Compensation of optical path difference for colorimetric temperature imaging

A compensation method of optical path difference for colorimetric temperature measurement is proposed. To ensure images from different paths focusing on the same plane, an optical positive lens was used in the shorter optical path to compensate the path difference. By placing the CCD sensor or focusing the camera lens on this plane, a sharp and clear monochromatic image can be obtained from each path. A colorimetric temperature imaging system was constructed by using the method proposed. Experimental results obtained by using a candle flame showed that the compensation method could effectively reduce the defocusing effect of images caused by optical path difference and improve the resolution of temperature image.