JPH05306957A - Infrared thermal imaging device - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To obtain continuous image information in an infrared thermal imager that images a moving object. A first memory 24 and a second memory 25, which store line-scanned image information, write and read independently of each other asynchronously, and a timing signal generator 34 for generating a timing signal. , The first memory 24 and the second memory 25 are controlled to switch the writing of the image information for one frame respectively, the writing completion is detected respectively, and the reading is started from the memory where the writing is completed. , A writing / reading control unit 36 that controls to repeatedly read the image information of the other memory until the writing to one of the memories is completed, and the first and second memories 24, And a read / write switching unit 26 for switching 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a line scan function used in a monitoring system for photographing an object such as a power transmission line while moving it or for monitoring an object moving on a manufacturing line in a factory. The present invention relates to an infrared thermal imager provided.

[0002]

2. Description of the Related Art Conventionally, in an infrared camera previously filed by the present applicant, as shown in FIG. 3, the light emitted from an object 1 passes through a silicon window 4 to generate visible light 2. It is blocked and only the infrared rays 3 pass through and enter the infrared camera. This infrared ray 3 is vertically scanned by a vertical scanning mechanism composed of a folding mirror 5 and a vibrating mirror 6 vibrating in the vertical direction, and then 6-8.
Is composed of plane mirrors 7a ... And is horizontally rotated by a horizontal scanning mechanism composed of a rotating mirror 7 rotating at a high speed and a folding mirror 8 which reflects scanning light toward the condenser lens 9. To be scanned. In this way, the scanning light scanned in the horizontal and vertical directions is collected by the condenser lens 9
It is incident on the infrared detector 10 via the, and photoelectrically converted to output a thermal image signal. This thermal image signal is sent to the amplifier 11
After being amplified by, the processor 12 performs various kinds of image processing and displays it as a thermal image on the display device 13.

When an image of a small object 1 which moves at a high speed in a certain direction is photographed by using such an infrared thermal imager, for example, when an image is photographed while moving a power transmission line or the like by a vehicle, FIG. As shown in, the display screen 14 displayed on the display device 13 is overlapped or skipped depending on the moving speed, the viewing angle, etc., and it is difficult to continuously display the temperature distribution. Therefore, as shown in FIG. 5, the scanning in the vertical direction is stopped at a fixed position, the object moving in the vertical direction with respect to the display screen 14 is continuously photographed, and the image information is continuously displayed on the TV image. Some have a so-called line scan function for converting into a signal.

That is, when the object 1 moves at a speed equal to the original vertical scanning speed, an accurate thermal image of the object 1 is obtained on the display screen 14 as shown in FIG.
When the object 1 is moved in the vertical direction, the sampling interval Δx is represented by Δx = v × Δt, where Δt is the scanning interval of one line and v is the moving speed of the object 1. Therefore, according to the above equation, when the target object 1 is moved at a high speed in the vertical direction, the sampling interval Δx is widened with respect to the target object 1 and is displayed on the display screen 14 as shown in FIG. The object 1 is displayed in a vertically reduced state. On the other hand, when the moving speed of the object 1 is slow, the sampling interval Δx is reduced with respect to the object 1 as shown in FIG. 8, so that the object 1 on the display screen 14 is enlarged in the vertical direction. The vertical resolution is improved. Thus, by adjusting the relative speed between the object 1 and the infrared camera, the vertical resolution with respect to the object 1 can be made variable. In this way, the temperature of the object 1 moving in the vertical direction can always be measured at a fixed position as seen from the infrared camera, but the temperature measurement interval at that time depends only on the moving speed of the object 1. become.

[0005]

Generally, when the object 1 moving at a high speed in a certain direction is photographed, it corresponds to the blanking period of the scanning line and the blanking period of the video signal.
There is a portion where the object 1 is not photographed. As described above, when the moving speed of the object 1 is high, the video signal in the blanking period cannot be obtained, and the display screen 14 is photographed in a scattered manner in every screen.
Depending on the moving speed, the video signals on the display screen 14 may be overlapped, and sometimes the contents may be skipped. A line scan function has been conventionally used as a means for solving such a problem.

However, even when the temperature of the moving object 1 is measured using such a line scan function, the frequency of the temperature data obtained from the infrared camera and the frequency of the video signal are different, Is converted into a video signal and displayed on the display device 14, but in this case, the frequency of the temperature data from the infrared camera is generally smaller than the frequency of the video signal. Therefore,
While writing the image information for one frame to the memory,
When reading, since the writing speed is slower than the reading speed, the reading from the memory overtakes the writing to the memory, and a continuous video signal cannot be obtained.

