Road surface illumination calculation method

Abstract

The present invention belongs to the field of transportation technology, and particularly relates to a method for calculating road surface illumination, wherein the ratio of the converted road surface illumination E to the measured illumination E' is first calculated and recorded as a conversion coefficient σ; then the measured illumination E' is detected on the road to be tested, and the converted road surface illumination is calculated by substituting the measured illumination E' into the formula E=σE'. The present invention can realize the conversion of illumination at different height positions, and provides a new solution for the situation where the target illumination measurement is difficult or impossible to measure.

Description

Technical Field

[0001] The invention belongs to the technical field of transportation, and in particular relates to a method for calculating road surface illumination. Background Art

[0002] The illuminance and uniformity of urban road lighting fixtures will directly affect the visual effect of drivers when vehicles are driving, and thus affect traffic safety. Therefore, road illumination detection is an indispensable part of road lighting system detection. At present, road illumination detection is performed by staff collecting illumination information in the lane. The measurement workload is large, the speed is slow, and the data technology and processing work are complicated. When measuring on roads that have been opened to traffic, the personal safety of the inspectors is difficult to guarantee.

[0003] Chinese patent CN104655402A discloses "an on-site testing device for LED street lamps", in which an illuminance collection board is arranged on the top of a traveling vehicle. The illuminance collected is the illuminance at the illuminance collection board, rather than the illuminance of the road surface. Therefore, it is impossible to accurately evaluate the road lighting effect, and it is also impossible to ensure the safety of vehicle driving. Summary of the invention

[0004] The object of the present invention is to provide a road surface illuminance calculation method capable of obtaining a road surface illuminance that conforms to the actual road surface illuminance based on detected illuminance data.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a method for calculating road surface illumination, S01: calculating the ratio of the converted road surface illumination E to the measured illumination E′, recorded as the conversion coefficient σ; S02: detecting the measured illumination E′ on the road to be tested, substituting it into the formula E=σE′ to calculate the converted road surface illumination.

[0006] The present invention can realize the conversion of illumination at different height positions, and provides a new solution for the situation where the target illumination measurement is difficult or impossible. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The following is a brief description of the contents and symbols in the drawings of this specification:

[0008] Figure 1 , 2 is a schematic diagram of the present invention;

[0009] In the figure: 10. Detection point, 20. Road surface projection point, 11. Street light one, 12. Street light two, 13. Street light three, 14. Street light four, 15. Street light five. DETAILED DESCRIPTION

[0010] The specific implementation of the present invention is further described in detail below through description of embodiments in conjunction with the accompanying drawings.

[0011] A road surface illumination calculation method.

[0012] S01: Calculate the ratio of the converted road illuminance E to the measured illuminance E′, which is recorded as the conversion coefficient σ;

[0013] S02: Detect and obtain the measured illuminance E′ on the road to be tested, and substitute it into the formula E=σE′ to calculate the converted road surface illuminance.

[0014] In this way, the illuminance of the target position at a different height can be obtained based on the measured illuminance, which provides a new solution for the situation where the illuminance measurement of the target position is difficult or impossible to measure.

[0015] The road surface illumination is usually obtained by superimposing the illumination of the street lamps around the detection point 10 at that location. Therefore, in this embodiment, the conversion coefficient is calculated by the following method:

[0016] The measured illuminance is the sum of the illuminance of the street lamps adjacent to the detection point 10, and the road surface illuminance is converted to the sum of the illuminance of the street lamps adjacent to the detection point 10 at the road surface projection point 20, that is,

[0017]

[0018]

[0019] but

[0020] Where n is the number of street lights near detection point 10,

[0021]

[0022] cosθ i =(H i -h) / r i ,

[0023] r i 2 =x i 2 +y i 2 +H i -h 2 ,

[0024]

[0025] cosα i =H i / R i ,

[0026] R i 2 =x i 2 +yi 2 +H i 2 ,

[0027] In the above formula,

[0028] E′ i The illuminance is measured for a single lamp of a street lamp;

[0029] E i Convert road illumination for a single street lamp;

[0030] θ i is the angle between the incident light of the street lamp and the normal of the detection point 10,

[0031] α i is the angle between the incident light of the street lamp and the 20° normal of the projection point on the road surface,

[0032] I′ i is the luminous intensity of the street lamp at the detection point 10, which is related to the type, specification and θ of the street lamp i Related,

[0033] I i is the luminous intensity of the street lamp at the projection point 20 on the road surface, which is related to the type, specification and α of the street lamp i Related,

[0034] r i is the distance between the street lamp and the detection point 10,

[0035] R i is the distance between the street lamp and the projection point 20 on the road surface,

[0036] x i is the distance between the street lamp and the detection point 10 in the direction of the road length, which is a known constant.

