Photometric Testing is an important step in ensuring the intensity and distribution uniformity of street lights. The luminance measurement is a commonly used testing instrument that can measure the photometric distribution of street lights and provide accurate data analysis. This article will discuss the methods and steps of using a luminance measurement for Photometric Testing, as well as some considerations.
LISUN LSG-6000 Moving Detector Goniophotometer (Mirror Type C) was manufactured by LISUN completely meets LM-79-19, IES LM-80-08, COMMISSION DELEGATED REGULATION (EU) 2019/2015, CIE-121, CIE S025, SASO 2902, IS16106 and EN13032-1 clause 6.1.1.3 type 4 requirements. LSG-6000 is the latest upgraded product of LSG-5000 and LSG-3000 in compliance with the requirements of the LM-79-19 standard Clause 7.3.1, its an automatic light distribution intensity 3D curve testing system for measuring light. The darkroom can be designed according to the customer’s existing room size.
LM-79 Moving Detector Goniophotometer (Mirror Type C) 
I. Definition
A luminance measurement is a photometer that can measure the spectral intensity of electromagnetic radiation. It analyzes the spectrum to obtain the distribution of light intensity at different wavelengths. The luminance measurement mainly consists of an optical system, a detector, and a signal processing system, and it has high accuracy and sensitivity.
II. Working principle
The working principle of a luminance measurement is based on the interference of light and the relationship between the voltage output of the detector and the light intensity. Specifically, when light enters the luminance measurement  through the optical system, it first passes through a dispersion element, such as a grating or diffraction element. This dispersion element disperses the light into its different wavelength components.

Next, the dispersed light enters a slit and reaches the detector. The detector is usually a photodiode or photomultiplier tube, which converts light into an electrical signal. When light enters the detector, it generates a voltage signal that is proportional to the intensity of the light. The output signal of the detector is amplified and filtered, and then transmitted to the signal processing system for digitization and analysis.
In the signal processing system, the luminance measurement  samples and records the light intensity at different wavelengths. In this way, we can obtain the distribution of the spectrum, which is the light intensity at different wavelengths. The luminance measurement  is usually equipped with a computer interface, which allows the measurement results to be transferred to a computer for further analysis and processing.
III. Using a Type-C goniophotometer for road lighting testing is an efficient and accurate method. Here are the methods and steps
1. Preparation: Before conducting the road lighting testing, make sure the luminance measurement  is in normal working condition. Check the battery level and indicator lights of the goniophotometer to ensure its proper functioning. Also, prepare a measurement record sheet to record the test results.
2. Position selection: Choose thelocation of the street lights that need to be tested. It is recommended to select typical samples from the street lighting system to ensure the representativeness of the test results.
3. Check the condition of the fixtures: Before testing, ensure that the fixtures to be tested are in normal working condition. Check for any damages or impurities in the fixtures and make sure they are functioning properly. If any issues are found, they should be repaired or replaced before testing.
4. Measurement setup: Place the luminance measurement  in an appropriate position to measure the light distribution of the entire fixture. Select the appropriate measurement angle and distance according to the testing requirements. Depending on the testing requirements, you can choose to use manual or automatic mode for measurement.
5. Start the measurement: Press the measurement button on the goniophotometer to start the measurement. The goniophotometer will automatically collect data, including the intensity and distribution of light. During the measurement process, keep the goniophotometer stable to avoid measurement errors.
6. Record the test results: Record the measurement results of the goniophotometer in the measurement record sheet. Include the numerical values of the light intensity and the distribution chart. Also, other relevant information such as environmental temperature, humidity, etc., can be recorded.
7. Data analysis and comparison: Analyze and compare the measurement results. Use software tools for automatic data analysis, such as generating photometric curves, isocandela diagrams, etc. Depending on the testing requirements, compare the measurement results with standard values to evaluate the uniformity of the light intensity and distribution.
IV. Considerations
1. Avoid light pollution: During road lighting testing, it is important to avoid light pollution. Enclose the testing area to prevent interference from external light sources. Additionally, use light filters on the goniophotometer to filter out interference from external light sources.
2. Select the measurement time: When choosing the measurement time, try to select a period with relatively stable lighting conditions. Avoid testing during periods of significant lighting changes, such as sunrise or sunset, to ensure the accuracy and comparability of the test results.
3. Multiple measurements and averaging: To improve the accuracy of the test results, it is recommended to perform multiple measurements and calculate the average value. This can help reduce measurement errors and uncertainties.
4. Proper use of the goniophotometer: When using the luminance measurement , it is important to follow the correct operation procedures. Read the operation instructionscarefully and follow them accordingly to avoid inaccuracies in the test results.
Using a luminance measurement  for road lighting testing is an efficient and accurate method. By properly operating the goniophotometer, selecting appropriate measurement positions and settings, one can measure the light intensity and distribution of street lights to evaluate their uniformity and quality. During testing, it is important to avoid light pollution, select suitable measurement times, and perform multiple measurements and averaging to enhance the accuracy of the results. By conducting road lighting testing using a luminance measurement , one can effectively improve the design and maintenance quality of street lighting systems, ensuring traffic safety and the quality of life for citizens.
V. Application range of Luminance Measurement 
Luminance measurement is a commonly used optical instrument, widely used in optical engineering, light source measurement, lighting design, stage lighting, optoelectronic engineering and other fields. In optical engineering, Luminance measurement  can be used to measure optical parameters such as light intensity distribution, beam brightness, and beam diameter of light sources, and to evaluate and optimize the quality of light sources. In the field of light source measurement, Luminance measurement  can be used to measure various types of light sources, including bulbs, tubes, LEDs, etc., to evaluate their light distribution characteristics and perform optoelectronic performance testing. In lighting design, Luminance measurement  can help designers evaluate the brightness, uniformity, and beam control performance of different lighting schemes, thus selecting the most suitable lighting scheme.
In the field of stage lighting, Luminance measurement  can be used to measure the brightness and beam distribution of stage lighting to ensure that the stage effects meet the design requirements. In optoelectronic engineering, TLuminance measurement  can be used to measure the optoelectronic characteristics of optoelectronic devices, including output optical power, luminous efficiency, and other parameters, to help optimize thedesign and production of optoelectronic devices. In summary, Luminance measurement  plays an important role in various optical applications, providing accurate and reliable measurement tools for optical engineers, lighting designers, and optoelectronic engineers.
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