Evaluation method for barrel weapon bore opening flame based on visible light radiation energy

Abstract

The invention provides a scientific and effective bore port flame evaluation method, which is characterized in that visible light radiation energy is used as an evaluation parameter, high-speed camera shooting testing and flame analysis software are combined, and a real-time flame sequence image is subjected to integral area calibration and gray processing, and the total energy radiated by the flame during the generation period is calculated, so that the evaluation accuracy of the bore port flame is improved. The barrel weapon bore opening flame evaluation method taking the visible light radiation energy as a standard parameter is constructed by taking the visible light radiation energy as three evaluation parameters, namely the visible light radiation energy, comprehensively reflecting the geometric dimension of the flame, the brightness of the flame and the duration time, so that the influence of a test environment can be eliminated, the bore opening flame can be comprehensively and accurately evaluated, and the harmful emission phenomenon can be effectively evaluated; therefore, powerful support is provided for construction of a propellant and charge comprehensive performance evaluation system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flame evaluation, in particular to a method for evaluating the muzzle flame of a barrel weapon based on visible light radiation energy. BACKGROUND

[0002] The muzzle flame is characterized by high temperature and visible light emission, and is a physical phenomenon in which the residual energy of the propellant gas in the aftereffect period burns near the muzzle and radiates visible light. The size of the flame is directly related to the environment, pressure, muzzle flow field, and propellant combustion products of the barrel weapon.

[0003] Currently, whether it is a light weapon or a medium and large caliber gun, the muzzle flame is tested by using high-speed cameras, cameras and other equipment to image the muzzle flame, and then the corresponding characterization parameters are obtained by processing the images. The characterization parameters can be summarized as three aspects of the geometric size, brightness and duration of the flame. The results are different in terms of expression, but none of them embodies the comprehensive characterization of the harmful phenomena of launching, and cannot obtain a comprehensive evaluation parameter that can express the harmful phenomena of launching. At the same time, the existing methods usually require specific environmental requirements when observing and testing the muzzle flame. Because the brightness of the reference light source in the test environment is unknown, it may lead to poor repeatability of the test results, which is not conducive to the scientific evaluation of the harmful phenomena of launching. SUMMARY

[0004] The present application provides a comprehensive evaluation method for the muzzle flame of a barrel weapon based on visible light radiation energy, which includes the following steps:

[0005] In the sampling space, a high-speed camera is used to shoot a sequence of pictures of the muzzle flame of the barrel weapon.

[0006] A flame analysis software is used to input the scale length to calculate the calibration length of a unit pixel, and the flame area in the picture is obtained according to the calibrated unit pixel length. The program calculates according to formula (1):

[0007] (1)

[0008] In the formula, L is the scale length, mm; N is the number of pixels occupied by the scale in the image; K is the calibration length of a unit pixel, mm;

[0009] At the same time, the gray scale processing is carried out, the reference light source is corrected by formula (2), the calibration gray value is calculated according to the corresponding relationship between the brightness and the gray scale obtained by the brightness meter, and the brightness value of the flame is calculated.

[0010] (2)

[0011] Calculate the luminous flux value of the muzzle flame according to the formula (3) for calculating luminous flux.

[0012] (3)

[0013] In the formula, L v Brightness, cd / m 2 ; Let be the luminous flux, representing the intensity of the radiation's stimulation of vision, expressed in lm; if S is the flame area, then for dS, By integration, we can obtain .

[0014] For muzzle flash, the wavelength of the flame light of similar weapons is relatively concentrated, so it is considered to be a constant, and thus the luminous flux is proportional to the radiant flux.

[0015] Finally, based on the duration of the flame, the visible light radiation energy of the muzzle flame was obtained (4).

[0016] j (4)

[0017] In the formula, t is the duration of the flame (ms); n is the number of reference light source points on the flame area; and m is the number of flame images captured.

[0018] For each propellant and charge, two valid data points were collected, and the average value was taken. The results should be rounded to one decimal place. Comparative analysis showed that the higher the visible light radiation energy, the more harmful the flame.

[0019] This invention provides a more comprehensive evaluation method for muzzle flash of barrel-type weapons compared to traditional characterization techniques. The luminescence of muzzle flash is essentially an energy transfer process; therefore, measuring the size of the flash from an energy perspective is scientifically sound. It comprehensively reflects the duration, brightness, and geometric dimensions of the flash, enabling effective assessment of this harmful firing phenomenon. Attached Figure Description

[0020] Figure 1 A schematic diagram of a high-speed photography testing system provided in an embodiment of the present invention;

[0021] Figure 2 The image shows the flame captured by the high-speed camera in Example 1.