[0037] y i is the distance between the street lamp and the detection point 10 in the road width direction, which is a known constant;

[0038] H i is the distance between the street lamp and the road surface, which is a known constant.

[0039] h is the distance between the detection point 10 and the road surface, which is a known constant.

[0040] When the illumination detection device is installed on the top of the vehicle and the road illumination is detected, the road to be tested has been built and the lanes have been divided. Therefore, after the detection device is arranged, y i It can be directly measured and is a known constant. The street lamp and detection device have been installed, so H i , h can be measured directly and are known constants.

[0041] xi It is determined by the position of the detection device on the road to be tested, and can be obtained according to the initial position of the detection device and its displacement direction and displacement length. The specific calculation scheme is that the detection device provides the distance x between the street lamp and the detection point 10 in the road length direction;

[0042] Assume that street lamp 11 is the street lamp with the smallest distance from detection point 10, and the distance between two adjacent street lamps is D. Then the value range of the distance x between the street lamp and detection point 10 in the road length direction is (0, D);

[0043] Assume that the detection device is at the detection starting position, the distance between the adjacent side street lamps in the road length direction is x0, and the displacement length of the detection device in the road length direction is l, then

[0044] x1=|x0+1-nD1| max ,

[0045] The distance between the street lamp 3 13 located on the same side of the street lamp 11 and arranged adjacent to the street lamp 11 and the detection point 10 in the road length direction is,

[0046] x3=D1-x1.

[0047] To simplify the calculation, each street lamp can be regarded as a point light source, and the luminous intensity of the street lamp in each direction is equal, that is, I′ i ≈I i .

[0048] When all street lamps are of the same type with the same specifications and consistent luminous intensity, the luminous intensity of each street lamp at the detection point 10 and the road surface projection point 20 is considered equal.

[0049]

[0050] Take the reciprocal and substitute it into the following formula to get the corresponding conversion coefficient value.

[0051]

[0052] In order to simplify the calculation while ensuring the accuracy of illumination conversion, when street lights are installed on only one side of the road to be tested, n=2 is taken.

[0053] When x1≠0, the detection illuminance is the sum of the illuminances of the two street lamps with the smallest distance from the detection point 10, that is, E′=E′1+E′2, E=E1+E2;

[0054] When x1=0, the distances between the two street lamps on both sides of the street lamp 11 and the detection point 10 are consistent, and the illumination of the two street lamps at the detection point 10 is also consistent, that is, E′=E′1+2E′2, E=E1+2E2.

[0055] When street lights are installed on both sides of the road, n=4.

[0056] Among them, street light one 11 is located on the side adjacent to the lane, street light two 12 is the street light farthest from the lane and the smallest distance from the detection point 10, street light three 13 is located on the same side of street light one 11 and arranged adjacent to it, and street light four 14 is located on the same side of street light two 12 and arranged adjacent to it;

[0057] The distance between the street lamp 3 13 located on the same side of the street lamp 11 and arranged adjacent to the street lamp 11 and the detection point 10 in the road length direction is,

[0058] When x1≠0, the detection illuminance is the sum of the illuminances of the four street lamps with the smallest distance from the detection point 10, that is, E′=E′1+E′2+E′3+E′4, E=E1+E2+E3+E4, as shown in the attached figure. Figure 1 As shown;

[0059] In this embodiment, the specifications of the street lamps are set to be the same, the luminous intensity is consistent, and the luminous intensity of each street lamp at the detection point 10 and the road projection point 20 is approximately equal, that is, I1, I2, I3, I4, I′1, I′2, I′3, and I′4 are considered equal. Then it can be concluded that

[0060]

[0061] Taking the inverse side of it, we get The value of Substituting into the following formula, we can get the corresponding conversion coefficient value.

