In order to improve the efficiency of laser-induced damage threshold test and expand the damage evaluation methods, a new method is proposed for judging the damage of optical thin films using the gray and RGB color features of the image.A laser damage test platform was set up.The images of HfO2 and LaTiO3 films irradiated by different laser energy were collected online by a charge coupled element Charge-coupled Device (CCD), and the images were binary processed by the differential method, with the gray value of the laser irradiated region obtained.The change rules of different laser energy and gray value were studied based on the analysis of the characteristics of gray value.The RGB characteristics of theimage were observed and analyzed with a digital microscope with the magnification of 100 times, with the RGB values of the damaged region of the image extracted, and the change rules of different laser energy and RGB values were obtained.The results of the image feature analysis indicate that when the gray value of HfO2 film is greater than 16.35, or the value of RGB is less than 125, 122 and 124, the film will be damaged.For LaTiO3 films, damage will occur when the gray value is higher than 28.43, or the value of RGB is higher than 180, 169 and 170.Not only does this method expand the damage assessment of thin films, but also provides a new criterion for evaluating the ability of thin film to withstand high power laser.%为了提高光学薄膜激光诱导损伤阈值测试效率,丰富扩展损伤评判方法,提出利用图像的灰度特征和RGB颜色特征对薄膜损伤进行判别.搭建激光损伤测试平台,采用电荷耦合元件(CCD)在线采集不同激光能量分别辐照HfO2和LaTiO3薄膜样片后的图像,利用差分方式对采集的图像进行二值化处理,获取激光辐照区域的灰度值,通过分析灰度值特征研究了不同激光能量与灰度值的变化规律;采用放大率为100倍的数码显微镜观察分析图像的RGB特征,提取了图像损伤区域的RGB值,研究了不同激光能量与RGB值的变化规律.图像特征分析结果表明:当HfO2薄膜的灰度值大于16.35,或者RGB临界值分别小于125,122和124时,薄膜将发生损伤;对于LaTiO3薄膜,当灰度值大于28.43,或者RGB临界值分别大于180,169和170时将会发生损伤.此方法不仅丰富和发展了薄膜损伤评判方法,而且为薄膜抗强激光作用能力评估提供了新的判据.
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