JPH08247852A - Infrared-ray image processing device which can photograph rotary body - Google Patents

Abstract

PURPOSE: To provide a device which can photograph a rotary image rotating at a random rotational frequency by using the thermography. CONSTITUTION: Subject to the output of a rotary position signal 22 to detect that a rotary body is positioned at a preset specific position only when the rotary body is positioned at the specific position when a line scanning in the horizontal direction is started, an image data 21 output by an infrared-ray receiving element 9 to convert an injection light 2 including the partial image of a subject 1 into the image data 21 to be an electric signal, is processed by an image processing device 15. When the rotary body is not positioned at the specific position when a line scanning in the horizontal direction is started, the image data obtained by injecting to an infrared-ray detector is not processed. By repeating such an operation, a still infrared-ray image of the whole body of the subject to be the rotary body can be obtained.

Description

Detailed Description of the Invention

[0101]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus utilizing infrared rays (hereinafter referred to as "thermography") for photographing an object rotating about a specific axis as a subject.

[0101]

2. Description of the Related Art Thermography obtains an infrared image of an object by subjecting infrared rays emitted from the object to image processing, and the image is widely used to examine the distribution state of the object such as temperature and stress. . Thermography is a scanning mirror that rotates or oscillates at a constant cycle around an axis having both ends of the axis in a direction orthogonal to the direction in the camera in order to perform line scanning in one direction of the subject, and orthogonal to the direction. In order to scan the scanning direction, there is another scanning mirror inside the camera that can rotate by a minute angle about an axis with both ends of the axis oriented in one direction. When the camera is installed in a normal state, it is often set such that one direction is horizontal and the direction orthogonal thereto is vertical. In a camera having such a structure, a scanning mirror provided for scanning in one direction is called a horizontal scanning mirror, and a scanning mirror provided for scanning in another axis is called a vertical scanning mirror.

One of the directions mentioned here is horizontal, and
The direction orthogonal to this is not specified as the vertical direction, but in order to simplify the description, in the following description, line scanning in one direction is horizontal scanning, and the scanning mirror that performs the scanning is horizontal. It is named a scanning mirror, and scanning in a direction intersecting at right angles with one direction is called vertical scanning, and a scanning mirror that performs the scanning is named a vertical scanning mirror.

When the thermography captures and records an object, first, a horizontal scanning mirror is line-scanned in the horizontal direction near the edge of the object to be photographed to detect an infrared partial image of one scanning line. The infrared rays thus made incident are sequentially image-processed by a known method to obtain partial image information of one line of infrared rays. Then, after the vertical scanning mirror is slightly rotated in the direction of the central portion of the subject, partial image information for the next one line in the horizontal direction is obtained by the same method. In this way, by rotating both scanning mirrors, infrared rays emitted from each part of the subject are sequentially image-processed to obtain an image of the entire subject.

[0004]

The wavelength range of infrared rays detected by thermography is the mid-infrared area or the far-infrared area. The sensitivity of the light receiving element used in such a wavelength range is far lower than that of the light receiving element in the visible range, and the response speed is extremely slow. In addition, the line scanning of the scanning line depends on the mechanical movement of the scanning mirror. . Therefore, the line scanning speed is much slower than that of a normal video camera that captures images in the visible range.
It usually takes about 1 second to capture one image by thermography. Therefore, it has been considered impossible to capture a dynamic image by thermography except for a special rotated image. Even a rotation image that can be taken is limited to the case where the rotation frequency is exactly the same as the rotation / frequency of the horizontal scanning mirror or the rotation frequency is an integer multiple of that rotation frequency, and It has been considered impossible to capture an image that rotates at a specific number of rotations or a rotating image that changes in rotation.

In order to solve such a problem, an object of the present invention is to make it possible to photograph a rotating image rotating at an arbitrary number of rotations by adding a simple device to the thermography.

[0006]

[Means for Solving the Problems] To achieve the above object,
In the present invention, image processing is performed only on a partial image of one scan line obtained by starting line scanning when the rotating body is near a predetermined specific position, and at other times, that is, horizontal line scanning. If the rotating body is not located at the specific position when starting the, the image processing of the partial image obtained by scanning is not performed.

After the image processing for one line is completed by the above method, the vertical scanning mirror is rotated by one line to prepare for photographing the horizontal scanning line of the next line. Then, when the next horizontal line scan is performed, the image of one scan line is processed by the same method as described above, only when the rotating body comes to the predetermined specific position. By repeating this operation, an infrared image of the entire rotating object is obtained.

[0008]

In order to carry out the above operation, the rotation axis of the subject has a special position (rotational position) at which the subject should photograph.
A well-known rotation angle sensor that detects and outputs to that effect at high position is attached. Further, in the thermography, only when the scanning line starts scanning near the time when there is an output signal from the rotation angle sensor,
A means for outputting information of a partial image of one scan line of the subject to a known image processing apparatus is attached. By taking such a means, it is possible to perform image capturing of a rotating subject.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a conceptual diagram including a block diagram showing an embodiment of the present invention. The internal function of the thermography 29 according to the present invention will be described below.

