JP2006038532A - Matter discriminating method and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a matter discriminating method capable of precisely calculating the feature quantity (feature data) of a cannonball from the X-ray perspective image of the cannonball to precisely discriminate the type of the cannonball. <P>SOLUTION: After the image component of the part of the component easy to damage the cannonball is removed from the X-ray perspective image, a threshold value for detecting the profile or structure of the cannonball according to the brightness histogram of the X-ray perspective image is determined and the feature quantity of the cannonball is detected from the image component extracted from the X-ray perspective image on the basis of the threshold value to determine the type of the cannonball. Especially, the feature quantity of the cannonball is detected based on the thick-walled bottom part of the cannonball. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an object identification method and apparatus suitable for identifying, for example, the type of shells left in the ground or the like from the X-ray fluoroscopic image.

When collecting and disposing of ammunition that has been left in the ground for a long time, it is important to identify the type of ammunition. Such identification of an object is performed exclusively by obtaining an X-ray fluoroscopic image of a shell as an inspection object using an X-ray apparatus, and examining features of its outer shape and internal structure (for example, see Patent Document 1). reference). Specifically, feature quantities such as the outer dimensions of the shell and the presence / absence and size of the internal structure are obtained, and the type of the shell is determined according to these feature quantities.
JP 2003-90700 A

  However, when a shell as an inspection object is left in the ground for a long period of time, there is a possibility that its outer shape or internal structure is deformed due to the influence of corrosion or deposits. Therefore, even if an X-ray fluoroscopic image of the inspection object (cannonball) is obtained, information on characteristic points necessary for determining the type of the shell from the X-ray fluoroscopic image, such as the maximum bullet diameter and the length of the transfer cartridge In addition, it is often difficult to accurately extract the presence or absence of the glaze cylinder. For example, if a cannonball that is the object to be inspected contains attachments such as cartridge case, warhead plug, tail wing, etc., there is a risk that the bottom of the bullet etc. may be erroneously detected from the above-mentioned attachments reflected in the fluoroscopic image. It is difficult to accurately detect the feature amount. In addition, when the thickness of the shell tube is changing due to the influence of corrosion or deposits, the characteristic dimensions and structure such as the maximum shell diameter and the features of the internal structure must be obtained accurately. It becomes difficult.

  The present invention has been made in consideration of such circumstances, and the purpose thereof is, for example, a shell that has been corroded or deformed due to being left in the ground for a long period of time. To provide an object identification method and apparatus capable of accurately obtaining characteristic quantities (feature information) unique to various shells from the X-ray fluoroscopic images, and accurately identifying the type of the shell based on the feature information. It is in.

In order to achieve the above object, an object identification method according to the present invention is described in claim 1.
<a> When obtaining an X-ray fluoroscopic image of an inspection object having features in the outer shape and the internal structure, and determining the type of the inspection object from the characteristic amount of the inspection object determined from the X-ray fluoroscopic image ( Prerequisites),
<b> After removing the image component of the easily damaged part portion in the inspection object from the fluoroscopic image,
<c> determining a threshold for detecting a characteristic portion of the inspection object according to a luminance histogram of the fluoroscopic image;
<d> A feature amount of the inspection object is determined by detecting a feature amount of the inspection object from an image component extracted from the fluoroscopic image based on the threshold value.

  Preferably, when the object to be inspected is a shell that has been left in the ground for a long period of time as described in claim 2, it corresponds to a part of the shell, such as a cartridge case, a warhead plug, and a tail wing. A threshold for use in extracting the image area of the shell from the X-ray fluoroscopic image is removed based on the luminance level at which the luminance histogram of the X-ray fluoroscopic image peaks. To set. And by detecting the characteristic part of the shell in the image region extracted from the X-ray fluoroscopic image according to this threshold, the feature amount is set as, for example, the maximum shell diameter, the presence / absence of a glaze cylinder, the length of the transfer cylinder, etc. It is characterized by seeking.

