JPH06503877A - Imaging methods for defining the structure of objects - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Imaging method for defining the structure of an object The present invention provides an imaging method for defining the structure of an object. An imaging method, comprising: an object to be examined and at least one radiation; The sources are moved relative to each other and therefore the object moves through the lines emitted by the sources. Ru.

For about 100 years, X-ray technology has been used to describe the internal structure of objects. It has been uttered. In an X-ray photograph, the details of the internal structure of the object being examined are revealed by the X-ray radiation. It can be found as a superimposed absorption difference. The object in question is an internal organ, for example in the abdominal region of the human body. If it contains several elements with the same absorption coefficient, such as It is difficult and requires experts to analyze its structure. X-ray technology is an example We have developed various methods to better find desired objects, such as opaque object photography. Ta. Currently, the most useful method is X-ray tomography. Tomography is the direction of examination gives a cross-sectional image as seen from It can be found in relatively bright places. The desired number of cross-sectional images are created in series in the vertical direction. When completed, a precise three-dimensional image of the target is obtained. Other ties of radiation Already used to create three-dimensional images of targets, Another well-known method is ultrasound scanning. In the future, imaging will This would probably be done by also using infrared radiation. Current equipment is It's sloppy, expensive, and slow. For example, tomography, which is required for examining the human body, takes only a few seconds Capture one image in succession.

A current image of the internal structure of the inspected object is automatically and quickly requested.

Contrary to the case of X-ray tomography machines designed for examination of the human body, in these cases does not require a resolution of less than 1 mm. A typical application of this type is preferably various objects, chips and objects to detect objects, chips and/or substances that are to scan the quality and define the internal structure of these materials and objects. Is Rukoto. In some cases this is sufficient to define the three-dimensional shape of the object. However, inspection of the internal structure is not necessary.

The aim of the invention is to introduce an imaging method for defining the structure of objects. , and the method allows for faster and more efficient use of the Also for various applications by using very simple and more economical equipment , a properly constructed three-dimensional image is obtained.

The object of the invention is characterized by the novel features listed in the appended claims. This is achieved by the following methods.

In the method of the invention, at least one detector is arranged at at least three different angles. measuring the intensity change of the at least partially absorbed line in the object under test. t; and these changes are measured as a function of the movement of the object. Therefore The structural points required for structural imaging are at least 3 defined from different directions, and the path of the line through the object is always at the moment of measurement. As is known, the three-dimensional structure of an object can be calculated. The greatest advantage of the present invention is that, for example, For example, in X-ray tomography, the movement of one or more X-ray tubes is caused by one stationary X-ray tube. Moreover, hundreds of radiation detectors can be replaced with just one detector.

The device is simple and economical to manufacture and maintain. required by the device If all that is needed is to define the external shape of the object, the radiation source used is The irradiating diode may be used as the irradiation diode, and the detector may be a photosensitive transistor. The transmitter/receiver pair required for imaging is very simple and inexpensive. It's not the price.

The method of the invention can be applied to automatic and quick scanning of internal structures of various objects. and used. Possible applications are, for example, dangerous substances inside the inspected object, e.g. For example, stones and stones that adhere to logs when the wood is sawn or cut into chips. Detection of other objects. Furthermore, the method includes a sawing process to optimize the sawing process. Define the location of defects and knots in wood that has been removed. Furthermore, the method provides It can be applied for a variety of other purposes, such as searching for gunpowder or weapons in suitcases.

The scanning speed in the method of the present invention is high, about 100-500 images/second. , the resolution obtained is sufficient for these purposes. In addition to this, the method can be used to define the three-dimensional shape of various objects. As an example, given Regulation of the size and shape of chips cut from raw material, e.g. chips in the pulp industry. regulation of the size and shape of crushed aggregates in the mining industry; Describe the size and shape.

The invention will now be described in detail with reference to the accompanying drawings.

FIG. 1A is a side view for explaining one embodiment of the method according to the invention; The figure is a top view of the embodiment of FIG. 1A, and FIG. 1C is one of the embodiments of FIG. 1B. diagrams showing various images obtained from different directions of the elements of 2A and 2B illustrate another embodiment of the method according to the invention, in which FIG. 3 shows a third embodiment of the method according to the invention, viewed from the side and from the top, respectively. FIGS. 4A and 4B are side views showing a fourth embodiment of the method according to the invention. FIG.

