JP2010261917A - Transmission image display device and radioscopic inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission image display device for displaying a color transmission image having improved visibility, and to provide a radioscopic inspection apparatus. <P>SOLUTION: The transmission image display device includes: a gradation conversion section 7d for performing gradation conversion on each transmission image data for each color component for the transmission image data for a plurality of color components, each having different sensitivity obtained by detecting X-ray beams 2 transmitted through a specimen 5 from an X-ray tube 1, by mutually different conversion functions; and a display section 7a for displaying the transmission image data in color. The radioscopic examination apparatus includes the transmission image display device. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an industrial or medical radiographic inspection apparatus that takes a transmission image of a subject by using transmissive radiation and inspects the inside of the subject, and a transmission image display apparatus that displays the transmission image.

  The radiographic inspection apparatus detects a radiation beam emitted from a radiation source and transmitted through a subject with a radiation detector, displays an output transmission image (transmission image data), and observes and inspects the inside of the subject. Device.

  As a radiation (X-ray) detector, for example, an X-ray image intensifier (hereinafter referred to as X-ray II) that converts an intensity distribution image of an X-ray beam into a visible light image and the visible light image are photographed. A radiation detector including a camera that outputs a transmission image (transmission image data) is used.

  In the radiographic inspection apparatus described above, in recent years, color display of a transmission image is performed using a radiation detector that outputs transmission images of a plurality of color components. As a first example of this type of radiation detector, a color detector using a color X-ray image intensifier (abbreviated as Color II (registered trademark) hereinafter) and a color camera is used. However, it is known from Patent Document 1 and the like.

  Color X-ray II is a scintillator layer on the input surface that converts the distribution of incident radiation (X-rays) into an electron distribution, accelerates the electrons to form an image on the output surface, and causes the color scintillator layer on the output surface to emit light. To convert it into a visible light image. The color scintillator on the output surface emits light in colors (multiple colors), but the emission characteristic curve is different for each color component (R, G, B: red, green, blue). That is, there is a characteristic that the sensitivity is higher in the order of R, G, and B with respect to the amount of incident electrons.

  The color camera captures the converted color visible light image and outputs a transmission image for each color component (R, G, B).

  As a second example, a radiation detector using a color scintillator and a color camera is known from Patent Document 2 and the like.

  In this method, radiation (X-rays) is incident on a color scintillator layer on the input surface to emit light, thereby converting the radiation distribution into a visible light image and photographing the visible light image with a color camera. The color scintillator emits light in color, but the emission characteristic curve is different for each color component (R, G, B: red, green, blue). That is, there is a characteristic that the sensitivity is higher in the order of R, G, and B with respect to the amount of incident radiation. The color camera captures the converted color visible light image and outputs a transmission image for each color component (R, G, B).

  When the transmission images of the plurality of color components described above are observed in color display, the low transmittance portion (low radiation portion) can be observed in red with high sensitivity, and the high transmittance portion (high radiation portion) can be observed in red. Saturates, but details are well observable in blue with low sensitivity. That is, a radiation detector with a wide dynamic range is possible with this configuration.

  FIG. 11 is a graph showing an example of a detection characteristic curve of a radiation detector that outputs transmission images of a plurality of color components. The horizontal axis represents the incident X-ray dose to one pixel, and the vertical axis represents the output (brightness) of one pixel. The input range for each color component R, G, B until the output reaches the saturation level from the noise level is the dynamic range. The dynamic range of the transmitted color image is a region of the logical sum of the dynamic ranges of the respective color components, and is increased as compared with the case of a single color.

JP 2006-179424 A JP 2003-202382 A

  In a conventional radiographic inspection apparatus, when color display of a transmission image is performed using a radiation detector that outputs a transmission image of a plurality of color components having a wide dynamic range, it cannot be said that the color display has the best visibility.

  The reason is that the high-transmittance part has low sensitivity in blue and details can be observed, but the red and green colors that appear to be saturated overlap, which reduces the contrast of the fine shades of blue, and the best discrimination is There is something to be done. Similarly, the intermediate transmittance part can be observed with green in the middle of the sensitivity, but details can be observed, but the saturated red color overlaps, which reduces the contrast of the fine shades of green, and for the best discrimination There is something to be done.

  An object of the present invention is to provide a radiographic inspection apparatus and a transmission image display apparatus that display a color transmission image with improved visibility.

