JP2007202714A - Radiographic apparatus - Google Patents

Radiographic apparatus Download PDF

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JP2007202714A
JP2007202714A JP2006023657A JP2006023657A JP2007202714A JP 2007202714 A JP2007202714 A JP 2007202714A JP 2006023657 A JP2006023657 A JP 2006023657A JP 2006023657 A JP2006023657 A JP 2006023657A JP 2007202714 A JP2007202714 A JP 2007202714A
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JP4769089B2 (en
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Masataka Ueki
雅敬 植木
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Toshiba Corp
Canon Electron Tubes and Devices Co Ltd
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Toshiba Electron Tubes and Devices Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide radiographic apparatus 11 which can improve the S/N ratio of an image signal without increasing the incident dose of X rays. <P>SOLUTION: The radiographic apparatus irradiates an object 12 with X rays 13 having an intensity distribution which causes a parallax in an X-ray image and confirms an interrelation between a pixel and surrounding pixels corresponding to a parallax involved by the intensity distribution of the X rays 13 for every pixel of an X-ray detector 15 at which an X-ray image transmitting the object 12 arrives. The apparatus processes only pixels having an interrelation as image signals alone of a true X-ray image. The processing removes a noise component and improves the S/N ratio of an image signal without increasing the incident dose of X rays. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、被写体をＸ線撮影するＸ線撮影装置に関する。   The present invention relates to an X-ray imaging apparatus for X-ray imaging of a subject.

従来、例えば医療用Ｘ線画像診断装置などのＸ線撮影装置では、Ｘ線源からのＸ線を被写体に照射し、この被写体を透過したＸ線をＸ線検出器に入射し、このＸ線検出器でＸ線イメージを画像信号に変換して被写体を透視した画像を得ている（例えば、特許文献１参照。）。   2. Description of the Related Art Conventionally, in an X-ray imaging apparatus such as a medical X-ray image diagnostic apparatus, X-rays from an X-ray source are irradiated onto a subject, and X-rays transmitted through the subject are incident on an X-ray detector. An X-ray image is converted into an image signal by a detector to obtain an image obtained by seeing through the subject (see, for example, Patent Document 1).

ところで、Ｘ線撮影における画質の劣化の要因として、被写体からの散乱線による散乱信号や、量子ノイズ、Ｘ線検出器の回路ノイズなどがある。   By the way, as a factor of image quality degradation in X-ray imaging, there are a scattered signal due to scattered rays from a subject, quantum noise, circuit noise of an X-ray detector, and the like.

散乱線の除去に関しては、散乱線の入射方向のランダム性を利用して、グリッドと呼ばれる薄い鉛とＸ線透過度の高い物質とを交互に積み重ねて製作した板をＸ線検出器の前に配置し、Ｘ線検出器の前においてコリメートされたＸ線の画像のみを撮影する技術がある。   Regarding the removal of scattered radiation, a random plate in the incident direction of the scattered radiation is used to place a plate made by alternately stacking thin lead called a grid and a substance having high X-ray transmittance in front of the X-ray detector. There is a technique for taking only an X-ray image that is arranged and collimated in front of an X-ray detector.

量子ノイズ、回路ノイズの除去に関しては、Ｘ線入射線量を増やしてＳ／Ｎ比を上げている。Ｘ線をパルス状に曝射して透視画像得る透視画像の場合は、ノイズのランダム性を利用し、複数の画像を積分するリカーシブルフィルタを設けてノイズを除去し、Ｓ／Ｎ比を上げている。
特開平９−１８７４５５号公報（第４頁、図２） Regarding the removal of quantum noise and circuit noise, the S / N ratio is increased by increasing the X-ray incident dose. In the case of a fluoroscopic image obtained by irradiating X-rays in the form of pulses, a recursive filter that integrates multiple images is removed by using the randomness of noise to increase the S / N ratio. ing.
Japanese Patent Laid-Open No. 9-187455 (page 4, FIG. 2)

しかしながら、散乱線の除去のためにグリッドを使用する場合、グリッドによりＸ線検出器に入射するＸ線の一部が遮られるため、Ｘ線の利用効率が低下し、画像のコントラストが低下する。そのため、入射Ｘ線量を増やす必要があるが、医療用画像診断装置の場合には被験者の被曝量が増加する。   However, when a grid is used for removing scattered radiation, a part of the X-rays incident on the X-ray detector is blocked by the grid, so that the use efficiency of the X-rays is reduced and the contrast of the image is reduced. Therefore, it is necessary to increase the incident X-ray dose, but in the case of a medical image diagnostic apparatus, the exposure dose of the subject increases.

