JPS58221932A - Image input apparatus - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image input device used for inputting, for example, an X-ray image obtained based on X-ray exposure to an image processing device.

[Technical background of the invention and its problems]

For example, as a diagnostic method for the human circulatory system, a catheter is inserted into the heart or blood vessels, a contrast agent is injected into the blood through the catheter, and the subsequent flow of the contrast agent is tracked and photographed using an X-ray imaging device. Contrast techniques are known φ. Then, various types of image processing are performed using computers etc. based on the taken X-ray images.
At this time, a method (digitization) for temporarily converting the 1X-ray image into digital data is required. As shown in Fig. 1, this digitization involves amplifying the density information of the target X-ray image 1 with an amplifier 2, and digitizing it with a converter 6. After processing in step 4, the data is stored in an external storage device (magnetic disk, etc.).

Generally, when observing a target site into which a contrast medium has been injected, its position and size within the entire image are greatly influenced by imaging conditions. Therefore, if the entire image is simply digitized uniformly, the size of the target area on the screen will be different as shown in Figures A, B, and C, or the accuracy of the data regarding the target area will change depending on the imaging conditions. This will greatly affect the calculation accuracy of subsequent analysis processing. To solve such problems, K.
One possible method is to change the imaging conditions in consideration of the position and size of the target region in the entire image, and perform digitization centered on the target region, thereby obtaining data that is always normalized in terms of accuracy.

However, the task of having the photographer intuitively determine the position and size of the target area in the X-ray image and change the imaging conditions accordingly results in a lot of time loss and increases the number of images. It gets trapped and expands. Particularly when processing is done online, trapping poses a major problem of increased X-ray exposure.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an image input device that can accurately and quickly digitize a target part of an original image. be.

[Summary of the invention]

In order to achieve the above object, the present invention automatically selects and extracts a region of interest corresponding to a target part from the original image when digitizing the original image, and converts the information of that part into digital data with high accuracy. It is characterized by the following.

[Embodiments of the invention]

The present invention will be specifically explained below using Examples.

FIG. 2 is a block diagram showing one embodiment of the present invention. In the same figure, 6 is an original image collection device that collects an original image, for example, a difference image (subtraction image) between a mask image obtained by an X-ray imaging device and an image after contrast agent injection;
7 is a region of interest extraction device that extracts image data in a region of interest including the target region from the subtraction image;
8 is a converter that converts analog data into digital data, and 9 is a processing control unit (also referred to as CpU) that controls the operation of each of the devices.

Next, the operation of the above device will be explained with reference to FIGS. 6 to 5. In the so-called cardiovascular angiography method, which generally involves inserting a catheter into the heart or blood vessels, injecting a contrast medium into the blood vessels through the catheter, and observing the flow of the contrast medium with an X-ray imaging device, during X-ray photography, A test is performed once or twice to confirm whether the contrast medium has been injected into the target area. In the present invention, during this test, the original image collecting device 6
In this case, as shown in Fig. 3, image 11 before contrast medium injection is obtained.
The difference between the image 12 and the image 12 after the injection of the contrast medium is determined (subtraction), and a difference image (subtraction image) 16 is obtained.

As a result, since there is no contrast agent in the area 13.14, no image appears, and the target area 15#'' - the effective pressure of the contrast agent [
Appears as an image.

Next, the region of interest extraction device 7 operates according to a control signal from the CpU 9, selects the position of the target region 15 in the subtraction image 16, and selects the position of the target region 15 in the subtraction image 16,
) and the minimum (XMIN ) and the maximum (Y
MAX) and minimum (YMIN) are calculated, and an area 17 surrounded by these coordinate data is determined.

In order to ensure that the ridge includes the target part 15,
Region of Interest 1 by adding predetermined widths ΔX and ΔY in each direction of the Y-axis
8 and extract the data therein.

At this time, ΔX and ΔY can be changed depending on the properties of the target site.

The region of interest image 18 thus extracted is subjected to processing as shown in FIG. That is, in CpU9, the following formula (1)
, (2+) to determine sampling dX, d, 7 in the X and Y directions.

Here, xw and yw are the width in the X-axis direction and the width in the Y-axis direction of the region of interest image 18, respectively, and N is the total number of sampling clocks.

Then, while reading the information based on the sampling, it is sequentially converted into digital data by the converter 8 and stored in a recording device (not shown) via the CPU 9.

The above operating procedure is shown in the flowchart of FIG.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide an image input device that can accurately and quickly digitize a target part in an original image. It becomes suitable for
If the radiation exposure dose can be reduced, there will be excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional image input device.
FIG. 2 is a block diagram of an image input device that is an embodiment of the present invention, FIG. 3 is an explanatory diagram of the operation of extracting a region of interest image by the inventive device, and FIG. 4 is an explanatory diagram of the conversion operation of the image by the present inventive device. , FIG. 5 is a flowchart for explaining the operation of the apparatus of the present invention. 6... Original image collection device, 7... Region of interest extraction device, 8... Le converter, 9... Processing control device. Agent: Patent Attorney Noriyuki Chika (and 1 other person) Figure 4

Claims (1)

[Claims] In an image input device that converts an original image obtained by an image acquisition device into digital data and inputs it to a recording device, a region of interest that includes a target part in the original image is set and image data within that region is extracted. An image input device comprising: a region extracting means; and a control section controlling the extracting means.