RU2087909C1 - Spatial distribution display device for incoherent-light emitting sources - Google Patents

Abstract

FIELD: display of spatial temperature distribution in medical diagnostics and in industry to control temperature inside solid parts, etc; flaw inspection of various materials. SUBSTANCE: device has m receiving channels each incorporating series-connected signal converter, amplifier, analog-to-digital converter, and storage unit, m-input correlation processor built up of series-connected multiplier and integrator and coupled with outputs of receiving channels, recording device connected to correlation processor output, control unit, and signal delay computing unit. Analog-to-digital converter starting control unit specifies coordinates of analyzed region points for signal delay computing unit and recording device. Signal delay computing unit passes computer signals to control inputs of storage units in receiving channels. EFFECT: enlarged functional capabilities. 4 cl, 7 dwg

Description

 The invention relates to the design of a device designed to display the spatial distribution of sources of emission of incoherent radiation, such as thermal radiation (having an acoustic or electromagnetic nature), acoustic emission signals of stressed structures (cracking) or the earth's crust (earthquake), electromagnetic radiation from lightning discharges, and t .P. In the general case, incoherent radiation is understood to mean radiation in which there are no correlations between time-spaced oscillations.

 In the case of receiving thermal radiation, the application of the invention provides a display of the spatial temperature distribution of the studied area of the object. Such information can be used in medicine for diagnostics, in industry to control the temperature distribution inside massive parts of glass, metal, etc. in meteorology to obtain the distribution of air temperature over height, in hydrography to measure the temperature distribution in water bodies, in the energy sector to obtain the temperature distribution inside nuclear reactors, etc.

 In the case of receiving non-thermal incoherent radiation, the invention can be used for flaw detection, as well as for receiving acoustic emission signals prior to the destruction of any structures. Another possible application of the invention is the determination of the coordinates of lightning discharges.

 A device for displaying the spatial distribution of acoustic thermal noise emission sources is designed for non-invasively measuring the temperature of the internal region of the body (US patent N 4246784, CL 73-339, publ. 01.27.81). This device contains many acoustic transducers connected through a switch to the input of the spectrum analyzer, to the output of which a recording device is connected. Its work is based on the frequency dependence of the attenuation of acoustic signals. To do this, receive the spectrum of acoustic thermal noise along the depth of the studied area of the object, convert it into electrical signals and perform their spectral analysis. At the same time, the spatial distribution of the sources of acoustic thermal noise emission over the depth of the studied area of the object is obtained on the recording device.

 The resolution of this device is small and amounts to 70% of the depth of the investigated area, which is due to the small dependence of the attenuation of the acoustic signal on the frequency.

 Of the known technical solutions, the closest in technical essence to the proposed one is a device for displaying the spatial distribution of acoustic emission sources, designed to determine the coordinates of defects in sheet materials (A.S. N 1201753, class G 01 N 29/14, 29/14, publ. .30.12.85 g.). Its action is based on correlation signal processing. It contains m receiving channels, each of which consists of a series-connected signal converter, amplifier, analog-to-digital converter and a memory block, the output of which is the output of this receiving channel, the first switch, m inputs of which are connected to the outputs of the memory blocks, the correlation processor is connected in series the inputs of which are connected to the corresponding outputs of the first switch, the unit for determining the differences of the arrival time and the second switch, connected in series to the block egg rejection, whose inputs are connected to respective outputs of the second switch, and a coordinate calculating unit control, the control output of which is connected to control inputs of the first and second switches, and a recording device.

 The correlation processor is made up of n channels, each of which contains a fast Fourier transform, inverse fast Fourier transform processor, the first and second inputs of which are channel inputs, and a mutual spectrum forming unit, the output of which is connected to the third input of the specified processor, and the output is channel output.

 The known device has limited functionality, namely, it provides sounding only in the plane, and only the coordinates of point-type emission sources are determined. At the same time, in many cases it is desirable to observe the emission pattern in three-dimensional space and to have the possibility of studying the continuous distribution of emission sources in space.

