Experimental Study on the Measuring Temperature Field by Real-Time Digital Holography

An experimental method and reconstruction arithmetic of temperature field are proposed. The fast Fourier transform followed by a digital low-pass filter and the inverse Fourier transform were applied to interference fringes for removing speckle noise, so that airflow field phase information is in high-contrast and low noise. Phase was unwrapped to calculate phase difference. The temperature distribution was obtained by the relation between phase and refractive index. The results are consist with the values measured by thermocouple. It is shown that the digital holographic interferometry is an effective method for measuring temperature field, so that the measuring precision can be greatly improved.