JPH0128993B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention efficiently extracts information regarding fluctuations in a moving part, such as the heart, from a series of digital images taken of that part, and extracts processing results. The present invention relates to a moving image processing device that displays images in an easy-to-understand manner.

[Technical background of the invention and its problems]

For example, as a method of processing and displaying a digital image series that captures a moving part such as the heart, the memory area of the image output device is divided into equal parts as shown in Figure 1, and each divided area is There is a method of superimposing processing results (for example, boundary point information) regarding images at each time on an input grayscale image using color information. However, according to this method, in order to recognize the difference between two images, it is necessary to compare and observe each, and the recognition is also difficult and inaccurate.

As a means for solving the above drawbacks, there is a method, as shown in FIG. 2, in which the processing results of two images of the same region taken at different times are displayed in a superimposed manner on one image. According to this method, for example t ₀
By displaying the image at t1 in red and the image at _t1 in blue, it is possible to recognize the boundary point information at each time.

However, when the diagnosis target is information on changes in boundary points between times rather than information on boundary points at each time, in other words, which parts of the body part are stationary and which parts are changing. If you want to recognize whether or how it has changed,
It is difficult to recognize the results displayed by the above method.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a moving image processing device that can clearly display information on changes in boundary points between time points for moving images. be.

[Summary of the invention]

The outline of this invention for achieving the above object is as follows:
An image memory that stores at least two temporally different images of moving parts as digital values, and a difference image creation system that creates a difference image between these two types of images and outputs it as a variable area. a first spatially differential image creating means for applying a spatially differential filter to an image from one of the image memories to create a spatially differentiated image; A second method for creating a spatially differentiated image by applying a spatially differential filter only to the variable region that is the output of the image creating means.
and the spatial differential values of the spatially differential images from the first and second spatially differential image generating means, and the boundary points of the stationary part and the boundary points before and after the fluctuation of the variable part from the fluctuation area. The present invention is characterized by comprising a boundary point extraction means for extracting the.

[Embodiments of the invention]

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

First, the principle of this invention will be explained with reference to FIG. Normally, the grayscale values of a region of interest are rarely at the same level over the entire region, and even between images of the same region taken at different times,
In many cases, the gradation value changes somewhat. but,
For example, in medical images, parts other than the part of interest are often captured in the image. At this time, the region of interest is usually photographed so that the contrast with the background (area other than the region of interest in the image) is strong. Therefore, in the difference image (shown in Figure 3c) obtained by calculating the difference between each corresponding image of two gray scale images (shown in Figure 3a and b) that capture the variation of the body part,
An area that is a set of images in which the absolute value of the difference value is large is considered to be an area through which the boundary of the body part has passed. This area is called a variation area A. On the fluctuation area A, there are boundary points before the fluctuation and boundary points after the fluctuation. According to this property, (a) a boundary point that fluctuates within the region, (b) a boundary point after the fluctuation of a boundary point that fluctuates within the region, and (c) a boundary point that remains stationary during the region are extracted. (B) is a point that is on the variation region A and has a high spatial differential value in the first image, (B) is a point that is on the variation region A and has a high spatial differential value in the last image, and (C) is a point that is on the variation region A and has a high spatial differential value in the last image. Although the differential value is high, this point is not on the fluctuation region A. In this way, by extracting the boundary points before and after the change in the changing part and the boundary points of the stationary part and displaying them, for example, in different colors, it is attempted to obtain the change information of the boundary points.

Next, an embodiment of the present invention based on the above principle will be described with reference to FIGS. 4 and 5. FIG. 4 is a block diagram of a moving image processing apparatus which is an embodiment of the present invention. In FIG. 4, an original image collection device 1 collects images taken by, for example, an X-ray imaging device. The A/D converter 2 converts analog data from the original image acquisition device 1 into digital data. This digital data is stored in the image memories 4 and 5 at each time under the control of the selector channel 3. The difference image creation device 6 is for taking the difference between the images in the image memories 4 and 5 and finding the above-mentioned variation area. The first spatially differentiated image creating device 7 inputs the image stored in the image memory 4 and creates a spatially differentiated image by applying a spatially differentiated filter over the entire screen. A second spatially differential image creating device 8 inputs the image stored in the image memory 5, and applies a spatially differential filter only to the variable region of this image, which is the output of the differential image creating device, to create a spatially differential image. Create a differential image. The boundary point extraction device 9 extracts the boundary points of the stationary part and the fluctuation region based on the outputs of the first and second spatial differential image creation devices 7 and 8 and the fluctuation region that is the output of the difference image creation device 6. The boundary points before and after the change in the area are extracted. The image display device 10 divides the three types of extraction information output from the boundary point extraction device 9 into individual color information, and stores the information in the image memory 4.
Alternatively, it is displayed superimposed on the image stored in the image memory 5. Although not shown, the flow of operations in each of the devices is controlled by the CPU.

The operation of the moving image processing apparatus configured as described above will be explained with reference to FIG. 5.
FIG. 5 is a schematic diagram for explaining the operation.

