JPS60108977A - Picture converter - Google Patents

Abstract

PURPOSE:To observe a sectional image in a really observed state by obtaining an expanded reconstitutional image of a converned area from scanned data and applying curved plane/section convertion processing to the reconstitutional image. CONSTITUTION:A mountding board 51 is stopped at a required rotational angle, and while radiating X rays intermittently from A-ray source 52, detected outputs obtained from a detector 53 are collected by a data collecting part 54 to obtain a scanned image. A computer 8 expands and reconstitutes the sectional image of the collected data at a required area on the basis of a set-up center position and a set expanded area. Consequently, a reconstituted image expanded around the previously set center position is obtained. The obtained picture is regarded as if a CT picture obtained by normal scanning, the expanding direction of the section is fixed and the section convertion processing is executed for the plane. Then, the computer 58 controls the display of the sectional image. Consequently, a sectional image obtained by the curved plane/section convertion processing is displayed on a CRT display 59.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image conversion device that obtains a cross-sectional image of a desired curved surface from a plurality of consecutive cross-sectional images.

[Technical background of the invention]

For example, there is an image diagnostic apparatus called a CT (computed tomography) apparatus used for medical purposes.

This device includes, for example, an X-ray source that emits one fan beam X-ray that spreads in a flat fan shape as a radiation source, and is placed facing this X-ray source through a subject, and is arranged in a direction in which the fan beam X-ray spreads. This
For example, move the radiation source and radiation detector in the same direction at 180° increments.
X-ray absorption data from multiple directions on the tomographic plane of the subject are collected while sequentially rotating and scanning from 360° to 360°, and then the image is reconstructed using a conbeater, etc. Since images can be reconstructed in as many as 2,000 gradations depending on the situation, the state of the tomographic plane can be known in detail.

Incidentally, a component image (hereinafter referred to as a CT image) obtained by such a CT 4% setting is determined by the thickness of the 7 am beam X# and the detection field of the radiation detector. In other words, a CT image is obtained from a region where X-rays incident on the radiation detector pass through the subject. This CT image of one cross-section is called a one-slice CT image, but since the slice thickness of two slices (thickness of Xm incident on the radiation detector) is small, in order to diagnose the area of interest, it is necessary to The slice position is sequentially shifted by about the slice thickness to cover the entire region, and CT images of multiple slices are obtained to obtain information on the region of interest.

However, since each of the plurality of CT images obtained in this way is a tomographic image, in order to know the appearance of the entire region of interest, after arranging the plurality of CT images CPI to CPn in the order of slice positions, the desired cross-section S is set, and image data on the cross section S is extracted to obtain an image P8 of the cross section S.

By the way, in the case of such a conventional method, the cross section S that can be set is limited to a two-dimensional plane, and as shown in FIG. In this case, the images on the cross section S are each CT image P1. ~C
As is clear from the figure, the region of interest R in each CT image does not necessarily exist on this line L8, so the cross section S can be the distribution area of the region of interest7
Even if you set the bits to match, you can actually get the disconnection +
Image Pl on s! As shown in FIG. 1, a part of the region of interest may be missing. Therefore, when performing a diagnosis in such a case, there is a drawback in that the whole picture of the region of interest R cannot be clearly seen, making it difficult to perform a diagnosis.2. .

In addition, in the contract month field, the section S in FIG. 1 is set vertically as shown at 81 in FIG. ) to 82
The fiN of this cross section (this is called coronal) is obtained by setting the rIcfffi plane S horizontally as shown in
As shown at 83 in Fig. 2(), the cross section S is set to be tilted around the axis of the subject to obtain an image of this cross section (this is called the axial axis), or as shown in Fig. 2() b) to s4
A cross-section set along the axis tilted relative to the subject dl+a and tilted obliquely to the horizontal as shown in ?
(This is called an oblique), but since these are all straight surfaces, if the area of interest is curved, a small needle 1 go similar to the one shown in Figure 1 or II will be obtained. arise.