  In order to achieve the above object, a transmission image display device according to claim 1 of the present invention includes a plurality of different sensitivities obtained by detecting radiation emitted from a radiation source toward a subject and transmitted through the subject. A gradation conversion unit that performs gradation conversion using a different conversion function for each of the transmission image data for each color component, and a transmission image for each color component that has been subjected to the gradation conversion. The gradation converting means comprises a display means for displaying data in color, and the output of the first color component having the highest sensitivity is monotonously reduced as the input increases within a predetermined range of values. Performs first gradation conversion, and performs second gradation conversion for the output data of the second color component with the lowest sensitivity, where the output increases monotonically with increasing input within a specified range of values. When the color component is 3 or more, at least one Degrees Whereas transmission image data of the third color component of the intermediate, is summarized in that performing the third gradation conversion of monotonic decrease after the output has increased monotonically with respect to increasing input in a predetermined range of values.

  This configuration uses a conversion function that monotonically decreases the output for the first color component with the highest sensitivity and increases the input for the second color component with the lowest sensitivity. For the third color component whose output is monotonically increasing, the gradation for each color component using a conversion function whose output monotonically increases and then monotonously decreases with increasing input for the third color component with intermediate sensitivity By converting, the low transmittance part is the first color component, the high transmittance part is the second color component, and the intermediate transmittance part is the third color component. Can be displayed.

  A transmission image display device according to a second aspect of the present invention is the transmission image display device according to the first aspect, wherein an input range indicating a value range of transmission image data for each color component is set for each color component. Input range obtaining means to obtain, and the gradation converting means performs gradation conversion with a conversion function that always converts the input range for each color component into a constant output range even if the input range changes. The gist is to add.

  With this configuration, an input range is obtained for each color component, and gradation conversion is performed using a conversion function that always converts this input range into a constant output range, so even if the range of incident radiation dose changes, the input range Can be converted without waste to the full output image signal width, and the color transmission image that is converted to gradation automatically becomes a color transmission image with the maximum contrast automatically, always improving visibility to the maximum. The transmitted color image can be displayed.

  The transmission image display device according to a third aspect of the present invention is the transmission image display device according to the second aspect, wherein the input range finding means is provided on each transmission image of the transmission image data for each color component. The gist of the present invention is that the input range is from a minimum value to a maximum value obtained within a predetermined range, or from a value that is predetermined larger than the minimum value to a value that is predetermined smaller than the maximum value.

  With this configuration, it is possible to obtain an input range, which is a range of values of transmission image data, without being affected by image quality deterioration such as lowering of brightness around the transmission image. Also, by setting an input range from a value larger than the minimum value to a value smaller than the maximum value, if there is an abnormal pixel, the input range can be obtained without being affected by this pixel.

  A transmission image display device according to a fourth aspect of the present invention is the transmission image display device according to the second or third aspect, wherein the first gradation conversion is the transmission image data of the first color component. On the other hand, the input range of the first color component is divided into two at a predetermined ratio, the low range monotonically decreases the output from the first value to the second value with respect to the increase of the input, and the high range outputs the output of the first color component. A binary gradation conversion, wherein the second gradation conversion divides the input range of the second color component by a predetermined ratio with respect to the transmission image data of the second color component; The gist is that the low range is the third value of the output, and the high range is the gradation conversion that monotonously increases the output from the third value to the fourth value with respect to the increase in input.

  With this configuration, the first gradation conversion and the second gradation conversion can be specifically performed.

  The transmission image display device according to claim 5 of the present invention is the transmission image display device according to any one of claims 2 to 4, wherein the third gradation is obtained when the color component is 3 or more. In the conversion, the input range of the third color component is divided into two by a predetermined ratio with respect to the transmission image data of the third color component, and the output of the lower range is increased from the fifth value to the sixth in response to an increase in input. The gist of the present invention is a gradation conversion that monotonically increases to a value and the high range is a monotonous conversion that monotonously decreases the output from the sixth value to the seventh value as the input increases.

  With this configuration, the third gradation conversion can be specifically performed.

  The transmission image display device according to a sixth aspect of the present invention is the transmission image display device according to any one of the first to fifth aspects, wherein the gradation converting unit is configured to monotonically increase the monotonous decrease. The gist of the invention is to add gradation conversion in which the monotonic increase is replaced by the monotonic decrease.