 The invention is aimed at solving the problem of displaying a continuous spatial distribution of emission sources not only in two-dimensional, but also in three-dimensional space. To solve this problem, a display device comprising m receiving channels, each of which consists of a series-connected signal converter, amplifier, analog-to-digital converter and a memory unit, the output of which is the output of this receiving channel, a correlation processor, a control unit and a recording device, in addition, a block for calculating the delay of signals with one input and m outputs, each of which is connected to the control unit of the memory of the corresponding receiving channel, is introduced, the correlation This processor contains a multiplier with m inputs serving as the inputs of the correlation processor, and an integrator whose input is connected to the output of the multiplier, and the output is the output of the correlation processor, the control unit contains m trigger outputs, each of which is connected to the control input of the analog-to-digital converter of the corresponding receiver channel, and the coordinate reference output connected to the input of the signal delay calculation unit and to the control input of the recording device, while the output of each receiver of the first channel is connected to the corresponding input of the correlation processor, the output of the latter is connected to the information input of the recording device, and the number of receiving channels and inputs of the correlation processor is m = 4.

 The indicated implementation of the correlation processor, which provides the necessary correlation processing of the four signals coming into it from the receiving channels, in combination with the remaining differences of the proposed device, allows us to obtain a picture of the continuous spatial distribution of emission sources in both two-dimensional and three-dimensional space. Moreover, in contrast to the prototype, only four receiving channels are required.

If it is necessary to obtain a picture of the spatial distribution of emission sources from different viewpoints, n additional receiving channels are introduced into the device, where n = 1, 2, 3, etc. similar to the implementation described above. In this case, p = C is introduced into the device to process the received signals $\genfrac{}{}{0ex}{}{\text{4}}{\text{(4 + n)}}$ -1 = [(n + 4)! / (4! N!)] - 1 additional correlation processors, similar to those described above, and an image synthesizer included in the input of the display is introduced into the recording device. The control unit contains n additional trigger outputs, each of which is connected to the control input of the analog-to-digital converter of the corresponding additional receiving channel, the signal delay calculation unit contains n additional outputs, each of which is connected to the control input of the memory block of the corresponding additional receiving channel. In this embodiment, each correlation processor is associated with the outputs of four respective receive channels.

 In another embodiment, simpler to implement, instead of p correlation processors, a switch has been introduced for signal processing, connecting the outputs of the receiving channels with the inputs of one correlation processor. At the same time, the signal processing time is slightly increased in comparison with the option described above.

 In this embodiment, the recording device may be equipped with an image synthesizer with a memory included at the input of the display.

 The image is illustrated by drawings.

 Figure 1-4 shows a block diagram of various embodiments of the proposed device.

 Figure 5 schematically shows the location of the transducers relative to the investigated object.

 In FIG. Figure 6 shows the signals coming from the object under study into the receiving channels as they are contained in the memory blocks.

 In FIG. 7 shows a picture of the spatial distribution of emission sources obtained using the invention.

 The proposed device contains four receiving channels 1 (Figure 1), each of which consists of a series-connected signal converter 2, an amplifier 3, an analog-to-digital converter 4 and a memory unit 5, a correlation processor 6, consisting of a series-connected signal multiplier 7 with four inputs and integrator 8, a recording device 9, a control unit 10, and a unit for calculating signal delays 11. The inputs of the signal multiplier 7 are inputs of the correlation processor 6 and each of them is connected to an output with corresponding receiving channel 1. The output of the integrator 8 is the output of the correlation processor 6 and is connected to the information input of the recording device 9. The control unit 10 contains four trigger outputs, each of which is connected to the control input of the analog-to-digital converter 4 of the corresponding receiving channel 1, and the task output coordinates, connected to the input of the unit for calculating the delay of signals 11 and with the control input of the recording device 9. The unit for calculating the delays 11 contains four outputs, each of which x is connected to a control input of the storage unit 5 corresponding to one reception channel.

 The device shown in Fig. 2 differs from the one described above in that n additional receiving channels 1 and p = [(d! + N!) / (4! N!)] 1 additional correlation processors 6, made in the same way, are introduced into it described above. In particular, FIG. 2 shows a device in which n = 1 and p = 4. The receiving channels 1 are grouped into four in a group and the inputs of each correlation processor 6 are connected to the outputs of the receiving channels of the corresponding group.

