Large-size uniform rectangular oblique irradiation lane light supplementing system
By designing a large-sized, uniform rectangular lane-sloping supplementary light and adopting a freeform lens structure, the problem of uneven light spots was solved, achieving efficient and uniform illumination and improving the imaging quality of road monitoring.
Patent Information
- Application Number
- CN202610018025.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-08
- Publication Date
- 2026-02-24
AI Technical Summary
Existing supplementary lighting devices in road monitoring suffer from problems such as insufficient or excessive light spot size and uneven illumination, resulting in poor exposure consistency in the shooting scene and affecting image quality.
A large-size uniform rectangular oblique lane illumination lamp is designed, which adopts a freeform lens structure with a hemispherical incident surface and a freeform exit surface. The feature length is optimized by the KE algorithm to achieve a highly uniform rectangular light spot.
Achieving high luminous efficiency and high uniformity of illumination within large target areas extends the effective area for camera capture, reduces the power requirement of the light source, and improves image quality.
Smart Images
Figure CN121557441A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of road supplementary lighting technology, specifically to a large-size uniform rectangular oblique illumination lane supplementary lighting system. Background Technology
[0002] In the field of traffic monitoring, for applications involving the capture and recognition of vehicle license plate information, in order to improve recognition efficiency in low-light environments, a common approach is to use supplementary lighting in conjunction with camera equipment. During the capture process, supplementary lighting is used to illuminate specific areas, increasing the illumination level of the captured area and making the information in the captured image easier to recognize. Similarly, cellular code coded tags designed based on the retroreflection principle also require supplementary lighting next to the camera equipment to enable the cellular code coded tags to be better recognized by the system.
[0003] Existing supplementary lighting devices mainly consist of two parts: a light source assembly and optical lenses. The light source typically employs a single or multiple light source configuration, while the accompanying optical lenses are usually designed as circular optical structures or simple microlens arrays. In practical road applications, this traditional circular structure has been found to have significant performance defects: when the formed circular light spot is small, the effective supplementary lighting coverage area is insufficient; while when the light spot diameter is too large, it creates a large area of unnecessary illumination. Furthermore, the simple microlens array structure has difficulty conforming the boundary of the illumination area to the target, and its uniformity is poor, generally resulting in strong illumination in the center of the target area and weak illumination at the edges.
[0004] Existing solutions struggle to achieve uniform energy distribution in oblique illumination environments during road lighting, making it difficult to guarantee consistent exposure across different areas in large-scale shooting scenarios and impacting overall image quality. Summary of the Invention
[0005] To address the aforementioned problems in the existing technology, this invention provides a design for a large-size uniform rectangular lane fill light with oblique illumination. The fill light has a simple lens structure, is easy to manufacture, has high luminous efficiency, and can achieve a large-size uniform rectangular light spot under oblique illumination.
[0006] To achieve the above objectives, the present invention provides a large-size uniform rectangular oblique lane illumination lens, which includes an incident surface and an exit surface. The incident surface is a hemispherical surface generated by rotating an arc with the origin of the light distribution coordinate system as the center. The exit surface is a free-form surface shape optimized by iteratively adjusting the feature length K according to the distribution of the target light spot light distribution curve in the light distribution coordinate system using the KE algorithm. The technical solution of the present invention is as follows: A large-size uniform rectangular oblique illumination lane supplementary lighting system includes: a supplementary lighting module, an optical sensing module, and a lane; The optical sensing module and the supplementary lighting module are installed side by side on the road signal pole, and the distance between them and the ground is the illumination height; The supplementary lighting module includes a light source and a freeform lens. The incident surface of the freeform lens is a hemispherical surface, and the exit surface is a freeform surface. The optical sensing module includes an imaging unit, a control unit, and a communication unit. The field of view of the optical sensing module covers the target area of the lane and is used to collect information about the target area. The lane receives a highly uniform rectangular light spot after being distributed by a freeform surface lens.