また、Ｘ線検出器によって得られた複数の画像を積分するリカーシブルフィルタを使用した場合、動く物体には残像が残る動体ぼけが生じ、動体画像が観察しにくくなる弊害がある。   In addition, when a recursible filter that integrates a plurality of images obtained by an X-ray detector is used, there is a problem that a moving object remains with an afterimage on a moving object, making it difficult to observe the moving object image.

このように、Ｘ線撮影に関して、コントラストの良い画像を得るためには、入射Ｘ線量を増やしてＳ／Ｎ比を改善する方法が一般的であるが、医療用Ｘ線画像診断装置の場合、被験者の被曝量と画質の向上とが引き換えになり、画質を良くする程、被曝量が増加することになる。   As described above, with respect to X-ray imaging, in order to obtain an image with good contrast, a method of increasing the incident X-ray dose and improving the S / N ratio is common, but in the case of a medical X-ray image diagnostic apparatus, The exposure amount of the subject and the improvement of the image quality are traded off, and the exposure amount increases as the image quality improves.

本発明は、このような点に鑑みなされたもので、Ｘ線入射線量を増加することなく、画像信号のＳ／Ｎ比を改善できるＸ線撮影装置を提供することを目的とする。   The present invention has been made in view of these points, and an object of the present invention is to provide an X-ray imaging apparatus capable of improving the S / N ratio of an image signal without increasing the X-ray incident dose.

本発明は、Ｘ線イメージに視差を生じさせるＸ線強度分布としたＸ線を被写体に照射するＸ線源と、前記被写体を透過したＸ線イメージを画像信号に変換する複数の画素を有するＸ線検出器と、前記Ｘ線検出器の画素毎にその画素と前記Ｘ線のＸ線強度分布に伴う視差に対応した周辺の画素との相関を確認し、相関のある画素のみを真のＸ線イメージの画像信号として処理する処理手段とを具備しているものである。   The present invention provides an X-ray source that irradiates an object with X-rays having an X-ray intensity distribution that causes parallax in the X-ray image, and an X having a plurality of pixels that convert the X-ray image transmitted through the object into an image signal. For each pixel of the X-ray detector, the correlation between the pixel and the surrounding pixels corresponding to the parallax associated with the X-ray intensity distribution of the X-ray is confirmed, and only the correlated pixels are true X And processing means for processing as an image signal of a line image.

本発明によれば、Ｘ線イメージに視差を生じさせるＸ線強度分布としたＸ線を被写体に照射することにより、被写体を透過したＸ線イメージが入射するＸ線検出器の画素毎にその画素とＸ線のＸ線強度分布に伴う視差に対応した周辺の画素との相関を確認し、相関のある画素のみを真のＸ線イメージの画像信号として処理するので、ノイズ成分を除去でき、Ｘ線の入射線量を増加することなく、画像信号のＳ／Ｎ比を改善することができる。   According to the present invention, by irradiating a subject with X-rays having an X-ray intensity distribution that causes parallax in the X-ray image, each pixel of the X-ray detector on which the X-ray image transmitted through the subject enters And the surrounding pixels corresponding to the parallax associated with the X-ray intensity distribution of the X-ray, and only the correlated pixels are processed as an image signal of a true X-ray image. The S / N ratio of the image signal can be improved without increasing the incident dose of the line.

以下、本発明の一実施の形態を図面を参照して説明する。   Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

図１および図２に示すように、Ｘ線撮影装置11としては、医療用Ｘ線画像診断装置であり、被験者である被写体12にＸ線13を照射するＸ線源14、被写体12を透過したＸ線13を入射してＸ線イメージを画像信号に変換するＸ線イメージセンサであるＸ線検出器15、およびこのＸ線検出器15で得られた画像信号を処理する処理手段16を備えている。   As shown in FIGS. 1 and 2, the X-ray imaging apparatus 11 is a medical X-ray image diagnostic apparatus that transmits an X-ray source 14 that irradiates a subject 12, which is a subject, and the subject 12. An X-ray detector 15 that is an X-ray image sensor that receives an X-ray 13 and converts an X-ray image into an image signal, and processing means 16 that processes the image signal obtained by the X-ray detector 15 are provided. Yes.

