| Photothermal Radiometry(PTR) is based on photoacoustic(PA) technology. It is a new detection technique with high sensitivity and without damaging effects. It is applied in many fields. In this paper, after introducing PTR technology, two methods of data processing of photothermal radiometry based on image are presented.(1) Data processing method of photothermal image fusion based on wavelet transformation. Firstly, basic theory of wavelet transformation and Mallat algorithm are introduced. Then photothermal images are fused using means of the fusion rules based on selecting larger coefficient absolute value and area-based maximum standard variance. It corrects the disturbance of object's surface status and reduces the influence of object's surface characteristic during infrared detection.(2) Data processing method of pulsed photothermal radiometry based on image. It increases defect's display definition through infrared image's histogram equalization and computing maximum contrast image, amplitude image and phase image of infrared image sequences, consequently it increases the capability of defect detection. The experimental results show that phase image well overcomes asymmetrical illumination phenomenon and noise is small. Edge detecting on maximum contrast image of image sequences was done as well, and the results show that effect of Canny operator is better. |