[0022] Figure 3 The image shows the flame captured by the high-speed camera in Example 2. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below according to specific embodiments of the present invention. The described embodiments are some, not all, of the embodiments of the present invention. The scope of protection of the present invention is not limited to the described content.

[0024] All embodiments were carried out under the following implementation conditions:

[0025] Test site: A test site with a width of 30m and 20m shall be set up in front of the muzzle, and the impact point shall be equipped with conditions for the warhead to be contained.

[0026] Ammunition: The ammunition used for testing should be qualified products, and the type of propellant should meet the technical requirements;

[0027] Experimental materials: Meter stick is 100 m long and has a graduation of 1 cm;

[0028] Meteorological conditions: No rain or snow, and relatively stable environmental conditions;

[0029] Implementing instruments, equipment, and testing apparatus:

[0030] The testing system consists of a barrel weapon, a high-speed camera, a scale, a data acquisition and processing system, a reference light source, and a luminance meter. A schematic diagram of the testing system is shown below. Figure 1 ;

[0031] The scale is 2000 mm long and 30 mm in diameter, and is decorated with alternating red and white stripes 200 mm long.

[0032] The weapons and armored vehicles meet the requirements of WJ2127-1993 or GJB 2971-1997, have passed inspection, and have a certificate of conformity.

[0033] High-speed camera: shooting speed of no less than 5000 frames / second, gigabit network cable interface, TTL trigger or switch trigger;

[0034] Reference light source: luminance ≥ 400 cd / m 2 Light-emitting area ≥300×300 mm 2 ;

[0035] Luminometer: Accuracy ±5%;

[0036] Data acquisition and processing system: flame analysis software with a resolution of no less than 16 bits, a sampling rate of no less than 100 K / s, multiple triggering modes, and functions for flame area calculation, grayscale processing, and brightness value calculation and statistics;

[0037] Test conditions:

[0038] ① Weapons and ammunition: The weapon chamber and ammunition must be wiped clean and free of oil and other impurities; ② Propellant and charge selection must meet the standard of qualified internal ballistic performance;

[0039] The gun-mounted weapons are in a horizontal firing position;

[0040] Gunner: Gunners should receive specialized training before the trial and must be proficient and accurate in their operations. They should operate according to the service guidelines for the corresponding weapon type.

[0041] Preheating of the testing instrument: Turn on the instrument system power and preheat for no less than 20 minutes;

[0042] High-speed camera: according to Figure 1 Set up the lens 10-30 m to the side of the weapon, with the lens optical axis perpendicular to the weapon barrel axis and the barrel axis horizontal. Adjust the focus and ensure, through testing, that the flame area is captured completely and clearly. The aperture setting should not exceed 5.6.

[0043] Example 1

[0044] Step 1: As Figure 1 A muzzle flash testing system was set up. After the instrument was preheated for 25 minutes, the shooter fired the weapon, and a high-speed camera recorded the sequence of flash images. Figure 2 ).

[0045] Step 2: Use flame analysis software to count the number of pixels in the flame area, convert it to the actual area, and calculate the flame area as 482.70 mm based on the length calibration formula to obtain the calibrated unit pixel length. 2 .

[0046] Step 3: Using the muzzle section as a reference, place a reference light source 1 m away from the muzzle, at the same height as the muzzle. Position a luminance meter next to the high-speed camera, directly facing the reference light source, at the same height. Measure the luminance of the reference light source using the luminance meter. Perform grayscale processing on the flame image using flame analysis software, obtaining an IOD of 19009906. Calculate the grayscale value of the reference light source to be 255; the luminance value of the reference light source is 800 cd / m². 2 The luminance value measured by the luminance meter was 739 cd / m². 2 The calibrated grayscale value of the corresponding reference light source was calculated to be 276 according to the grayscale value calibration formula; the software analysis showed that the flame grayscale value was 132, and the flame brightness value was calculated to be 382.61 cd / m². 2 .

[0047] Step 4: The luminous flux value of the image is 0.32 lm obtained from the luminous flux calculation formula. The flame duration is measured to be 29 ms, and the number of flame amplitudes captured is 1. Substitute these values ​​into the visible light radiation energy calculation formula: j =9.702×10 −3 lm·s.

