JPH07222058A - X-ray television receiver - Google Patents

Abstract

PURPOSE:To improve the resolution of an image by eliminating a non-use area produced on an image receiving face of a TV camera. CONSTITUTION:An image intensifier 30 has a couple of parallel electrodes 36 arranged at the outside of electrodes 33, 34 forming an electronic lens system in the horizontal or vertical direction, the electrodes 36 forms the electric field distribution in an image face direction not to be symmetrical around a center axis, resulting that, a circular image corresponding to a shape of an input fluorescent screen 31 is converted into an elliptic image.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray TV apparatus that uses a fluoroscopic image as an image signal on a TV system.

[0002]

2. Description of the Related Art In an X-ray TV apparatus, a subject (examinee)
X-rays are radiated to the image intensifier, the transmitted X-rays are made incident on the image intensifier, the X-ray image is converted into an optical image, and the output image is guided to a TV camera by an optical system and converted into an image signal. Then, by sending this image signal to an image display device (monitor device) and displaying it, the X-ray fluoroscopic image can be observed in real time, or the image signal is recorded, and various image processing is performed. Or

In the conventional X-ray TV apparatus, the ratio of the scale of the input X-ray image in the vertical direction to the horizontal direction (1: 1) is maintained as it is and then output from the image intensifier. Further, the aspect ratio is maintained even in the optical system, and the aspect ratio is maintained as it is on the image signal obtained by the TV camera. That is, the ratio of the vertical scale to the horizontal scale of the image is consistently maintained at 1: 1 from input to output (display).

Here, even in the X-ray TV apparatus, a general-purpose TV camera has to be used because of the manufacturing cost. However, a general-purpose TV camera has a solid-state image sensor (CCD) instead of a camera tube. We are moving to the one we used. The aspect ratio of the image receiving surface of the TV camera using this solid-state image pickup device is for a normal TV system, and the aspect ratio is horizontal 4: 3, high-definition TV
V) For a system, the width is 16: 9 and the width is rectangular in any case.

However, in the image intensifier, both the input surface and the output surface are circular, and the aspect ratio of the screen is 1: 1. Therefore, if it is assumed that a general-purpose TV camera is used, portions on both sides in the horizontal direction of the image receiving surface of the TV camera will be unused areas, resulting in waste.

Therefore, conventionally, it has been considered that the unused area generated on the image receiving surface of the TV camera is eliminated to eliminate waste and the image resolution is improved by positively using the area. . There, the aspect ratio of the circular image output from the image intensifier is changed to an elliptic image whose major axis / minor axis ratio corresponds to the aspect ratio of the image receiving surface of the TV camera. Using an optical system, let this deformed image enter the TV camera,
The signal of the deformed image is obtained from this TV camera, and the image signal is processed later to restore the vertical / horizontal scale ratio of the image to the original 1: 1 relationship.

[0007]

However, when changing the ratio of the vertical scale and the horizontal scale of the image in the optical system as in the conventional case, a special optical system must be used. There is a problem that the lens design is difficult, and it is not possible to easily cope with a change in the aspect ratio of the image receiving surface of the TV camera.

[0008] In view of the above, the present invention eliminates the unused area generated on the image receiving surface of the TV camera, eliminates waste, and improves the image resolution while avoiding the trouble of changing the optical system. It is an object to provide an X-ray TV device.

[0009]

In order to achieve the above object, in an X-ray TV apparatus according to the present invention, an X-ray generator for irradiating a subject with X-rays and an X-ray input through the subject. An image intensifier that outputs an image as an optical image after changing the scale ratio in the vertical and horizontal directions, and an optical system that transmits an output image of the image intensifier, are transmitted. A TV camera for converting an image into an image signal, and changing the ratio of the vertical and horizontal scales of the image in the image signal so as to restore the ratio of the vertical and horizontal scales of the original X-ray image. It is characterized by including a conversion device.