The principle of the imaging method according to the present invention is illustrated in FIGS. 1A, 1B and fllclc. The imaging of the internal structure of a log is illustrated in the figures as an example. is shown. The radiation source is an X-ray tube that transmits X-ray radiation over a wide scanning angle. be. The log to be inspected is passed through the shell of a conical X-ray beam. radiation The lines are measured by line scan detectors 4.5.6.7 and 8. of the detector The line extends below and across the log. Line scan detection The instrument may consist of several (e.g. 100 to 500) parallel separate X-ray detectors. or consisting of one long detector with good position sensitivity. i.e., any detector has a detected point with respect to its length. detect and define the location of the Figure 1c shows that the X-ray tube is Shows images of a single element from different angles as it passes through the body . The numbers 4, 5, 6, 7 and 8 at the bottom of Figure 1c are in these directions. Each line detector used to scan is shown. The elements mentioned above are for example The straight line may be 0.5 cm. The density of the wood elements is determined by each element being imaged from a different angle. Determined based on what is displayed. These combined absorptions are according to the time when scanned by each detector of the scanning detector. always obtained from each detector. As a rule of thumb, a scan should include at least 2 tests. An output line is always required. In the example, five detectors are used. Detector The number of lines may vary in different applications. Also, increase the number of detectors. Generally speaking, the more vivid the image, the clearer the image. The image is As in regular tomography, for example, cross-sectional images 1 to 6, a predetermined plane is Calculated as a cross-sectional image. Once all cross-sectional images have been processed, here It is possible to obtain a three-dimensional density image of the log in question, and along with this, the knot , corroded areas, cracks, etc. are noted, and often a height distribution can also be obtained. Canada Additionally, the device is equipped with a profile leader that defines the external shape of the log. Good too.

This will help with calculations when constructing the sawing image. All the essentials of a log The material is imaged from multiple directions, and is then created by sawing a log. It is also possible to directly know the location of knots present in the product.

In the embodiment of FIGS. 2-4, the radiation source and detector are paired. . One of them is stationary and the other one is measuring by moving along a circular path. The defined radiation surface has a conical shape. The object to be inspected cannot pass through this conical surface. However, images are usually constructed by a computer. Actual application status In some cases, it is also possible to use multiple detectors or multiple radiation sources. . Of course, modifications using different combinations are also possible. For example, a vertical image The scanning is performed by a line of stationary detectors, and the tilted image from both sides shows the rotating plate. Obtained by using

Test example 1 Figure 2 shows a log tomography device that transmits continuous X-rays. A radiation source 11 (X-ray device) and a radiation detector 1 that measures the amount of X-ray radiation when desired It consists of 2. During inspection, the object, ie the log 13, is placed on a conveyor bell, for example. It passes through the tomography device at a constant speed. The log entered the cone of the X-ray beam. At this time, the absorption curve of the cross section is measured at spot 15, and the density distribution state of the cross section is obtained. It will be done. When the log passes through the second surface 16 of the X-ray beam, a horizontal density state is obtained. Ru. From these intersecting images, we can see that inside the log, as explained earlier in the specification, The density distribution can be clarified, and based on the density distribution, knots, cracks, etc. in the log can be identified. The location of corrosion can be calculated. In practice, the imaging speed should be set to 2m, for example. /s, and if the measurement areas are made 1 cm apart. For example, the imaging speed is 200 areas per second. If two X-ray detectors is placed in a circumferential path (with a phase difference of 90°), the rotation speed is 6000 rpm. It is. This rotational speed is achieved using conventional techniques. As seen in Figure 2, A protective screen is equipped to protect the detector from the radiation that will soon fall on it.

The device can incorporate one or several detectors and the data can be transmitted to a computer. along the line to the detector 14, so that only one detector at a time Exposure to radiation. Reveals the cross-sectional profile of a log before inspecting its internal structure For example, the device can be equipped with an optical laser profilter to Ru. This information helps create cross-sectional images faster and more accurately.

Test example 2 Figure 3 shows the stone detector. For example, stones in beets that are burned as fuel, Detection of stones in the flow of slabs carved into chips is an important task, but at present For the first time, no method was completely satisfactory. Because the resolution required here is This is because the radiation source 21 is not substantially the same as the case, and the radiation source 21 is a radiation isotope source (e.g. For example, 100 mci Am-Hl). Detector 22 measures radiation density It is installed in a static manner for this purpose. The difference in density of the transported material 23 is determined by a computer. 24 from the absorption on the conical vertical surface 25 and the inclined conical surface 26. Ru.

