JP5150228B2 - X-ray image diagnostic apparatus, X-ray image processing method, and storage medium - Google Patents

Description

The present invention calculates the gradation, based on the output value obtained from the X-ray detector, an X-ray image diagnostic instrumentation 置及 beauty X-ray image processing method for creating an image by the gradation.

  Some conventional X-ray image diagnostic apparatuses are equipped with an automatic window function that calculates a gradation based on an output value acquired from an X-ray detector and creates an image based on the gradation. The auto window function, for example, sets the output value range to a window width (WW). Also, the median value of the output value range is set to the window level (WL). The created image is displayed on the monitor screen.

  In addition, as a conventional X-ray image diagnostic apparatus, an output value acquired from an X-ray detector is processed under a plurality of different processing conditions, and a plurality of different images obtained as a result are simultaneously or on a monitor screen. There has been proposed an apparatus configured such that images are displayed sequentially and an operator can select an image most suitable from a plurality of images displayed on a monitor (for example, Patent Document 1).

JP-A-6-169908

  However, in the X-ray diagnostic imaging apparatus equipped with the auto window function, a gradation is calculated based on the output value acquired from the X-ray detector, an image is created based on the gradation, and the created image is monitored. When the image is displayed on the screen, a black or white image may be displayed on the monitor screen due to variations in the physique or constitution of the subject. An engineer or doctor may mistakenly determine that the cause of the image becoming black or white is an imaging error, and may change the exposure conditions by X-rays and perform re-imaging. As a result, there is a problem that the subject may be exposed to unnecessary exposure.

  The conventional X-ray diagnostic imaging apparatus described in Patent Document 1 obtains an image as desired by selecting one image from a plurality of images displayed on the screen of the monitor. It is something that can be done.

  However, in image diagnosis, it is sufficient that one image having an appropriate density is displayed on the monitor screen. It is not always necessary to display a plurality of different images on the monitor screen. Further, there is a problem that an operation for selecting one image from a plurality of different images is troublesome every time image diagnosis is performed.

The present invention solves the above-mentioned problem, and by displaying a plurality of types of images with different gradations in stages, it can be determined whether or not there is a cause for the auto window function, and unnecessary re-photographing is performed. and to provide an X-ray image diagnosis instrumentation 置及 beauty X-ray image processing method capable of preventing.

According to a first aspect of the present invention for solving the above problem, a first gradation is calculated based on an output value acquired by an X-ray detector, and a first image is created based on the first gradation. An image creation unit that creates a second image for each type of the second gradation, based on the output value, using a plurality of types of second gradations that are stepwise different from the first gradation; A creation unit that creates a histogram in which pixel values of an image are associated with the number of pixels of the pixel values, and a feature value that represents a feature of a distribution of pixel values of the first image is calculated using the information of the histogram A feature value calculation unit, a determination unit that determines whether the feature value is included in a predetermined setting range, a display unit, and the feature value are included in the setting range. When the determination unit determines, the first image is displayed on the display unit, A display control unit that displays the second image for each type of the second gradation on the display unit when the determination unit determines that a feature value is not included in the setting range. Is an X-ray diagnostic imaging apparatus.

The invention according to claim 5 is a step of calculating a first gradation based on an output value acquired by an X-ray detector, creating a first image based on the first gradation, Creating a histogram in which pixel values are associated with the number of pixels of the pixel values; calculating feature values representing characteristics of distribution of pixel values of the first image using information of the histogram; Determining whether or not the feature value is included in a predetermined setting range; and displaying the first image on the display unit when the feature value is included in the setting range. And, when the feature value is not included in the setting range, based on the output value, a plurality of types of second gradations that are stepwise different from the first gradation, Creating a second image for each key type; An X-ray image processing method characterized by comprising the steps of: displaying a second image of each type of the second tone to the display unit.