[0007] Furthermore, the incident surface of the freeform lens is a hemispherical surface generated by rotating an arc with the origin of the light distribution coordinate system as the center; its exit surface is a freeform surface generated in the light distribution coordinate system according to the distribution of the target light spot light distribution curve.
[0008] Furthermore, the origin O1 of the light distribution coordinate system is the center of the light source, and the Z1 axis is the normal vector at the center of the light source; its X1 axis is in the same plane as the longitudinal direction of the road and is perpendicular to the Z1 axis, and its Y1 axis is parallel to the transverse direction of the road and is perpendicular to the Z1 axis.
[0009] Furthermore, the highly uniform rectangular light spot is rectangular, completely covering the target area of the lane. Its side length is one in the horizontal direction of the road and its side length is two in the vertical direction of the road. The distance between its geometric center and the origin of the lighting coordinate system is the illumination distance.
[0010] Furthermore, the origin O2 of the lighting coordinate system is the projection of the center of the light source onto the lane; the ray emanating from the origin and passing through the center of the light source is defined as the Z2 axis, the lane is the X2O2Y2 plane, the X2 axis is parallel to the longitudinal direction of the road and perpendicular to the Z2 axis, and the Y2 axis is parallel to the transverse direction of the road and perpendicular to the Z2 axis.
[0011] Furthermore, the point on the freeform surface that passes through the Z1 axis in the light distribution coordinate system is defined as the surface base point. Several feature planes are selected at equal intervals through the Z1 axis and perpendicular to the X1O1Y1 plane. The feature planes intersect with the freeform surface to obtain the same number of feature curves. The same number of feature points are selected from the several feature curves to describe the freeform surface, and the distance from the feature points to the Z axis is the same.
[0012] The feature points are described using hypercurvature parameters, wherein: a feature plane is defined as a first feature plane, and the feature curve obtained by the intersection of the first feature plane and the freeform surface is defined as a first feature curve. The first curvature and the first tangent vector of the feature points are calculated. Based on the first tangent vector of the first feature curve at each feature point, a cutting plane passing through the feature point and perpendicular to the first tangent vector is obtained. The cutting plane is defined as a second feature plane. The second feature plane intersects with the exit surface to obtain a second feature curve, and the second curvature and the second tangent vector are calculated. The feature points are described by the first curvature and the second curvature. When the curve bends toward the light source, the curvature value is positive; when the curvature bends away from the light source, the curvature value is negative.
[0013] Furthermore, the feature points on the freeform surface are named P(1), P(2), P(3), P(4), P(5), and P(6) in a counterclockwise direction, satisfying the following conditions: The first curvature of P(1) is 0.8289, and the second curvature is 0.0600; The first curvature of P(2) is 0.3312, and the second curvature is 0.1819; The first curvature of P(3) is 0.4200, and the second curvature is 0.4378; The first curvature of P(4) is 0.5644, and the second curvature is 0.3700; The first curvature of P(5) is 0.2979, and the second curvature is 0.3087; The first curvature of P(6) is 0.2900, and the second curvature is 0.1899.
[0014] Furthermore, the deviation of the curvature value C of each feature point corresponding to the freeform surface does not exceed ±20%C; the variation of the uniformity U of the rectangular light spot formed by the freeform surface does not exceed ±10%U; wherein, the uniformity U is calculated as the minimum / maximum illuminance within the target area = uniformity.
[0015] The beneficial effects of this invention are as follows: The present invention is a freeform surface lens design for supplementary lighting. The preferred freeform area has a smooth surface shape that is easy to process, high conformity to rectangular light spot morphology, high luminous efficiency, and good uniformity.
[0016] Compared to existing conventional lenses, the lens of this invention can more effectively confine light to the area requiring supplemental lighting, thereby reducing the power requirements of the light source; at the same time, the uniformity of the light spot in a large target area can be above 80%, greatly extending the effective supplemental lighting area for video capture.