[0048] Example 2

[0049] Step 1: The operating environment is the same as in Example 1, using the same propellant and charge as in Example 1, without changing the operation, and a high-speed camera records the flame sequence images. Figure 3 ).

[0050] Step 2: Use flame analysis software to count the number of pixels in the flame area, convert it to the actual area, and calculate the calibrated unit pixel length using the length calibration formula. Figure 3 The peak flame area (a) is 502.21 mm. 2 The area of ​​the other flame (b) is 216.35 mm. 2 .

[0051] Step 3: The calibrated grayscale value of the reference light source is 276. The software analysis shows... Figure 3 In (a), the flame ash value is 121, and the calculated flame brightness value is 350.72 cd / m². 2 ; Figure 3 (b) The flame ash value is 94, and its flame brightness value is 272.46 cd / m². 2 .

[0052] Step 4: Obtain from the luminous flux calculation formula Figure 3 (a) has a luminous flux of 0.30 lm. Figure 3 (b) has a luminous flux of 0.13 lm, a measured flame duration of 32 ms, and 2 flame amplitudes captured. Substituting these values ​​into the visible light radiation energy calculation formula: j =1.233×10 −2 lm·s.

[0053] Step 5: Take the average visible light radiation energy of Examples 1 and 2, rounding it to one decimal place. The average visible light radiation energy is 1.1 × 10⁻⁶. −2 lm·s, which is used to characterize the intensity of the muzzle flash of a barrel weapon.

[0054] The above description is a preferred embodiment of the present invention and not a limiting description. Any person skilled in the art, upon understanding the principles of the present invention, can make various improvements or changes to the embodiments. These derivative solutions that incorporate the key points of the method of the present invention, as long as they still fall within the technical scope defined by the claims, should be considered as the object of protection of the present invention.

Claims

1. A method for evaluating the muzzle flash of a barrel weapon based on visible light radiation energy, characterized in that, Includes the following steps: (1) Within the sampling space, a high-speed camera is used to capture images of the muzzle flash sequence of the barrel weapon; (2) The calibration process is performed using flame analysis software: the calibration length K of a unit pixel is calculated by inputting the ruler length, where K = L / N, and L is the actual length of the ruler (mm) and N is the number of pixels occupied by the ruler in the image; (3) Calculate the flame area based on the calibration results; (4) Perform grayscale processing on the image using the formula: The grayscale values ​​are corrected, and the brightness values ​​of each point in the image are obtained based on the correspondence between brightness and grayscale obtained from the luminance meter. (5) Calculate the luminous flux value using the luminous flux calculation formula, which is: In the formula L v Brightness, cd / m 2 ; Let be the luminous flux, representing the intensity of the radiation's stimulation of vision, expressed in lm; if S is the flame area, then for dS, By integration, we can obtain ; (6) The visible light radiation energy is calculated by formula based on the flame duration t (ms) and the number of reference light source points n on the flame area.

2. The method for evaluating the muzzle flash of a barrel-shaped weapon according to claim 1, characterized in that: Under the test conditions, the weapon must meet the requirements of WJ2127-1993 or GJB 2971-1997 and be in a horizontal firing position.

3. The method for evaluating the muzzle flash of a barrel-shaped weapon according to claim 1, characterized in that: When setting up the device, the high-speed camera should be installed 10m-30m away from the weapon, with the lens optical axis perpendicular to the weapon tube axis and the tube axis horizontal, and the aperture set no higher than 5.

6.

4. The method for evaluating the muzzle flash of a barrel-shaped weapon according to claim 1, characterized in that: Take at least two valid data points for each propellant and charge, calculate the average value, and keep the result to one decimal place.

5. The method for evaluating the muzzle flash of a barrel-shaped weapon according to claim 1, characterized in that: The formula for calculating visible light radiation energy is: , where m is the number of images of the flame captured; — The luminous flux corresponding to the j-th image, in lm; E — the energy radiated during the flame's formation, which is simplified due to the proportional relationship and is therefore used as a dimensionless value for comparison; E is the final evaluation index.

6. The method for evaluating the muzzle flash of a barrel-shaped weapon according to claim 1, characterized in that: The evaluation results are used to characterize the harmfulness of the muzzle flash of a barrel weapon. The larger the E value, the higher the harmfulness of the flash. The visible light radiation energy value is positively correlated with the harmfulness.

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