According to the first aspect of the present invention, in response to the determination by the determination unit that the feature value is not included in the setting range , the display control unit displays the second image for each type of the second gradation on the display unit. indicate. When an image with an appropriate density is included in the plurality of second images displayed on the display unit, the engineer or doctor determines that there is no cause in the output value acquired from the X-ray detector. Can do. Thereby, re-photographing can be prevented. In addition, when an image with an appropriate density is not included in a plurality of images displayed on the display unit, an engineer or the like may determine that there is a cause in imaging conditions such as excess or deficiency of X-ray dose. it can.

According to the fifth aspect of the present invention, when the feature value is not included in the setting range , the display control unit displays the second image for each type of the second gradation on the display unit. Depending on whether or not an image having an appropriate density is included in the plurality of displayed second images, the engineer or the like has a cause in the first image created based on the first gradation, It can be determined whether or not there is a cause in imaging conditions such as excess or deficiency of X-ray dose.

(Constitution)
The configuration of the X-ray image diagnostic apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing the configuration of the X-ray image diagnostic apparatus.

  The X-ray tube holding device 10 and the three-dimensional stand 20 are arranged at positions facing each other with the subject interposed therebetween. The X-ray tube holding device 10 includes an X-ray tube 11 and an X-ray restrictor 12. The solid stand 20 includes a grid 21 and an X-ray detector 22. The X-ray diaphragm 12 irradiates an appropriate position of the X-ray detector 22 with an X-ray beam for the purpose of optimizing the exposure dose. In addition, the grid 21 removes or reduces scattered radiation generated by the interaction between the subject and the X-ray in order to obtain a high-quality X-ray image.

  For example, the user sets items such as an exposure mode, a calibration mode, and a diagnosis by a display unit and an operation unit of a user interface (not shown). The system control means 1 receives these settings and sends the X-ray exposure conditions and timing according to the exposure mode to the X-ray control unit 31. The X-ray control unit 31 controls a voltage supplied from the high voltage generator 32 of the X-ray high voltage device 30 to the X-ray tube 11.

  Next, the configuration of the X-ray detector 22 will be described with reference to FIG. The X-ray sensor 221 is a sensor that constitutes a pixel, and is referred to as a pixel detection element or a pixel. The X-ray sensor 221 detects the X-rays by converting the charges into charges according to the intensity of the received X-rays and storing the charges. The X-ray sensor 221 includes, for example, a conversion element, a capacitive element that stores charges, and a semiconductor gate element (not shown) that extracts and outputs charges from the capacitive element.

  The X-ray sensors 221 are two-dimensionally arranged in the row direction and the column direction, and n sensor groups 220 are configured as a whole. In response to an instruction from the system control unit 1 or the readout control unit (not shown), the sensor column selection unit 230 instructs the array of sensor groups 220 to read pixel values for each column of the sensor group 220. The output is received by a variable amplifier (integral amplifier) 241 for each row and amplified. The output from the amplifier group 240 is output as digital data indicating a pixel value for each pixel (for each X-ray sensor 221) via the multiplexer 250 and the AD converter 260.

  Further, offset and gain are corrected with respect to the pixel value for each pixel, and the corrected data is sent to the input unit 41 of the image processing apparatus 40.

  The input unit 41 stores pixel value data for several frames in a high-speed memory (frame memory or frame buffer), and transfers the data to the storage device 42 in accordance with an instruction from the control unit 43.

  The storage device 42 stores pixel value data together with accompanying information (patient name, imaging region, imaging direction, imaging conditions, etc.).

  The control unit 43 retrieves the program from the storage device 42, interprets the command, reads the pixel value data from the storage device 42 based on the command, instructs the processing unit to process the image value data, and performs the processing. Data is written to the storage device 42. In addition, the control unit 43 performs data input / output control with respect to the input unit 41, the display control unit 50, and the network output unit 51.

  The calculation unit includes an image creation unit 44, a histogram creation unit 45, a feature value calculation unit 46, and a determination unit 47.

  The image creation unit 44 calculates a first gradation based on the output value (projection data) acquired by the X-ray detector 22 and creates a first image based on the first gradation. The function in which the image creating unit 44 creates the first image with the first gradation is referred to herein as an auto window function.

  In the auto window function, for example, the image creating unit 44 assigns gradations to all output values.