Ｘ線源14としては、高真空中で加速された電子を陽極に衝突させて発生する制動輻射の原理を用いてＸ線13を発生させる回転陽極型のＸ線管21を示す。このＸ線管21は、真空外囲器22を備え、この真空外囲器22内に図示しない陰極である電子銃とそれに対向する傘状の回転する陽極であるターゲット23とが設けられている。真空外囲器22には、電子銃より高電圧で加速された電子がターゲット23に衝突して発生するＸ線13を外部に取り出す出力窓24が設けられている。出力窓24より取り出されたＸ線13は、図示しないＸ線管容器のゲートおよび図示しない絞りを経て被写体12に照射される。   As the X-ray source 14, a rotating anode type X-ray tube 21 that generates X-rays 13 using the principle of bremsstrahlung generated by colliding electrons accelerated in a high vacuum with the anode is shown. The X-ray tube 21 includes a vacuum envelope 22 in which an electron gun that is a cathode (not shown) and a target 23 that is an umbrella-shaped rotating anode facing the cathode are provided. . The vacuum envelope 22 is provided with an output window 24 for taking out X-rays 13 generated when electrons accelerated by a high voltage from the electron gun collide with the target 23. The X-ray 13 taken out from the output window 24 is irradiated to the subject 12 through a gate of an X-ray tube container (not shown) and a diaphragm (not shown).

なお、図１および図２には、被写体12中の病変部12aにおいて集束するＸ線13の線束13aを示すが、Ｘ線13は被写体12の所定の範囲に照射される。   FIGS. 1 and 2 show a bundle 13a of X-rays 13 that converge at a lesioned part 12a in the subject 12, and the X-rays 13 are irradiated to a predetermined range of the subject 12. FIG.

Ｘ線管21が発生するＸ線13は、被写体12中の同一の病変部12aの陰影がＸ線検出器15において数〜数十ピクセル分シフトした位置に視差が生じるようなＸ線強度分布としている。図１および図２には、ターゲット23に対して電子が衝突する点状の複数の電子衝撃面25を示し、電子衝撃面25は、中心部25aとこの中心部25aに対して上下左右方向に交差する周辺位置の複数の周辺部25bとの５つの点を十字形に配置した形状とする。なお、電子衝撃面25を点で構成する場合は、構成する点の実効焦点寸法は、０．３ｍｍ以下の微小焦点が望ましい。   The X-ray 13 generated by the X-ray tube 21 has an X-ray intensity distribution such that parallax occurs at a position where the shadow of the same lesion 12a in the subject 12 is shifted by several to several tens of pixels in the X-ray detector 15. Yes. 1 and 2 show a plurality of dot-like electron impact surfaces 25 on which electrons collide with the target 23, and the electron impact surfaces 25 are vertically and horizontally with respect to the central portion 25a and the central portion 25a. It is assumed that five points with a plurality of peripheral portions 25b at the intersecting peripheral positions are arranged in a cross shape. When the electron impact surface 25 is configured with dots, the effective focal spot size of the configured points is preferably a micro focus of 0.3 mm or less.

図３には、Ｘ線撮影装置11の図１のＡ平面での被写体12からＸ線管21を見た場合のＸ線13のＸ線強度分布の模式図を示す。Ｘ線13のＸ線強度分布は、ターゲット23における電子衝撃面25の形状に対応して、中心部とこの中心部に対して上下左右方向に交差する周辺位置の複数の周辺部との５つの点を十字形に配置した形状のＸ線強度分布としている。   FIG. 3 shows a schematic diagram of the X-ray intensity distribution of the X-ray 13 when the X-ray tube 21 is viewed from the subject 12 on the plane A of FIG. The X-ray intensity distribution of the X-rays 13 corresponds to the shape of the electron impact surface 25 in the target 23, and is divided into five parts: a central part and a plurality of peripheral parts at peripheral positions intersecting the central part in the vertical and horizontal directions. The X-ray intensity distribution is such that the points are arranged in a cross shape.