[0007]

According to the present invention, the line-scanned image information is respectively stored, and writing and reading are performed independently and asynchronously from each other.
The memory, the timing signal generator that generates the timing signal, and the timing signal are controlled so that the reading speed is faster than the writing speed to the memory.
The writing of the image information for at least one frame is controlled to be switched between the first memory and the second memory, and the completion of writing to the first memory and the second memory is detected, and the writing is completed. A writing / reading control unit for controlling writing / reading to / from the memory so that reading from the memory is started and image information of the other memory is repeatedly read until writing to one of the memories is completed, and the writing / reading control unit. A continuous switching of image information is provided by providing a write switching unit and a read switching unit that switch between the first memory and the second memory in response to a command from the read control unit.

[0008]

When the data is being written in the first memory, the data is read from the second memory, and when the writing in the first memory is completed, the write switching section is switched to write in the second memory. Is started. The reading of the second memory is performed until the writing to the first memory is completed.
It is repeatedly read. When the writing to the second memory is started, the read switching unit is switched at the time when the reading of the second memory is completed, and the reading of the first memory is performed. Thus, when the end of writing to the memory is detected, the reading from this memory is started. This operation is controlled by a command from the write / read controller with reference to the timing signal from the timing signal generator.

[0009]

Embodiments of the present invention will be described in detail with reference to FIGS. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram, and FIG. 3 is a perspective view of a main part showing an optical system scanning mechanism of an infrared camera previously filed by the present applicant. In FIG. 1, reference numeral 20 denotes the optical system scanning mechanism shown in FIG. 3, which includes an object 1 by a folding mirror 5 and a vibration mirror 6.
It is composed of a vertical scanning mechanism for scanning in the vertical direction, and a horizontal scanning mechanism for scanning in the horizontal direction by the rotating mirror 7 and the folding mirror 8. The object 1 is scanned in the horizontal and vertical directions. There is. Reference numeral 21 denotes a line scan function control unit, which controls the driving and stopping of the vertical vibration of the vibration mirror 6 via the drive circuit 29. Reference numeral 22 is an A / D converter, which is shown to be included in the amplifier 11 in FIG. Reference numeral 23 is a write switching unit that sequentially switches writing of image information to the first memory 24 and second memory 25, and 26 is a read switching unit that sequentially switches reading of image information stored in the memories 24 and 25. is there.

The first memory 24 and the second memory 25 store image information for one frame, respectively, and are dual-both capable of independently and asynchronously writing and reading image information. A two-phase configuration memory is configured by using a memory. Reference numeral 27 is a D / A converter, and 28 is a display device for a thermal image signal (video signal), which is also commonly used as the display device 13 shown in FIG. 29
Is a drive circuit for driving the optical system scanning mechanism 20. Thirty
3 is a timing signal generating section, as shown in FIG. 3, a reflection plate 31 provided on the upper surface of the rotating mirror 7, a photo sensor 32, a photoelectric conversion circuit 33, a timing generation circuit 34, and an A / D conversion circuit. And a container 35. Since the number of rotations of the rotary mirror 7 is detected by the reflection plate 31 and the photo sensor 32, the present invention is not limited to this embodiment. For example, a slit is provided on the upper surface of the rotary mirror 7. However, the same effect can be obtained. 36
Is a write / read controller, which includes a write counter 37 that counts horizontal scanning lines when writing to the memories 24 and 25, and a read counter 38 that counts reads from the memories 24 and 25. And the read switching unit 26.

Next, the operation will be described. First, the timing signal that serves as a reference for the operation of the write / read controller 36 will be described. A reflection plate 31 is provided on the upper surface of the rotating mirror 7, and the reflection plate 31 is provided.
A photo sensor 32 (not shown in FIG. 3) is arranged above and above. Therefore, when the rotating mirror 7 rotates, the photosensor 3 is rotated every time the reflection plate 31 passes.
The optical signal from 2 is detected, and the optical signal corresponding to the rotation speed of the rotating mirror 7 is detected. This optical signal is converted into an electric signal by the photoelectric conversion circuit 33, and the timing generation circuit 34 generates a timing signal based on the rotation speed of the rotation mirror 7. This timing signal is A /
The digital signal is converted by the D converter 35.