For example, if we obtain a sagittal image of the first side of the toy S for the image P shown in Fig. 31(a)', the result will be as shown in Fig. 3(b), and a part of the region of interest R is 11 Only what remains. Furthermore, when an oblique image of cross section S4 is obtained for the same image P as shown in Fig. 4(,), it becomes as shown in Fig. 4(b), and in both cases, most of the region of interest is missing and the target image is cannot be observed.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and it is possible to obtain a cross-sectional image obtained by cutting an object along an arbitrary curved surface from a plurality of continuous slice tomographic images obtained by a CT wave device. The purpose of the present invention is to provide an image conversion device.

[Summary of the invention]

That is, in order to achieve the above-mentioned object, the present invention is an apparatus for obtaining data of continuous cross-sectional images of a photographic subject and generating a desired cross-sectional image that intersects with the drawing of the photographic subject. means for setting the center of the desired cross-sectional body F of the cross-sectional image and setting an enlarged reconstruction region centered on the center; and pre-enlargement using the data of the continuous cross-sectional images also centering on the set cross-sectional position center. means for performing an enlarged reconstruction process on the scaled region; and a step for obtaining, by image conversion, a cross-sectional image of a plane in a predetermined width direction passing through the center position of the enlarged scaled cross-sectional image of the subject. , a means for displaying the converted cross-section rfu fJJ, sets the center of the desired cross-section U゛ for each of the consecutive cross-sectional images of the object, and sets an enlarged reconstructed image centered at the center point t. Then, the set position and area are enlarged and reconstructed to obtain an enlarged reconstructed image centered on the set shinso tuna using each enlarged book configuration, thereby determining the number of bales in which the desired part is centered. A ladle configuration image is obtained, and from these multiple reconstructed images, a cross-sectional image on a plane having an expanse in a predetermined direction passing through the center is obtained. By performing I, it is possible to obtain a cross-sectional image of the region of interest which is distributed in a curved manner, and by applying an orthogonal projection to this Vr-plane image, it is possible to obtain the cross-sectional image in a state that corresponds to the actual condition. Be able to see the basics.

[Example of implementation of q)]

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

First, an example of generating an h-plane image in which a curved region of interest (tissue) is displayed without interruption will be described.

To generate cross-sectional images, we use image data obtained by target tracking, which scans by setting the scan position of the subject and the center position of the tissue of interest. Image data corresponding to the target cross section is extracted in the same way from each of the multiple -I image gutters obtained in this way,
By performing the cross-section conversion, a curved cross-section converted image with the target region of interest can be obtained.

FIG. 5 is a Zoroku diagram showing water projection) Un's (:' + construction), and is an example in which a CT device is used to collect image data.

In the figure, reference numeral 51 denotes a pedestal for the CT apparatus δ, and this pedestal 5) is rotatably supported, and is provided with a hole 51ta in the center for arranging the subject S. This frame 5 has the hole 51'.
a to an X-ray source 52 and a detector 5 for x, l and zo detection.
3 are placed facing each other.

The XIII source 52 has a heavy metal constriction on its X-ray emission port 1 [11], and this constriction makes it flat and 1
A fan beam X-ray FB having a spread of 1.5 mm can be emitted toward the detector 5. The spread angle of this fan beam X-ray FB is
Set in advance to f4 DI, which can hold a 1m aperture diameter of 8", and use it.

1, did the detector 53 respond to the intensity of -4Jfthl? V+, envelope (before radiation outputting ij) detection collection 53
Multiple m with 111'45 of Ha17i, fan beam
2) They are arranged in parallel in the direction in which the lines F and B extend, and are provided with multi-spatial resolution. Then, each radiation detection element 53g corresponds to each radiation detection element 53-'* and Xi.
Follow the X-ray path (X-ray path) connecting X-ray source 52 to X-ray source 5.
The intensity of the X-rays arriving from 2 is detected.

Reference numeral 54 denotes a data collection section, which receives detection outputs for each X-ray projection angle that can be output from each of the detectors 53a of the detector 53, and determines two points of X-ray intensity.

55 applies a high voltage to the X-ray source 52, and also
%! A high-pressure generation and X-ray control section controls the exposure, 56 is a bed on which the subject is placed, and 57 is a pedestal and bed control section that controls the rotation of the pedestal 51 and the positioning of the bed 56.

The bed 56 has a top plate on the upper part of the main body, on which the subject can be placed and the top plate can be sent in the direction of the hole 51g of the pedestal 5. Data on the tomographic plane of the object can be collected by sequentially changing the position of the cislice.

