在MATLAB中加载此PNG时，为什么会得到全黑/灰度图像? [英] Why do I get an all-black/grayscale image when I load this PNG in MATLAB?

问题描述

当我运行此代码时:

>> I = imread('D:\Works\matlab\SecCode.php.png','png');
>> imshow(I);

它始终显示全黑图像.怎么了?

It always shows an all-black image. What's wrong with it?

我正在使用的图像就是这个:

The image I'm using is this one:

推荐答案

啊，我明白了.问题是您有一个索引图像并且还需要从 imread 中获取colormap参数.试试这个:

Ahhh, I see now. The problem is you have an indexed image and need to get the colormap argument from imread as well. Try this:

[I, map] = imread('D:\Works\matlab\SecCode.php.png', 'png');
imshow(I, map);

可以找到这里.这是一个简短的摘要:

A description of the different types of images in MATLAB can be found here. Here's a brief summary:

• 二进制图像:该图像是 logical 数组，其中每个像素的值为0或1.
• 索引图像 :图像中的像素将索引存储到一个颜色映射表中，该颜色映射表是RGB值的M×3数组.色彩图通常与索引图像一起存储在图像文件中.
• 强度(灰度)图像 :图像中的每个像素都包含一个代表强度的值.
• RGB(真彩色)图像 :图像是一个M×N×3的阵列，其中每个像素都有红色，绿色和蓝色的分量.

• Binary images: The image is a logical array where each pixel has the value 0 or 1.
• Indexed images: The pixels in the image store indices into a colormap, which is an M-by-3 array of RGB values. The colormap is often stored with the indexed image in the image file.
• Intensity (Grayscale) images: The pixels in the image each contain a single value representing the intensity.
• RGB (Truecolor) images: The image is an M-by-N-by-3 array where each pixel has a red, green, and blue color component.

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