两个多元高斯的绘图决策边界 [英] Drawing decision boundary of two multivariate gaussian

问题描述

我正在尝试绘制类似于以下内容的内容:

I am trying to plot something similar to below:

我正在使用Matlab.我实现了绘制等高线图.但是我无法区分.谁能展示示例Matlab代码或给出一些想法来区分?

I am using Matlab. I achieved drawing contour plots. However I could not draw the discriminant. Can anyone show a sample Matlab code or give some idea to draw the discriminant?

推荐答案

如果您知道给定点(x,y)的每个高斯的概率密度函数，可以说其pdf1(x,y)和pdf2(x,y)，那么您可以只需绘制f(x,y) := pdf1(x,y) > pdf2(x,y)的轮廓线即可.因此，将功能f定义为1且pdf1(x,y)>pdf2(x,y).这样，唯一的轮廓将沿着曲线放置，其中pdf1(x,y)==pdf2(x,y)是决策边界(区分).如果您想定义"nice"功能，则只需设置f(x,y) = sgn( pdf1(x,y) - pdf2(x,y) )即可完成，并绘制其轮廓图将导致完全相同的判别.

If you know the probability density function of each of the gaussian for a given point (x,y), lets say its pdf1(x,y) and pdf2(x,y) then you can simply plot the contour line of f(x,y) := pdf1(x,y) > pdf2(x,y). So you define function f to be 1 iff pdf1(x,y)>pdf2(x,y). This way the only contour will be placed along the curve where pdf1(x,y)==pdf2(x,y) which is the decision boundary (discriminant). If you wish to define "nice" function you can do it simply by setting f(x,y) = sgn( pdf1(x,y) - pdf2(x,y) ), and plotting its contour plot will result in exact same discriminant.

这篇关于两个多元高斯的绘图决策边界的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！