また、Ｘ線検出器15は、アクティブマトリクス型の平面検出器で、図４(b)に示すように、Ｘ線入射面には複数の画素28がマトリクス状に二次元的に配列されている。Ｘ線検出器15に入射したＸ線13を直接的または間接的に電荷信号に変換し、その電荷信号を各画素28にて取得し、被写体12を透過したＸ線イメージの画像信号を出力する。   The X-ray detector 15 is an active matrix type flat detector, and a plurality of pixels 28 are two-dimensionally arranged in a matrix on the X-ray incident surface as shown in FIG. 4B. . The X-ray 13 incident on the X-ray detector 15 is directly or indirectly converted into a charge signal, the charge signal is acquired by each pixel 28, and an image signal of an X-ray image transmitted through the subject 12 is output. .

また、処理手段16は、Ｘ線検出器15の画素28毎にその画素28とＸ線13のＸ線強度分布に伴う視差に対応した周辺の画素28との相関を確認し、相関のある画素28のみを真のＸ線イメージの画像信号として処理する機能を有し、さらに、Ｘ線検出器15によって得られた画像に対して任意の濃度段階で等濃度部分を等高線で繋ぎ、等高線で囲まれる領域を認識し、その領域を囲む等高線に対してＸ線強度分布との相関を確認し、相関が認められる場合はその領域のコントラストを強調処理する機能、また、Ｘ線検出器15によって得られた画像に対して連続的に濃度シフトがある境界をエッジと認識し、このエッジとして認識した境界の濃度分布に対してＸ線強度分布との相関を確認し、相関が認められる場合はそのエッジを強調処理する機能を有している。   Further, the processing means 16 confirms the correlation between each pixel 28 of the X-ray detector 15 and the surrounding pixel 28 corresponding to the parallax associated with the X-ray intensity distribution of the X-ray 13, and there is a correlated pixel. It has a function to process only 28 as an image signal of a true X-ray image. Furthermore, the image obtained by the X-ray detector 15 is connected with contour lines at an arbitrary density step and surrounded by contour lines. A function that confirms the correlation between the contour line surrounding the region and the X-ray intensity distribution, and if there is a correlation, enhances the contrast of the region, and obtains the contrast by the X-ray detector 15. A boundary where there is a continuous density shift in the obtained image is recognized as an edge, and the correlation between the density distribution of the boundary recognized as this edge and the X-ray intensity distribution is confirmed. Has a function to emphasize edges

次に、Ｘ線撮影装置11の作用を説明する。   Next, the operation of the X-ray imaging apparatus 11 will be described.

Ｘ線管21から被写体12にＸ線13を照射し、被写体12を透過したＸ線13をＸ線検出器15に入射してＸ線イメージを画像信号に変換する。   The X-ray tube 21 irradiates the subject 12 with the X-ray 13 and the X-ray 13 transmitted through the subject 12 enters the X-ray detector 15 to convert the X-ray image into an image signal.

このとき、図４(a)に示すように、Ｘ線13のＸ線強度分布は、被写体12中の病変部12aに対して広がりのある視差を持つ。そのため、図４(b)に示すように、Ｘ線検出器15で取得される画像信号には、被写体12中の病変部12aに対応した画素28で真の画像信号31が取得され、その画素28に対してＸ線13のＸ線強度分布に伴う視差に対応した周辺の画素28にも病変部12aと相関する相関信号32が生じる。これに対して、被写体12中の病変部12a、空気、他の臓器などによる散乱線による散乱信号33や、量子ノイズ、回路ノイズによるランダムなノイズ34が画像信号に混入してくる。   At this time, as shown in FIG. 4A, the X-ray intensity distribution of the X-ray 13 has a wide parallax with respect to the lesioned part 12 a in the subject 12. Therefore, as shown in FIG. 4B, a true image signal 31 is acquired from the pixel 28 corresponding to the lesioned part 12a in the subject 12 as the image signal acquired by the X-ray detector 15, and the pixel The correlation signal 32 correlated with the lesioned part 12a is also generated in the peripheral pixel 28 corresponding to the parallax associated with the X-ray intensity distribution of the X-ray 13 with respect to 28. On the other hand, a scattered signal 33 due to scattered rays from the lesioned part 12a in the subject 12, air, other organs, and the like, and random noise 34 due to quantum noise and circuit noise are mixed in the image signal.