Reference numeral 58 denotes a computer, which controls the entire system, receives data collected by the data collection unit 54, processes the data and reconstructs an image, and selects a desired image containing white meat from the reconstructed images of a plurality of continuous sections. It has a function of creating an image of a cross section when the cross section is cut. 59 is the operation
The display section has a CRT (cathode ray tube) display, a keypad, a trackball, etc., and input/output commands for each unit to the converter 58 are performed by keyboard operations, and images created by the computer 580 are displayed on the CRT display. By manipulating the ball and specifying coordinates, etc., it is possible to specify the cross section, etc. to be displayed. Here, a trackball is a spherical body held so that it can be rotated in any direction, and when this spherical body is rotated by hand or the like in a desired direction, position information corresponding to the direction and amount of rotation is generated. With this input device, it is possible to display a marker on the CRT display screen position corresponding to the position information input using this trackball.

Reference numeral 60 denotes a large-capacity auxiliary storage device for storing data such as images created by the converter 58 or data collected by the data collection unit 54, such as a magnetic tesor device.
(MT), floppy disk drive (FDD)
), a bird disk device, etc. are used.

Reference numeral 61 is a line printer for obtaining a hard copy of input/output data from the computer 58 or the like.

Next, the operation of this device having the above configuration will be explained. FIG. 6 i is a diagram showing the procedure, and the process is performed in accordance with this procedure on the 01 computer 58. That is, in this apparatus, first of all, control is performed to obtain a scanogram of the photographic subject. This opening side 1 is performed by a command from the key 1 hand.

Here, the scanogram is the object A as shown in Figure 7 KA'.
This is an image that appears to have been obtained by projecting it from one direction on the pedestal.The gantry 51 is stopped at a desired rotation angle, and the X-ray source 52 continuously emits 6 X-rays while continuously moving the bed 56. The top plate is fed into the hole 51a, and at that time, the detection output obtained from the detector 53 is collected as data by the data collection unit 54, and is obtained by arranging the data in the order of movement.

FIG. 7 shows an example in which the X-ray source 52 is located directly beside the subject.

After completing the image data collection of the Scano statue
displays the scanogram obtained through this collection on a CRT display.

The operator sets desired cross-sectional positions CPa# CPb1 . . . for each slice position (or desired slice position) SaySb . . . while viewing this scanogram.

This is done by operating the keyboard and track roll, and the procedure is as follows.

1) Slice position S for future scanning on the scanogram
Specify a, Stz... with straight lines.

2) For each slice position, specify one point on the above-mentioned straight line indicating the position. This designated point is later used to determine the reconstruction center in the enlarged reconstruction processing routine.

3) The “enlarged reconstruction region” used in the enlarged reconstruction processing routine is a rectangular ROI (ROI: RegionOfInte
Specify using "region of interest specification function").

After these specifications are completed, the conbeater 58 controls the system to begin the next scan data collection operation.

This involves rotating the pedestal 5 and scanning the bed 5 in order to obtain both CT images at each slice position according to the plan created in 1) above.
6 is sequentially shifted, and data is collected via the data collection unit 54.

After data collection is completed, the conbeater 58 then moves to P in FIG.
A reconstructed image is created at the Sa and Sb positions such as ll r Pbn . . . , and then enlarged reconstruction work begins.

This work enlarges and reconstructs the tomographic image of the desired area.The collected data is enlarged and reconstructed based on the center position and enlarged area determined in the previous settings, and the PZ@
, Sa like PZb*...

Obtain an enlarged reconstructed image of Sb. As a result, a reconstructed image centered on the center position determined in the previous settings is obtained.

Next, curved surface cross section conversion processing begins. This uses the previously obtained enlarged and reconstructed image to perform cross-sectional conversion processing.

These image data have been enlarged and reconstructed focusing on the area of interest, but these images can be viewed as if they were both CT images obtained in a normal scan, and the extent of the cross-section can be compared. The direction is determined and conventional cross-section conversion processing is performed on that plane. This plane is the projection direction of the scanogram (C), but a desired direction can be specified if necessary.

