A Quantitative Measurement System and Method for Refractive Index Field Based on Phase Calibration

Abstract

The invention relates to a phase calibration based quantitative measurement system and method for a refractive index field. The system comprises a light source as well as a focusing lens, a microporediaphragm, a collimating lens, a detection area, an imaging lens, a knife edge and a detector which are arranged sequentially behind the light source, wherein during calibrating, the detection area isused for accommodating a standard phase control element, and during measuring, the standard phase control element is replaced with a to-be-detected field to be put in the detection area; the system further comprises a control unit used for controlling the detector and the standard phase control element; during calibrating, the control unit controls the standard phase control element to produce refractive index gradient with different strengths in different positions and controls the detector to execute recording, and therefore, a response relation of different sizes of bending angles in different positions of the system on the detector is acquired; during measuring, the detector is controlled to detect the to-be-detected field, and refractive index distribution of the to-be-detected fieldis acquired according to the response relation. According to the system and the method, measurement errors can be reduced, and accurate and quantitative measurement for the refractive index field canbe realized.

Description

technical field [0001] The invention relates to the technical field of schlieren optical imaging for detecting the distribution of the refractive index field of a fluid, and more particularly relates to a system and method for quantitatively measuring the refractive index field based on phase calibration. Background technique [0002] Schlieren technology was first proposed and used by German physicist August Toepler. After continuous improvement and development, various schlieren imaging technologies such as black and white schlieren, color schlieren, and interference schlieren have been developed. Schlieren technology can be used to observe the refractive index distribution of the field to be measured, and obtain the distribution field information of the corresponding physical quantities from the relationship between the fluid refractive index and other properties such as density, pressure, temperature, and chemical composition. It has a wide range of applications in exper...

AI Technical Summary

Problems solved by technology

Both of the above two methods have strict requirements on the light source, but for black and white schlieren, there are less restrictions on the light source, but due to insufficient contrast and the influence of optical path errors on the results, they are rarely used in quantitative analysis

Images