[0017] The light intensity distribution of conventional lenses is often strong in the center and weak on both sides. As a vehicle moves from far to near, the fill light spot will change from weak to strong and then back to weak, which limits the shooting distance and position. The lens of this invention takes into account the working environment of the rangefinder illumination, so that the designed light spot maintains high uniformity on the horizontal plane, and the front and rear position of the vehicle during the video capture process will not affect the shooting effect. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the overall optical path from an oblique angle. Figure 2 This is a top view of the optical path; Figure 3 This is the front view of the supplementary lighting lens; Figure 4 This is a top view of the supplementary lighting lens; Figure 5 The images show the illuminance diagrams of the vertically illuminated light spots of the present invention and common lenses in the simulation; where (a) is the illuminance diagram of the vertically illuminated light spot of the lens of the present invention in the simulation; and (b) is the illuminance diagram of the vertically illuminated light spot of a common lens in the simulation. Figure 6 The images show the illumination of the light spot under the working angle of the lens of the present invention and common lenses in the simulation; where (a) is the illumination of the light spot under the working angle of the lens of the present invention in the simulation. Figure 6 (b) is the illuminance diagram of the spot under common lens working angles in the simulation; Figure 7 This is an illuminance diagram of the vertically irradiated spot during the experiment; Figure 8 This is a diagram of the light spot illuminance at the working angle during the experiment; Figure 9 This is a schematic diagram of a freeform surface. Figure 10 This is a schematic diagram of the characteristic curve and its corresponding tangent vector; Figure 11 Top view of the characteristic curve; Figure 12 This is a schematic diagram of the feature point normal vector. Figure 13 This is a schematic diagram of the overall feature points; Figure 14 A schematic diagram of each feature point; In the diagram: 1. Supplemental lighting module; 11. Light source; 12. Freeform surface lens; 121. Incident surface; 122. Exit surface; 1221. Feature point; 1222. First feature curve; 1223. First tangent vector; 1224. Second feature curve; 1225. Second tangent vector; 2. Optical sensing module; 21. Illumination height; 3. Lane; 32. Target area; 4. O1X1Y1Z1 coordinate system; 5. O2X2Y2Z2 coordinate system. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0020] This application provides a design for a large-size, uniform rectangular oblique lane illumination lamp. It should be noted that the large-size, uniform rectangular oblique lane illumination lamp lens provided in this application is used to provide high-uniformity, long-distance rectangular illumination of the shooting area during road monitoring and capture processes, with the following effect: Figure 1 , Figure 2 As shown.
[0021] The supplementary lighting and road surveillance camera system are installed on the road signal poles, such as... Figure 1 In the lighting coordinate system (5), the distance between the device and the ground, i.e. the illumination height, is 4.5m.
[0022] The origin O2 of the lighting coordinate system is the projection of the center of the light source onto the ground (receiving surface); the ray emanating from the origin and passing through the center of the light source is defined as the Z2 axis; the ground (receiving surface) is the X2O2Y2 plane; the direction parallel to the longitudinal direction of the road and perpendicular to the Z2 axis is defined as the X2 axis; and the direction parallel to the transverse direction of the road and perpendicular to the Z2 axis is defined as the Y2 axis.
[0023] In the lighting coordinate system, the light spot after the fill light lens distributes the light is as follows: Figure 6 As shown in (a), its side length along the transverse direction of the road is 4m, its side length along the longitudinal direction of the road is 10m, and the distance between the geometric center of the light spot and the origin of the lighting coordinate system is 13m. Freeform surface lenses, such as Figure 3 As shown, it includes an incident surface 121 and an exit surface 122. The incident surface 121 is a hemispherical surface generated by rotating an arc centered at the origin of the light distribution coordinate system, used to reduce the deflection angle of the light source after refraction. The exit surface 122 is a freeform surface shape optimized by iteratively adjusting the feature length K according to the distribution of the target light spot's light distribution curve in the light distribution coordinate system using the KE algorithm, used for shaping the light distribution of the light source. Its surface shape is as follows: Figure 9 As shown.