 Thus, the output of each receiving channel is connected to the inputs p of the correlation processors. The recording device 9 contains an image synthesizer 12 with (p + 1) = 5 inputs, which are the information inputs of the device 9, one input serving as the control input of the latter, and two outputs, as well as a display 13, one output of which is connected to the information and the other to control outputs of the synthesizer 12 image. In this case, the control unit 10 contains one additional trigger output connected to the control input of the analog-to-digital converter of the additional receive channel 1, and the delay calculation unit 11 contains one additional output 6 connected to the control input of the memory block 5 of the same receive channel.

 The device shown in FIG. 3 differs from that shown in FIG. 2 in that instead of p correlation processors, a switch 14 with five information inputs and one control input is inserted into it. The switch 14 communicates the receiving channels 1 with the inputs of one correlation processor 6. In this case, the control unit 10 is equipped with another output connected to the control input of the switch 14.

 The device shown in FIG. 4, differs from that shown in FIG. 3 in that the recording device 9 comprises an input image synthesizer 15 with a memory 13 and a display 13 connected to its outputs. The synthesizer 15 is connected by its information input to the output of the correlation processor 6, and the control device to the coordinate output control unit 10.

 The following describes the operation of the proposed device for the case of obtaining a picture of the spatial distribution of emission sources of an acoustic thermal noise signal. In this case, the signal converters 2 are piezoelectric transducers. They are placed relative to the studied area 16 of the object, as shown in Fig. 5, namely, so that the studied area 16 is in the overlapping area of the radiation patterns of all the transducers 2 (shown by dashed lines). The direction from the studied area of the object to the transducers coincides with the Z axis, the XZ plane is perpendicular to the drawing plane. Acoustic noise signals from the studied area 16 of the object reach the transducers 2 (figure 1), where they are converted into electrical signals. The latter, after amplification in amplifiers 3, are fed to the inputs of analog-to-digital converters 4. The launch of analog-to-digital converters 4 is carried out periodically simultaneously on all channels 1 by supplying a signal from the outputs of the start of the control unit 10. The repetition period of the control signals is determined by the specified spatial resolution.

In the analog-to-digital converters 4, the instantaneous values of the signals are converted into digital codes, which are fed to the information inputs of the memory units 5, where they are stored. Figure 6 presents the real signals received from the object, with a Gaussian distribution in the space of the emission intensity (of the type exp {-r ² / w ² } where r is the distance from the origin, and w is the effective radius of the emitting region). As can be seen, the signals are noise-like in nature. After filling the information capacity of the memory blocks 5, the processing of accumulated signals begins. In this case, from the output of the job of the coordinates of the control unit 10, the set values of the coordinates of the points of the studied area of the object are sequentially issued, in which the values of the radiation emission intensity are obtained as a result of processing. The coordinate values (x, y, z) of each point are simultaneously supplied to the control inputs of the block 11 for calculating the signal delay and the recording device 9. In block 11, the values of the signal delay values generated for the analysis of the emission at the point (x, y, z) are output from 5 memory blocks to the inputs of the correlation processor 6.

где

бегущие координаты точки, задаваемые из блока управления 10,

координаты одного из преобразователей 2, принятого за опорный,

- координаты i-го преобразователя 2, v скорость звука в исследуемой области. Значение τ_i передается с выхода блока 11 на управляющий вход i-ого блока памяти, в результате информация из блока 5 памяти выводится с задержкой τ_i.The calculation operation consists in calculating for each of the receiving channels with number i the delay value τ _i relative to the reference channel according to the formula

Where

the running coordinates of the point specified from the control unit 10,

the coordinates of one of the transducers 2, taken as the reference,

- coordinates of the i-th transducer 2, v is the speed of sound in the studied area. The value of τ _i is transmitted from the output of block 11 to the control input of the i-th memory block, as a result, information from the memory block 5 is output with a delay of τ _i .