[0062]

[0063] When x1=0, if the street lamps on both sides of the road are staggered, the distance between the two street lamps on both sides of the street lamp 11 and the detection point 10 is consistent, and the distance between the two adjacent street lamps on the opposite side of the street lamp 11 and the detection point 10 is also consistent, then E′=E′1+2E′2+2E′3, E=E1+2E2+2E3. Figure 2 As shown, the distances between street lamp 2 12 and street lamp 4 14 and detection point 10 are equal, and the distances between street lamp 3 13 and street lamp 5 15 and detection point 10 are equal, so E′2=E′4, E′3=E′5.

[0064] If the street lights on both sides of the road are arranged symmetrically, the distance between the two street lights on both sides of street light 11 and the detection point 10 is consistent, and the distance between the two street lights on both sides of street light 2 12 and the detection point 10 is consistent, then E′=E′1+E′2+2E′3+2E′4, E=E1+E2+2E3+2E4.

Claims

1. A method for calculating road illumination, characterized in that: S01: Calculate the ratio of the converted road illuminance E to the measured illuminance E′, which is recorded as the conversion coefficient σ; S02: Detect and obtain the measured illuminance E′ on the road to be tested, and substitute it into the formula E=σE′ to calculate the converted road surface illuminance; In step S01, the conversion coefficient is calculated using the following method: The measured illuminance is the sum of the illuminances of the street lamps adjacent to the detection point (10), and the road surface illuminance is converted to the sum of the illuminances of the street lamps adjacent to the detection point (10) at the road surface projection point (20), that is, Where n is the number of street lights near the detection point (10), cosθ i =(H i -h) / r i , r i 2 =x i 2 +y i 2 +(H i -h) 2 , cosα i =H i / R i , R i 2 =x i 2 +y i 2 +H i 2 , In the above formula, E′ i The illuminance is measured for a single lamp of a street lamp; E i Convert road illumination for a single street lamp; θ i is the angle between the incident light of the street lamp and the normal of the detection point (10), α i is the angle between the incident light of the street lamp and the normal of the projection point (20) on the road surface, I i ′ is the luminous intensity of the street lamp at the detection point (10), which is related to the type, specification and θ of the street lamp i Related, I i is the luminous intensity of the street lamp at the projection point (20) on the road surface, which is related to the type, specification and α of the street lamp i Related, r i is the distance between the street lamp and the detection point (10), R i is the distance between the street lamp and the projection point (20) on the road surface, x i is the distance between the street lamp and the detection point (10) in the direction of the road length, which is a known constant. y i is the distance between the street lamp and the detection point (10) in the road width direction, which is a known constant; H i is the distance between the street lamp and the road surface, which is a known constant. h is the distance between the detection point (10) and the road surface, which is a known constant.

2. The road surface illumination calculation method according to claim 1, characterized in that: When each street lamp is a point light source with the same luminous intensity, I i ′≈I i .

3. The method for calculating road illumination according to claim 1, characterized in that: If the road to be tested is equipped with street lights on only one side, take n = 2. When x1≠0, the detection illuminance is the sum of the illuminances of the two street lamps with the smallest distance from the detection point (10) at that location, that is, E′=E′1+E′2, E=E1+E2; When x1=0, the distance between the two street lamps on both sides of street lamp 1 (11) and the detection point (10) is consistent, and the illumination of the two street lamps at the detection point (10) is also consistent, that is, E′=E′1+2E′2, E=E1+2E2.

4. The method for calculating road illumination according to claim 1, characterized in that: If street lights are installed on both sides of the road, take n = 4. Among them, street light one (11) is located on the side adjacent to the lane, and street light two (12) is the street light farthest from the lane and with the shortest distance from the detection point (10); When x1≠0, the detection illuminance is the sum of the illuminances of the four street lamps with the smallest distance from the detection point (10) at that location, that is, E′=E′1+E′2+E′3+E′4, E=E1+E2+E3+E4; When x1=0, if the street lights on both sides of the road are arranged symmetrically, the distance between the two street lights on both sides of street light one (11) and the detection point (10) is consistent, and the distance between the two street lights on both sides of street light two (12) and the detection point (10) is consistent, then E′=E′1+E′2+2E′3+2E′4, E=E1+E2+2E3+2E4; if the street lights on both sides of the road are arranged in a staggered manner, the distance between the two street lights on both sides of street light one (11) and the detection point (10) is consistent, and the distance between the two adjacent street lights on the opposite side of street light one (11) and the detection point (10) is also consistent, then E′=E′1+2E′2+2E′3, E=E1+2E2+2E3.

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