The cross-sectional image thus obtained is shown in FIG. 8 as an image indicated by PC. This cross-sectional image pc is obtained by processing the above-mentioned procedure, and the cross-section s and I along the cross-sectional position S8 where the region of interest, which is the curved R, of the subject as shown by A in FIG.
It becomes an expanded image of the image of . Thereafter, the computer 58 performs a display control operation to display this cross-sectional image pc. As a result, the cross-sectional image pc obtained by performing the above-described curved cross-section conversion process is displayed on the CRT display.

Incidentally, if necessary, the above-mentioned images or the collected data and data of the scanogram are stored in the auxiliary storage device 60 so that they can be used later.

While viewing the scanogram in this way, set the center position for enlarged reconstruction of the region of interest for each slice position using a cross cursor, etc., and set the enlarged reconstruction area, and then use the mount for each slice position. CT by performing rotational scanning of
Collect data for the image, then enlarge and reconstruct the specified enlarged reconstruction area using the center position set above for these collected data as the center, and create an enlarged reconstructed image for each slice position. By extracting the data of the respective set center positions and arranging them in the order of slice positions to obtain a cross-sectional image, it is possible to obtain an image of a desired curved cross-section viewed from a desired projection direction with respect to the subject. Therefore, it is possible to obtain an image of the region of interest obtained by cutting the curved region of interest at a desired cross section along the distribution direction.

In addition, in the above example, the curved cross-section conversion was set using the scanogram, and then the curved cross-section conversion was performed, but the curved cross-section conversion can be applied in the following cases without using the scanogram. .

In other words, as shown in FIG. 9, there are multiple pieces of data for images a, to d that show continuous regions of interest R, and the cross-sectional position S for each of them can be specified using Roy et al.
As a result, the image obtained by performing cross-sectional transformation based on the table position and extracted data of each image becomes a curved cross-sectional transformed image.

The cross-sectional image obtained according to the above explanation is an expanded image of a cross-section along a desired curved curve. In addition, the cross section must be parallel to the direction of the irradiated Xm in order to obtain a scanogram.

Setting the cross section in any direction (without twisting) regardless of the direction of the X-rays can be achieved by the method described below.

Here, in order to ensure accuracy, when performing cross-sectional conversion in a CT device, the center position of each planned slice of the tissue of interest is calculated before collecting scan data of the subject.
As shown in FIG. 10, the determination can be made from scano images taken from two different directions, but in this case, it is also possible to perform the determination based on scano images taken from one direction as in the method described above. ), so that the region of interest is visible in the center of the enlarged reconstructed image after scanning. If conventional cross-sectional conversion is performed from these M19 scan images on an arbitrary plane parallel to the central axis direction line dlLX shown in FIG. 10, a cross-sectional image shown as B in FIG. 11 is obtained. When this cross-sectional image is converted in consideration of the relative position of the actual subject, an image shown by C in FIG. 11 is obtained.

The final image obtained is the curved surface Sc in Figure 12, which is obtained by cutting the tissue of interest R, which is not flat, that is, distributed in a curved manner, with a cross section that is curved to match the distribution area. It is the same as the cross-sectional image of paddy harvesting.

The example will be described below.

FIG. 13 is a flowchart showing the method 111.
Follow this line between stations. The conbeater 58 generates the i[IIl image with one hand along this line.

Carefully take a picture of Scano 1iii in a certain direction 1 (S). Next, display a scanogram in another direction 2 that is not opposite to direction 1 (1). Based on the scanogram, the position of the region of interest of the subject is determined (S3). Here, we will implement this using the following steps.

Step 1 - Center setting operator for both image display area is surface l! Start the 1-page conversion program and press C
Display the scano image according to direction 1 (2) toward the RT display. Seven points are designated as the region of interest R on this image using a track cursor. Next, the scanome 11 image in direction 2 (1) is displayed on the display. Since the "first heir" in one direction has already been determined, use the cursor Me to specify a point on the line (displayed by the f program) corresponding to that position (Fig. 10 (b)). Go back and determine all the centers.

Step 2 - Enlargement size designation A rectangle Roy is displayed on the image, and its size is freely set using Truck Beer, and is set as the size of the enlarged reconstruction area after scanning.

When this is completed, the pedestal 5 is rotated and scanned, the top plate of the bed 53 is shifted, and a scan is executed to obtain a CT image to collect data (S4).