Эта операция, как было показано авторами заявки, позволяет получать значение амплитуды эмиссии в точке (x, y, z), определяемой значениями времени задержки τ₂,τ₃ и τ₄. Выходной сигнал T(x, y, z), пропорциональный интенсивности эмиссии в точке (x, y, z), подается на регистрирующее устройство 9, куда одновременно подается управляющий сигнал, определяющий координаты (x, y, z) точки зондирования, так что в результате последовательного перебора точек исследуемой области на регистрирующем устройстве 9 получается целиком изображение T(x, y, z). Это изображение, как это принято в томографии, может быть сечениями распределения T(x, y, z) различными плоскостями, либо трехмерными изображениями, которые по команде оператора могут представляться с различных точек обзора.Thus, respectively, the delayed signals S _i (t + τ _i ) are supplied to the inputs of the correlation processor 6, where in block 7 they are multiplied. The output of the multiplier 7 produces the product:
S ₁ (t) • S ₂ (t + τ ₂ ) • S ₃ (t + τ ₃ ) • S ₄ (t + τ ₄ ),
which is fed to the integrator 8, where it is integrated. As a result of the correlation processor 6, the following operation on the signals is implemented:

This operation, as shown by the authors of the application, allows to obtain the value of the emission amplitude at the point (x, y, z), determined by the values of the delay time τ ₂ , τ ₃ and τ ₄ . The output signal T (x, y, z), which is proportional to the emission intensity at the point (x, y, z), is supplied to the recording device 9, where a control signal that determines the coordinates (x, y, z) of the sensing point is simultaneously supplied, so that as a result of sequential enumeration of the points of the studied area on the recording device 9, the whole image T (x, y, z) is obtained. This image, as is customary in tomography, can be sections of the distribution of T (x, y, z) by different planes, or three-dimensional images, which, at the command of the operator, can be presented from different points of view.

 7 shows the distribution of the intensity of acoustic emission in the form of a section of the obtained image by the XZ plane. As you can see, the image of the object has the form of a pronounced peak located at a distance of 7 cm from the signal converters, with a size at half height about 0.3 cm. At the periphery from the peak, a noise-like emission behavior is observed corresponding to the intrinsic noise of the device. These noises can be significantly (more than 100 times) reduced by increasing the integration time. The presented picture shows that the obtained spatial resolution (about 0.3 cm) is significantly better compared with the capabilities of the method (Bowen T. Acoustic imaging, 1982, p. 549-561) (about 5 cm).

If it is necessary to obtain information on the spatial distribution of the emission intensity from different viewpoints, the circuit shown in FIG. 2, with more than 4 receiving channels. In this case, the processing is performed according to the algorithm described above, i.e. using 4 functions at the input of the correlation processor. However, in this case, from the total number of receiving channels 1, several different combinations of 4 are formed. This number is given by the well-known expression of the number of combinations of 4 out of n + 4 elements of C $\genfrac{}{}{0ex}{}{\text{4}}{\text{(4 + n)}}$ . As shown in figure 2, all the outputs of the receiving channels, grouped in four in all possible ways, are connected to the inputs of the correlation processors 6, the number of which is equal to the number of combinations of channels p + 1. As a result of correlation processing at the outputs of all processors 6, C $\genfrac{}{}{0ex}{}{\text{4}}{\text{(4 + n)}}$ different images, characterized in that they are formed using groups of transducers that are differently located relative to the study area, for example, from different sides.

в каждой точке, т.е. в соответствии с формулой:

Работа устройства, показанного на фиг.3, отличается от работы устройства на фиг. 2 тем, что сигналы от различных групп приемных каналов 1 обрабатываются не одновременно, а последовательно путем подключения с помощью коммутатора 14 разных групп (по 4 штуки) приемных каналов к входам корреляционного процессора 6. Более детально работа этого варианта происходит следующим образом. После заполнения блоков 5 памяти информацией первые 4 канала с помощью коммутатора 14 подключаются к корреляционному процессору 6, на выходе которого возникает изображение T(x, y, z), которое отображается на регистрирующем устройстве 9. После этого с помощью коммутатора 14 к корреляционному процессору 6 подключается другая группа приемных каналов (по выбору оператора). В результате на выходе образуется другое изображение. Таким образом, происходит последовательный просмотр полученных с разных точек обзора изображений.Thus, the obtained images are images of the object from different points of view. At the request of the operator, by setting on the control unit, it is possible to sequentially output the images to the recording device, or using the synthesizer 12, the arrangement of them is one in common, which includes information contained in all images. In the simplest case, the image synthesizer can be made on the basis of a multiplier, the work of which is to simply multiply the partial values of the emission intensity

at each point, i.e. according to the formula:

The operation of the device shown in FIG. 3 differs from the operation of the device in FIG. 2 in that the signals from the various groups of receiving channels 1 are not processed simultaneously, but sequentially by connecting 14 different groups (4 pieces) of the receiving channels to the inputs of the correlation processor 6 using a switch. In more detail, this option works as follows. After filling the memory blocks 5 with information, the first 4 channels are connected to the correlation processor 6 using the switch 14, the output of which is the image T (x, y, z), which is displayed on the recording device 9. After that, using the switch 14 to the correlation processor 6 another group of receiving channels is connected (at the operator’s choice). As a result, another image is formed at the output. Thus, sequential viewing of images obtained from different viewpoints takes place.

 The device variant shown in Fig. 4 works similarly to the previous one, but unlike the latter, it allows to obtain a combined (synthesized) image, as in the device shown in Fig. 2. Considering that the images from signals coming from different groups of receiving channels 1 are formed sequentially in time, a synthesizer 15 has a memory in which all images are stored so that a common image can be created from them, similar to how it is done in the synthesizer 12 variant of FIG. 2. The operation of the device in this case is as follows. After the memory blocks 5 are filled with information, the signal processing begins, consisting in sequential correlation processing of all groups of signals (4 each) with storing images in the memory of the synthesizer 15. After introducing all the images into the memory of the synthesizer 15, they are synthesized into one image, which is output device display 13.

Claims (4)

 1. A device for displaying the spatial distribution of incoherent emission sources, including m receiving channels, each of which consists of a series-connected signal converter, amplifier, analog-to-digital converter and a memory unit, the output of which is the output of this receiving channel, a correlation processor, a control unit, and a recording device, characterized in that a block for computing signal delays with one input and m outputs, each of which is connected to a control unit, is inserted into it With the corresponding input of the memory block of the corresponding channel, the correlation processor contains a signal multiplier with m inputs, which are the inputs of the processor, and an integrator, the input of which is connected to the output of the multiplier, and the output is the output of the processor, the control unit contains m trigger outputs, each of which is connected to the control input the analog-to-digital Converter of the corresponding receiving channel, and the output of the coordinates, connected to the input of the delay calculation unit and the control input of the recording device, the output of each receiving channel is connected to the corresponding input of the correlation processor, the output of the latter is connected to the information input of the recording device, and the number of receiving channels is m 4.  2. The device according to claim 1, characterized in that n additional receiving channels are introduced into it, where n 1, 2, 3, etc. similar to the aforementioned receiving channels, p = [(4 + n)! / (4! / n!)] - 1 additional correlation processors similar to the above, the recording device contains an image synthesizer with (p + 1) inputs, which are information inputs of the recording device, one input serving as the control input of the latter, and two outputs, as well as a display, one input of which is connected to the information, and the other with the control output of the image synthesizer, the control unit contains n additional trigger outputs, each of which is dined with the control input of the analog-to-digital converter of the corresponding additional receiving channel, the delay calculation unit contains n additional outputs, each of which is connected to the control input of the memory block of the corresponding additional receiving channel, each correlation processor is connected by its inputs to the outputs of four corresponding receiving channels, and the output each correlation processor is connected to the corresponding input of the recording device.  3. The device according to claim 1, characterized in that n additional receiving channels are introduced into it, where n 1, 2, 3, etc. similar to the aforementioned receiving channels, and a switch with (4 + n) information inputs, one control input and four outputs, connecting the outputs of the receiving channels with the inputs of the correlation processor, the control unit contains n additional trigger outputs, each of which is connected to the analog-digital control input the converter of the corresponding additional receiving channel, and the control switch output connected to the control input of the switch, the delay computing unit contains n additional outputs rows, each of which is connected to a control input of the storage unit corresponding additional reception channel.  4. The device according to claim 3, characterized in that the recording device contains an image synthesizer with a memory having two outputs, one of which is information and the other as a control input of the recording device, and two outputs, as well as a display, one output of which is connected to information, and the other with the control outputs of the image synthesizer.

Images