そして、図５(a)(b)にて、Ｘ線撮影装置11で撮影された画像中のノイズに埋もれた信号から、真の画像信号31を拾い出すアルゴリズムの概念を説明する。   5A and 5B, the concept of an algorithm for picking up a true image signal 31 from a signal buried in noise in an image captured by the X-ray imaging apparatus 11 will be described.

図５(a)は、ある画素28である中央の画素28に真の画像信号31がある場合、その中央の画素28に対してＸ線13のＸ線強度分布に伴う視差に対応した周辺の画素28に相関信号32が発生しているため、中央の画素28の信号は真の画像信号31と判定し、中央の画素28の真の画像信号31を生かす。   FIG. 5 (a) shows that when there is a true image signal 31 in a central pixel 28 which is a certain pixel 28, a peripheral pixel corresponding to the parallax associated with the X-ray intensity distribution of the X-ray 13 with respect to the central pixel 28 is shown. Since the correlation signal 32 is generated in the pixel 28, the signal of the center pixel 28 is determined as the true image signal 31, and the true image signal 31 of the center pixel 28 is utilized.

図５(b)に示すように、ある画素28に散乱線やノイズ34によって発生した偽の信号がある場合、ある画素28に信号が存在しても、その周辺の画素28にＸ線強度分布と相関のある信号が存在しないため、散乱線やノイズ34によって発生した偽の信号と判定し、ある画素28の信号を切り捨てる。   As shown in FIG. 5B, when there is a false signal generated by scattered radiation or noise 34 in a certain pixel 28, even if a signal is present in a certain pixel 28, the X-ray intensity distribution is distributed to the surrounding pixels 28. Therefore, it is determined that the signal is a false signal generated by scattered radiation or noise 34, and the signal of a certain pixel 28 is discarded.

このような処理をＸ線検出器15の全ての画素28に対して総当りに実施する。この際、Ｘ線検出器15の周縁部においては、画素28とＸ線強度分布との位置関係のずれによる視差のズレを補正する。また、被写体12中の病変部12aの奥行方向の位置関係のずれによる視差のずれを補正するために、探索する周辺の画素28のピクセル量を可変する。   Such processing is performed for all the pixels 28 of the X-ray detector 15. At this time, in the peripheral portion of the X-ray detector 15, a shift in parallax due to a shift in the positional relationship between the pixel 28 and the X-ray intensity distribution is corrected. Further, in order to correct the shift in parallax due to the shift in the positional relationship in the depth direction of the lesioned part 12a in the subject 12, the pixel amount of the peripheral pixels 28 to be searched is varied.

このように、Ｘ線イメージに視差を生じさせるＸ線強度分布としたＸ線13を被写体12に照射し、被写体12を透過したＸ線イメージが入射するＸ線検出器15の画素28毎にその画素28とＸ線13のＸ線強度分布に伴う視差に対応した周辺の画素28との相関を確認し、相関のある画素28のみを真のＸ線イメージの画像信号31として処理するので、ノイズ成分を除去でき、Ｘ線13の入射線量を増加することなく、画像信号のＳ／Ｎ比を改善することができる。   In this way, the X-ray image 13 is irradiated with X-rays 13 having an X-ray intensity distribution that causes parallax in the X-ray image, and the X-ray image transmitted through the object 12 is incident on each pixel 28 of the X-ray detector 15. Since the correlation between the pixel 28 and the surrounding pixel 28 corresponding to the parallax associated with the X-ray intensity distribution of the X-ray 13 is confirmed and only the correlated pixel 28 is processed as the image signal 31 of the true X-ray image, noise The components can be removed, and the S / N ratio of the image signal can be improved without increasing the incident dose of the X-rays 13.

