中文摘要：

提出一种基于方向功率谱与投影梯度的直边缘物体宽度测量方法，通过对目标图像功率谱进行极坐标变换得到方向功率谱，并由此计算出直边缘物体的伸展方向；然后对原始图像按照该伸展方向进行灰度投影，并由投影梯度结果得到待测宽度。该方法无需对目标图像进行边缘检测、阈值分割等预处理操作，因而测量结果更加准确、可靠，且计算量较小、测量效率高。数值模拟与实验结果表明，本文所提方法能够保证1像素的测量精度，且物体长度方向的几何尺寸不影响宽度测量结果。

英文摘要：

A method to measure the width of straight -edge object is presented,which is based on directional powerspectrum and projection gradient.The directional power spectrum is obtained through polar transformation to powerspectrum of the target image,and thus the extending direction of the straight -edge object is calculated.Then thegray projection of the original image is executed along the extending direction,and the width value is obtained accord-ing to the projection gradient.The proposed method does not require some preprocessing operations such as edge de-tection and threshold segmentation,and hence its measuring result is more accurate and reliable.In addition,theproposed method holds low calculation and high measuring efficiency.The results of numerical simulation and experi-ment show that the proposed method can ensure the measurement precision with one pixel and the length dimension ofthe object to be measured has no effect on the width measuring result.