  In particular, as described in claim 3, the length or the like of the charge transfer cylinder is based on the bottom of the shell, which is one of the characteristic points detected from the X-ray fluoroscopic image. It is characterized in that each distance to a point is measured with high accuracy, and the feature value is calculated from these measured values by reverse calculation. In other words, a portion that is difficult to corrode and deform, such as the bottom of a shell, is set as a reference point for measurement, and the positional relationship of each feature point from this reference point is accurately measured to determine the length of the transfer cartridge, etc. It is characterized by obtaining accurately.

An object identification device according to the present invention is as described in claim 4.
<A> An X-ray fluoroscopic apparatus that obtains an X-ray fluoroscopic image of an inspection object characterized by an outer shape and an internal structure, and an image processing apparatus that performs image processing on the X-ray fluoroscopic image and determines the type of the inspection object (Prerequisite)
The image processing apparatus includes:
<B> a first image processing means for removing an image component of a component part that is easily damaged in the inspection object from the X-ray fluoroscopic image;
<C> A threshold value for detecting a feature portion of the inspection object is determined according to a luminance histogram of the X-ray fluoroscopic image, and the characteristic portion of the inspection object in the X-ray fluoroscopic image is extracted based on the threshold value Second image processing means for
<D> It is characterized by comprising a determination means for obtaining a feature amount in the feature portion extracted by the second image processing means and determining the type of the inspection object according to the feature amount.

  Preferably, when the object to be inspected is a cannonball that has been left in the ground or the like as described in claim 5, the first image processing means includes a cartridge case, a warhead plug, a tail wing, etc. An image region in the X-ray fluoroscopic image of the accessory part is detected, and the image region is excluded from the image processing target. Further, in the second image processing means, the luminance level at which the luminance histogram of the X-ray fluoroscopic image reaches a peak is regarded as a level for specifying the outer cylinder portion of the shell, and this luminance level is used for the shell region. The characteristic portion of the shell is extracted from the X-ray fluoroscopic image as a prescribed threshold value and is used for detection of the characteristic amount.

Further, according to a sixth aspect of the present invention, in the determination means, the feature quantities in the plurality of feature portions of the inspection object obtained by the second image processing means are deformed in advance of the inspection object. It is configured so as to be obtained respectively from the measured values up to the above-described characteristic part measured with reference to a part that is clearly difficult.
It should be noted that the portion of the inspection object that is clearly difficult to be deformed in advance is hardly corroded or deformed even if it is a shell that has been left in the ground for a long period of time as described in claim 7, for example. It is set as a bullet bottom having a predetermined thickness that does not occur.

  According to the object identification method and apparatus according to the present invention, parts of an inspection object that are easily damaged, specifically, image components of accessory parts such as cartridge shells, warhead plugs, and tail wings are removed from the fluoroscopic image. After that, a threshold value for detecting a characteristic part of the inspection object is determined according to a luminance histogram of the X-ray fluoroscopic image, and a feature amount of the inspection object is detected from the X-ray fluoroscopic image based on the threshold value Therefore, it is possible to accurately detect the feature amount necessary for the determination of the type, regardless of the corrosion caused by the inspection object (cannonball) or the deformation caused by the adhered matter.

  In particular, since image components of accessory parts such as shells, warhead plugs, and tail wings are removed from the X-ray fluoroscopic image, it is possible to correctly detect a bullet region including a feature amount necessary for determining the type. Furthermore, since the shell region is extracted from the fluoroscopic image according to the threshold value determined based on the luminance histogram, only the shell region image is not affected by the outer surface of the shell, etc. Can be extracted accurately. As a result, feature quantities such as the maximum bullet diameter can be measured with high accuracy, and the internal structure and the like can be accurately recognized. ) Type can be identified with high accuracy.

  Furthermore, when detecting the characteristic amount of a shell, the position of each feature point from the reference position is measured based on a portion that is difficult to be corroded or deformed, such as the bottom of a shell, for example, the propagation inside the shell. Since the length of the gunpowder cylinder and the like are calculated backward, the feature amount can be obtained with high accuracy. By the way, when the bullet head is used as a reference as in the prior art, the position of the bullet head itself may change due to the presence or absence of a bullet plug, deformation thereof, or the like. Accordingly, as described above, if the feature values of each part of the shell are measured with reference to the bottom of the shell, the reference itself can be determined stably, so that the measurement accuracy for the feature value can be sufficiently increased. It is possible to easily increase the reliability of determination.