また、Ｘ線検出器15によって得られた画像において、低コントラストの広い分布を持つ病変に対しては、画像全体について、任意の濃度段階で等濃度部分を等高線で繋ぎ、等高線で囲まれる領域を認識し、その領域を囲む等高線の閾値をさらに細かく区切ったうえで、その領域を囲む等高線に対して上述したようにＸ線強度分布と相関があるか判定し、相関が認められる場合には、その等高線で囲まれた領域の濃度にゲインをかけてコントラストを強調する処理をする。これにより、高コントラストの高周波領域のみだけでなく、低コントラストの低周波領域の画像情報を損なうことなく画質を改善できる。   Further, in the image obtained by the X-ray detector 15, for a lesion having a wide distribution with a low contrast, the entire image is connected to an isodensity portion with contour lines at an arbitrary density step, and an area surrounded by the contour lines is defined. Recognize and further subdivide the threshold of the contour line surrounding the region, determine whether there is a correlation with the X-ray intensity distribution as described above for the contour line surrounding the region, and if a correlation is recognized, A process for enhancing the contrast by applying a gain to the density of the area surrounded by the contour lines. As a result, the image quality can be improved without impairing the image information not only in the high-contrast high-frequency region but also in the low-contrast low-frequency region.

また、Ｘ線検出器15によって得られた画像において、連続的に濃度シフトがある境界をエッジと認識して交差する線で繋ぎ、このエッジとして認識した境界の濃度分布に対してＸ線強度分布との相関を確認し、相関が認められる場合には、そのエッジを強調する処理をする。これにより、エッジが明確になり、画質を改善できる。   Further, in the image obtained by the X-ray detector 15, a boundary having a continuous density shift is recognized as an edge and connected by an intersecting line, and an X-ray intensity distribution with respect to the density distribution of the boundary recognized as the edge. If the correlation is recognized, the edge is emphasized. Thereby, the edge becomes clear and the image quality can be improved.

なお、Ｘ線13のＸ線強度分布は、十字形に配置した５個の点に限らず、アスタリスク記号状の９つの点や、それ以上の多数の点に配置してもよく、あるいは、連続した形状に配置してもよく、Ｘ線イメージに視差を生じさせることが可能であればどのような形状でもよい。   Note that the X-ray intensity distribution of the X-ray 13 is not limited to five points arranged in a cross shape, and may be arranged at nine points with an asterisk symbol shape or many points beyond that, or continuously. The X-ray image may be arranged in any shape as long as parallax can be generated.

また、Ｘ線13のＸ線強度分布を形成する場合、Ｘ線イメージに視差を生じさせるＸ線強度分布のＸ線13を一度に発生させるのに限らず、Ｘ線管21の陰極から放出する電子を時間差を置いて電子的に走引しながらターゲット23に衝突させて電子衝撃面25の位置を変えることにより、つまりＸ線13の発生位置を移動させることにより、Ｘ線イメージに視差を生じさせるＸ線強度分布を得るようにしてもよい。   Further, when forming the X-ray intensity distribution of the X-rays 13, the X-ray intensity distribution X-rays 13 that cause parallax in the X-ray image are not necessarily generated at once, but are emitted from the cathode of the X-ray tube 21. By changing the position of the electron impact surface 25 by colliding with the target 23 while moving the electrons electronically at a time difference, that is, by moving the position where the X-rays 13 are generated, parallax is generated in the X-ray image. An X-ray intensity distribution to be obtained may be obtained.

本発明の一実施の形態を示すＸ線撮影装置の平面図である。1 is a plan view of an X-ray imaging apparatus showing an embodiment of the present invention. 同上Ｘ線撮影装置の側面図である。It is a side view of an X-ray imaging apparatus same as the above. 同上Ｘ線撮影装置の図１のＡ平面での被写体からＸ線管を見た場合のＸ線強度分布の模式図である。It is a schematic diagram of X-ray intensity distribution at the time of seeing an X-ray tube from the to-be-photographed object in the A plane of FIG. 1 of an X-ray imaging apparatus same as the above. 同上Ｘ線撮影装置のＸ線強度分布と被写体の病変部とＸ線イメージとの関係を示し、(a)は図１のＡ平面での病変部とＸ線強度分布との関係を示す模式図、(b)は図１のＢ平面でのＸ線検出器のＸ線イメージの模式図である。The relationship between the X-ray intensity distribution of the X-ray imaging apparatus, the lesioned part of the subject, and the X-ray image is shown, and (a) is a schematic diagram showing the relationship between the lesioned part and the X-ray intensity distribution on the A plane in FIG. (B) is a schematic diagram of the X-ray image of the X-ray detector in the B plane of FIG. 同上Ｘ線撮影装置のＸ線検出器の画素を示し、(a)はある画素と周辺の画素とに相関がある場合の模式図、(b)はある画素と周辺の画素とに相関がない場合の模式図である。The X-ray detector pixel of the same X-ray imaging apparatus is shown, (a) is a schematic diagram when there is a correlation between a certain pixel and the surrounding pixels, (b) there is no correlation between the certain pixel and the surrounding pixels It is a schematic diagram in the case.

