中文摘要：

铁氧体裂纹缺陷的位置和形态对其性能有不同程度的影响,现有的检测方法不能同时满足远距离、非接触的直观反应缺陷情况的需求。将基于激光热成像缺陷检测方法用于铁氧体工件检测,分析了激光扫描路径平行裂纹时的试样表面温度分布规律,提出了延时对称点温差的表征裂纹方法,将该方法与垂直裂纹扫描时的扫描路径上最高温的方法相融合,并将该方法用于检测真实的铁氧体裂纹。检测结果可更直观清晰的显示出铁氧体试样任意角度的裂纹的位置和形态。

英文摘要：

The electrical properties of ferrite are seriously affected by the location and shape of crack defects,but the existing detection methods can not satisfy some inspection requirements which include far distance,non-contact and visually displaying of the crack status. The detection method based on laser spot thermography will be applied to the detection of ferrite work pieces. The main idea is to analyze the temperature distribution of sample surface when the laser scan path is parallel to the crack. A new method is presented based on delayed temperature difference at symmetric points（ DTDSP） to characterize the crack in the thermal image. Combined with the method of maximal temperature when the laser scan path is perpendicular to the crack,this method are used to detect the real crack of ferrite. The results show that this method can intuitively and clearly display the location and form of each direction crack.