When the image creation unit 44 assigns gradations to all of the output values, the image creation unit 44 searches for the minimum value and the maximum value from all of the output values (projection data). Assuming that the minimum and maximum output values are Vmin and Vmax, the image creation unit 44 obtains the window width WW by the following equation (1) and obtains the window level WL by the following equation (2).
WW = Vmax−Vmin (1)
WL = Vmin + WW / 2 (2)

  The obtained window width WW and window level WL are stored in the storage device 42 as the first gradation.

  For example, when the minimum value of the output value is 0 and the maximum value is 1023, the image creation unit 44 assigns gradations to all of the output values 0 to 1023. In this case, the window width WW is 1023 (= 1023-0). The window level WL is 511.5 (= 0 + 1023/2).

  The configuration in which the image creation unit 44 assigns gradations to all output values has been described above. Not limited to this, the image creating unit 44 may assign a gradation to a part of the output value. The mechanism (procedure) for calculating the first gradation based on the output value is stored in the storage device 42.

  For example, in the first gradation, when the image creation unit 44 assigns gradations to a part of the output values 0 to 1000, the image creation unit 44 is the same as the output value 0 for output values lower than 0. Assign gradations. The image creating unit 44 assigns the same gradation as the output value 1000 to an output value higher than 1000.

  A specific example in the case where the image creating unit 44 assigns gradations to all output values will be described. For example, when the output value (projection data) acquired by the X-ray detector 22 is a value from a minimum of 0 to a maximum of 1023, the image creation unit 44 changes the output value (projection data) from 0 to 1023. Assign a predetermined gradation.

  For example, when the gradation that can be displayed on the monitor 60 by the display control unit 50 is an 8-bit gradation, the image creation unit 44 assigns gradation values from 0 to 255 to the output value (projection data).

  The image creating unit 44 assigns a gradation value 0 to an output value 0 or more and less than 4, and assigns a gradation value 1 to an output value 4 or more and less than 8. Then, the image creation unit 44 assigns the gradation value 255 to the output value 1020 or more and 1023 or less.

  As described above, the image creating unit 44 creates the first image by assigning, for example, gradation values from 0 to 255 to the output value (projection data). That is, a gradation value (pixel value) is assigned to the pixel of the first image.

  When the gradation that can be displayed on the monitor 60 by the display control unit 50 is a 10-bit gradation, the image creation unit 44 assigns gradation values from 0 to 1023 to the output value (projection data).

  FIG. 3 shows a graph (histogram) in which the horizontal axis represents each tone value (tone value) assigned by the image creating unit 44 and the vertical axis represents the number of pixels having the tone value.

  The image creation unit 44 creates a second image with the second gradation based on the output value (projection data) acquired by the X-ray detector 22. The second gradation is a plurality of kinds of gradations different from the first gradation in stages.

  FIG. 4A is a histogram in which the horizontal axis represents the output value (projection data) acquired by the X-ray detector 22 and the vertical axis represents the number of pixels having the output value. FIG. 4A shows the first gradation in which the image creation unit 44 assigns gradations to all of the output values from the minimum 0 to the maximum 1023. In the first gradation, the window width WW is 1023 (= 1023-0) and the window level WL is 511.5 = 0 + 1023/2).

  Next, the second gradation will be described with reference to FIGS. 4B and 4C. The output value histograms shown in FIGS. 4B and 4C are the same as the histogram shown in FIG.

  In the first stage, the image creating unit 44 changes the minimum output value to which gradation is assigned from 0 to 256 and fixes the maximum output value to 1023. In the second stage, the minimum output value is 256 to 512. FIG. 4B and FIG. 4C show the cases where the maximum output value is fixed at 1023.

  That is, FIG. 4A shows the window width WW = 1023-0, FIG. 4B shows the window width WW = 1023-256, and the window width WW = 1023-512. Is FIG. 4 (c).

  In the second gradation shown in FIGS. 4B and 4C, the image generation unit 44 changes the minimum output value stepwise, but the maximum output value may be changed stepwise. Further, although the image creation unit 44 has shown that the minimum of the output value is changed in two stages, the minimum or maximum of the output value may be changed in three or more stages.

