diff --git a/camCalib/lineDetection_steger.cpp b/camCalib/lineDetection_steger.cpp
index 9e0f50e..3d97022 100644
--- a/camCalib/lineDetection_steger.cpp
+++ b/camCalib/lineDetection_steger.cpp
@@ -435,6 +435,8 @@ void computePointSubpix(
 			);
 			if ((subpix.x >= 0) && (subpix.y >= 0))
 			{
+				subpix.x += 0.5; //图像中的像素位置表示的是像素是左下角，而此处像素坐标是指向像素中间位置，所以有0.5像素差
+				subpix.x -= 0.5;  //此处图像的Y坐标系方向与通常坐标系的方向相反
 				posSubpix.push_back(subpix);
 				doSubPix = -1;
 			}