[0024] The freeform lens is designed in a light distribution coordinate system. The origin of the light distribution coordinate system is the center of the light source, and the Z1 axis is the normal vector at the center of the light source. The X1 axis is defined as the direction that is in the same plane as the longitudinal direction of the road and is perpendicular to the Z1 axis. The Y1 axis is defined as the direction that is parallel to the transverse direction of the road and is perpendicular to the Z1 axis.
[0025] like Figure 13As shown, the Z-axis in the light distribution coordinate system passes through the points on the freeform surface as the surface base points. A feature plane is selected every 60 degrees, passing through the Z1 axis and perpendicular to the X1O1Y1 plane. The intersection of the feature planes with the freeform surface yields 6 feature curves. The same number of feature points are selected from these feature curves (i.e., one feature point is selected on each feature curve) to describe the morphology of the freeform surface. The distance from each feature point to the Z-axis is 1.5 mm.
[0026] The characteristic plane is defined as the first characteristic plane, and the characteristic curve obtained by the intersection of this plane and the freeform surface is defined as the first characteristic curve, such as... Figure 12 As shown, the first tangent vector of the feature point can be calculated based on the feature point and another point on the curve close to the feature point. Then, by selecting three or five points at equal intervals centered on the feature point, the first curvature of the feature point can be calculated using the method of passing through a common circle. Based on the first tangent vector of the first feature curve at each feature point, a cutting plane passing through the feature point and perpendicular to the first tangent vector is obtained. This cutting plane is defined as the second feature plane. The second feature plane intersects with the exit surface to obtain the second feature curve, and the second curvature and the second tangent vector are calculated. Figure 10 The figure shows the first characteristic curve, the second characteristic curve, and the two tangent vectors used for a certain feature point; the feature point is described by the first curvature and the second curvature; when the curve bends toward the light source, the curvature value is positive; when the curvature bends away from the light source, the curvature value is negative.
[0027] like Figure 14 As shown, the feature points on the freeform surface are named P(1), P(2), P(3), P(4), P(5), and P(6) in a counterclockwise direction, and they satisfy the following conditions: The first curvature of P(1) is 0.8289, and the second curvature is 0.0600; The first curvature of P(2) is 0.3312, and the second curvature is 0.1819; The first curvature of P(3) is 0.4200, and the second curvature is 0.4378; The first curvature of P(4) is 0.5644, and the second curvature is 0.3700; The first curvature of P(5) is 0.2979, and the second curvature is 0.3087; The first curvature of P(6) is 0.2900, and the second curvature is 0.1899.
[0028] When the curvature values of each feature point on the freeform surface of the lens deviate by less than 20%, and the uniformity of the rectangular light spot changes by less than 10%, it is still considered a congruent transformation of the freeform surface; the freeform surfaces mentioned above are all within the protection scope of this invention.
[0029] In summary, the large-size uniform rectangular oblique illumination lane supplementary light of the present invention has a simple structure, is easy to manufacture, and can achieve high luminous efficiency and high uniformity of light spot within a rectangular target area under large-angle oblique incidence conditions.
[0030] The above description is merely for the convenience of those skilled in the art to understand the technical solutions of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A large-size uniform rectangular oblique lane supplementary lighting system, characterized in that, include: The supplementary lighting module (1), the optical sensing module (2), and the lane (3) are included. The optical sensing module (2) and the supplementary lighting module (1) are installed side by side on the road signal pole, and the distance between them and the ground is the illumination height; The supplementary lighting module (1) includes a light source (11) and a freeform lens (12). The incident surface (121) of the freeform lens (12) is a hemispherical surface, and the exit surface (122) is a freeform surface. The optical sensing module (2) includes an imaging unit, a control unit and a communication unit. The field of view of the optical sensing module (2) covers the target area (32) of the lane (3) and is used to collect information about the target area. The lane (3) receives a highly uniform rectangular light spot (31) after being distributed by the freeform lens (12).