  Therefore, according to the present invention, it is possible to accurately identify (determine) the type of the inspection object (cannonball) according to the characteristic amount obtained from the X-ray fluoroscopic image without being affected by the deformation of the inspection object (cannonball). In practice, a great effect can be obtained.

Hereinafter, an object identification method and apparatus according to an embodiment of the present invention will be described with reference to the drawings, taking as an example identification identification of various shells dug from the ground or the like.
FIG. 1 is a schematic configuration diagram of a main part of an object identification device that obtains an X-ray fluoroscopic image of a shell (inspection object S) and performs image processing on the X-ray fluoroscopic image to identify the type of the shell. This object identification apparatus is schematically composed of an X-ray fluoroscopic device 10, a conveyor mechanism 20 that transports a shell (inspection object) S and performs a fluoroscopic inspection by the X-ray fluoroscopic device 10, and the X-ray fluoroscopic device 10. And an image processing device 30 that inputs a fluoroscopic image of a shell (inspection object) S obtained by using and determines the type of the shell (inspection object) S.

  The conveyor mechanism 20 includes a belt conveyor 23 that is transported and driven by a motor 22 that is rotationally driven by an inverter 21, and a shell (inspection object) S is placed on the belt conveyor 23 so as to perform the X-ray fluoroscopy. The device 10 is used for fluoroscopic inspection. In particular, a cannonball (inspection object) S that has a substantially cylindrical shape and is easy to roll is placed on, for example, the gantry 24 and is conveyed by the conveyor mechanism 20 in a state in which the rolling is prevented. The cannonball (inspection object) S is conveyed by the conveyor mechanism 20 in a state where the axial direction of the cannonball (inspection object) S is aligned with the conveyance direction of the conveyor mechanism 20, for example.

  On the other hand, the X-ray fluoroscopic device 10 is provided at a side portion of the conveyor mechanism 20 and is driven by the X-ray control device 11 to generate X-rays that cross the conveyance path by the conveyor mechanism 20 at a substantially right angle. A generator 12 and a line sensor 13 that is provided to face the X-ray generator 12 across the conveyor mechanism 20 and detects X-rays transmitted through the shell (inspection object) S are provided. As shown in FIG. 2, the line sensor 13 plays a role of detecting the amount of X-ray transmission in the cross section in a linear form in a state where the shell (inspection object) S on the belt conveyor 23 is cut into a circle.

  In this way, information on the amount of X-ray transmission detected linearly by the line sensor 13 is synchronized with the transfer (transfer) of the shell (inspection object) S by the belt conveyor 23, and the shell (inspection object). Obtained sequentially for each part different in the axial direction of S, and by connecting the information of the X-ray transmission amount in each of these parts to the transport direction of the belt conveyor 23 (axial direction of the bullet S), 1) One (1 frame) X-ray transmission image over the entire S is obtained.

  On the other hand, the image processing apparatus 30 mainly composed of, for example, a microcomputer captures an X-ray transmission image over the entire shell (inspection object) S detected through the line sensor 13 and performs image processing. A frame grabber 31 is provided. Then, the image processing device 30 obtains feature information on the outer shape of the shell S and its internal structure by performing image processing to be described later on the X-ray transmission image of the shell S, and further obtains the feature amount. The type of the shell S that is the inspection object is identified.

  In the figure, reference numeral 32 denotes a display incorporated in the image processing apparatus 30 and used for displaying the above-described X-ray transmission image, displaying the image processing result, and the like. In the figure, 33 is a keyboard used for inputting various control parameters for image processing, and 34 is a mouse as a pointing device for various information displayed on the display 32.

