图像梯度角计算 [英] image gradient angle computation

问题描述

我实际上是按照论文的说明进行

I am actually following the instructions of a paper:

输入应该是二进制的边缘"图像.输出应为新图像，并按本文中的说明进行修改.我对指令的理解是，要获取边缘图像的渐变图像并对其进行修改，并使用修改后的渐变来创建新图像.因此，在MATLAB/OpenCV中是否可以用新的渐变创建相同的图像?

The input is supposed to be a binary "edge" image. The output should be a new image, modified by the instructions in the paper. My understanding of the instructions is, that one takes the gradient image of the edge image and modifies it and creates a new image with the modified gradient. Therefore is there a possibility in MATLAB/OpenCV of creating the same image with a new gradient?

参考论文:李鸿宇和陈磊.使用基于轮廓的分类器消除了目标检测中的误报."ICIP.2010.

Reference to the paper: Li, Hongyu, and Lei Chen. "Removal of false positive in object detection with contour-based classifiers." ICIP. 2010.

推荐答案

我想显示的公式将弧度的梯度方向转换为像素强度，范围从0到255(许多图像格式的标准).在matlab中，如果您具有图像处理工具箱"，则可以按以下方式获取图像渐变方向:

The formula displayed, I suppose, converts the gradient orientation form radians to pixel intensity ranging from 0 to 255 (standard for many images format). In matlab, if you have the Image Processing Toolbox, you can get the image gradient direction as follows:

[Gmag, Gdir]=imgradient(YourImage);

现在，如手册中所述， Gdir 包含角度(以度为单位)在[-180 180]范围内.如果您希望它们在[0 255]范围内以遵循本文的内容，请按照公式中的说明进行操作:

Now, as said in the manual, Gdir contains angles in degrees within the range [-180 180]. If you wish to have them in the [0 255] range to follow what is in this paper, do as the formula says:

GdirI=(Gdir+180)*(255/360);

您还可以使用 imagesc(Gdir)以原始格式显示角度图.

You can also display an angle plot in its original format using imagesc(Gdir).

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