Bitmap contrast issue

2011 6 24
2 个回答
回答已采纳
10 次查看（30 天）

0 个投票

When I use the imread function to open a grayscale .bmp image, the contrast displayed is far darker than the original image, which causes problems for image processing. Converting the image to .jpeg eliminates the contrast issue, but I have several thousand images to read and I don't want to have to convert them all. Is there a way to get MATLAB to read .bmp files correctly?

请先登录，再回答此问题。

 采纳的回答

Sean de Wolski
Sean de Wolski 2011-6-24

0 个投票

Are you sure it's not reading them correctly but you're just viewing a small range?
try:
imshow(imread('example.bmp'),[]); %whole range
Edition:
What class is the bitmap file?
I = imread('example.bmp');
class(I)
and then what class is the corresponding JPG file?
I = imread('sameexample.jpg');
class(I)

2 个评论
显示 无 隐藏 无

Wesley
Wesley 2011-6-24
That helps, although it's not quite the same as the contrast on the original image. It should be workable, though-- thank you!
Wesley
Wesley 2011-6-24
Bitmap: uint8
JPEG: uint8

请先登录，再进行评论。

更多回答（1 个）

Walter Roberson
Walter Roberson 2011-6-24

2 个投票

BMP files can have color palettes stored, and indeed must use such palettes when they are less than 8 bits deep. A color palette corresponds to MATLAB's colormap.
[YourImage, YourColormap] = imread('example.bmp');
image(YourImage);
if ~isempty(YourColorMap); colormap(YourColorMap); end

类别

在 帮助中心 和 File Exchange 中查找有关 Contrast Adjustment 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by