JPS6247036B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in an imaging device that clearly captures an unclear image such as a fluoroscopic image caused by, for example, radiation (such as X-rays).

[Technical background of the invention]

Generally, transparent radiation such as X-rays is
After passing through an object, the intensity of radiation changes depending on the state of the object (thickness, uniformity, etc.). Therefore, taking advantage of these properties, X-rays are used in the industrial field for various inspections and measurements. In particular, X-rays are exclusively used in so-called non-destructive inspections (inspection of welds, etc.) in which inspection is performed without directly applying external force to the object.

By the way, in the past, fluoroscopic images of objects obtained using the transparency of X-rays had to be captured using an imaging device or the like due to the small size of the screen or the safety aspects of handling radiation. After that, the image is reproduced and a visual inspection is performed. In other words, an X-ray tube irradiates the subject with X-rays, and an image system equipped with an X-ray sensor placed behind the subject creates an image of the subject according to the intensity of the X-rays. The signal is converted into a visible light image signal using an imaging device such as a television camera, and the subject is then visually inspected using a monitor television or the like located away from the site.

[Problems with background technology]

By the way, the above-mentioned apparatus has the disadvantage that the reproduced image has a poor signal-to-noise ratio (clearness of the target signal) due to the sensitivity of the X-ray sensor and the insufficient output of the X-ray tube. It is very difficult to identify small defects. In such cases, adding video signals to improve the signal-to-noise ratio is often used, but this is limited to when the subject is stationary; when imaging a moving subject in a factory process, etc. There is a problem that the addition cannot be performed properly due to the discrepancy caused by the

[Purpose of the invention]

According to the present invention, for example, when a moving subject is examined using a radiographic fluoroscopic image, the unclear fluoroscopic image can be captured as an image with sufficient contrast. The purpose is to provide an imaging device.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention provides two image memories that alternately store image signals outputted from the imaging unit and which have a frame-by-frame shift due to the movement of the subject, and specifies a specific image from one of the two image memories. A partial image is extracted, this specific partial image is compared with each partial image of the image in the other image memory, and a matching or very similar partial image is selected. Calculating the amount of image shift by a means for calculating a difference, and correcting the amount of shift to one of the images in both image memories,
The imaging device aims to improve the contrast by adding the images in both image memories.

[Embodiments of the invention]

An embodiment of the present invention is shown in the configuration diagram of FIG. 1, and will be described. 1 is an X-ray tube that outputs X-rays, and a subject 2 to be fluoroscopically inspected is moving in the direction of the arrow in the X-ray output direction of this X-ray tube 1. An image system 3 is placed so as to face the X-ray tube 1 with the subject 2 in between. This image system 3 is composed of an X-ray sensor, a phosphor, an amplifier, etc., and projects a fluoroscopic image of the subject 2. This perspective image is captured by a camera in a television camera control unit 4 (hereinafter referred to as TVCCU) and output as an image signal for each frame.
Two image memories 5 and 6 are used to convert this image signal into a digital image signal and store it.
They are installed in parallel at the rear of TVCCU4. Further, a channel selector 7 is provided which alternately reads out the images stored in the image memories 5 and 6 by a predetermined operation. An image shift detection circuit 9 stores an image of a specified portion in a specific partial image memory 8, and compares the image read out from the image memory 6 with the image stored in the specific partial image memory 8. It is provided. An adder 10 is provided which adds the images in the image memories 5 and 6 and stores the result in the image memory 5 based on the amount of deviation obtained from the comparison result of the image deviation detection circuit 9. 11 is a monitor television that reproduces images based on the added image data of the image memory 5; 12 is an output terminal for directly taking out the added image data; and an automatic defect determination circuit (not shown) is connected to this. etc. are connected. Further, 13 is a central processing unit that controls the image memories 5 and 6, the channel selector 7, the image shift detection circuit 9, and the adder 10.

Next, the operation of the apparatus configured as described above will be explained with reference to the seam (weld line) sectional view in FIG. 2 and the specific partial image in FIG. 3.