Test example 3 FIG. 4 shows the detection of chip particle size. Important objects in the pulp industry The measurements are the diameter, length, width and height distribution of the chip particles. Because if you look at the internal structure This is because there is no need to detect the radiation, and a normal light source is sufficient as the radiation source. Figure 4 In the measuring device, the light source employed is a light emitting diode 30, and the detector is two photoelectrons. These are multiplier tubes 31 and 32. The light sources are 20 or more and are mounted on the rotary plate 36. In this case, the rotating plate rotates at a speed of approximately 10.00 rpm. Ru. Chips 33 are placed on a transparent conveyor belt 35 so that they do not fall off the top of each other. They are scattered all over the place. For example, the belt is carried at a pace of 1 m/s, and its t : From below the transparent conveyor belt 35, the light from each light source is imaged upward. It is continuously sent to device 37. If the number of light sources is 20 and the rotation speed is 10. At 00Orpm, the belt is scanned at intervals of 1/3 of a second. vertically upward An investigation based on the blackout time (dark time) of a photomultiplier tube placed in The width of the chip at the scanning point is obtained. Detection from an inclined direction From the difference in the appearance times of the edges, detected by means of the photomultiplier tube 32, each step is The height of the tip at the canning point is obtained. Based on these readings Then, the length, length and height of the tip are calculated by computer.

Additionally, other types of deformation may be used in the imaging method to The speed of imaging as well as the speed of imaging may vary for different applications. mentioned above In a preferred embodiment of the invention, the test object is moved relative to the radiation source and the detector. However, in other embodiments, the radiation source and and/or the detector may be moved. Stationary detector array plus l or multiple rotations A flexible plate or plant form may also be used. Another preferred embodiment radiators for different radiation intensities arranged on a rotatable platform. There is a line detector, in which case more than one inclined area can be measured.

When using the method of the invention, the radiation used may be visible light, X-ray radiation, radiation −, gamma, neutron, infrared or microwave radiation, pulsed magnetic fields or It may be another radiation or a combination of these, the radiation being mutually influence each other. An area of interest in tomography is the neutron, a plate that can be rotated manually. This is a neutron tomography system installed in the detector. If the diameter is 3-5m, To scan vehicles, containers, etc. when searching for organic materials such as gunpowder or drugs. This method can be used to

The invention is not limited to the preferred embodiments described above, but is defined in the appended claims. :Changes may be made within the scope of the invention.

niLshirJB 2T sirrJC 1 mu 1 mu international search report international search report PCT/FI 91100304

Claims (1)

[Claims] 1. Test object (3; 13; 23; 33) and at least one detector (4-8; 12; 22; 31; 32) are moved relative to each other, the object to be inspected becomes the radiation source ( 1; 11; 21; 30) passing through radiation transmitted by 1. A method, wherein the one or more detectors are viewed at least partially from at least three different angles. It is used to measure the change in the intensity of the radiation absorbed by the object under test. are measured as a function of the object's movement, and the path of the radiation through the object is determined. Since the point of measurement is always known, the three-dimensional structure of the object can be calculated. An imaging method for defining the structure of a featured object. 2. The object to be inspected (3) is located laterally to the stationary X-ray tube (1) in the direction of movement of the object to be inspected. and the X-ray detectors (4 to 8) arranged in the A claim characterized in that radiation of an X-ray tube is observed from at least three different angles. Imaging method in Section 1. 3. The object to be inspected (13; 23; 33) has at least one conical imaging table. (15, 16; 25, 26), the imaging surface is at least one radiation source (11; 21; 30) and at least one radiation detector ( 2; 22; 31, 32), at least one of which is 2. The device according to claim 1, wherein the device is moved along a circular path when in a resting state. Imaging method. 4. A three-dimensional tomographic image of the inspection object is created, and to create the image, A stationary X-ray tube (11) from at least two divergence zones (15, 16) of the object under examination. ) using the value obtained from the reading of the radiation intensity transmitted by the at least one detector (12) arranged on a rotatable platform (17) 4. The imaging method according to claim 3, wherein the imaging method is measured by: 5. On the rotatable platform there are detectors arranged along a circular path ( 12), and when another detector measures the area (15, 16), the detector Claim 4 characterized in that the remainder is arranged under a radiation protection screen (18). imaging method. 6. A radiation source (2) consisting of radioisotopes arranged on a rotatable plate (27). 3) and the radiation detector (22), the abnormal density can be detected by passing the material between the is identified in the material arrow (23) and the radiation detector is Image according to claim 3, characterized in that radiation is measured in the areas (25, 26). method. 7. By using light as the radiation used, the shape of the three-dimensional object (33) a light source mounted on a rotatable platform (36); (30), a protrusion parallel to the surface of the object is illuminated by the imaging device ( The detector (31) is installed vertically above the detector (37). 1) and a detector (32) facing the same light source from an inclined angle. The height is calculated from the difference in checkout times and therefore the final image of width, length and height. the speed data of these detectors (31, 32) and the transparent belt (35). An imaging method according to claim 3, characterized in that it is constructed based on. 8. Radiation for different radiation intensities arranged on a rotatable platform line detector, therefore three or more inclined areas are measured for tomographic images. The imaging method according to any one of claims 3 to 6, characterized in that the imaging method can be set. 9. Both alarm detectors used simultaneously arranged in line and requested area and a rotatable detector for measuring. method.