  With this configuration, the transmission image for each color component subjected to gradation conversion is inverted in brightness, the color display is inverted in color, the low transmittance portion is a complementary color of the first color component, and the high transmittance portion is the first. 6. The intermediate transmittance portion of the complementary color of the second color component can display a transmitted image of a color with a high contrast and improved visibility by the complementary color of the third color component, and the same effects as in claims 1 to 5. Can give.

  According to a seventh aspect of the present invention, there is provided a radiographic inspection apparatus according to the present invention, a radiation source that emits radiation toward a subject, and a plurality of color components that detect radiation transmitted through the subject and have different sensitivities to radiation. The transmission image display apparatus according to any one of claims 1 to 6, wherein a radiation detection unit that outputs the transmission image data of the image and a transmission image data for each of the color components is subjected to gradation conversion to perform color display. It is summarized as having.

  With this configuration, a color transmission image with improved visibility can be displayed.

  The radiographic inspection apparatus according to an eighth aspect of the present invention is the radiological inspection apparatus according to the seventh aspect, wherein the radiation detecting means detects radiation and converts it into a color visible light image. And imaging means for taking a visible light image of the color and outputting transmission image data for each of a plurality of color components.

  With this configuration, a color transmission image with improved visibility can be displayed.

  According to the present invention, it is possible to provide a radiographic inspection apparatus and a transmission image display apparatus that display a color transmission image with improved visibility using a radiation detector that outputs transmission images of a plurality of color components. it can.

The schematic diagram (front view) which showed the structure of the radiographic inspection apparatus which concerns on 1st embodiment of this invention. The graph which shows the example of the detection characteristic function of the X-ray detector which concerns on 1st embodiment. FIG. 3 is a flowchart of transmission image display according to the first embodiment. An example of the input range calculation area | region on the transmission image which concerns on 1st embodiment. The graph which shows an example of the input range of the transmission image which concerns on 1st embodiment. An example of the conversion function of the gradation conversion which concerns on 1st embodiment. An example of color display of a transmission image in the first embodiment (color display obtained by gray scale conversion) ((a) before gradation conversion, (b) after gradation conversion). An example of the conversion function of the gradation conversion which concerns on the modification 2 of 1st embodiment. An example of the conversion function of the gradation conversion which concerns on the modification 3 of 1st embodiment. An example of a conversion function of gradation conversion according to Modification 4 of the first embodiment ((a) in the case of 2 colors, (b) in the case of 5 colors). The graph which shows the example of the detection characteristic curve of the radiation detector which outputs the permeation | transmission image of a several color component.

  Embodiments of the present invention will be described below with reference to the drawings.

(Configuration of the first embodiment of the present invention)
The configuration of the first embodiment of the present invention will be described below with reference to FIGS.

  FIG. 1 is a schematic view (front view) showing a configuration of a radiographic inspection apparatus according to the first embodiment of the present invention.

  X-rays that detect a pyramidal X-ray beam (radiation) 2 that is a part of the X-rays emitted from the X-ray tube (radiation source) 1 and the X-ray focal point F of the X-ray tube 1 with two-dimensional resolution. The X-ray beam 2 transmitted through the subject 5 placed on the table 4 so as to enter the X-ray beam 2 is disposed by facing the detector (radiation detection means) 3 by the X-ray detector 3. Detected and output as a transmission image (transmission image data).

  The table 4 is subjected to three-dimensional parallel movement, rotation along the table surface, tilting of the table surface, and the like by the table driving mechanism 6, and the fluoroscopic position, the fluoroscopic angle, the magnification rate, etc. of the subject 5 are changed.

  The X-ray detector 3 includes a color X-ray image intensifier (abbreviated as color II (registered trademark), hereinafter referred to as color X-ray II) (radiation-visible light conversion means) 3a and a color camera (imaging means). 3b.

  The color X-ray II3a is obtained by converting the incident radiation (X-ray) distribution into a photoelectron distribution by the scintillator layer and the photoelectric layer of the input surface 3aa, and accelerating the photoelectrons to form an image on the output surface 3ab. The 3ab color scintillator layer emits light and converts it into a color (multicolor) visible light image. The color scintillator layer of the output surface 3ab has a different emission characteristic curve for each color component (R, G, B: red, green, blue). That is, there is a characteristic that the sensitivity is higher in the order of R, G, and B with respect to the amount of incident electrons.