Here, image processing for an X-ray transmission image of the shell (inspection object) S in the image processing apparatus 30 will be described. This image processing is basically executed according to the procedure shown in FIG.
That is, when an X-ray transmission image of the shell (inspection object) S obtained using the X-ray fluoroscopic apparatus 10 is obtained (step S1), the image processing apparatus 30 first sets the density for the X-ray transmission image. Conversion processing is executed (step S2). In this density conversion process, the characteristic portion of the shell is clearly clarified by extending (enlarging) the brightness difference in the portion (dark portion) where the brightness level of the region that mainly transmits the shell in the X-ray transmission image is low. It consists of processing to make it appear. That is, the image of the shell portion in the X-ray fluoroscopic image is often biased to an image component of a low luminance level because the shell shell of the shell is thick. Therefore, in order to increase the contrast at the low luminance level and clearly express the characteristics of the features of the shell, the X-ray fluoroscopic image is subjected to density conversion processing according to the relationship of the display brightness to the sensor output as shown in FIG. The contrast of the X-ray transmission image in the transmitted portion is increased, and the contrast of the background portion of the high luminance level that does not transmit the shell is compressed. As a result, for example, as shown in FIG. 5A and FIG.

  After that, only the shell region that clearly expresses the features of the shell from the X-ray transmission image is extracted (step S3). This process detects noise elements other than cannonballs, specifically, image components of accessory parts such as shell cartridges, warhead plugs, and tail wings using, for example, the continuity of the image area and the difference in brightness level, This process includes processing for excluding these pieces of information from image processing targets. That is, as shown in FIGS. 5A and 5B, an X-ray transmission image of a shell often includes image components such as a cartridge case, a warhead plug, and a tail wing attached to the shell portion. Moreover, these accessory parts are often greatly deformed compared to the shell part due to corrosion or the like, and are often not involved in the characteristics that specify the type of the shell.

  Therefore, for example, a median filter process is performed on the X-ray transmission image to remove a noise component of 1 pixel width. Further, after binarizing the above-mentioned X-ray transmission image, the binarized image is subjected to contraction / expansion processing a predetermined number of times to remove linear portions, and an isolated minute image region is to be inspected. Remove from. That is, when an X-ray transmission image as shown in FIG. 5B is binarized with a predetermined threshold value, for example, as shown in FIG. 6A, the binarized image can be obtained. If shrinkage processing is performed on such a binarized image, a thin line portion having a predetermined width or less disappears due to shrinkage of the image area as shown in FIG. 6B, and if this shrinkage image is subjected to expansion processing, FIG. As shown in (c), only an image area having a certain size is left. Then, if an image area having a predetermined area or more is determined as a shell part, and an image area isolated from the shell area is determined to be a part part attached to the shell, FIG. As shown, it is possible to extract only the image of the shell part from which the accessory part has been removed.

  In this way, if the image components of the attached parts (shell cartridge, warhead plug, tail wing, etc.) that are likely to be deformed are removed and only the image area of the shell part is extracted, the characteristics related to the shell area Information, specifically its area, average brightness value, brightness variance value, etc. are stored. Then, the central axis of the shell is obtained (determined), the image is rotated so that the central axis is horizontal, and image processing for subsequent feature amount detection is facilitated (step S4). As for this image rotation process, for example, the moment of the above-mentioned shell area is calculated, and the position of the center of gravity is obtained from the primary moment. Next, if the inclination of the main axis (center axis of the shell) passing through the center of gravity is obtained from the position of the center of gravity and the secondary moment of the shell area, the image is rotated so that the center axis of the shell is horizontal according to this inclination. good.

  When the pre-processing for the X-ray transmission image is completed as described above, the feature amount relating to the outer shape, specifically, the length of the bullet, the width of the bullet head and the bottom, the maximum bullet Each diameter is measured, and further, the presence or absence of a warhead plug is determined (step S5). Next, the internal structure of the cannonball is examined from the X-ray transmission image, in particular, the charge transfer cylinder inside the cannonball is detected, and the characteristic amount relating to the transfer charge cylinder, specifically the position of the transfer charge cylinder, the length of the transfer charge cylinder, and its The width, the amount of misalignment with respect to the center axis of the shell, and the like are measured (step S6).

  Thereafter, it is examined from the X-ray transmission image whether or not a glaze cylinder is present inside the shell, and when there is a glaze cylinder, its position, length, width, misalignment amount with respect to the central axis of the shell, etc. Each of the feature quantities related to the glaze cylinder is measured (step S7). Then, if the characteristic quantities related to some characteristic parts of the shell are obtained as described above, these characteristic quantities are comprehensively determined, and collated with the characteristics of various shells previously stored in a database (not shown). By doing so, the type of shell to be inspected is determined (step S8).

