Matlab-图像的比例色条 [英] Matlab - Scale Colorbar of Image

问题描述

如何缩放假彩色图像的colorbar轴?

How can I scale the colorbar axis of a false color image?

我阅读了这篇文章，并复制了代码，但似乎无法正常工作:

I read this post,and copied the code but it seems not to work correctly:

MATLAB Colorbar-相同的颜色，比例值

请参见下面的两个图像.在第一个(没有缩放比例)中，色轴变为

Please see the two images below. In the first (without the scaling) the coloraxis goes

[1 2 3 4 5 6]*10^4 

在第二张图片中

[0.005 0.01 0.015 0.02 0.025]

正确的缩放比例(使用C = 100000)应该是

The correct scaling (with C = 100000) would be

[0.1 0.2 0.3 0.4 0.5 0.6]

不缩放

缩放错误

我希望色轴按1/C缩放，并且我可以自由选择C，这样当像素值= 10^4和C=10^6时，缩放比例应显示为10^-2.

I want that the coloraxis is scaled by 1/C and I can freely choose C, so that when the pixel value = 10^4 and C=10^6 the scale should show 10^-2.

我首先将图像乘以C的原因是要获得更多的小数位，因为所有小于1的值都将显示为零，而无需C缩放.

The reason why I multiply my image first by C is to get more decimals places, because all values below 1 will be displayed as zero without the C scaling.

运行代码时，我得到yticks作为具有以下值的工作区变量:

When I run the code I get yticks as a workspace variable with the following values:

[500 1000 1500 2000 2500]

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我的代码:

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My code:

RGB = imread('IMG_0043.tif');% Read Image 
info = imfinfo('IMG_0043.CR2'); % get Metadata
C = 1000000; % Constant to adjust image

x = info.DigitalCamera; % get EXIF
t = getfield(x, 'ExposureTime');% save ExposureTime
f = getfield(x, 'FNumber'); % save FNumber
S = getfield(x, 'ISOSpeedRatings');% save ISOSpeedRatings
date = getfield(x,'DateTimeOriginal');
I = rgb2gray(RGB); % convert Image to greyscale
K = 480; % Kamerakonstante(muss experimentel eavaluiert werden) 
% N_s = K*(t*S)/power(f,2))*L 
L = power(f,2)/(K*t*S)*C; %
J = immultiply(I,L); % multiply each value with constant , so the Image is Calibrated to cd/m^2 

hFig = figure('Name','False Color Luminance Map', 'ToolBar','none','MenuBar','none');
% Create/initialize default colormap of jet.
cmap = jet(16); % or 256, 64, 32 or whatever.
% Now make lowest values show up as black.
cmap(1,:) = 0;
% Now make highest values show up as white.
cmap(end,:) = 1;

imshow(J,'Colormap',cmap) % show Image in false color
colorbar % add colorbar

h = colorbar; % define colorbar as variable

y_Scl = (1/C);
yticks = get(gca,'YTick');

set(h,'YTickLabel',sprintfc('%g', [yticks.*y_Scl]))

ylabel(h, 'cd/m^2')% add unit label
title(date); % Show date in image
caxis auto % set axis to auto
datacursormode on % enable datacursor

img = getframe(gcf);
nowstr = datestr(now, 'yyyy-mm-dd_HH_MM_SS');

folder = 'C:\Users\Taiko\Desktop\FalseColor\';
ImageFiles = dir( fullfile(folder, '*.jpg') );
if isempty(ImageFiles)
    next_idx = 1;
else
    lastfile = ImageFiles(end).name;
    [~, basename, ~] = fileparts(lastfile);
    file_number_str = regexp('(?<=.*_)\d+$', basename, 'match' );  
    last_idx = str2double(file_number_str);
    next_idx = last_idx + 1;
end

newfilename = fullfile( folder, sprintf('%s_%04d.jpg', nowstr, next_idx) );

imwrite(img.cdata, newfilename);

推荐答案

问题:

1)您正在获得图形的YTick(gca)，但没有获得颜色栏.这将为您提供图形的像素"坐标，而不是实际值.使用yticks = get(h,'YTick');.

1) You are getting YTick of the figure (gca) but not the color bar. That would give you the "pixel" coordinates of the graph, instead of the actual values. Use yticks = get(h,'YTick');.

2)caxis auto应该在覆盖YTicks之前(以及启用颜色栏之后)；否则刻度和刻度将不匹配.

2) caxis auto Should come before overwriting YTicks (and after enabling the color bar); otherwise the scale and ticks will mismatch.

3)您是说C = 100000吗?

结果:

这篇关于Matlab-图像的比例色条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！