FIG. 2 is a graph showing an example of a detection characteristic function of the X-ray detector according to the first embodiment. The horizontal axis represents the incident X-ray dose I to one pixel, and the vertical axis represents the brightness of one pixel (the larger the detector output, the brighter it is). The detection characteristic functions of R, G, and B are represented by R _I (I), G _I (I), and B _I (I), respectively. The sensitivity is high in the order of R, G, and B with respect to the incident amount of radiation (X-rays), and is saturated at a low X-ray dose in the order of R, G, and B.

  The color camera 3b captures the converted color visible light image and outputs a transmission image (transmission image data) for each color component (R, G, B) as digital data.

  As other components, the table driving mechanism 6 is also controlled, and a control processing unit (transmission image display device) 7 that processes a transmission image from the X-ray detector 3, a display unit 7a that displays a processing result, and the like. There is an X-ray control unit (not shown) for controlling the X-ray tube 1.

  The display unit 7a is composed of a liquid crystal panel that performs color display.

  The control processing unit 7 is a normal computer, and includes a CPU, a memory, a disk (nonvolatile memory), a display unit 7a, an input unit (keyboard, mouse, etc.) 7b, a mechanism control board, an interface, and the like.

  The control processing unit 7 receives the signal of the operation position output from the table driving mechanism 6 by the mechanism control board and controls the table driving mechanism 6 to align the subject.

  Further, the control processing unit 7 collects transmission images sequentially transmitted as moving images from the X-ray detector 3, performs image processing, displays them on the display unit 7 a in real time as moving images, and displays the transmission images stored in the memory. Then, it is displayed on the display unit 7a as a moving image or a still image.

  Further, the control processing unit 7 issues a command to an X-ray control unit (not shown), specifies tube voltage and tube current, and instructs X-ray emission and stop. The tube voltage and tube current can be changed according to the subject.

  As shown in FIG. 1, the control processing unit 7 reads the software and functions as a function block for the CPU to function as an input range finding unit 7c that obtains an input range of transmission image values input from the X-ray detector 3. A gradation converting unit 7d that converts the gradation of the transmission image reflecting the input range is provided.

(Operation of the first embodiment)
The operation will be described with reference to FIGS.

  FIG. 3 is a flow chart of transmission image display according to the first embodiment.

  Transmission images R, G, and B for each color component to be displayed in step S1 are input from the X-ray detector 3 or from the memory of the control processing unit 7 to the input range finding unit 7c.

  In step S2, the input range obtaining unit 7c obtains an input range that is a value range for each of R, G, and B as follows.

  FIG. 4 is an example of the input range calculation area on the transmission image according to the first embodiment. An area on the transmission image 10 excluding the periphery is an input range calculation area 11.

The input range finding unit 7c obtains the minimum values R _min , G _min , B _min and the maximum values R _max , G _max , B _max in the input range calculation area 11 for each of the transmission images R, G, B, and this minimum The values R _min , G _min , B _min and the maximum values R _max , G _max , B _max are input ranges.

  FIG. 5 is a graph showing an example of an input range of a transmission image according to the first embodiment. The horizontal axis is the X-ray dose I, the vertical axis is the brightness R, G, B, and the R input range 13 is in a bright position corresponding to the X-ray dose range 12 incident on the input range calculation region 11. Input range 14 in the middle, and B input range 15 in the dark position.

  Returning to FIG. 3, in step S3, the gradation conversion unit 7d performs gradation conversion for each of the transmission images R, G, and B as follows.

  FIG. 6 is an example of a conversion function for gradation conversion according to the first embodiment. The horizontal axis is the input of gradation conversion, and the vertical axis is the output of gradation conversion.

As shown in FIG. 6, the conversion function is basically the same as the transmission image data, and the R component conversion function R _V (r) having the highest sensitivity within the predetermined range of the value is output as the input increases. A monotonically decreasing function is used, and the B component conversion function B _V (b) having the lowest sensitivity uses a function whose output monotonously increases with an increase in input. Further, as the conversion function G _V (g) for the G component having an intermediate sensitivity, a function that decreases monotonically after the output increases monotonously with respect to an increase in input is used. Here, monotonically decreasing means that any value is less than or equal to the previous value, and monotonically increasing means that any value is greater than or equal to the immediately preceding value. In the case of the conversion function of FIG. 6, the above-mentioned “predetermined range of values for transmission image data” corresponds to the input range obtained in step 2 of FIG.

  It should be noted that the R component and the G component are sufficient because there is little influence even if there is a slight increase / decrease (for example, 1/10 or less of the total output width) after monotonous decrease within the input range. Further, the B component and the G component are sufficient because there is little influence even if there is a slight increase / decrease (for example, 1/10 or less of the total output width) before monotonous increase within the input range. In this case, the “predetermined value range with respect to the transmission image data” is a portion obtained by excluding a slight increase / decrease portion from the input range.

