The new method for non-destructive quality inspection of materials and a 
videomonitor realizing this method have a very broad field of application. 
They can be used in gas and oil extracting industry--for pipe weld quality 
testing, in machine building industry--for detecting defects in rolled 
products, in ship-building industry--for testing the quality of welds of 
ship hulls and tanks, and in other fields where non-destructive quality 
inspection of materials is readily applicable. 
In addition, the proposed method and device can be used in medicine. 
The proposed invention can be used for many purposes. It can be easily 
adapted for various methods of non-destructive testing, such as 
ultrasonic, magnetographic, heat, etc. The use of the new method is a 
positive contribution which can make quality inspection more reliable and 
thrusworthy, increase its information content, and, at the same time, make 
the work of operators engaged in this process more efficient. 
This invention is most profitable when used to test extended objects or 
when the time for readout of information on the quality of the tested 
material is strictly limited. 
The invention's primary object is to reveal the state of the tested 
material, but it can also be used to locate the position and determine the 
length of any portion of the tested material, whose quality deviates from 
a standard. It can be used for detailed analysis of some portions of the 
tested material by adjusting the resolution of the image on the proposed 
videomonitor.