On the other hand, in the normal state, based on FIG.
As described above, the object 1 is horizontally and vertically scanned by the optical system scanning mechanism 20, and the thermal image is displayed on the display device 13. Therefore, when the object 1 moves, the line scan function is used, but in order to perform the line scan, a galvanometer (not shown) in the drive circuit 29 is used in the vertical direction within the range of vertical viewing angle. The vibrating vibration mirror 6 must be stopped. Therefore, when a control signal from the line scan function controller 21 is input to the drive circuit 29, the vibration of the vibration mirror 6 is stopped and only the rotary mirror 7 is rotated so that the horizontal scanning line is displayed on the display screen 14. Only displayed. Therefore, only the infrared rays 3 of the object 1 moving in the vertical direction on the display screen 14 are incident on the infrared detector 10, the infrared rays 3 are converted into an electric signal, amplified by the amplifier 11, and then the A / D converter. Two
It is converted into a digital signal by 2 and input to the write switching unit 23.

In the state shown in FIG. 1, the write switching unit 23 is connected to the memory 24 side, so that writing to the memory 24 is started first. At this time, the read switching unit 26 is connected to the memory 25 side and the memory 2
The image information stored in 5 is being read,
The read image information is converted into an analog signal (thermal image signal) by the D / A converter 27 and displayed on the display device 28. It should be noted that the write counter 37 is used when data is being written to or read from the memories 24 and 25, respectively.
And is always counted by the read counter 38. Therefore, while writing to the memory 24, reading from the memory 25 is repeatedly performed, and the stored old image information is read again.

This state will be described with reference to the waveform chart shown in FIG. In the waveform diagram shown in FIG. 2, the writing speed (writing frame rate) and the reading speed (reading frame rate) have a relationship of 1: 2, and Writing and reading of image information to and from the memories 24 and 25 are displayed at a high level. First, at time T ₁ , when the image information for one frame is written in the memory 25, the write counter 37 is reset and the writing / reading control unit 36 detects the end of writing in the memory 25. .. Then, the writing / reading control unit 36 inputs a writing switching command based on the timing signal to the writing switching unit 23, switches from the memory 25 side to the memory 24 side, and starts writing the image information to the memory 24. It

On the other hand, at time T ₁ , the image information is stored in the memory 2
4 is read from the memory 24, and from the time T ₁ when the writing to the memory 24 is started to the time T _1a when the reading from the memory 24 is finished, the writing and the reading of the image information are simultaneously performed in the memory 24. However, since the writing speed of the image information to the memory 24 is slower than the reading speed, the writing does not skip the reading. In this way, when the reading of the image information from the memory 24 is completed at the time T _1a , the reading counter 38 is reset by the command from the writing / reading control unit 36, and the reading switching unit 26 stores the information in the memory 25. The switching is started, the reading of the image information is started, and the reading of the image information for one frame is completed at the time T _2a.
Since the writing to the memory 25 is still continuing, the reading of the memory 25 returns to the beginning, the reading of the old information is started, and the reading is repeatedly performed until the writing to the memory 24 is completed. When the writing to the memory 24 is completed, the memory 25
Even if the writing to the memory 25 is started, the reading from the memory 25 is continued until the time T _{3a at} which the reading from the memory 25 ends, and the reading from the memory 25 ends. When a write end command and a read switching command from the write / read control unit 36 are input to the read switching unit 26, the read / write control unit 36 is switched to the memory 24 side, and reading from the memory 24 is started. In this way, the reading is always performed by the writing / reading control unit 36 only to the memory in which the end of writing is detected.

As described above, writing and reading are simultaneously performed in the memory 25. However, since the reading speed is faster than the writing speed, the writing does not skip the reading, and when the reading of the memory 25 is completed, Next, since new image information is read from the memory 24 in which writing has been completed, reading into the memories 24 and 25 does not skip writing, and continuous image information can always be obtained. Thus, even if the writing speed of the memory 24 or the memory 25 being written is slower than the reading speed, reading to the memory does not overtake writing as in the conventional case. Even if there is a phase difference between the timing signals for writing and reading, there is no problem because writing and reading are always performed in independent asynchronous states as shown in FIG. The image information read from the memories 24 and 25 is converted into a TV signal by the D / A converter 27 and displayed as a thermal image on the display device 28.

The first memory 24 and the second memory 2
5 is for scan conversion of thermal image to TV image,
Since the thermal image data is for temporarily storing two screens, the present invention is not limited to the above-mentioned embodiment. For example, a memory having a storage capacity of two screens or more is used and By dividing the memory into a first memory and a second memory by addressing, it is possible to virtually function as two memories. In this case, the addressing command of the write / read controller 36 is given. Thus, the same effect can be obtained by converting the write address and the read address in the write switching unit 23 and the read switching unit 26, respectively.

