本文介绍了imshow(img,cmap = cm.gray)为128值显示白色的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我正从MatLab转到python,并正在使用imshow函数.

I'm moving from MatLab to python and playing around with the imshow function.

我似乎无法理解为什么它没有将128值显示为灰色,而我已将cmap选择为灰度.

I can't seem to get my head around why it doesn't show the value 128 as grey with I have chosen the cmap to be gray-scale.

似乎它对最高(128)和最低值使用灰度..我希望它对[0:255]使用灰度.我该怎么办?

It seems as it uses the grayscale for highest (128) and lowest values.. I want it to use the grayscale for [0:255]. How do I do that?

推荐答案

使用vminvmax参数:

plt.imshow(bg, cmap=plt.get_cmap('gray'), vmin=0, vmax=255)

plt.imshow在未指定vminvmax的情况下,将其范围自动调整为数据的最小值和最大值.

Without specifying vmin and vmax, plt.imshow auto-adjusts its range to the min and max of the data.

我不知道为所有imshow图设置默认的vminvmax参数的方法,但是您可以使用functools.partial来准备一个自定义的类似imshow的命令,并设置默认参数:

I do not know of a way to set default vmin and vmax parameters for all imshow plots, but you could use functools.partial to prepare a custom imshow-like command with default parameters set:

import matplotlib.pyplot as plt
import numpy as np
import functools

bwimshow = functools.partial(plt.imshow, vmin=0, vmax=255,
                             cmap=plt.get_cmap('gray'))

dots = np.random.randn(10, 10)*255
bwimshow(dots)
cbar = plt.colorbar()

plt.show()

这篇关于imshow(img,cmap = cm.gray)为128值显示白色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!

10-12 23:13