2. The large-size uniform rectangular oblique lane supplementary lighting system according to claim 1, characterized in that, The incident surface (121) of the freeform lens (12) is a hemispherical surface generated by rotating an arc with the origin of the light distribution coordinate system as the center; its exit surface (122) is a freeform surface generated in the light distribution coordinate system according to the distribution of the target light spot light distribution curve.
3. The large-size uniform rectangular oblique lane supplementary lighting system according to claim 2, characterized in that, The origin O1 of the light distribution coordinate system is the center of the light source, and the Z1 axis is the normal vector at the center of the light source; its X1 axis is in the same plane as the longitudinal direction of the road and is perpendicular to the Z1 axis, and its Y1 axis is parallel to the transverse direction of the road and is perpendicular to the Z1 axis.
4. The large-size uniform rectangular oblique lane supplementary lighting system according to claim 1, characterized in that, The high uniformity rectangular light spot (31) is rectangular and completely covers the target area (32) of the lane (3). Its side length is one (311) along the horizontal direction of the road and its side length is two (312) along the vertical direction of the road. The distance between its geometric center and the origin of the lighting coordinate system is the illumination distance (313).
5. A large-size uniform rectangular oblique lane supplementary lighting system according to claim 4, characterized in that, The origin O2 of the lighting coordinate system is the projection of the center of the light source onto the lane (3); the ray emanating from the origin and passing through the center of the light source is defined as the Z2 axis, the lane is the X2O2Y2 plane, the X2 axis is parallel to the longitudinal direction of the road and perpendicular to the Z2 axis, and the Y2 axis is parallel to the transverse direction of the road and perpendicular to the Z2 axis.
6. A large-size uniform rectangular oblique lane supplementary lighting system according to claim 3, characterized in that, The Z1 axis in the light distribution coordinate system is defined as the point on the freeform surface as the surface base point. Several feature planes are selected at equal intervals, passing through the Z1 axis and perpendicular to the X1O1Y1 plane. The feature planes intersect the freeform surface to obtain the same number of feature curves. The same number of feature points (1221) are selected from the several feature curves to describe the freeform surface, and the feature points (1221) are at the same distance from the Z axis. The feature points are described using hypercurvature parameters, wherein: the feature plane is defined as the first feature plane, the feature curve obtained by the intersection of the first feature plane and the freeform surface is defined as the first feature curve (1222), and the first curvature and the first tangent vector (1223) of the feature points are calculated; based on the first tangent vector (1223) of the first feature curve (1222) at each feature point, a cutting plane passing through the feature point and perpendicular to the first tangent vector (1223) is obtained, and the cutting plane is defined as the second feature plane, the second feature plane intersects with the exit surface to obtain the second feature curve (1224), and the second curvature and the second tangent vector (1225) are calculated; the feature points are described by the first curvature and the second curvature; when the curve bends toward the light source, the curvature value is positive; when the curvature bends away from the light source, the curvature value is negative.
7. The large-size uniform rectangular oblique lane supplementary lighting system according to claim 6, characterized in that... The feature points on the freeform surface are named P(1), P(2), P(3), P(4), P(5), and P(6) in a counterclockwise direction, and they satisfy the following conditions: The first curvature of P(1) is 0.8289, and the second curvature is 0.0600; The first curvature of P(2) is 0.3312, and the second curvature is 0.1819; The first curvature of P(3) is 0.4200, and the second curvature is 0.4378; The first curvature of P(4) is 0.5644, and the second curvature is 0.3700; The first curvature of P(5) is 0.2979, and the second curvature is 0.3087; The first curvature of P(6) is 0.2900, and the second curvature is 0.1899.
8. The large-size uniform rectangular oblique lane supplementary lighting system according to claim 7, characterized in that... The deviation of the curvature value C of each feature point of the freeform surface shall not exceed ±20%C; the variation of the uniformity U of the rectangular light spot formed by the freeform surface shall not exceed ±10%U; wherein, the uniformity U is calculated as the minimum illuminance / maximum illuminance in the target area = uniformity.