  The “predetermined range of values with respect to the transmission image data” is a main value range in which the output of the gradation conversion almost covers the entire output range within the input range.

Also, as shown in FIG. 6, the conversion functions R _V (r), G _V (g), and B _V (b) are converted so that the input range for each color component is output to a constant output range. That is, even if the input range changes, the output range is always constant, and almost the entire image signal width is used as the output range.

Specifically, the conversion functions R _V (r), G _V (g), and B _V (b) are determined for the inputs r, g, and b that are normalized with respect to the input range for each color component. It is a conversion function. In other words, the conversion function changes following the change of the input range, and the output is determined at the position of the input with respect to the input range (how many% position).

If the input values for each color component are R, G, B, and the input values normalized to the input range are r, g, b, then r, g, b are
r = (R−R _min ) / (R _{max −min} ) (1)
g = (G−G _min ) / (G _max −G _min ) (2)
b = (B−B _min ) / (B _max −B _min ) (3)
Calculated by Here, r, g, and b are 0 when R, G, and B are min, and 1 when max.

Specifically, the conversion function of the gradation conversion shown in FIG. 6 is that the R component conversion function R _V (r) divides the R input range into two by a predetermined ratio (1: 1), and the low range is The output is monotonously decreased from the first value R1 to the second value R0 with respect to the increase in input, and the high range is a function that sets the output to the second value R0. The conversion function B _V (b) of the B component is The input range is divided into two by a predetermined ratio (1: 1), the output in the low range is the third value B0, and the output in the high range is monotonically increased from the third value B0 to the fourth value B1 with respect to the increase in input. It is a function. Furthermore, the G component conversion function G _V (g) divides the input range of G by a predetermined ratio (1: 1), and the lower range outputs the fifth value G0 to the sixth value as the input increases. The function increases monotonically up to G1, and the high range is a function that monotonously decreases the output from the sixth value G1 to the seventh value G0 ′ as the input increases.

で表される。ここで、定数Ｒ０，Ｇ０，Ｇ０’，Ｂ０，Ｒ１，Ｇ１，Ｂ１は任意に選べ るが、画像信号幅を広く使うように選ぶ。例えば、８ビット画像信号の場合、Ｒ０，Ｇ ０，Ｇ０’，Ｂ０を０、Ｒ１，Ｇ１，Ｂ１を２５５とする。The conversion functions R _V (r), G _V (g), and B _V (b) of the gradation conversion shown in FIG.

It is represented by Here, the constants R0, G0, G0 ′, B0, R1, G1, and B1 can be arbitrarily selected, but are selected so that the image signal width is widely used. For example, in the case of an 8-bit image signal, R0, G0, G0 ′, and B0 are set to 0, and R1, G1, and B1 are set to 255.

For each of the transmission images R, G, and B, the gradation conversion unit 7d uses the equations (1), (2), (3), (4), (5), and (E) for each pixel in the transmission image 10. The transmission images R _V , G _V , and B _V after gradation conversion are obtained by calculating Expression (6) (Step S3 in FIG. 3).

In step S4 of FIG. 3, the transmission images R _V , G _V , and B _V for the color components R, G, and B are sent to the display unit 7a for color display.

As described in the above flow, when the transmission images R, G, and B for each color component are input to the input range obtaining unit 7c, the gradation-converted transmission images R _V , G _V , and B _V are displayed on the display unit. 7a. Here, when the transmission images R, G, B are sequentially sent from the X-ray detector 3 as moving images, the gradation images of the transmission images R _V , G after gradation conversion are displayed by sequentially converting the gradations. _V, and _{B V} can be displayed on the display section 7a in real time as a moving image. Further, the transmission images R, G, and B stored in the memory can be subjected to gradation conversion and displayed on the display unit 7a as a moving image or a still image.

(Effects of the first embodiment)
FIG. 7 is an example of a color display of a transmission image in the first embodiment (a color display obtained by gray scale conversion), which is a transmission image obtained by photographing a capacitor. FIG. 7A shows a display before gradation conversion, and FIG. 7B shows a display after gradation conversion.