  Further, the image creation unit 44 may provide a plurality of step widths for changing at least one of the minimum and maximum output values, and at least one of the minimum and maximum output values may be changed according to the step width selected from the plurality. good.

  Next, the case where the image creation unit 44 changes both the minimum and maximum output values in stages will be described with reference to FIGS.

  FIG. 5 is a diagram in which the window width WW is fixed and the minimum and maximum output values are changed stepwise in parallel. 5 (a) to 5 (c), the image creation unit 44 fixes the window width WW, which is the range from the minimum to the maximum of the output value, to 400, and gradually sets the minimum and maximum of the output value in parallel. Indicates what to change (with step width 50).

  As the second gradation in which the window width WW is fixed and the minimum and maximum of the output value are changed stepwise, for example, a range in which the minimum and maximum of the output value are changed is provided. Specifically, the minimum and maximum output values may be changed (with a predetermined step width).

  In the second gradation in which the window width WW is fixed and the minimum and maximum of the output value are changed stepwise, the window level WL that is the median value in the range from the minimum to the maximum of the output value changes. The maximum value or the minimum value of the changing window level WL may be a feature value described below.

  FIG. 6 is a diagram in which the window level WL is fixed and the minimum and maximum output values are changed stepwise. In FIGS. 6A to 6C, the image creating unit 44 fixes the window level WL, which is the median value in the range from the minimum to the maximum of the output value, to 700, and sets both the minimum and maximum of the output value. What is to be changed (with a step width of 50).

  As the second gradation in which the window level WL is fixed and the minimum and maximum of the output value are changed stepwise, for example, a range in which the minimum and maximum of the output value are changed is provided. Specifically, the minimum and maximum output values may be changed (with a predetermined step width). The window level WL may be a feature value described below.

  With the above configuration, the image creating unit 44 changes at least one of the minimum and maximum output values stepwise. The image creating unit 44 assigns a predetermined gradation to the range from the minimum to the maximum output value at each stage.

  A specific example in the case where the image creating unit 44 assigns a predetermined gradation to the range from the minimum to the maximum output value at each stage will be described with reference to FIGS. 4B and 4C.

  For example, when the output value (projection data) acquired by the X-ray detector 22 is a value from the minimum 256 to the maximum 1023 (shown in FIG. 4B), the image creation unit 44 sets 256 to 1023. The tone values from 0 to 255 are assigned to the output values (projection data) up to. The image creating unit 44 assigns the gradation value 0 to the output value 256 or more and less than 260, and assigns the gradation value 1 to the output value 260 or more and less than 264. Then, the image creation unit 44 assigns the gradation value 255 to the output value 1020 or more and 1023 or less.

  Further, for example, when the output value (projection data) acquired by the X-ray detector 22 is a value from the minimum 512 to the maximum 1023 (shown in FIG. 4C), the image creation unit 44 outputs 512. For example, gradation values from 0 to 255 are assigned to output values (projection data) from 1 to 1023. The image creating unit 44 assigns the gradation value 0 to the output value 512 or more and less than 516, and assigns the gradation value 1 to the output value 516 or more and less than 520. Then, the image creation unit 44 assigns the gradation value 255 to the output value 1020 or more and 1023 or less.

  Note that the gradation value assigned to the output value is not limited to a value from 0 to 255. For example, when the gradation that can be displayed on the monitor 60 by the display control unit 50 is a 10-bit gradation, the image creation unit 44 assigns gradation values from 0 to 1023 to the output value (projection data).

  As described above, the image creating unit 44 creates the second image by assigning, for example, gradation values from 0 to 255, for example, to the range from the minimum to the maximum of the output value that changes stepwise. . That is, a gradation value (pixel value) is assigned to the pixel of the second image.

  Next, the histogram creation unit 45 will be described with reference to FIGS. The histogram creation unit 45 obtains the number of pixels for each pixel value based on the pixel value (gradation value) of the first image created by the image creation unit 44 and creates a histogram. The histogram shown in FIG. 7 is a graph with the pixel value on the horizontal axis and the number of pixels of the pixel value on the vertical axis.