  That is, the shell to be inspected has different characteristics depending on its type. For example, as shown in FIG. 7 (a) to (h), typical shell characteristics, the outer shape and size (bullet diameter, bullet), the so-called 75 mm bullet, 90 mm bullet, 105 mm bullet, and 150 mm bullet are formed by the shell 1. The length) is different, and the length of the charge transfer cylinder 2 which is the internal structure is different. Depending on the type of shell, there are those equipped with the glaze cylinder 3 (so-called red bullets) and those not equipped (so-called yellow bullets). There are other shells called so-called blue and white bullets, but they are omitted here. Therefore, if the characteristics of the shell obtained in the above-described steps S6 to S8 are examined from the above-described X-ray transmission image, it becomes possible to identify the type of the shell used for the inspection from the feature amount.

  However, the shells to be inspected have been left in the ground for a long period of time as described above, and are often deformed due to corrosion or deposits (mud or rust). Then, due to this shape deformation, the thickness of the shell in the X-ray transmission image changes, and there is a possibility that the maximum bullet diameter is erroneously measured. In addition, it may be difficult to distinguish between the shell 1 of the shell and the glaze cylinder 3 which is an internal structure thereof. Further, due to the deformation of the warhead to which the adapter is mounted, there is a possibility that the length of the charge transfer cylinder 2 which is the internal structure is erroneously measured.

In particular
(a) The maximum bullet diameter is measured larger than the actual bullet diameter due to the influence of deposits such as mud and rust.
(b) The boundary between the deposit and the shell 1 is erroneously determined to be the boundary between the glaze cylinder 3 due to the influence of the deposit and the presence / absence of the glaze cylinder 3 is erroneously determined.
(c) The shell shell is mistakenly detected as part of the shell, and the shell outline extraction fails.
(d) The presence or absence of a warhead plug is misjudged, and failure to detect the position of the warhead tends to cause inconveniences such as erroneous measurement of the length of the shell or the length of the transfer cartridge 2.

  Therefore, in the present invention, as described above, when detecting the characteristic amount of the shell from the X-ray transmission image, a luminance histogram of the X-ray fluoroscopic image is obtained, and the characteristic portion of the inspection object is detected according to the luminance histogram. A threshold is set. Specifically, focusing on the fact that the brightness level at which the brightness histogram of the X-ray fluoroscopic image reaches a peak mainly represents the shell (outer part) 1 of the shell, the threshold value is based on the brightness level at the peak in the brightness histogram. Is dynamically set, and a shell region is extracted from the X-ray transmission image using this threshold value.

  That is, when accurately recognizing the outer shape of a shell and measuring the maximum shell diameter, it is possible to reliably remove deposits on the surface of the shell (bullet shell) from the X-ray transmission image and extract only the shell region. It is important to optimally set the threshold. Therefore, when the histogram of the brightness level in the X-ray transmission image of the shell is obtained, the brightness level that takes a peak changes depending on the thickness of the shell 1 of the shell, and the brightness level on the low brightness level side with this brightness level as a boundary. It was found that the image components of the shells are concentrated.

  Specifically, as shown in FIG. 8, an example A of a luminance histogram of a 75 mm bullet (yellow bullet) having a glaze cylinder and an example B of a luminance histogram of a 90 mm bullet (yellow bullet) having a glaze cylinder are shown in FIG. The luminance levels of the image components forming the image are distributed on the low luminance level side having a certain luminance level as a peak. Since the luminance level that takes the peak varies depending on the thickness of the outer shell (bullet shell) of the shell, it can be recognized that the luminance level exclusively represents the luminance of the outer shell (bullet shell) portion of the shell. In addition, the appearance frequency of high-luminance image components exceeding the peak luminance level rapidly decreases, and these high-luminance level image components include components that have been transmitted exclusively through the internal space of the shell, and the background portion around the shell. It is recognized that the image component is shown.