  In the display before gradation conversion shown in FIG. 7A, the high transmittance portion that is blue and can express a light and shaded color is not clear because the saturated red and green colors are added and light reddish. In addition, the intermediate transmittance part that can be displayed in green with fine shading is also reddish and unclear because of the addition of saturated red, and the low transmittance part is dark red and is entirely reddish and unclear. .

  On the other hand, in the display after gradation conversion in FIG. 7B, the low transmittance part is red and the details can be observed with good contrast, and the intermediate transmittance part is not added with a saturated red color. The details can be observed in green with good contrast, and the high transmittance portion can be displayed in blue with high contrast because the saturated red and green are not added.

That is, according to the first embodiment, for the R component with the highest sensitivity, the conversion function R _V (r) whose output monotonously decreases with the increase in input is used, and for the G component with an intermediate sensitivity. The conversion function G _V (g) that monotonously decreases after the output monotonously increases with respect to the input increases, and the conversion function B monotonically increases with respect to the input increase for the B component having the lowest sensitivity. _By converting the gradation for each color component using _V (b), the low transmittance portion is red, the intermediate transmittance portion is green, and the high transmittance portion is blue. An image can be displayed.

  In addition, according to the first embodiment, an input range is obtained for each color component, and each input range is always converted into a fixed output range (to input r, g, b normalized to the input range, respectively). Since gradation conversion is performed using a conversion function (determined for the input), even if the incident X-ray dose range 12 (see FIG. 5) changes, the input ranges 13, 14, and 15 (see FIG. 5) automatically. The conversion function changes following this change, and the input range is converted without waste to the full width of the output image signal (see FIG. 6). The color transmission image is increased to the limit, and a color transmission image with improved visibility can be displayed at all times.

  Furthermore, according to the first embodiment, since the input range is obtained in the input range calculation area excluding the periphery on the transmission image, the input range can be obtained without being affected by image quality deterioration such as a decrease in peripheral brightness. it can.

(Modification of the first embodiment)
In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. Also, the following modifications can be applied in combination.

(Modification 1)
In the first embodiment, the gradation conversion is performed by first obtaining r, g, and b using Equation (1), Equation (2), and Equation (3), and then Equation (4), Equation (5), and Equation. The transmission images R _V , G _V , and B _V after the gradation conversion are obtained by conversion in (6), but this is a description for easy understanding of the explanation, and actually, the expressions (1) and ( 2) Substituting Equation (3) into Equation (4), Equation (5), and Equation (6) to eliminate r, g, and b, and using the conversion function that is arranged, find r, g, and b. The transmission images R _V , G _V , and B _V obtained after direct gradation conversion are obtained directly from R, G, and B. Even in this case, the conversion function changes in accordance with the calculation and is equivalent to the change of the input range, and is “determined for the input r, g, and b normalized for the input range for each color component. The gradation conversion is still performed using the “conversion function” or “the conversion function that always converts the input range for each color component into a constant output range even if the input range changes”.

(Modification 2)
In the first embodiment, the conversion function for gradation conversion may be a conversion function that inverts light and dark. In this case, a conversion function is used in which the monotonic decrease is replaced with a monotone increase and the monotonic increase is replaced with a monotone decrease with respect to the conversion function in the first embodiment.

  FIG. 8 is an example of a conversion function for gradation conversion according to Modification 2 of the first embodiment. The horizontal axis is the input of gradation conversion, and the vertical axis is the output of gradation conversion. The conversion function of FIG. 8 is a function obtained by inverting the vertical axis direction of the conversion function of FIG. 6, and R0, G0, G0 ′, B0 is 255, R1, G1, B1 is 0, and Expressions (4) and (5) , There is a function represented by the equation (6) as it is.

When the conversion function of FIG. 8 is used, the colors of the converted color transmission images R _V , G _V , and B _V are inverted, and red, green, and blue appearing portions are complementary blue-green, red purple, and yellow, respectively. The image looks like this. That is, the low transmittance part is blue-green, the intermediate transmittance part is reddish purple, and the high transmittance part is yellow. However, just by changing red to blue-green, green to magenta, and blue to yellow, it is possible to display a color transmission image with improved contrast and good visibility as in the first embodiment.

  Note that the conversion by the conversion function of FIG. 8 is the same as the conversion by the conversion function of FIG. Further, the conversion by the conversion function of FIG. 8 is the same as the conversion by the conversion function of FIG. 6 after the conversion by the inversion conversion for inverting light and dark.