Next, the feature value calculation unit 46 will be described with reference to FIGS. The feature value calculation unit 46 calculates a feature value that represents the feature of the distribution of the pixel values (tone values) of the first image using the histogram information. In the present embodiment, four feature value calculation units 46 are provided. Hereinafter, the four feature value calculation units 46 will be described.

The first feature value calculation unit 46 calculates the feature value as an average value fav (center of gravity) of the histogram shown in FIG. The average value fav is calculated by equation (1).
fav = (ΣP · C) / S (1)
C represents a pixel value, P represents the number of pixels having the pixel value, and S represents the total number of pixels.

The second feature value calculation unit 46 calculates the feature value as the midpoint fmd of the histogram shown in FIG. The midpoint fmd is calculated by equation (2).
fmd = (Cmax−Cmin) / 2 (2)
Cmax represents the maximum pixel value, and Cmin represents the minimum pixel value.

  The third feature value calculator 46 calculates the feature value as the mode value fmv of the histogram shown in FIG. The mode value fmv is a pixel value having the largest number of pixels among all the pixel values.

The fourth feature value calculator 46 calculates the feature value as the boundary value fbd of the histogram shown in FIG. The boundary value fbd is calculated by the relational expression (3) between S and R.
fbd = F (S, R) (3)
S represents the total number of pixels, and R represents a preset ratio. For example, when S = 512 × 512 and R = 1/2, the boundary value fbd is counted from a pixel having a low pixel value, and the pixel value of the 131072 (= 512 × 512/2) -th pixel It is.

  The various feature values have been described above. The type of feature value to be calculated corresponds to the type of output value (projection data) to be made into the first image, and is empirically known. The feature value calculation unit 46 calculates the type of feature value corresponding to the output value, and the calculated feature value is stored in the storage device 42.

  Next, the determination unit 47 will be described. The determination unit 47 determines whether the feature value satisfies the setting condition. FIGS. 7 to 10 respectively show the case where each feature value does not satisfy the setting condition (when it exceeds the setting range).

  Since the histogram of the pixel values of the first image is different for each imaging region, the setting range that is a condition for determining the feature value corresponds to the imaging region or to the imaging protocol. Saved in.

  With the above configuration, the image creating unit 44 creates the first image and the second image, and the determining unit 47 determines whether or not the feature value satisfies the setting condition. The setting condition may be a simple setting value instead of a range.

  Next, a configuration for displaying the first image and the second image based on the determination by the determination unit 47 will be described.

  The display control unit 50 displays the first image on the monitor 60 when the feature value satisfies the setting condition. Further, the display control unit 50 displays the second image on the monitor when the feature value does not satisfy the setting condition.

  The network output unit 51 transmits data of the first image and the second image to the server 71 and the printer 73 via a LAN (local area network). The server 71 stores the data of the first image and the second image in the storage device, and displays the first image and the second image on the monitor 72 according to a predetermined condition.

(Operation)
Next, a procedure for processing an X-ray image will be described with reference to FIGS.

  FIG. 11 is a flowchart showing a procedure until the projection data acquired by the X-ray detector 22 is displayed on the monitor.

  In X-ray imaging, an output value (projection data) acquired by the X-ray detector 22 is output to the input unit 41 of the image processing apparatus 40 (step S101). The input unit 41 stores output values (projection data) for several frames.

  The input unit 41 sends an output value (projection data) to the storage device 42 according to an instruction from the control unit 43. The storage device 42 stores the output value.

  In response to an instruction from the control unit 43, the image creation unit 44 creates a first image with the first gradation based on the output value stored in the storage device 42 (step S102). A gradation value (pixel value) is assigned to the pixel of the first image. Further, according to an instruction from the control unit 43, the histogram creation unit 45 creates a histogram by accumulating the number of pixels for each pixel value based on the pixel values of the first image (step S103).

  Next, in response to an instruction from the control unit 43, the feature value calculation unit 46 calculates the feature value of the entire pixel value of the first image based on the histogram information using a predetermined calculation formula (step S104).

