So the edgeextracting must be done for grain measurement.
为了测量颗粒粒径，需要做边缘提取。
2
The algorithm consists of two part: edge statistical judgement and edgeextracting.
该算法包括边缘统计判决及边缘检测两部分。
3
Owing to the difficulties in extracting iris edge image, a new iris location algorithm using geometric symmetry feature and edge detection from gray scale image is presented.