(Modification 3)
In the first embodiment, the conversion function (FIG. 6) for gradation conversion is not limited to this, and various modifications are possible. For example, R0, G0, G0 ′, and B0 are not 0, but may be values close to the end of the image signal width, and may be different from each other. R1, G1, and B1 may be values close to the other end of the image signal width instead of 255, and may be different from each other.

  In addition, the input range is divided into two at a predetermined ratio (1: 1), and the slope of the function is switched between a low range and a high range. However, this ratio may not be 1: 1, but R, G, B May be different.

  In addition, the range where the input range of R is high and the range where the input range of B is low are constant values. However, if the slope is gentle even if it is not exactly a constant value, the image can be accepted with little change whether it is uphill or downhill.

  The conversion function may be a combination of a large number of straight lines such as a line graph, or may be a curved line.

  FIG. 9 is an example of a conversion function for gradation conversion according to Modification 3 of the first embodiment. This is an example of a curve conversion function.

  In addition, as a modification from the first embodiment, after the R conversion function monotonously decreases within the input range, even if there is a slight increase / decrease (for example, 1/10 or less of the total output width) instead of the flat portion, This increase / decrease is not noticeable due to bright B (blue) or G (green).

  Similarly, even if the conversion function of B has a slight increase / decrease (for example, 1/10 or less of the total output width) instead of the flat portion before monotonically increasing within the input range, this increase / decrease is bright R (red ) Or G (green).

  Similarly, even if the G conversion function has a slight increase / decrease (for example, 1/10 or less of the total output width) before monotonically increasing within the input range, this increase / decrease is bright R (red). Even if there is a slight increase / decrease (for example, 1/10 or less of the full width of the output) after the monotonous increase and then the monotonic decrease within the input range, this increase / decrease is bright B (blue). There is no problem if it becomes inconspicuous.

(Modification 4)
In the first embodiment, there are three color components, but any number of colors may be used. FIG. 10 is an example of a conversion function for gradation conversion according to Modification 4 of the first embodiment. FIG. 10A shows the case of two colors R and B, and FIG. 10B shows the case of five colors R, Y (yellow), G, B, and P (purple).

(Modification 5)
In the first embodiment, the input range is obtained in the input range calculation area 11 on the transmission image 10, but the input range calculation area 11 can be selected by the operator if the entire transmission image 10 is acceptable. It may be.

(Modification 6)
In the first embodiment, when the input range is obtained, the minimum value and the maximum value of the input range calculation area 11 on the transmission image 10 are obtained and set as the input range, but the minimum value to the maximum value are arranged in ascending order. Thus, the input range may be from a value that is predetermined larger than the minimum value to a value that is predetermined smaller than the maximum value. Similarly, a histogram of image values (frequency of the number of pixels with respect to the image value) is created, and an input range from a position where the number of integrated pixels is a predetermined number from the bottom to a position where the number of integrated pixels is a predetermined number from the top. You can also

  Thereby, when there is an abnormal pixel that generates an abnormal value (for example, always 0), the input range can be obtained without being affected by this pixel.

(Modification 7)
In the first embodiment, the transmission image for each color component output from the X-ray detector 3 is subjected to gradation conversion as it is. However, after the image processing is performed, the conversion function used in the first embodiment is used for the scale conversion. Tone conversion may be performed. Examples of image processing include LOG conversion, sensitivity correction, offset correction, average processing, filter processing, and the like.

(Modification 8)
In the first embodiment, the color camera 3b is used to output a transmission image as digital data, but may be converted into digital data by the control processing unit 7 as an analog output.

(Modification 9)
In the first embodiment, the radiation detector 3 constituted by the color X-ray II (radiation-visible light conversion means) 3a and the color camera (imaging means) 3b is used, but is not limited thereto. For example, a plate having a color scintillator layer may be used as a radiation-visible light conversion means, a scintillator layer and a photoelectric layer are provided on the input surface of a microchannel plate for amplifying electrons, and a color scintillator layer is provided on the output surface. May be used.

(Modification 10)
In the first embodiment, tone-converted color transmission images R _V , G _V , and B _V can be stored in a memory, read from the memory, and displayed as they are.

In addition, the control processing unit 7 of the first embodiment communicates the collected color transmission images R, G, and B or the gradation-converted color transmission images R _V , G _V , and B _V via a LAN or the like. Or by using a medium such as a DVD or the like and sent to another computer.