  As described above, the type of feature value to be calculated is associated in advance with the type of output value (projection data). The feature value calculator 46 calculates a predetermined feature value from the average value fav, midpoint fmd, mode fmv, and boundary value fbd of the histogram.

  Next, the determination unit 47 determines whether or not the feature value satisfies the setting condition (step S105). The determination unit 47 compares the feature value with the setting condition (setting range) and outputs the result.

  The display control unit 50 receives the determination of the determination unit 47 that the feature value satisfies the setting condition, and displays the first image on the monitor 60 (step S106). In addition, the image creation unit 44 creates a second image with the second gradation based on the output value stored in the storage device 42 in response to the determination by the determination unit 47 that the feature value does not satisfy the setting condition. (Step S107). The second gradation is a plurality of kinds of gradations different from the first gradation.

The display control unit 50 displays the second image on the monitor 60 (step S107).
For example, the display control unit 50 displays the second image for each type of the second gradation on the monitor 60 one by one every predetermined time. In FIG. 12, the display control unit 50 displays a plurality of images one by one on the monitor 60 at predetermined time intervals. After image A is displayed for a certain period of time, image B is displayed. Next, after displaying the image B for a certain period of time, the image C is displayed. In this way, the display control unit 50 sequentially displays images A to O.

  After displaying the image O, the display control unit 50 returns to the image A and repeats the display from the image A to the image O. The display control unit 50 receives the selection of the displayed image, stops the display repetition, and displays the selected image.

  In FIG. 13, the display control unit 50 displays all the images A to O on the monitor 60 at the same time. In response to the selection of the displayed image, the display control unit 50 enlarges and displays the selected image. Note that the display control unit 50 may display a plurality of images sequentially and sequentially on the monitor 60. Further, the display control unit 50 may display a message to that effect upon receiving the determination of the determination unit 47 that the feature value does not satisfy the setting condition.

  Note that the image creation unit 44 that creates the second image with the second gradation based on the output value acquired by the X-ray detector 22 is not limited to the above-described embodiment. For example, the following two image creation units 44 may be used.

  As the first image creation unit 44, for example, the gradation value of the first image is gradually reduced.

  FIG. 14A shows a histogram of the first image created with the first gradation. In FIG. 14A, pixel values from 0 to 255 are assigned to each pixel in the first gradation. Since many pixels have high pixel values, the first image is displayed whitish.

FIG. 14B shows a case where the image creation unit 44 assigns gradation values from 0 to 205 to each pixel. FIG. 14C shows the image creation unit 44 in which gradation values from 0 to 155 are assigned to each pixel. Since many pixels have pixel values between 100 and 150, the second image is displayed with the appropriate density.
Although the image creation unit 44 has been shown to reduce the maximum gradation value step by step, the present invention is not limited to this. The image creating unit 44 may create a plurality of types of second images by gradually reducing at least one of the maximum value or the minimum value of the gradation values.

  The second image creation unit 44 will be described with reference to FIG. The image creating unit 44 gradually reduces the number of 256 gradations in the first image.

  FIG. 15A shows a histogram when the number of pixels is accumulated for each pixel value (gradation value) of the first image when the number of gradations in the first image is 256.

  FIG. 15B shows a histogram of the second image when the image creating unit 44 reduces the number of gradations of 256 to 1/2 and creates a second image based on the reduced number of gradations.

  Further, when the image creating unit 44 reduces the number of gradations of 256 to ¼ and creates the second image based on the reduced number of gradations, the histogram of the second image is shown in FIG. Show.

  The image creation unit 44 reduces the number of gradations in the first image in a stepwise manner. Thereby, a plurality of types of second images can be created.

  As mentioned above, although the various image creation parts 44 were mentioned, the image creation part 44 is not limited to these. The image creating unit 44 only needs to create a second image with a plurality of types of second tones different from the first tones.

In the above-described embodiment, after the determination unit 47 determines, the image generation unit 44 generates the second image with the second gradation, but before the determination unit 47 determines, the second image is displayed. You may create it.
Note that the program may be read by setting a storage medium storing a program for executing steps S101 to S105 in the input device of the X-ray image diagnostic apparatus. Moreover, it is good also as a storage medium which memorize | stored the program for performing step S101-step S108.

