CN102495030B - Device and method for measuring homologous dual-target transmission visibility - Google Patents

Abstract

A homologous dual-target transmission visibility measurement device, including a data acquisition unit, a data processing unit and a target unit, the data processing unit is a computer that performs filtering processing on collected images and can perform calculations on data parameters. The target unit includes a first dark box, a second dark box, an LED light source, a beam splitter, and an optical fiber. Both the first dark box and the second dark box have two channel cavities with the same shape, one of which is a bright cavity, and the other channel cavity The cavity is a black cavity. The LED light source is divided into two beams of light through two optical fibers in the beam splitter. The two optical fibers are respectively placed in the bright cavity of the first dark box and the bright cavity of the second dark box. The cavity ports are all within the field of view of the camera lens. The invention has ingenious design, small size, low production cost, simple installation, easy operation, no special maintenance cost, can be used even in special weather such as rainy days and foggy days, and is convenient for popularization and use.

Description

Homologous dual-target transmission visibility measuring device and its measuring method

technical field

The invention belongs to the field of visibility detection and relates to a device and method for measuring visibility.

Background technique

Atmospheric visibility occupies an important position in modern transportation and communication technology, and has always attracted people's attention. With the development of transportation networks, especially the development of expressways, water transportation, and aviation industries, it is necessary to monitor atmospheric visibility in real time and accurately judge Whether to close airports, highways or stop certain operations, etc.

Real-time observation of visibility has become an indispensable and important content in real life. The so-called visibility refers to the maximum horizontal distance that a person with normal eyesight can distinguish a black target of a certain size (with an angle of view greater than 30') from the sky background near the horizon under the prevailing weather conditions. In meteorology, visibility is represented by the MOR value of the meteorological optical range. The meteorological optical range refers to the path length that the luminous flux of a parallel beam with a color temperature of 2700K emitted by an incandescent lamp weakens to 5% of the initial value in the atmosphere. Visibility is an index that reflects the transparency of the atmosphere and is closely related to the weather conditions at that time. When weather processes such as rainfall, fog, haze, and sandstorms occur, the transparency of the atmosphere is low, so visibility is poor.

At present, the traditional method of measuring atmospheric visibility is generally by visual inspection, and some measuring instruments such as transmission visibility meter, forward scattering visibility meter or laser visibility automatic measuring instrument are also used for measurement. Manual visual inspection is relatively poor in standardization and objectivity. Atmospheric transmissometer is used, which is bulky, complicated to install, and has a long measurement baseline. It is necessary to directly measure the air column transmittance through the beam through the atmospheric column between two fixed points, so as to calculate the value of visibility and the reliability of the measurement. Affected by the working stability of the light source and other hardware systems, it is generally only suitable for observations with below-medium visibility, and in low-visibility weather such as rain and fog, large errors will be caused by complex conditions such as water vapor absorption. The forward scatter visibility meter selects the weak near-infrared light absorbed by the atmosphere, measures the angular scattering coefficient at a direction of 35 degrees to the propagation direction of the detection beam, and then calculates the total scattering coefficient according to a certain atmospheric optical mode, and determines the visibility according to the Koschmieder law. Scattering visibility meters are susceptible to interference from various factors. The incident light beam collected by the light receiving part is not strictly a parallel light beam, but a light beam distributed within a large cone angle. The resulting scattering coefficient is larger than the actual scattering coefficient. . The laser visibility automatic measuring instrument calculates the visibility by measuring the atmospheric extinction coefficient with a laser. Relatively speaking, it is more objective and accurate, but this instrument is expensive, maintains high, and is complicated to operate. It is also difficult to carry out in rainy and foggy days. Normal observation is difficult to generalize.

In order to solve the above-mentioned problems, there is an urgent need for a device and method for measuring visibility that avoids the above-mentioned disadvantages and has low production costs. It adopts a measurement method that directly captures the selected target object and its background image through an industrial camera, and then transmits the collected image to the computer, and analyzes and calculates the obtained image to obtain the value of visibility.

Contents of the invention

The purpose of the present invention is to provide a homologous dual-target transmission visibility measurement device and its measurement method, which can measure the visibility in real time and accurately, and solve the defects of the existing transmission visibility instruments, which have high requirements for optical axis alignment and are easily affected by window pollution. This improves measurement accuracy and simplifies equipment maintenance.

