Early Tests of Background-Oriented Schlieren Imaging Based on a Non-Intrusive Detection Margi Sasono (1*), Setyawan P. Sakti(1*), Johan A.E. Noor (1*), and Hariyadi Soetedjo (2*)
1. Department of Physics, Brawijaya University, Jl Veteran, Malang 65145, Indonesia
2. Department of Physics, Ahmad Dahlan Unversity Yogyakarta
Abstract
Optical imaging has developed rapidly for various applications, particularly in medicals and industrials. This technique is considerably interesting due to some safety reasons, such as non-radiative, non-intrusive, and non-contact. Currently, optical imaging based on the schlieren technique has been widely used to visualize the change in the refractive index of air. The main advantage of this technique provides a means to visualize invisible physical phenomena, such as shock waves, thermal plumes, and optical imperfections. In this research work, a Background-Oriented Schlieren (BOS) technique was introduced as a new variant to the family of schlieren techniques. The BOS technique has inexpensive and easy-to-use optical setups. In this paper, the early test of developed BOS technique had been carried out to visualize of thermal plume produced by a warm surface of objects such as candles flame and hot plate. These objects were placed between background patterns (imaged target) and a digital camera in the home-made BOS apparatus. There was hot air buoyancy over a warm surface, and these phenomena resulted in a change in the refractive index of air. A digital camera captured these phenomena as a distorted image of background. Thus, the BOS technique can produce a visualization of thermal plume after the post-processing of the images. This result was potential to be used as metrological tools, such as in the visualization of ultrasound fields in the quality assurance (QA) of medical therapeutic devices.