  In addition, the control processing unit 7 of the first embodiment transmits the color transmitted from the same fluoroscopic inspection apparatus as that of the other first embodiment through a LAN or the like or using a medium such as a DVD. It is also possible to perform color conversion on the images R, G, and B and perform color display.

(Modification 11)
The present invention is not related to the system of the mechanism part, and can be applied to any type of radiographic inspection apparatus as long as it has radiation detection means for outputting transmission image data for each color component.

(Modification 12)
In the present invention, not only X-rays but also radiation that is transmissive to the subject such as γ rays and microwaves can be used depending on the subject.

  DESCRIPTION OF SYMBOLS 1 ... X-ray tube, 2 ... X-ray beam, 3 ... X-ray detector, 3a ... Color X-ray II, 3aa ... Input surface, 3ab ... Output surface, 3b ... Color camera, 4 ... Table, 5 ... Subject, DESCRIPTION OF SYMBOLS 6 ... Table drive mechanism, 7 ... Control processing part, 7a ... Display part, 7b ... Input part, 7c ... Input range acquisition part, 7d ... Tone conversion part, 10 ... Transmission image, 11 ... Input range calculation area, 12 ... X dose range, 13 ... R input range, 14 ... G input range, 15 ... B input range

Claims (8)

For transmission image data for each of a plurality of color components having different sensitivities obtained by detecting radiation emitted from a radiation source toward the subject and transmitted through the subject, Gradation conversion means for applying gradation conversion with different conversion functions, and display means for color-displaying transmission image data for each color component subjected to the gradation conversion,
The gradation converting means performs first gradation conversion in which the output monotonously decreases with respect to an increase in input within a predetermined range of values with respect to the transmission image data of the first color component having the highest sensitivity. Is applied to the transmission image data of the second color component having the lowest value in the predetermined range of the value, and the second gradation conversion in which the output monotonously increases with respect to the increase of the input. A third gradation conversion in which the output monotonically increases and then monotonously decreases with respect to the increase in input in a predetermined range of values is performed on the transmission image data of the third color component having an intermediate sensitivity. A transmission image display device. The transmission image display device according to claim 1,
Input range obtaining means for obtaining an input range representing a range of values of transmission image data for each color component for each color component;
The transmission image display apparatus characterized in that the gradation conversion means performs gradation conversion with a conversion function that always converts the input range for each color component into a constant output range even if the input range changes. . The transmission image display device according to claim 2,
The input range finding means is a minimum value to a maximum value obtained within a predetermined range on each transmission image of the transmission image data for each color component, or from a value that is a predetermined value larger than the minimum value to a maximum value. A transmission image display apparatus having the input range up to a predetermined smallest value. The transmission image display device according to claim 2 or 3,
The first gradation conversion divides the input range of the first color component by a predetermined ratio with respect to the transmission image data of the first color component by a predetermined ratio, and the low range outputs an output with respect to an increase in input. A monotone decrease from the first value to the second value, and a high range is gradation conversion in which the output is the second value, and the second gradation conversion is performed on the transmission image data of the second color component. The input range of the second color component is divided into two by a predetermined ratio, the output of the lower range is the third value, and the output of the higher range is monotonically increasing from the third value to the fourth value with respect to the increase in input. A transmission image display apparatus that performs gradation conversion. The transmission image display device according to any one of claims 2 to 4,
When the color component is 3 or more, the third gradation conversion is performed by dividing the input range of the third color component into two by a predetermined ratio with respect to the transmission image data of the third color component, and a low range. The transmission image display is a gradation conversion that monotonically increases the output from the fifth value to the sixth value with an increase in input, and the high range monotonously decreases the output from the sixth value to the seventh value with respect to the increase in input. apparatus. The transmission image display device according to any one of claims 1 to 5,
The transmissive image display device, wherein the gradation converting means applies gradation conversion in which the monotonic decrease is replaced with a monotone increase and the monotonic increase is replaced with a monotonic decrease. A radiation source that emits radiation toward the subject; and radiation detection means that detects the radiation transmitted through the subject and outputs transmission image data for each of a plurality of color components having different sensitivities to the radiation;
The radiographic inspection apparatus having the transmission image display device according to any one of claims 1 to 6, wherein the transmission image data for each color component is subjected to gradation conversion to perform color display. The radiographic inspection apparatus according to claim 7,
The radiation detection means comprises radiation-visible light conversion means for detecting radiation and converting it into a color visible light image, and an imaging means for photographing the color visible light image and outputting transmission image data for each of a plurality of color components. Radioscopic inspection equipment.

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