In order to achieve the above object, the present invention adopts the following technical solutions: a homologous dual-target transmission visibility measurement device, including a data acquisition unit, a data processing unit and a target unit, the data acquisition unit is provided with a camera, and the camera is used for Shooting the target unit directly in front of the lens, and transmitting the captured image to the data processing unit, the signal output interface of the camera is connected to one end of the data line, and the other end of the data line is connected to the data input interface of the data processing unit,

The data processing unit is a computer that filters the collected images and calculates the data parameters. The computer includes a filter processing unit for filtering the images collected by the camera, and is used to extract each point of the image A brightness value unit for extracting brightness values, a visibility calculation unit for calculating visibility parameter values, and a storage unit for image data storage; the data processing unit performs filtering processing on the input images respectively to obtain bright cavities on each image The brightness value of the light spot at the light exit port and the brightness value at the port of the black cavity use the distances between the first dark box and the second dark box and the camera as input parameters. the

The target unit includes a first dark box, a second dark box, an LED light source, a beam splitter, and an optical fiber. Both the first dark box and the second dark box have two channel cavities with the same shape, one of which is a bright cavity, The other channel cavity is a black cavity; the LED light source is divided into two beams of light through two optical fibers in the beam splitter, and the two optical fibers are respectively placed in the bright cavity of the first dark box and the bright cavity of the second dark box, and the first The light outlet port of the bright cavity and the port of the black cavity of the obscura and the second obscura are all within the lens field of view of the camera.

The distance between the first dark box and the camera is not equal to the distance between the second dark box and the camera.

Each of the first and second dark boxes has a vertical partition or partition at their respective central axes, and the partition or partition divides the respective dark boxes into two equal passage cavities.

The light exit port of the bright cavity and the port of the black cavity are circular or square with the same size.

There are two parallel fiber channels in the main body of the beam splitter, and the two fiber channels share a lighting surface near the light source.

The camera is an industrial camera with a computer interface.

The computer is a desktop computer or a laptop computer.

A measuring method of a homologous double-target transmission visibility measuring device, the measuring steps are as follows: Step 1, turn on the LED light source, the camera and the computer.

Step 2: The light emitted by the LED light source is directly irradiated on the lighting surface of the two optical fibers, and two paths of light are separated through the optical fibers, and the two paths of optical fibers are respectively inserted into the bright cavity of the first dark box and the bright cavity of the second dark box.

Step 3, the camera collects the images of the first dark box with a distance of _R1 and the second dark box with a distance of _R2 , and shoots and records the brightness of the light spots of the light outlet port of the bright cavity and the port of the black cavity of the first dark box and the second dark box, and The collected image data is transmitted to the computer through the data line.

Step 4, the computer performs filtering processing on the collected image of the target unit.

Step 5, the brightness value extraction unit respectively obtains the brightness values of the light spots of the two bright cavity light outlet ports of the first dark box and the second dark box, which are respectively I ₁ and I ₂ , wherein I ₁ is the light spot brightness value of the first dark box, and I ₂ is the light spot brightness value of the second dark box, and the brightness values of the first dark box and the second dark two black cavity ports are respectively Ih ₁ and Ih ₂ , wherein Ih ₁ is the brightness value of the black cavity port of the first dark box, Ih ₂ is the brightness value of the black cavity port of the second dark box, and it is input to the visibility calculation unit.

Step 6, the visibility calculation unit of the computer uses the set calculation formula I ₁ - Ih ₁ = (I ₂ - Ih ₂ )*e ^-xk /(R ₂ /R ₁ )^2, X= R ₂ -R ₁ , calculate the K value, and calculate the P value of the Meteorological Optical Range (MOR) by P=(X*Ln(20))/K.

Compared with the prior art, the present invention has the following features and beneficial effects: Meteorological optical visual range is only measured by the present invention to measure the brightness ratio of two paths of light. Since the splitting ratio of the two paths of light is stable, the same camera is selected for the measurement, and the same light source is used to split the light into two beams of light through the optical fiber. The light is sent out through the light port of the bright cavity of the dark box, and the ratio of the light intensity of the two beams is relatively stable, so the brightness ratio of the two lights can be measured more accurately. The camera captures the image of the light port of the bright cavity and the side-by-side black cavity port The filtering process extracts brightness values respectively, and then obtains more accurate meteorological optical visual range values through simple calculation.

The invention is ingeniously designed, the entire measuring device is small in size, low in manufacturing cost, simple in installation, easy in operation, does not require special maintenance costs, and can be used even in special weather such as rainy days and foggy days. Since the present invention uses an industrial camera as a sensor, image data is obtained, and as long as the light emitted by the two optical fiber ports and the black cavity port fall within the image framing area of the industrial camera, image acquisition and measurement can be performed, reducing the The position alignment requirements of the light source and the sensor are higher than that of the forward scattering visibility meter, and the installation and maintenance requirements are much lower than that of the traditional transmission type visibility meter, so as to realize real-time and accurate visibility measurement.

Description of drawings

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a schematic diagram of optical fiber splitting in the present invention.

Fig. 3 is a structural schematic diagram of the dark box of the present invention.