[0018]

According to the present invention, first and second memories that store line-scanned image information and write and read independently and asynchronously with each other, and a timing signal generator for generating a timing signal. And, based on the timing signal, the reading speed is controlled to be higher than the writing speed to the memory, and the writing of at least one frame of image information is switched to the first memory and the second memory. Controlling a first memory and a second
The end of writing to each memory is detected, the reading is started from the memory where this writing is completed, and the image information of the other memory is repeatedly read until the writing to one of the memories is completed. Since a writing / reading control unit that controls writing and reading to and from the writing / reading control unit and a writing switching unit and a reading switching unit that switch between the first memory and the second memory in response to commands from the writing / reading control unit are provided. The continuous image information without jumps, breaks, and overlaps can be obtained for an object that moves in a certain direction, such as a product that moves on the manufacturing line of a factory. Further, the sampling interval of the image information is related to only the moving speed of the object regardless of the shooting distance, the shooting lens, etc., so that the data analysis from the obtained image information is easy. Also, for a stationary object or an object with a slow moving speed, a very minute temperature distribution point can be placed on the horizontal scanning line, so that part is enlarged in the vertical direction and displayed easily. Image information is obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a waveform diagram showing an embodiment of the present invention.

FIG. 3 is a perspective view of essential parts showing an optical system scanning mechanism of a conventional infrared camera.

FIG. 4 is an explanatory diagram illustrating a line scan function.

FIG. 5 is an explanatory diagram for explaining a line scan function.

FIG. 6 is an explanatory diagram for explaining a line scan function, and is a display screen showing a case where an object is stationary.

FIG. 7 is an explanatory diagram for explaining a line scan function, and is a display screen showing a case where an object is moving fast.

FIG. 8 is an explanatory diagram for explaining a line scan function, and is a display screen showing a case where an object is moving relatively slowly.

[Explanation of symbols]

 1 Object 3 Infrared 6 Vibration mirror 7 Rotation mirror 10 Infrared detector 13 Display device 14 Display screen 20 Optical system scanning mechanism 21 Line scan function control unit 23 Write switching unit 24 Memory 25 Memory 26 Read switching unit 28 Display device 30 Timing signal generator 36 Write / read controller

Claims (2)

[Claims] 1. An optical system scanning mechanism having a horizontal scanning mechanism and a vertical scanning mechanism for independently scanning a subject in a horizontal direction and a vertical direction, respectively, and receiving two-dimensionally scanned infrared light from the optical system scanning mechanism. Infrared detector for outputting as a thermal image signal, and A for A / D converting the thermal image signal
A D / D converter, a drive circuit for driving the optical system scanning mechanism, a line scan function controller for stopping the vertical scanning mechanism and performing a line scan, and a display device for displaying line-scanned image information. In the infrared thermal imager, first and second memories that store the line-scanned image information and write and read independently of each other and asynchronously, and a timing signal generator that generates a timing signal. Controlling the reading speed to be faster than the writing speed to the memory based on the timing signal,
And controlling the writing of the image information for at least one frame to the memory and the end of writing to the first memory and the second memory respectively,
Writing is started from the memory in which the writing is finished, and writing / reading is controlled so that the image information in the other memory is repeatedly read until the writing in one of the memories is finished. An infrared thermal imaging apparatus comprising: a read control unit; and a write switch unit and a read switch unit for switching between the first memory and the second memory according to commands from the write / read controller. 2. An optical system scanning mechanism having a horizontal scanning mechanism and a vertical scanning mechanism for independently scanning a subject in a horizontal direction and a vertical direction, and receiving two-dimensionally scanned infrared light from the optical system scanning mechanism. Infrared detector for outputting as a thermal image signal, and A for A / D converting the thermal image signal
A D / D converter, a drive circuit for driving the optical system scanning mechanism, a line scan function controller for stopping the vertical scanning mechanism and performing a line scan, and a display device for displaying line-scanned image information. In the infrared thermal imager, the first memory and the second memory that store the line-scanned image information by addressing and perform writing and reading independently and asynchronously with each other.
A memory having a storage capacity of at least 2 frames, which is divided into a memory and a memory, a timing signal generating unit for generating a timing signal, and a reading speed higher than a writing speed to the memory based on the timing signal. To control the writing of the image information for at least one frame to the memory portion addressed to the first memory and the memory portion addressed to the second memory, respectively. Detecting the completion of writing to the first memory and the second memory, respectively, and starting reading from the memory where the writing has been completed, and writing to either the first memory or the second memory Writing to the memory so as to repeatedly read the image information of the other memory until the end, writing to control the reading A read / write control unit, and a write switching unit and a read switching unit for switching the addresses of the first memory and the second memory according to an address designation command of the write / read control unit. Infrared thermal imager.