Here, the above-mentioned image intensifier may be an ordinary one additionally provided with an electrode for changing the electric field distribution in the image plane direction.
Further, instead of newly providing an electrode as described above, the existing electrode forming the electron lens system may be changed from a cylindrical shape having a perfect circular cross section to a cylindrical shape having an elliptical cross section. In addition, the existing cylindrical electrode with a perfect cross section,
The electric field distribution in the image plane direction may be changed by dividing in the image plane direction, that is, in the circumferential direction and applying different voltages.

Further, in the image signal obtained from the TV camera, the ratio of the vertical scale and the horizontal scale of the image is changed to be converted back to the original vertical scale ratio of the X-ray image. As the device, a video circuit in the camera control unit can be used, or a signal processing device can be used separately. Also,
In the image display device, by changing the inclination of the vertical deflection signal (sawtooth wave) and the horizontal deflection signal (sawtooth wave) of the picture tube,
The ratio of the vertical and horizontal scales of the displayed image may be changed.

[0012]

The ratio between the vertical scale and the horizontal scale of the X-ray image input to the image intensifier is
Changed in this image intensifier. That is, if the ratio of the vertical scale to the horizontal scale of the original X-ray image is 1: 1, this is changed and converted to another ratio (for example, 3: 4). Therefore, the circular image of the input surface of the image intensifier is converted into an elliptical image. The major axis / minor axis ratio of this ellipse is converted to the horizontal / vertical direction of the image receiving surface of the TV camera. If the conversion ratio of the above scale ratio is determined so as to correspond to the ratio, the image receiving surface can be used without waste.
The image represented by the image signal obtained from the TV camera is as if the original X-ray image was stretched in the vertical or horizontal direction, so that it is returned to the original scale ratio by the conversion device. Therefore, it is possible to display an image with increased resolution in the expanded direction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the drawings. In FIG. 1, X
The X-ray beam 11 is emitted from the X-ray tube 10 toward the subject 20. The X-ray beam that has passed through the subject 20 enters the input phosphor screen 31 of the image intensifier 30. The image intensifier 30 has an input phosphor screen 31, a photocathode 32, an accelerating and focusing electrode 33, an anode 34, and an output phosphor screen 35 arranged in a vacuum envelope. .

In this embodiment, the image intensifier 30 includes electrodes 33 and 3 which form these electron lens systems.
4 has a pair of parallel electrodes 36 arranged in the horizontal direction or the vertical direction on the outer side (or an appropriate place such as the inner side). The input phosphor screen 31 and the photocathode 32 are circular. Further, the electrodes 33 and 34 have a generally circular cross section when cross-sectioned in a plane (image plane) orthogonal to the central axis of the electron beam, and the photocathode 3 is different from the photocathode 32.
The farther the distance from 2, the higher the positive high voltage is applied. The parallel electrode 36 is applied with a positive potential higher or lower than the peripheral electrode 33 so that the electric field distribution in the image plane direction is not symmetrical about the central axis. Therefore, a circular image corresponding to the shapes of the input phosphor screen 31 and the photocathode 32 is converted into an elliptical image due to the asymmetric electric field distribution. This elliptical image appears on the output phosphor screen 35.

The elliptical image output from the output phosphor screen 35 in this manner is an optical system 4 constructed by combining lenses.
0 forms an image on the solid-state image sensor 51 of the TV camera 50. Since the solid-state imaging device 51 has a rectangular shape with a horizontal / vertical ratio of 4: 3 or 16: 9, the major axis / minor axis ratio of the input elliptical image corresponds to that ratio. Is being done. That is, the image intensifier 30 is set so that the major axis / minor axis ratio of the elliptical image output from the image intensifier 30 corresponds to the horizontal / vertical ratio of the rectangular image receiving surface of the solid-state imaging device 51. The degree of deformation at is adjusted. This adjustment is performed by adjusting the potential applied to the parallel electrode 36.

An image signal representing an elliptical image output from the TV camera 50 is input to the camera control unit 60. In this embodiment, in the camera control unit 60, the ratio of the vertical scale and the horizontal scale of the image represented by the image signal is the original 1 :.
It has a video circuit that performs signal conversion such that the relationship of 1 is satisfied, that is, an elliptical image becomes a perfect circle image. Therefore, this camera control unit 6
In the image signal output from 0, the ratio between the vertical scale and the horizontal scale of the X image incident on the input phosphor screen 31 of the image intensifier 30 is reproduced. This image signal is sent to the TV monitor device 70,
The image is displayed. As a result, the display image is a reproduction of the input X-ray image of the image intensifier 30 without vertical and horizontal distortion.

