Method and apparatus for measuring sky brightness distribution based on full-automatic spectrum beam-splitting scanning

Abstract

The invention relates to an apparatus for measuring sky brightness distribution based on full-automatic spectrum beam-splitting scanning. The apparatus is characterized in that the apparatus comprises a measuring probe portion, a precise rotary table, and a main control cabinet. The measuring probe portion consists of a lens cone, a calibration lamp, an optical shutter, a spectrograph, a temperature sensor, a control circuit and a thermally-insulated cover; the spectrograph is used for measuring skylights; and the temperature sensor is arranged inside the spectrograph so as to detect the temperature changing of the spectrograph at any time. The precise rotary table includes a driving control circuit and a rotary table body; the measuring probe portion is installed at the precise rotary table; and the driving control circuit drives the rotary table body to make rotations so as to drive the measuring probe portion. And the main control cabinet includes an embedded PC, a power supply unit, an Ethernet switch, a timing switching machine unit, and a power supply unit.

Description

technical field [0001] The invention relates to a device and method for measuring sky brightness and its distribution, in particular to a device and method for measuring sky brightness distribution by full-automatic spectral spectroscopic scanning. Background technique [0002] Sky brightness and its distribution are the basis and premise of natural lighting design and calculation. Obtaining accurate sky brightness test data is of great significance to the theoretical research and engineering practice of natural lighting. However, it is difficult to measure the brightness of the sky. First, because the state of the sky changes rapidly, the measurement must be very fast. Second, the brightness of the sky has a large range of changes, and it is difficult to ensure sufficient accuracy in such a large range of brightness intervals. . At present, there are two main technologies for measuring the brightness of the sky, one is to measure by combining optical filters and photodete...

AI Technical Summary

Problems solved by technology

[0014] 2. There is an error in the response to infrared radiation

[0015] The spectral range of luminance measurement is the visible light region. An ideal detector should not respond to infrared radiation. However, some photodetectors, such as silicon photodiodes, have strong responsivity in the near-infrared region. If the added V(λ ) to correct the cut-off of the filter for infrared radiation is not zero, which will cause significant errors

[0016] 3. There is an error in the response to ultraviolet radiation

[0017] Luminance measurement also cannot respond to radiation in the ultraviolet region, and the photomultiplier tubes and silicon photodiodes used in the luminance meter have varying degrees of response in the ultraviolet region, which will also cause certain errors

[0018] 4. The nonlinear error of the detector

[0020] 5. Temperature error

[0024] 1. Error caused by photo quality

[0025] This technology mainly uses digital image processing for measurement, so it has high requirements for photo quality, and the quality of photos has a lot to do with parameters such as optical lens and exposure time. Due to the limitation of coating process, the optical lens cannot guarantee the consistency of all lenses. The quality of the photos produced between the devices cannot be consistent, and there will be certain errors in the results of the measurement

[0026] 2. Errors caused by image processing algorithms

[0027] Using this technique usually requires mathematical processing of the image, and these software algorithms will produce certain errors in the measurement results

[0028] 3. Errors caused by photo deformation

[0029] Due to the lens, the photos taken by digital cameras have different degrees of geometric deformation, including barrel and pincushion distortion, which will also bring certain errors to the measurement results

[0030] 4. There are limitations on the measurement range and resolution

[0032] 5. Difficulty in calibration and calibration

[0033] At present, there is still a lack of verification technical regulations for image luminance meters, and the calibration and correction methods of traditional luminance meters are time-consuming and labor-intensive, which limits image luminance measurement to a certain extent.

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