Online digital diameter measuring instrument is a kind of measuring equipment integrating high-precision sensor, optical system and advanced image processing technology, which can measure and display the diameter size of the object in real time and accurately, and is widely used in the fields of industrial automation, quality control and scientific research experiment.

I. Composition of on-line digital rangefinders

CMOS Monitor Camera

① Function: Ultra-compact CMOS camera can accurately capture the real image of the measurement point and provide basic data for subsequent measurement and analysis.

② Advantage: CMOS cameras are characterised by small size, low power consumption and fast response speed, which are suitable for real-time and accuracy requirements in on-line measurement.

High brightness GaN green LED light source

① Function: The Gallium Nitride (GaN) green LED light source unique to the measuring head provides short wavelength and reliable operation, ensuring light intensity and stability during measurement.

② Advantage: GaN material is characterised by high brightness, high efficiency and long life, which significantly improves measurement accuracy and stability.

HL-CCD

① Function: The specially designed CCD improves measurement speed and accuracy and is one of the core sensors in the rangefinder.

② Advantage: With optimised design and algorithms, the HL-CCD is able to capture measurement data more quickly while maintaining high accuracy to meet the demands of online measurement.

Telecentric Optical System

① Function: Adopting a structure that in principle receives only parallel light, it is possible to fully suppress the effects of temperature changes and ambient light on measurement results.

② Advantage: The telecentric optical system ensures that the imaging size is less likely to change during thermal expansion, thus improving measurement stability and accuracy.

II. Principle of application of on-line digital rangefinders

1、Light source irradiation: High-brightness GaN green LED light source emits short wavelength light, irradiated to the object under test, the light is reflected on the surface of the object under test, and then enters the telecentric optical system.

2、Optical imaging: telecentric optical system receives parallel light, to ensure that the imaging size is not affected by temperature changes and ambient light, the reflected light through the telecentric optical system, the formation of a clear image and projected onto the HL-CCD.

3、Image Capture and Processing: HL-CCD quickly captures the image data and transmits it to the CMOS display camera, which converts the image data into digital signals and carries out preliminary processing.

4、Measurement and analysis: through the analysis of digital signals, calculate the size of the measured object, distance and other parameters, the measurement results through the display or data transmission interface output for users to view and use.

The online digital rangefinder achieves accurate measurement of object size and distance through the combination of a high-precision CMOS display camera, a high-brightness GaN green LED light source, a HL-CCD and a telecentric optical system. Its application principle is based on optical measurement and image processing technology, which has the advantages of fast measurement speed, high precision and good stability.