A fluoroscopic image of the subject 2 having a seam cross section as shown in FIG. In addition, in the figure, 20 indicates a seam, 21 indicates a defective portion, and 22 indicates a subject body. Therefore, the video created by the image system 3 is converted into an image signal by the TVCCU 4. This image signal is first sent to the image memory 5,
The next image signals are stored alternately in the image memory 6, but since the subject 2 is moving, the images stored in both image memories 5 and 6 may have deviations even if they are of the same subject 2. There is. This deviation is determined by how many frames the image signals of the camera of the TVCCU 4 are stored in the image memories 5 and 6 in accordance with the moving speed of the subject 2. Therefore, the image shift in both image line memories 5 and 6 is usually a shift of one frame period, but in some cases it may be a shift of an integer multiple of one frame period.

Next, the channel selector 7 selects the image memory 5 and inputs the image A as shown in FIG. In this image shift detection circuit 9, the readout position SA of the input image A is
An image 23A of a specific part of the subject 2 having the image is extracted and stored in the specific part image memory 8.

Next, the channel selector 7 selects the image memory 6, reads out the image B which is shifted from the image A in the image memory 5 due to the movement of the subject 2, and inputs it to the image shift detection circuit 9. The image shift detection circuit 9 cuts out the image B in the image memory 6 to create a partial image, and compares this partial image with the image 23A stored in the specific partial image memory 8. Then, when both partial images match or are most similar,
From the read position SB of the image 23B cut out from the image memory 6, the amount of deviation SA-SB between the partial images 23A and 23B is calculated. As a result, the amount of deviation between the image memories 5 and 6 caused by the movement of the subject 2 is determined. Then, this amount of deviation is calculated by the adder 1
Input to 0. The adder 10 reads from the image memory 6 an image shifted in the opposite direction to the moving direction of the subject 2 by the input shift amount, and further reads the image from the image memory 6.
An image is read out from , the two images are added, and the added image is stored in the image memory 5 again. This stored added image data is displayed on the monitor television 11.
If the image is reproduced in , the defective portions 21A and 21B will be added to the image, and the defective portion 21 of the subject 2 can be visually inspected with an image with improved contrast. Also,
Similarly, image data with improved contrast is obtained at the output end 12, and subsequent processing can be performed accurately.
Note that the shaded areas 20A and 20B in FIG.
The seam 20 in the figure is shown.

In addition, the central processing unit 13 controls the timing of each part of the device, and also controls the overall operation, such as extracting a specific partial image of a new image for the next addition after completion of addition, and specifying the number of additions. do.

Note that when extracting images of specific parts in cases such as welding inspections, if the specific part is a complex-shaped part such as the seam of a weld as in the above embodiment, the amount of image signals will be significantly larger than other parts. Of course, this is convenient for tracking specific parts.

〔Effect of the invention〕

According to the present invention, the amount of deviation between the two images is electronically detected based on the images stored in the two image memories, and the images are added after applying correction corresponding to the amount of deviation. When a moving subject is imaged using radiation, the contrast of the unclear image can be easily improved, and small defects in the subject can be easily discovered.

Furthermore, since the amount of deviation is detected electronically, images can be added more accurately than when the amount of deviation is mechanically detected from the moving speed of the subject. Therefore, it is possible to provide an imaging device that can produce clearer reproduced images.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of an imaging device according to the present invention, FIG. 2 is a seam sectional view of a subject, and FIG. 3 is an image diagram illustrating a specific partial image in the device configured as in FIG. 1. . 4...TVCCU, 5,6...image memory, 7...
... Channel selector, 8 ... Specific partial image memory, 9 ... Image shift detection circuit, 10 ... Adder,
13...Central processing unit.

Claims (1)

[Claims] 1. An imaging unit that images a subject and outputs an image signal for each frame, a plurality of image memories that sequentially store the image signals of this imaging unit with a difference in predetermined frame periods, and selectively reads images stored in these image memories. a selection means for extracting a specific partial image of the image read from one image memory by the selection means, and comparing the partial image of the image read from the other image memory with the specific partial image; means for outputting the amount of image shift stored in the image memory;
an adder that shifts the images in the image memory that have been collated in accordance with the amount of image shift outputted by this means, matches the images, and adds the images; An imaging device characterized by the ability to