Reference numeral 1 denotes a subject which rotates at an arbitrary number of revolutions, and an infrared ray 2 emitted from the subject is rotated and vibrated at a constant cycle by a known horizontal scanning mirror driving device 4 so as to move in the horizontal direction of the subject. Known horizontal scanning mirror 3 for scanning
Pass through. Then, it passes through a known vertical scanning mirror 5 which sequentially rotates by a known vertical scanning mirror driving device 6 to scan a vertical image of a subject, and further passes through a known optical system such as a condenser and relay lenses 7 and 8. Then, the light enters the well-known infrared light receiving element 9 which is cooled to a low temperature by the well-known cooling device 10. When the horizontal scanning mirror and the vertical scanning mirror perform a predetermined operation, partial images obtained by scanning the subject are sequentially incident on the infrared light receiving element 9. The element converts the light thus entered into an electric signal by a known method and outputs it as image information 21 to an image signal control device 14 having a function described later.

A known rotation position sensor 11 mounted near the rotation axis of the subject 1 notifies a rotating subject when the rotating subject is located at a predetermined rotation position for taking an infrared image. Is output to the horizontal scanning control device 12 having a known AND gate function. A horizontal scanning start signal 23 for notifying that the horizontal scanning mirror driving device 4 starts horizontal scanning is also input to the control device.

FIG. 2 is a timing chart showing details of a situation where the two signals are input to the horizontal scanning control device 12.
Shown in .. in the upper row indicate the pulses of the horizontal scanning start signal 23 for notifying that the horizontal scanning mirror rotating and vibrating at a constant period n starts horizontal scanning, and A in the lower row A, b, c ... B, C, D, ... Show the pulses of the rotation position signal 22 for notifying the fact that the object rotating at an arbitrary rotation speed is located at the rotation position where an image should be taken. As shown in the figure, both signals are synchronized with the pulse d when the pulse C is generated. In this way, the horizontal scanning line group obtained by performing the line scanning by selecting the timing in which the two signals are synchronized with each other is the distance that the rotating body moves within the time required for scanning one line because the peripheral speed of the subject 1 is high. Except when cannot be ignored, it represents a subject image in which the subject is substantially stationary at the position where the rotational position signal 22 is output. As a result, the infrared image obtained by processing the partial images of these scanning lines is also a substantially still image.

In the present embodiment, in order to perform such a process, the state shown in pulses d and C in FIG.
On condition that the two signals are synchronized, the horizontal scanning control device 12 is activated to output a photographing command 25 to the effect that the thermography should start photographing the object, one of which is the image information 21. The image signal control device 14 which controls the vertical scanning control device 13 outputs the other command.

Each time the horizontal scanning mirror 3 completes horizontal scanning, the horizontal scanning completion signal 24 for notifying the vertical scanning control device 13 is also input from the horizontal scanning mirror driving device 4 to the vertical scanning control device 13. The vertical scanning mirror controller 13 has a known logic circuit,
The operation is started when the horizontal scanning completion signal 24 is input to the apparatus after the shooting command 25 is output, that is, when the scanning of one scan line is completed, and the vertical scanning mirror driving device 6 operates the vertical scanning mirror. The command 26 is output, and at the same time point, the shooting completion signal 27 is output to the image signal control device 14.

The vertical scanning mirror driving device 6 receives the above-mentioned vertical scanning mirror operation command 26, and slightly rotates the vertical scanning mirror to prepare for scanning and photographing an image for one line next to the scanning line. .

On the other hand, image information 2 from the infrared light receiving element 9
The image signal control device 14 that has input 1 becomes operative when the shooting command 25 is input, and outputs the above image information to the known image processing device 15, and then the shooting completion signal 2
Image information 21
The output to the image processing device 15 is stopped. In this way, the image processing device 15 is limited to the case where the image signal control device 14 operates, that is, only when the rotating body is located at the predetermined specific rotation position at the time of starting the horizontal line scanning. The image information 21 output from the infrared light receiving element 9 is input, and at other times, that is, when the rotating body is not located at the specific rotation position when starting the horizontal line scanning, the image information 21 is input. do not do. By performing such control, the image processing device 15 inputs only the image information for which the horizontal scanning is started when the rotating body is located at the predetermined specific rotation position.

The image processing device 15 outputs vertical scanning mirror position information for notifying the horizontal scanning completion signal 24 output from the horizontal scanning mirror driving device 4 and the current position of the vertical scanning mirror 5 from the vertical scanning mirror driving device 6 as necessary. 28 is also input, and an infrared image of the subject is created by a known method from the image information input only when horizontal scanning is started when the rotating body is located at the predetermined specific rotation position. The image processed in this way becomes a still image in a state in which the rotating body is located at the specific rotation position for the reason described above. The image is output to and displayed on a known color monitor 16 and is printed on a printer (not shown) as necessary.