  Therefore, in the present invention, a threshold value for extracting a shell region is dynamically set on the basis of the luminance level at which the histogram described above takes a peak, and this threshold value forms a boundary between the shell shell of the shell and its background. Thus, a bullet region is extracted from the X-ray transmission image. As a result, it is possible to optimally set a threshold value that can discriminate a subtle difference between the brightness level of the shell shell portion and the brightness level of dirt or rust adhering to the surrounding shell. Image components such as adhering mud and rust can be removed, and only the shell region surrounded by the shell can be accurately cut out. Therefore, it is possible to accurately measure the characteristic amount such as the maximum bullet diameter of the shell and the length of the shell.

Here, the outer shape detection process, the transfer cylinder detection process, and the glaze cylinder detection process shown in steps S5, S6, and S7 described above will be described in a little more detail.
The outer shape detection process (step S5) basically includes a process for measuring (detecting) characteristic quantities such as the length of the bullet, the width of the warhead and the bottom, the maximum warhead diameter, and the presence or absence of the warhead plug. It is executed according to the processing procedure shown in FIG. Specifically, its width and position are detected along the central axis of the shell (step S11), and the position where the shell width is maximum and its maximum width as shown in FIG. To determine the warhead diameter (step S12). Next, the width is sequentially examined along the central axis toward the shell tail part, and for example, the position to a part that is more than a predetermined distance away from the center of gravity of the shell and has a certain diameter or more is obtained, and the final position Is detected as a bullet bottom (step S13). Similarly, the width is sequentially examined along the central axis toward the shell head side, and for example, the position to a part that is more than a predetermined distance away from the center of gravity of the shell and forms a bullet diameter of a certain width or more is obtained. The position is detected as a warhead (step S14).

  Thereafter, on the basis of the width at the warhead obtained as described above, a search is made for how long the region where the width is narrower than the width of the warhead continues. If the length is longer than the predetermined length α, it is determined that the image portion indicates the warhead plug mounted on the warhead (step S15). When the warhead plug is detected, the position of the warhead is corrected if the position excluding the warhead plug is the warhead. Then, the distance from the warhead to the bottom is obtained as the length of the shell. When there is bullet shell distortion, the line connecting the center positions of the shell widths obtained as described above is a curve. Therefore, it is also useful to detect the amount of deviation between this curve and the above-mentioned central axis (step S16), and to obtain this amount of deviation as the distortion of the shell.

  On the other hand, the above-described detection process (step S6) of the charge transfer cylinder is executed according to the processing procedure shown in FIG. 11, for example. That is, in the image area of the shell extracted as described above, first, the bottom of the charge transfer cylinder is detected. In the bottom detection of the charge transfer cylinder, a lateral edge enhancement process is performed on the X-ray transmission image to emphasize the vertical line component on the image including the bottom of the transfer charge transfer cylinder (step S21). Thereafter, the vicinity of the center axis of the shell is searched to detect a vertical line detection position close to the warhead, and the detection position is determined according to the approximate relationship between the shell of the shell and the transfer cartridge shown in FIG. It is detected as the bottom of the cylinder (step S22). In addition, when a vertical line cannot be detected, it is assumed that the process for detecting the charge transfer cylinder has failed.

  Next, the position of the bottom portion of the charge transfer cylinder, the distance from the bottom position to the warhead, the distance from the bottom position to the bottom of the bullet, and the like are measured as the feature quantities related to the bottom of the transfer charge cylinder (step S23). In particular, the bottom of a shell is generally thick, and even if the shell is left in the ground for a long period of time, its deformation is considered to be extremely small. It is preferable to obtain. In other words, for the bullet head of a shell, the reliability of the feature amount itself may be lower than that of the above-mentioned bullet bottom due to the presence or absence of warhead plugs or deformation, so it is better to use the bullet bottom as a reference. It can be said that the characteristic amount of the charge transfer cylinder can be obtained with high accuracy.