In this method, the number of images to be photographed is determined first, the enlarged size is kept constant, and the top of the busy bed is moved so that the scan slice plane includes the center position, and the scans are performed sequentially.

Then, enlarged reconstruction (S5) is started. This enlarges and reconstructs the data collected by the above scan based on the center and enlargement size of the image display area determined in s3c (FIG. 14).

(The above would be nothing but tardado trucking.)
Next, a curved surface section conversion process (Sc) is executed.

This involves adding the following processing to the enlarged and reconstructed image data.

Processing 1 Cross-section conversion using an integral axis-parallel plane The operator performs cross-section conversion using a conventional cross-section conversion operation, with the center of the image passing through a plane parallel to the body axis.

Process 2 - Mapping to obtain the original cross-sectional image The cross-sectional image obtained in Process 1 in S6 is mapped with a mapping function determined by the plane used in Process 1 and the two scano directions, and a curved cross-section is obtained. Get the converted image.

Then, display (87) of the curved surface cross-section converted image is executed,
The cross-sectional image is displayed on a CRT display.

That is, in this embodiment, in order to obtain a cross-sectional image of a curved region of interest R of the subject shown in FIG. 12, a cross-sectional ScO image PSe set along the distribution area of the region of interest R is orthogonally projected, and An image PSe' can be obtained by orthogonal projection.

In principle, as shown in Fig. 14, enlarged reconstructed images PZaIPzb, . . . The region of interest R is placed at the center of each image, and the images are arranged in order of slice position, as shown in FIG. 11.
An image is obtained, and an image PA obtained by cutting the region of interest R at a planar cross section Sf is mapped to obtain a realistic image Pr.
restore.

That is, as shown in FIG. 15, a cross-sectional image appearing on a plane S parallel to the body axis direction y and passing through the center 0 in the enlarged and reconstructed image of the subject A shown in FIG. 11 is defined as PA.

Direct #i on PA! When position correction in the normal force direction (direction 3) with respect to H is added to the cross-sectional image, the curved cross-section transformed image Pr
is obtained.

The meanings of the symbols in the diagram are shown below.゛θI: Angle made by direction 1 and direction 3 θ2: Angle made by direction 2 and direction 3 1kl (y), E2 (y): Direction 1 component and direction 2 component (y Ao(y)'' Position correction in direction 3 (varies with y) -eo is determined by the following equation.

, 8o (y) = Al(y) co! Iθ1 +4
32 (y) Find the right side of the point where the cos θ2 center position is set, and use them to perform mapping f. Figure 16 shows this process.

In the above example, scano images obtained from two parallel directions were used as a means for determining the center position of the region of interest, but this is because the data for determining the position of the tissue is subject to cross-sectional transformation. This is an effective method if you are not advised before applying.

Therefore, when the above-mentioned data is available, it becomes possible to perform curved cross-section conversion without using two scan images, and examples thereof include the following.

■ When a CT reconstructed image has been obtained If a reconstructed image has already been obtained, image PO1 in which the region of interest (cross section) 1+ appears from multiple images as shown in Fig. 17.
,~PO4 are extracted and image-centered respectively. is specified with the cursor (cross mark in the figure), and the specified image center Ic and t
Determine the positional relationship of i. If the plane that cuts ti is specified as a straight line on one image, the slope of that straight line is used to calculate the tI of each image.
cut. From the above operations, processing S3 (not shown in FIG. 13) is performed.
This means that the curved cross-section conversion in process S6 becomes possible.

However, two or more images including ii are required.

Also, in the case of ■, if you have one scano image, use it together with the reconstructed image. It is clear that the -ti positional relationship is determined.

(2) When a tomographic image is obtained using a device other than CT, curved cross-section conversion is also possible from a tomographic image obtained from an X-ray tomography device or the like.

According to the embodiments described above, an image obtained by orthogonally projecting an image of a curved cross section of a region of interest distributed in a curved manner onto a plane can be obtained, and thus it is possible to observe an image that corresponds to reality.

The present invention is not limited to medical use, but can be fully applied to industrial and other destructive inspections, measurements, etc. Image data can be obtained by using NMR-CT (nuclear magnetic resonance- ) and positron CT.

Alternatively, it can be applied to images obtained with various devices such as ultrasound devices.

