Image-based tunnel interior and exterior luminance detection system and detection method

Abstract

The invention relates to the technical field of luminance detection, and in particular relates to an image-based tunnel interior and exterior luminance detection system and detection method. The detection system comprises a switching power supply, a camera, an upper computer, a standard luminance meter, and an embedded processor; the camera is provided with focal length, aperture and an exposure time adjustable lens and is used for regulating the focal distance, the aperture and the exposure time as needed; the upper computer is used for displaying a video frame in real time, adjusting an installation angle, selecting an image region meeting a field angle at 20 DEG, and sending a focal length setting instruction of the camera according to the video frame. The image-based tunnel interior and exterior luminance detection system disclosed by the invention is precise in direction and field angle, short in measurement time, simple in data processing, and high in measurement precision in the measurement process of the interior and the exterior luminance; the system has the remote monitoring function, is convenient for maintenance, upgrading and updating, and saves the cost and improves the economic benefit at the same time.

Description

Technical field [0001] The invention relates to the technical field of brightness detection, in particular to an image-based brightness detection system and a detection method for the inside and outside of tunnels. Background technique [0002] The brightness outside the cave refers to the average brightness measured at a field angle of 20° in the direction of the cave entrance close to the starting point of the segment 1.5m from the ground. Generally, the traditional brightness meter is an aiming point type brightness meter. During the measurement process, the beam of the target to be measured enters the front objective lens, passes through the holed reflector and filter, and shines on the photodetector. The measuring field angle is measured by the holed reflector. Different diameters are determined by the circular holes, and different apertures can be selected by rotating the mirror with holes. It can be seen that the determination of the field of view requires a higher measure...

AI Technical Summary

Problems solved by technology

Generally, the traditional luminance meter is an aiming-point luminance meter. During the measurement process, the light beam of the target to be measured enters the front objective lens, passes through the perforated reflector and filter, and shines on the photodetector. The field of view is measured by the perforated reflector. Different diameters of circular holes are determined, and different apertures can be selected by rotating the perforated mirror. The determination of the visible field of view requires high measurement experience and operating level, and the measurement error is relatively large; The directionality and angle cannot be well controlled, and it is difficult to meet the standard requirement of a 20° field of view. Usually, the detected brightness value cannot truly represent the brightness value outside the cave, and there are unpredictable measurement deviations; and the traditional brightness measurement method outside the cave mainly Using table look-up calculation method, blackness test method and environmental diagram method, the above methods have disadvantages such as long measurement time, cumbersome data processing and large measurement errors; in addition, traditional brightness meters do not have remote monitoring functions, and troubleshooting must be carried out on site. , the upgrade and update must be returned to the factory, which is not conducive to maintenance and update; at the same time, in order to realize the closed-loop control of the dimming control system, the traditional implementation method needs to install a luminance meter outside the tunnel and an illuminance meter inside the tunnel to obtain the inside and outside of the tunnel. Brightness, while the traditional illuminance meter can only measure the brightness of road points, and the points are easily affected by the smoothness of the road surface and the bright state of a single lamp, which not only leads to a large error in the measured brightness value in the cave, but also greatly increases the cost of equipment and construction. cost, maintenance cost

Images