That is, as shown in FIG. 2, the circular image 81 corresponding to the circular input phosphor screen 31 of the image intensifier 30 should appear on the output phosphor screen 35 of the image intensifier 30. Due to the anisotropy of the electric field distribution due to the electrodes 36, an elliptical image 82 stretched in the lateral direction appears, and the major axis / minor axis ratio of this elliptical image 82 is the rectangular image receiving surface 83 of the solid-state image sensor 51. Since the aspect ratio corresponds to the aspect ratio, the elliptical image 82 appears on the entire rectangular image receiving surface 83.
As a result, image intensifier 3
When the circular image 81 is output from 0, the shaded area 84
It is possible to improve the fact that is not used and is wasted, and it is possible to eliminate the wasted area 84. Moreover, the circular image 81
Is expanded into an elliptical image and then input to the rectangular image receiving surface 83 of the solid-state image sensor 51, so that the resolution in the expanded direction (here, the lateral direction) can be improved. Since the action of the parallel electrode 36 is such,
It does not necessarily have to be arranged geometrically in parallel, but it is because the electric field distributions in the respective directions corresponding to the vertical and horizontal directions of the rectangular image receiving surface 83 of the solid-state imaging device 51 are made different. , Must be placed in one direction, corresponding to its vertical or horizontal direction.

In the above embodiment, parallel electrodes for changing the electric field distribution in the image plane direction are newly provided in the electrode structure of the normal image intensifier.
Instead of newly providing electrodes in this way, the existing electrodes 33 and 34 forming the electron lens system may be changed from a cylindrical shape having a perfect circular cross section to a cylindrical shape having an elliptical cross section. Furthermore, by dividing the existing cylindrical electrodes 33, 34 having a perfect circular cross section in the image plane direction, that is, in the circumferential direction, and applying different voltages,
The electric field distribution in the image plane direction may be changed.

Further, in the camera control unit 60, the scale ratio in the vertical direction and the horizontal direction of the image is changed with respect to the image signal obtained from the TV camera 50. Of course, a signal processing device (not shown) is separately provided. This can be done using the TV monitor 7 as well.
At 0, the inclination of the vertical deflection signal (sawtooth wave) and the horizontal deflection signal (sawtooth wave) of the picture tube may be changed to change the ratio of the vertical and horizontal scales of the displayed image.

[0020]

As described in the above embodiments, according to the X-ray TV apparatus of the present invention, the unused area generated on the image receiving surface of the TV camera is eliminated, waste is eliminated, and the image resolution is improved. be able to. Moreover, the ratio of the vertical scale to the horizontal scale of the input X-ray image can be calculated by the TV.
It is also easy to adjust according to the aspect ratio of the image receiving surface of the camera.

[Brief description of drawings]

FIG. 1 is a schematic view of an embodiment of the present invention.

FIG. 2 is a diagram showing an image in each part.

[Explanation of symbols]

 10 X-ray tube 11 X-ray beam 20 Subject 30 Image intensifier 31 Input phosphor screen 32 Photocathode 33 Accelerating and focusing electrode 34 Anode 35 Output phosphor screen 36 Parallel electrode 40 Optical system 50 TV camera 51 Solid-state image sensor 60 Camera control unit 70 TV monitor

Claims (1)

[Claims] 1. An X-ray generator for irradiating a subject with X-rays, and an X-ray image input through the subject is changed optically by changing the scale ratio in the vertical and horizontal directions. An image intensifier that outputs as an image,
An optical system for transmitting the output image of the image intensifier, a TV camera for converting the transmitted image into an image signal, and an original image by changing the scale ratio of the image in the vertical direction and the horizontal direction in the image signal. An X-ray TV apparatus, comprising: a conversion device that converts the X-ray image so as to return to a ratio of vertical and horizontal scales.