符号の説明Explanation of symbols

11 Ｘ線撮影装置
12 被写体
13 Ｘ線
14 Ｘ線源
15 Ｘ線検出器
16 処理手段
28 画素 11 X-ray equipment
12 Subject
13 X-ray
14 X-ray source
15 X-ray detector
16 Processing means
28 pixels

Claims (5)

Ｘ線イメージに視差を生じさせるＸ線強度分布としたＸ線を被写体に照射するＸ線源と、
前記被写体を透過したＸ線イメージを画像信号に変換する複数の画素を有するＸ線検出器と、
前記Ｘ線検出器の画素毎にその画素と前記Ｘ線のＸ線強度分布に伴う視差に対応した周辺の画素との相関を確認し、相関のある画素のみを真のＸ線イメージの画像信号として処理する処理手段と
を具備していることを特徴とするＸ線撮影装置。 An X-ray source that irradiates the subject with X-rays having an X-ray intensity distribution that causes parallax in the X-ray image;
An X-ray detector having a plurality of pixels for converting an X-ray image transmitted through the subject into an image signal;
For each pixel of the X-ray detector, the correlation between the pixel and peripheral pixels corresponding to the parallax associated with the X-ray intensity distribution of the X-ray is confirmed, and only a correlated pixel is a true X-ray image signal. An X-ray imaging apparatus comprising: processing means for processing as follows. Ｘ線源は、中心部とこの中心部に対して交差する周辺位置に位置する複数の周辺部とを有するＸ線強度分布としたＸ線を被写体に照射する
ことを特徴とする請求項１記載のＸ線撮影装置。 The X-ray source irradiates a subject with X-rays having an X-ray intensity distribution having a central part and a plurality of peripheral parts located at peripheral positions intersecting the central part. X-ray imaging equipment. Ｘ線源は、Ｘ線の発生位置を移動させて視差を生じさせるＸ線強度分布としたＸ線を被写体に照射する
ことを特徴とする請求項１または２記載のＸ線撮影装置。 The X-ray imaging apparatus according to claim 1, wherein the X-ray source irradiates the subject with X-rays having an X-ray intensity distribution that generates a parallax by moving an X-ray generation position. 処理手段は、Ｘ線検出器によって得られた画像に対して任意の濃度段階で等濃度部分を等高線で繋ぎ、等高線で囲まれる領域を認識し、その領域を囲む等高線に対してＸ線強度分布との相関を確認し、相関が認められる場合はその領域のコントラストを強調処理する
ことを特徴とする請求項１ないし３いずれか記載のＸ線撮影装置。 The processing means connects the equal density portions to the image obtained by the X-ray detector at an arbitrary density step with contour lines, recognizes the area surrounded by the contour lines, and distributes the X-ray intensity distribution to the contour lines surrounding the area. The X-ray imaging apparatus according to any one of claims 1 to 3, wherein the correlation between the region and the region is confirmed, and if the correlation is recognized, the contrast of the region is enhanced. 処理手段は、Ｘ線検出器によって得られた画像に対して連続的に濃度シフトがある境界をエッジと認識し、このエッジとして認識した境界の濃度分布に対してＸ線強度分布との相関を確認し、相関が認められる場合はそのエッジを強調処理する
ことを特徴とする請求項１ないし３いずれか記載のＸ線撮影装置。 The processing means recognizes a boundary having a density shift continuously with respect to an image obtained by the X-ray detector as an edge, and correlates the density distribution of the boundary recognized as the edge with the X-ray intensity distribution. The X-ray imaging apparatus according to any one of claims 1 to 3, wherein the X-ray imaging apparatus according to any one of claims 1 to 3, wherein the X-ray imaging apparatus confirms and, if a correlation is recognized, emphasizes the edge.
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