Imaging brightness meterIt is a high-precision instrument capable of measuring the brightness distribution of light sources or display devices. Its core function is to obtain brightness information through imaging technology and present the brightness distribution in the form of images. Imaging brightness meters are widely used in display technology, lighting engineering, optical research, and other fields to evaluate and optimize the brightness performance of devices such as light sources, display screens, projectors, etc. Its working principle is mainly based on four core links: optical imaging, photoelectric conversion, image processing, and data calibration.
Imaging brightness meterOperation steps:
1. Equipment preparation and calibration
Power on preheating: First, turn on the imaging brightness meter and let it preheat for a period of time (usually recommended to be a few minutes) to ensure that the device reaches a stable working state.
Calibration: Prior to any measurement, the brightness meter needs to be calibrated. This usually includes two steps: dark current compensation and brightness calibration. Dark current compensation is the process of recording the background noise of a sensor in the absence of light exposure; Brightness calibration is achieved by adjusting the reading of a brightness meter using a standard light source with known brightness to ensure its accuracy.
2. Sample preparation
Place the test sample at an appropriate distance so that the image can be captured clearly. The selection of distance should take into account the focal length of the lens and the brightness range to be measured.
Ensure that the environmental conditions meet the testing requirements, such as avoiding external stray light interference and maintaining stable ambient temperature, which may affect the accuracy of measurement results.
3. Measurement settings
Adjust the lens focal length to make the image clear, and use an ND filter if necessary to reduce the intensity of light entering the sensor, especially when the measured light source is very bright.
If necessary, adjust the aperture size to simulate the changes in the human eye pupil, in order to achieve a more realistic visual experience.
4. Data collection
Turn on the light source and let the brightness meter automatically take pictures and record data. For certain applications, such as AR/VR display testing, special attention needs to be paid to matching the positions of the Eye Box exit pupil and the testing instrument entrance pupil to ensure the validity of the measurement results.
Use supporting software to control the brightness meter for data acquisition and monitor image quality in real-time. If any problems are found, the settings can be adjusted immediately.
5. Data analysis
Use supporting software to process the collected data and generate brightness distribution maps and other related parameter reports. For example, statistical information such as average brightness, maximum value, and minimum value can be calculated.
For specific application scenarios, such as display screen detection, further analysis can be conducted on indicators such as chromaticity uniformity, contrast, MTF sharpness, etc.
6. Interpretation and Optimization of Results
Based on the analysis results, determine whether the sample meets the expected brightness standards and propose improvement measures for the parts that do not meet the standards.
In some cases, by combining "machine vision+AI" technology, deep learning models can be used to predict users' visual experiences in different usage scenarios, thereby optimizing product design.