Fig. 4 is a process flowchart of the present invention.

Reference signs: 1-camera, 2-computer, 3-first obscura, 4-second obscura, 5-fiber inlet, 6-bright cavity light output port, 7-black cavity port, 8-optical fiber, 9-lighting surface , 10-partition, 11-LED light source, 12-beam splitter.

Detailed ways

Embodiment Referring to FIG. 1 , a schematic structural diagram of the present invention. This homologous dual-target transmission visibility measurement device includes a data acquisition unit, a data processing unit and a target unit. The data acquisition unit is provided with a camera 1, and the camera 1 is an industrial camera with a computer interface. The camera 1 is used to photograph the target unit directly in front of the lens, and transmits the captured image to the data processing unit. The signal output interface of the camera 1 is connected to one end of the data line, and the other end of the data line is connected to the data processing unit. Data input interface connection.

The data processing unit is a computer 2 that filters the collected images and performs operations on data parameters, and the computer 2 is a desktop computer or a portable computer. The computer 2 includes a filter processing unit for filtering the image collected by the camera, an extraction brightness value unit for extracting the brightness value of each point of the image, a visibility calculation unit for calculating the visibility parameter value, and an image data storage unit. The storage unit; the data processing unit performs filter processing on the input images respectively, obtains the light spot brightness value of the light outlet port of the bright cavity and the brightness value of the black cavity port on each image, and combines the first dark box and the second dark box with the camera The distance, the spot brightness value of the light exit port of the bright cavity and the brightness value of the black cavity port are used as shooting parameters.

The target unit includes a first dark box 3 , a second dark box 4 , an LED light source 11 , a beam splitter 12 and an optical fiber 8 . As shown in Figure 3, the structure diagram of the dark box of the present invention. The first dark box 3 and the second dark box 4 all have two channel cavities with the same shape, and each of the first dark box 3 and the second dark box 4 has a vertical partition 10 at their respective central axes. A partition divides the respective obscura into two equal access cavities. One of the channel cavities is a bright cavity with an optical fiber. The far end of the bright cavity is the fiber inlet 5, and the near end of the bright cavity is the light exit port 6 of the bright cavity. The camera can photograph the light spot of the optical fiber at the light exit port of the bright cavity. The channel cavity is a black cavity, and the cavity is empty. The black cavity has a black cavity port, and the black cavity port and the light output port of the bright cavity are both facing the camera. The light output port 6 of the bright cavity and the black cavity port 7 are circles of equal size shape or square.

As shown in FIG. 2 , the optical fiber splitting schematic diagram of the present invention. There are two parallel optical fiber channels in the main body of the beam splitter 12, and the two optical fiber channels share a lighting surface 9 at the end near the light source. The LED light source 11 is divided into two beams of light through the two optical fibers 8 in the beam splitter 12, and the two optical fibers are respectively inserted into the bright cavity of the first dark box and the bright cavity of the second dark box through the two optical fiber inlets 5, and the second light The light outlet port 6 of the bright cavity and the port 7 of the black cavity of the first dark box and the second dark box are all within the lens field of view of the camera 1, and the distance between the first dark box 3 and the camera 1 is not equal to the distance between the second dark box 4 and the camera 1 .

As shown in FIG. 4, the processing flow chart of the present invention. The measurement method of the same-source dual-target transmission visibility measurement device, the installation steps are as follows:

Step 1, turn on the LED light source, camera and computer.

Step 2: The light emitted by the LED light source is directly irradiated on the lighting surface of the two optical fibers, and two paths of light are separated through the optical fibers, and the two paths of optical fibers are respectively inserted into the bright cavity of the first dark box and the bright cavity of the second dark box.

Step 3, the camera collects images of the first dark box with a distance of _R1 and the second dark box with a distance of _R2 , and the images are captured and recorded for the light spots of the bright cavity light outlet 6 of the first dark box 3 and the second dark box 4 and the black cavity port 7 Brightness, and the collected image data is transmitted to the computer through the data line.

Step 4, the computer performs filtering processing on the collected image of the target unit.

Step 5, the brightness value extraction unit respectively obtains the brightness values of the light spots of the two bright cavity light outlet ports of the first dark box and the second dark box, which are respectively I ₁ and I ₂ , wherein I ₁ is the light spot brightness value of the first dark box, and I ₂ is the light spot brightness value of the second dark box, and the brightness values of the first dark box and the second dark two black cavity ports are respectively Ih ₁ and Ih ₂ , wherein Ih ₁ is the brightness value of the black cavity port of the first dark box, Ih ₂ is the brightness value of the black cavity port of the second dark box, and it is input to the visibility calculation unit.

