红外双色比能够表征目标的温度信息，但点目标双色比受噪声、探测器盲闪元以及跨像元因素干扰，难以准确测量，影响测温精度。应用递归图法定性分析和判断了点目标双色比的非平稳性。针对这一特性，先对点目标信号应用移动平均滤波做预处理，再通过小波软阈值去噪对双色比进行降噪处理。试验结果表明，在信噪比大于12的条件下，该方法可以实现静态点目标1 K温度分辨率，慢速动态点目标2 K温度分辨率。

Infrared dual waveband radiation ratio can denote the blackbody′s temperature information, and can be used for temperature measurement. When using infrared dual waveband radiation ratio to measure the temperature of point target, it is difficult to achieve high-accuracy because of various kinds of noises. The recurrence plot theory was used to analyze the non-station of infrared dual waveband radiation ratio. According to the non-station of infrared dual waveband radiation ratio, the target′s response signal in IR single waveband was processed by moving average filter. The IR dual waveband radiation ratio was processed by wavelet soft-threshold filter. Experimental result indicate that, when the SNR>12, 1 K temperature accuracy can be achieved with above processing method for static point target, and 2 K temperature accuracy can be achieved for slow moving point target.