  After that, in order to detect the side of the charge transfer cylinder, a mask area is set in the vicinity of the area surrounding the bottom of the transfer charge cylinder and the warhead in accordance with the feature amount (step S24). It is used for feature amount detection processing. For detection of the feature amount of the upper and lower side surfaces of the charge transfer cylinder, first, the X-ray transmission image described above is first subjected to vertical edge enhancement processing, and the horizontal line on the image including the side of the transfer charge cylinder The component is emphasized (step S25). Next, the horizontal line component at the bottom position of the charge transfer cylinder is searched using the image subjected to the enhancement process of the horizontal line component (step S26), and the horizontal line component detection position is detected as the side face of the transfer charge cylinder. If the side view of the charge transfer cylinder is detected, the feature amount at the side portion is detected as, for example, the distance from the central axis, the shift amount, or the like (step S27).

  On the other hand, the above-described glaze cylinder detection process (step S7) is executed according to the processing procedure shown in FIG. 13, for example. Unlike the above-described transfer cylinder, the glaze cylinder detection process has a bottom part of the glaze cylinder in the vicinity of the bottom of the shell, making it difficult to distinguish it from the shell bottom. Done. Specifically, since the glaze cylinder generally exists along the inner wall surface of the shell, first, a mask area in which the outer area of the cannonball is contracted is set as the presence area of the glaze cylinder (step S31). Then, after performing the edge enhancement processing on the X-ray transmission image described above, the upper part is searched with respect to the position of the center of gravity of the shell, and according to the positional relationship between the shell of the shell and the glaze cylinder shown in FIG. The upper side is detected (step S32). Similarly, the lower part of the side surface of the glaze cylinder is detected by searching below the center of gravity of the shell. If the side surface of the glaze cylinder cannot be detected within the predetermined range, it is assumed that the detection process has failed. If the side surface of the glaze cylinder is detected, the distance between the upper part and the lower part of the side surface is detected as the width of the glaze cylinder, and further the deviation from the central axis is detected as the feature amount (step S33).

  After that, since the bottom of the glaze cylinder is considered to exist at a position connecting the end of the upper side of the side surface and the end of the lower side of the side detected as described above, a rectangular region including these ends is defined as the glaze cylinder. It is set as a mask area where the bottom exists (step S34). Then, the vertical line component of the image in the mask region is edge-enhanced to detect the bottom of the glaze cylinder, and the feature amount is obtained (step S35). What is necessary is just to obtain | require the feature-value of the bottom part of this glaze cylinder, for example as a distance from a bullet head, a distance from a bullet bottom part, etc., for example.

  Thus, according to the present apparatus for identifying the type of shell based on the feature amount related to the outer shape of the shell obtained as described above, the feature amount related to the internal charge transfer cylinder, and further the feature amount related to the glaze cylinder, In the state where the image components of the ammunition parts such as warhead plugs are removed, only the image of the ammunition area is extracted under the threshold value set according to the luminance histogram and used for the feature amount detection process. The feature amount can be detected with high reliability by effectively eliminating the influence of deformation and deposits. Therefore, it is possible to increase the reliability of the shell type determination to a practically sufficient level.

  Furthermore, when detecting the feature values of each part, the positional relationship and dimensions of multiple feature parts are obtained with reference to the shell bottom that is not easily affected by corrosion or deformation because it is thick. Reliability can be sufficiently increased. Therefore, also in this respect, the reliability of the shell type determination can be sufficiently increased. In particular, bullet heads are often equipped with warhead plugs, or warhead plugs themselves are greatly deformed.As described above, it is better to measure the features of shells with reference to the bottom of the shell. There are advantages such that the intrusion can be reduced and the measurement reliability can be easily increased.

  The present invention is not limited to the embodiment described above. For example, the threshold value set based on the brightness level histogram of the X-ray transmission image can be determined as a brightness level where the histogram value rapidly decreases in the vicinity of the peak brightness level. Further, by removing the concave part for mounting the bullet plug from the head of the shell from the feature quantity detection target, it is also possible to accurately detect the position of the bullet head. Furthermore, the feature amount detection processing procedure and the like can be variously changed according to the detection target, its detection specification, and the like. In addition, the present invention can be variously modified and implemented without departing from the scope of the invention.