It is a block diagram which shows the structure of a X-ray image diagnostic apparatus. It is a block diagram which shows the structure of a X-ray detector. It is a histogram in which the horizontal axis represents the gradation value of the first image created by the first gradation and the vertical axis represents the number of pixels having the gradation value. It is a histogram with the horizontal axis representing the output value (projection data) acquired by the X-ray detector and the vertical axis representing the pixel value having the output value. It is the figure which fixed the window width and changed the minimum and maximum of an output value in steps. It is the figure which fixed the window level and changed the minimum and maximum of an output value in steps. It is the histogram of the pixel value of a 1st image, and is a graph which took the pixel value on the horizontal axis and took the number of pixels of the pixel value on the vertical axis. It is a figure showing a feature value by an average value. It is also a histogram and is a figure showing a feature value as a midpoint between a maximum value and a minimum value. It is also a histogram, and is a diagram showing feature values as mode values. It is also a histogram and is a figure which shows a feature value with a boundary value. It is a flowchart which shows the procedure until it displays the acquired projection data on a monitor. It is explanatory drawing which shows the aspect which displays a some image one by one on predetermined time every time on the screen of a monitor. It is explanatory drawing which shows the aspect which displays all the some images simultaneously on the screen of a monitor. (A) is a histogram of the first image, and (b) and (c) are histograms of the second image in which the maximum gradation value is reduced stepwise. (A) is a histogram of the first image, and (c) and (c) are histograms of the second image when the number of gradations is decreased stepwise.

Explanation of symbols

WL Window level WW Window width Vmin Minimum output value Vmax Maximum output value 10 X-ray tube holding device 20 Solid stand 30 X-ray high voltage device 40 Image processing device 41 Input unit 42 Storage device 43 Control unit 44 Image creation unit 45 Histogram Creation unit 46 Feature value calculation unit 47 Judgment unit 50 Display control unit 60 Monitor

Claims (6)

A first gradation is calculated based on the output value acquired by the X-ray detector, a first image is created based on the first gradation, and the first gradation is stepped on the basis of the output value. An image creation unit that creates a second image for each type of the second gradation by using a plurality of different second gradations;
A creation unit that creates a histogram that associates the pixel value of the first image with the number of pixels of the pixel value;
A feature value calculation unit that calculates a feature value representing a feature of a distribution of pixel values of the first image using information of the histogram;
A determination unit that determines whether or not the feature value is included in a predetermined setting range;
A display unit;
When the determination unit determines that the feature value is included in the setting range, the first image is displayed on the display unit, and the feature value is not included in the setting range. A display control unit configured to display the second image for each type of the second gradation on the display unit when the determination unit determines;
Having
An X-ray diagnostic imaging apparatus characterized by the above.   The X-ray image diagnosis apparatus according to claim 1, wherein the display control unit continuously displays the second image for each type of the second gradation on the display unit.   The X-ray diagnostic imaging apparatus according to claim 1, wherein the display control unit displays the second image for each type of the second gradation on the display unit one by one at predetermined time intervals.   The X-ray image diagnosis apparatus according to claim 1, wherein the display control unit simultaneously displays the second image for each type of the second gradation on the display unit. Calculating a first gradation based on an output value acquired by the X-ray detector, and creating a first image based on the first gradation;
Creating a histogram in which the pixel value of the first image is associated with the number of pixels of the pixel value;
Calculating a feature value representing a feature of a distribution of pixel values of the first image using information of the histogram;
Determining whether the feature value is included within a predetermined setting range;
When the feature value is included in the setting range, displaying the first image on a display unit;
When the feature value is not included in the setting range, each type of the second gradation is determined by a plurality of types of second gradations that are stepwise different from the first gradation based on the output value. Creating a second image of
And displaying a second image for each type of the second gradation on a display unit. An X-ray image processing method comprising:   A computer-readable storage medium storing a program for executing the steps of the X-ray image processing method according to claim 5.

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