Wafer notch detection

Notch detection methods and modules are provided for efficiently estimating a position of a wafer notch. Capturing an image of specified region(s) of the wafer, a principle angle is identified in a transformation, converted into polar coordinates, of the captured image. Then the wafer axes are recovered from the identified principle angle as the dominant orientations of geometric primitives in the captured region. The captured region may be selected to include the center of the wafer and/or certain patterns that enhance the identification and recovering of the axes. Multiple images and/or regions may be used to optimize image quality and detection efficiency. 本发明提供用于高效估计晶片缺口的位置的缺口检测方法及模块。捕获晶片的指定区域的图像，在所述所捕获图像的被转换为极坐标的变换中识别主角。接着，从所述经识别主角将晶片轴恢复为所述所捕获区域中的几何基元的主定向。所述所捕获区域可经选择为包含所述晶片的中心及/或增强对所述轴的识别及恢复的特定图案。可使用多个图像及/或区域以优化图像质量及检测效率。