1 is a schematic configuration diagram of an object identification device according to an embodiment of the present invention. The figure which shows the form of the X-ray fluoroscopic inspection of the detection target object (cannonball) by a X-ray fluoroscopic apparatus. The figure which shows an example of the process sequence of the object identification which concerns on this invention. The figure which shows the example of a characteristic of the density conversion process with respect to a fluoroscopic image. The figure which shows the example of the X-ray fluoroscopic image of a cannonball. The figure which shows the concept of the removal process of attachment parts, such as a medicine casing, from a X-ray fluoroscopic image. The figure which shows the characteristic of a typical shell. The figure which shows the example of the brightness | luminance histogram in the X-ray fluoroscopic image of a cannonball. The figure which shows the rough process sequence of an external shape detection process. The figure which shows typically the external shape and its characteristic of a shell. The figure which shows the rough process sequence of the detection process of a charge transfer cylinder. The figure which shows the structure and its characteristic of a charge transfer cylinder in a shell. The figure which shows the rough process sequence of the detection process of a glaze cylinder. The figure which shows the structure of the glaze cylinder in a shell, and its characteristic.

Explanation of symbols

S Inspection object (cannonball)
DESCRIPTION OF SYMBOLS 1 Bullet shell 2 Fire transfer cylinder 3 Glaze cylinder 10 X-ray fluoroscope 12 X-ray generator 13 Line sensor 20 Conveyor mechanism 30 Image processing apparatus

Claims (7)

When obtaining an X-ray fluoroscopic image of an inspection object having features in the outer shape and the internal structure, and determining the type of the inspection object from the characteristic amount of the inspection object obtained from the X-ray fluoroscopic image,
After removing the image component of the easily damaged part portion in the inspection object from the X-ray fluoroscopic image, determine a threshold value for detecting the characteristic part of the inspection object according to the luminance histogram of the X-ray fluoroscopic image; An object identification method comprising: detecting a feature amount of the inspection object from an image component extracted from the X-ray fluoroscopic image based on the threshold value, and determining a type of the inspection object. The inspection object is a cannonball that has been left in the ground, and the image components to be removed from the X-ray fluoroscopic image are image portions corresponding to parts such as a cartridge case, a warhead plug, and a tail wing in the cannonball. ,
The threshold is set based on a luminance level at which the luminance histogram of the X-ray fluoroscopic image reaches a peak, and is used for extracting the image area of the shell from the X-ray fluoroscopic image,
The object identifying method according to claim 1, wherein the feature amount is obtained as a maximum bullet diameter, a presence / absence of a glaze cylinder, a length of a transfer cylinder, and the like shown in an image area of the bullet.   The object identification method according to claim 2, wherein the length or the like of the transfer cartridge is obtained from a distance to a feature point measured with reference to a bottom of the shell. An X-ray fluoroscopic apparatus that obtains an X-ray fluoroscopic image of an inspection object having features in an outer shape and an internal structure, and an image processing apparatus that performs image processing on the X-ray fluoroscopic image and determines the type of the inspection object. And
The image processing apparatus includes: a first image processing unit that removes an image component of a component part that is easily damaged in the inspection object from the fluoroscopic image;
A threshold value for detecting a characteristic part of the inspection object is determined according to a luminance histogram of the fluoroscopic image, and a characteristic part of the inspection object in the X-ray fluoroscopic image is extracted based on the threshold value. Image processing means,
An object identification apparatus comprising: a determining unit that obtains a feature amount of the extracted feature portion and determines a type of the inspection object according to the feature amount. The inspection object is a shell that has been left in the ground,
The first image processing means detects an image area in the fluoroscopic image such as a cartridge case, a warhead plug, a tail wing, etc. in the shell, excludes the image area from an image processing target, and performs the second image processing. The means for extracting the characteristic portion of the shell in the X-ray fluoroscopic image using a threshold value set based on a luminance histogram of the X-ray fluoroscopic image and providing the characteristic amount to the detection. The object identification device described.   The determination unit is configured to measure the feature amounts in the plurality of feature portions of the inspection target obtained by the second image processing unit with reference to a portion of the inspection target that is clearly difficult to deform in advance. The object identification device according to claim 4, wherein the object identification device is obtained from each measured value up to the characteristic portion.   The object identifying device according to claim 6, wherein the part of the inspection object that is clearly difficult to be deformed in advance is a bullet bottom of a shell that is left in the ground.

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