The image data collected by the original image collection device 1 at time t ₀ for a predetermined moving part to be photographed is as follows:
The image is digitized by the A/D converter 2 and stored in the image memory 4 as an image 11 under the control of the selector channel 3. Similarly, the image 12 at time _t1 is stored in the image memory 5. These two images 11 and 12 are input to the difference image creation device 6, and a difference is performed for each corresponding pixel of the images.
A difference image 13 (an image with high pixel values in the variation region) is created. On the other hand, the image 11 stored in the image memory 4 is also input to the first spatial differential image creation device 7, where a spatial differential filter is applied over the entire screen to create a spatial differential image. 14 is created. Furthermore, the image 12 stored in the image memory 5 is also input to the second spatial differential image creation device 8. here,
A spatial differential filter is applied to the image 12 only within the high pixel value region of the difference image 13, that is, within the fluctuation region, to create a spatial differential image 15. Next, the boundary point extraction device 9 extracts the first and second
Based on the outputs of the spatial differential image creation devices 7 and 8 and the output of the differential image creation device 6, the boundary points of the stationary portion and the boundary points before and after the fluctuation of the fluctuation portion are extracted. That is, points with high spatial differential values are determined for the spatially differentiated image 14, and points that do not exist on the fluctuation region are determined as boundary points of the stationary portion, and points that exist on the fluctuation region are determined as boundary points before fluctuation of the fluctuation portion. Extract. or,
For the spatially differentiated image 15, a spatially differentiated value on the fluctuation region is determined, and this is determined as a boundary point after the fluctuation of the fluctuation portion. Therefore, as the output of the boundary point extraction device 9, three types of boundary points are obtained as shown in the illustrated image 16. The display device 10 allocates individual color information to each of these three types of boundary points, and
This is superimposed on the image 11, and the display image 17 is displayed at a predetermined dividing position on the image display device 10.
With this display, it is possible to clearly determine which part of the imaged region has changed and which part has remained stationary between consecutive times.

Next, when obtaining fluctuation information in the image between time t ₁ and time t ₂ , the image 1 is stored in the image memory 4.
Image 19 at time t ₂ is stored instead of image 1 at time t 2 . Thereafter, by performing similar processing, a display image 23 with clear variation information can be obtained. Note that image 20 shows a difference image between times t ₁ and t ₂ , image 21 shows a spatial differential image of image 19 , and image 22 shows an extracted display of variation information over times t ₁ and t ₂ . In this way, in the second and subsequent moving image processing, digital images are stored alternately in the image memories 4 and 5, and a spatial differential image is created only for the newly stored image, and the previously created spatial differential image is What is necessary is to process it with the differential image. Then, by displaying the processing results at each time on each divided plane on the display device 10, it is possible to clearly see which parts of the imaged region have changed and which parts have remained stationary at each successive time interval. can be recognized.

It goes without saying that the present invention is not limited to the embodiments described above, and includes various modifications within the scope of the gist of the invention. For example, the present invention can be used to detect the volume of a moving part such as the heart at each time. This will be explained with reference to FIG. In FIG. 6, images 17 and 23 are images obtained as a result of processing by the moving image processing device, that is, images 17 and 2 shown in FIG.
The same image as 3 is shown. First, from the image 17, the boundary line of the stationary part and the boundary line before the fluctuation of the fluctuating part are extracted, and the boundary line 2 of the heart at time t ₀ is extracted.
Display 4. Then, by searching on the single closed curve as this boundary line 24, time t ₀
It is possible to calculate the volume of the heart at . Next, to calculate the volume of the heart at time t ₁ ,
First, the boundary line before the change in the boundary line 24 is
Boundary line 2 by replacing it with the changed boundary line
Extract and display 5. This boundary line 25 is the boundary line of the heart at time _t1 . Therefore, the volume of the heart can be easily calculated from this boundary line 25. Thereafter, by performing similar operations, the volume of the heart after time _t2 can be calculated by using the boundary line of the stationary part as it is and sequentially replacing the boundary line of the fluctuating part.

As described above, if this invention is applied to automatic detection of the volume of the heart, etc., detection accuracy will be improved by searching on clearly displayed boundary lines, and when detecting the volume at different times, the detection accuracy will be improved. Since it is only necessary to replace the boundary line, processing time can also be shortened.

〔Effect of the invention〕

As explained above, according to the present invention, by processing two types of temporally different images of moving parts, the boundary line of the stationary part and the boundary line before and after the fluctuation of the changing part between time points can be determined. A moving image processing device that can display images clearly can be provided. Therefore, it is possible to easily recognize which parts have changed and how they have changed over time, and furthermore, if this invention is applied to automatic volume detection, it is possible to improve accuracy and shorten processing time. can.

[Brief explanation of drawings]

1 and 2 are schematic explanatory diagrams showing the display of processing results in a conventional moving image processing device, and FIG. 3a,
b, c are schematic explanatory diagrams for explaining the principle of this invention, FIG. 4 is a block diagram showing a moving image processing device which is an embodiment of this invention, and FIG. 5 is a moving image processing shown in FIG. 4. FIG. 6 is a schematic explanatory diagram for explaining the operation of the apparatus. FIG. 6 is a schematic explanatory diagram for explaining the operation when the present invention is applied to an apparatus for automatically detecting the volume of a heart or the like. 1...Original image collection device, 2...A/D converter,
3...Selector channel, 4, 5...Image memory, 6...Differential image creation device, 7...First spatial differential image creation device, 8...Second spatial differential image creation device, 9...Boundary Point extraction device, 10... image display device.

Claims (1)

[Claims] 1. An image memory that stores at least two temporally different images of a moving part as digital values, and a differential image that creates a differential image between these two types of images and outputs this as a variable area. a first spatially differentiated image creating means for applying a spatially differential filter to an image from one of the image memories to create a spatially differentiated image;
a second spatial differential image creating means for creating a spatially differential image by applying a spatial differential filter only to the variation region output from the difference image creating means; and a spatial differential image from the first and second spatially differential image creating means. A moving image processing device comprising: a boundary point extracting means for extracting a boundary point of a stationary portion and a boundary point before and after a fluctuation of a changing portion from a spatial differential value of an image and the fluctuation region.