Step 6, the visibility calculation unit of the computer uses the set calculation formula I ₁ - Ih ₁ = (I ₂ - Ih ₂ )*e ^-xk /(R ₂ /R ₁ )^2, X= R ₂ -R ₁ , calculate the K value, and calculate the P value of the Meteorological Optical Range (MOR) by P=(X*Ln(20))/K.

Claims (8)

1. A homologous dual-target transmission visibility measurement device, including a data acquisition unit, a data processing unit and a target unit, the data acquisition unit is provided with a camera (1), and the camera (1) is used to photograph The target unit in front transmits the captured image to the data processing unit, the signal output interface of the camera (1) is connected to one end of the data line, and the other end of the data line is connected to the data input interface of the data processing unit, characterized in that : The data processing unit is a computer (2) that performs filtering processing on the collected images and performs operations on data parameters, and the computer includes a filtering processing unit for filtering the images collected by the camera, for extracting The brightness value unit for extracting the brightness value of each point of the image, the visibility calculation unit for calculating the visibility parameter value, and the storage unit for image data storage; the data processing unit performs filtering processing on the input images respectively to obtain each image The light spot brightness value of the light exit port of the upper bright cavity and the brightness value of the black cavity port take the distance between the first dark box and the second dark box and the camera as input parameters; The target unit includes a first dark box (3), a second dark box (4), an LED light source (11), a beam splitter (12) and an optical fiber (8), and the first dark box (3) and the second dark box (4 ) have two channel cavities with the same shape, one channel cavity is a bright cavity, and the other channel cavity is a black cavity, and the LED light source (11) passes through two optical fibers (8) in the beam splitter (12) Divided into two beams of light, the two optical fibers are respectively placed into the bright cavity of the first dark box and the bright cavity of the second dark box through the optical fiber inlet (5), and the black cavity port (7) of the first dark box and the second dark box and the bright cavity The light outlet ports (6) of the cavity are all within the lens field of view of the camera (1). 2. The same-source dual-target transmission visibility measuring device according to claim 1, characterized in that: the distance between the first dark box (3) and the camera (1) and the distance between the second dark box (4) and the camera (1) The spacing is not equal. 3. The same-source dual-target transmission visibility measuring device according to claim 1, characterized in that: the first dark box (3) and the second dark box (4) each have a vertical partition at their respective central axes (10) or partition, which divides the respective camera obscura into two equal access cavities. 4. The same-source dual-target transmission visibility measurement device according to claim 1, characterized in that: the light exit port (6) of the bright cavity and the port (7) of the black cavity are equal in size to a circle or a square. 5. The same-source dual-target transmission visibility measurement device according to claim 1, characterized in that: there are two parallel fiber optic channels in the main body of the beam splitter (12), and the two fiber channels share one at the end near the light source Lighting surface (9). 6. The same-source dual-target transmission visibility measurement device according to claim 1, characterized in that: the camera (1) is an industrial camera with a computer interface. 7. The same-source dual-target transmission visibility measuring device according to claim 1, characterized in that: the computer (2) is a desktop computer or a portable computer. 8. A measuring method using the same-source dual-target transmission visibility measuring device according to any one of claims 1-7, characterized in that the measuring steps are as follows: Step 1, turn on the LED light source, camera and computer; Step 2, the light emitted by the LED light source is directly irradiated on the lighting surface of the two optical fibers, and two paths of light are separated through the optical fibers, and the two paths of optical fibers are respectively inserted into the bright cavity of the first dark box and the bright cavity of the second dark box; Step 3, the camera collects the images of the first dark box with a distance of _R1 and the second dark box with a distance of _R2 , and shoots and records the light spots of the light exit port (6) of the bright cavity of the first dark box (3) and the second dark box (4) and the brightness of the black cavity port (7), and transmit the collected image data to the computer through the data line; Step 4, the computer performs filtering processing on the collected image of the target unit; Step 5, the brightness value extraction unit respectively obtains the brightness values of the light spots of the two bright cavity light outlet ports of the first dark box and the second dark box, which are respectively I ₁ and I ₂ , wherein I ₁ is the light spot brightness value of the first dark box, and I ₂ is the light spot brightness value of the second dark box, and the brightness values of the first dark box and the second dark two black cavity ports are respectively Ih ₁ and Ih ₂ , wherein Ih ₁ is the brightness value of the black cavity port of the first dark box, Ih ₂ is the brightness value of the black cavity port of the second dark box, and it is input to the visibility calculation unit; Step 6, the visibility calculation unit of the computer uses the set calculation formula I ₁ - Ih ₁ = (I ₂ - Ih ₂ )*e ^-xk /(R ₂ /R ₁ )^2, X= R ₂ -R ₁ , calculate the K value, and calculate the P value of the meteorological optical range by P=(X*Ln(20))/K.

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