The rotation / vibration cycle of the horizontal scanning mirror in ordinary thermography is as short as several ms, and as a result, the generation cycle of the horizontal scanning start signal shown in FIG. 2 is also short. However, even then, there are usually not many opportunities for the two signals, the rotational position signal 22 and the horizontal scanning start signal 23, to be synchronized as shown by the pulses d and C in FIG. 2, and as a result, the time required for photographing is long. Turn into. As a countermeasure, even if the two signals are not completely synchronized, even if there is a slight difference in generation time t between the two signals as shown in the relationship between the pulses h and F, this is regarded as synchronization and line scanning is performed. If this is done, it is possible to prevent the time required for shooting from being lengthened.

The allowable range of the time difference t between the two signals depends on the resolution (sharpness) required for the captured image, the number of rotations of the subject (particularly the peripheral speed of the subject) and the scanning speed. Involved. As a general theory, when the distance that the subject moves within the image within the range of the time difference t is smaller than the width of the scanning line, there is not much problem. This is because it is difficult to recognize the minute movement of the subject within the dimensional range of the image for one scanning line on the image.

FIG. 3 is a timing chart showing the state of generation of both signals when the signals are regarded as synchronous by allowing the above-described slight time difference t between the signals, and FIG. The concept of is also shown. In the figure, the same symbols as those in FIG. 2 have the same functions and the same roles as in the figure. There is a slight time error t on the condition that both signals are considered to be synchronized.
If is allowed, the following method is used to determine that synchronization has occurred.

When the pulse A of the horizontal scanning start signal shown in the figure is used as a reference and a pulse A of the rotary member position signal is obtained during the time (n-t) to (n + t) from this time point, it is synchronized. It should be considered. Since the generation period n of the horizontal scanning start signal is constant, when the pulse of the rotor position signal is obtained within the above-described elapsed time, the pulse b of the horizontal scanning start signal generated after the pulse a of the horizontal scanning start signal is generated. This is because the difference in generation time of the pulse A of the rotor position signal is t or less.

In order to implement such a method, a clock and a logic circuit, if necessary, are added to the inside of the horizontal scanning control device 12 shown in FIG. When the rotational position signal 22 is input during the elapsed time (n−t) to (n + t) from this time point, the clock is started at the time when the occurrence of the above occurs, and a means for detecting that is known logic circuit. The shooting command 25 may be generated under the condition that the means detects the fact.

The above-described method is merely one embodiment of the present invention, and the essential method for carrying out the present invention is that the subject is specified in the vicinity of the time when the scanning line starts scanning. Various implementation methods can be considered as a method of processing the partial image obtained by scanning only when the partial image is located near the rotation position.

[0024]

As described above, according to the present invention, the processing of the partial image obtained only when the subject is located near the specific rotation position near the time when the scanning of the scanning line is started is performed in various ways. Even if the subject rotates at various rotation speeds,
It is possible to take an image that is almost stationary.

[Brief description of drawings]

FIG. 1 is a diagram including a conceptual diagram in a block diagram for processing a partial image obtained by a scanning line only when an object is located near a specific rotation position according to an embodiment of the present invention.

FIG. 2 is a timing chart showing a generation timing of a signal used when processing a partial image obtained by a scanning line only when a subject is located near a specific rotation position according to an embodiment of the present invention. is there.

FIG. 3 is a diagram showing an embodiment of the present invention in which, when a partial image obtained by scanning lines is processed only when a subject is located near a specific rotation position, a difference in the generation timings of two signals to be used is allowed. 4 is a timing chart showing the concept of an implementation method when is allowed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Subject 3 Horizontal scanning mirror 4 Horizontal scanning mirror driving device 5 Vertical scanning mirror 6 Vertical scanning mirror driving device 7 Condensing lens 9 Infrared light receiving element 11 Rotation position sensor 12 Horizontal scanning control device 13 Vertical scanning control device 14 Image signal control device 15 Image processing device 21 Image information 22 Rotational position signal 23 Horizontal scanning start signal 24 Horizontal scanning completion signal 25 Imaging command 26 Vertical scanning mirror operation command 27 Imaging completion signal 28 Vertical scanning mirror position information 29 Thermography

Claims (1)

[Claims] 1. An infrared image of the entire subject by successively inputting partial images of the subject obtained by successively translating a scanning line for scanning in one axial direction in an axial direction orthogonal to the axis. In the infrared image processing apparatus that obtains, when the subject is an object that rotates around a specific axis, the scanning line is obtained only when the subject is located near the specific rotation position near the time when the scanning line starts scanning. Image processing apparatus capable of photographing a rotating body characterized by performing image processing on a partial image