〔Effect of the invention〕

As described above, the present invention is an apparatus that obtains data of continuous cross-sectional images of a subject and generates an image of a desired cross-section that intersects with the cross-section of the subject. means for setting a desired cross-sectional position center and an enlarged reconstruction area centered on the center; and means for setting the enlarged reconstruction region centered on the set cross-sectional position center based on the data of the cross-sectional image to be examined. means for performing enlarged reconstruction processing on a region; means for obtaining, by image conversion, a cross-sectional image of a plane in a predetermined spreading direction passing through the center position of the continuous cross-sectional images of the subject configured at the enlarged angle; a means for displaying cross-sectional images obtained by setting a desired cross-sectional position center for each of successive cross-sectional images of a subject, and setting an enlarged reconstruction area centered on the center position; and areas are enlarged and reconstructed, and each enlarged reconstruction obtains an enlarged reconstruction process centered on the set center position, thereby creating a plurality of reconstructed images in which the target part is centered, respectively; From these plural reconstructed images, cross-sectional images of the region of interest distributed in a curved manner are obtained by obtaining cross-sectional images on a plane having a spread in the Qr fixed direction passing through the center. Therefore, it is now possible to obtain an image of a curved cross-section of the region of interest, which is partially interrupted in the past, without causing any interruption in the image. By orthogonally projecting the image, it is possible to provide an image conversion device that is extremely effective for diagnosis, such as making it possible to observe the cross-sectional image in an actual state.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining an example of a conventional image conversion method, Fig. 2 is a diagram showing an example of a cross-sectional view, and Fig. 3
4 is a diagram for explaining an example of the cross section and a transformed image obtained from the side, FIG. 5 is a block diagram showing an embodiment of the present invention, and FIG. 6 is a diagram of the apparatus of the present invention. 7 and 8 are diagrams illustrating and explaining the processing procedure, FIG. 9 is a diagram for explaining a modification example, and FIGS. 10 to 12 and Fig. 14 is a diagram for explaining the method for obtaining an orthogonal projection image of a desired cross section from a scanogram viewed from two directions, Fig. 13 is a flow chart thereof, and Figs. 15 and 16 are orthographic projection images. FIG. 17 is a diagram for explaining the principle of the invention, and FIG. 17 is a diagram for explaining a modification. 5 No... Frame, 52... XffM source, 53... Detector, 54... Data collection unit, 56... Bed, 57
... trestle. Bed control unit, 58... Computer, 59... Operation/display unit, 60... Auxiliary storage device. Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 (a) Figure 3 (b) (b) Figure 9 a Figure 10 (b) Figure 11 y! U Fig. 12 psc' Fig. 13 Fig. 14 1'Q Fig. 15 X = j! o(9)÷X Figure 17

Claims (2)

[Claims] (1) As a device that obtains data of continuous cross-sectional images of a subject and generates an image of a desired cross-section that intersects with the cross-section of the subject, the center of the desired cross-sectional position of the continuous cross-sectional images of the subject is set. and means for setting an enlarged reconstruction region centered at the center thereof, and enlarged reconstruction processing for the enlarged reconstruction region centered at the set cross-sectional position center based on data of the continuous cross-sectional images. means for obtaining, by image conversion, a cross-sectional image of a predetermined wide deer-facing plane passing through the center position of the continuous cross-sectional images of the subject configured at the enlarged angle, and the converted cross-sectional images. An image conversion device characterized in that the image conversion device comprises means for displaying ψ111. (2) Obtain data on continuous cross-sectional images of the object, and use this to generate images of the desired cross-section and another desired cross-section of the object. Set the center of the desired cross-sectional position of the continuous cross-sectional images of the object as a shift device. and means for setting an enlarged reconstruction area centered at the center thereof, and enlarged reconstruction of the enlarged reconstruction area centered at the set cross-sectional position center based on the data of the continuous cross-sectional images. processing means, means for image conversion to obtain a cross-sectional image of a predetermined spread deer-facing plane passing through the central position IL1 of the enlarged and reconstructed continuous cross-sectional images of the subject;
An image conversion device comprising: means for orthogonally projecting a Tnu image; and means for displaying a cross-sectional image obtained by the orthogonally projecting process.