Can anyone help me why this code gives me this error " In EnhanceMulticolorImages1 (line 41) Error using imread>parse_inputs (line 445) The file name or URL argument must be a character vector.? I need to calculate the % intensity of each color.

[filename, pathname] = uigetfile( ...
{'*.*','All Files (*.*)'}, ...
   'Pick a file','C:\Users\gnya01\Desktop\Backup from L drive\DermaScope Images'); %Change Based on where you want default location
%Load image;
imname409=uigetfile('*.jpg','select jpg image',pathname);
truecolor =imread(strcat(pathname,imname409));
figure
imshow(truecolor);
title('Truecolor Composite (Un-enhanced)')
text(size(truecolor,2), size(truecolor,1) + 15,...
  'Image courtesy of Space Imaging, LLC',...
  'FontSize', 7, 'HorizontalAlignment', 'right');
%By viewing a histogram of the red band, for example, you can see that the data is concentrated within a small part of the available dynamic range. This is one reason why the truecolor composite appears dull.
figure
imhist(truecolor(:,:,1))
title('Histogram of the Red Band (Band 3)');
%Another reason for the dull appearance of the composite is that the visible bands are highly correlated with each other. Two- and three-band scatterplots are an excellent way to gauge the degree of correlation among spectral bands. You can make them easily just by using plot.
r = truecolor(:,:,1);
g = truecolor(:,:,2);
b = truecolor(:,:,3);
figure
plot3(r(:),g(:),b(:),'.')
grid('on')
xlabel('Red (Band 3)')
ylabel('Green (Band 2)')
zlabel('Blue (Band 1)')
title('Scatterplot of the Visible Bands');

%When you use imadjust to apply a linear contrast stretch to the truecolor composite image, the surface features are easier to recognize.
stretched_truecolor = imadjust(truecolor,stretchlim(truecolor));
figure
imshow(stretched_truecolor)
title('Truecolor Composite after Contrast Stretch');
%A histogram of the red band after applying a contrast stretch shows that the data has been spread over much more of the available dynamic range.
figure
imhist(stretched_truecolor(:,:,1))
title('Histogram of Red Band (Band 3) after Contrast Stretch');
%Another way to enhance the truecolor composite is to use a decorrelation stretch, which enhances color separation across highly correlated channels. Use decorrstretch to perform the decorrelation stretch (followed by a linear contrast stretch, as specified by the optional parameter-value pair 'Tol' and 0.1).
decorrstretched_truecolor = decorrstretch(truecolor, 'Tol', 0.4);
figure
imshow(decorrstretched_truecolor)
title('Truecolor Composite after Decorrelation Stretch');
%As expected, a scatterplot following the decorrelation stretch shows a strong decrease in correlation.
r = decorrstretched_truecolor(:,:,1);
g = decorrstretched_truecolor(:,:,2);
b = decorrstretched_truecolor(:,:,3);
figure
plot3(r(:),g(:),b(:),'.')
grid('on')
xlabel('Red (Band 3)')
ylabel('Green (Band 2)')
zlabel('Blue (Band 1)')
title('Scatterplot of the Visible Bands after Decorrelation Stretch');
% %Construct a CIR composite by reading from the original LAN file and composing an RGB image that maps bands 4, 3, and 2 to red, green, and blue, respectively.
% CIR = multibandread('paris.lan', [512, 512, 7], 'uint8=>uint8', ...
%                     128,  'bil', 'ieee-le', {'Band','Direct',[4 3 2]});
% %Even though the near infrared (NIR) band (Band 4) is less correlated with the visible bands than the visible bands are with each other, a decorrelation stretch makes many features easier to see.
stretched_CIR = decorrstretch(truecolor, 'Tol', 0.1);
figure
%img1 = imshow(stretched_CIR);
%title('CIR after Decorrelation Stretch');
%A property of color infrared composites is that they look red in areas with a high vegetation (chlorophyll) density. Notice that the Bois de Boulogne park is red in the CIR composite, which is consistent with its green appearance in the decorrelation-stretched truecolor composite.
img1 = imread(stretched_CIR);
imh = imshow(img1);
% Create a mask using freehand ROI
img1 = imwrite(stretched_CIR, truecolor);
imshow(test);
h = imfreehand;
m = createMask(h, img1);
%delete(h)
% Extract individual color channels
r = img1(:,:,1);
g = img1(:,:,2);
b = img1(:,:,3);
% Get sum of intensity of each channel
r_s = sum(r(m));
g_s = sum(g(m));
b_s = sum(b(m));
% Calculate percentage of intensity of each color
r_p = r_s / (r_s + g_s + b_s) * 100;
g_p = g_s / (r_s + g_s + b_s) * 100;
b_p = b_s / (r_s + g_s + b_s) * 100;

Answer 1

[Walter Roberson]

You have

imname409=uigetfile('*.jpg','select jpg image',pathname);
truecolor =imread(strcat(pathname,imname409));

You should be using

[imname409, pathname2] = uigetfile('*.jpg', 'select jpg image', pathname);
if isnumeric(imname409); return; end      %user cancelled
truecolor = imread( fullfile(pathname2, imname409) );

[Walter Roberson]

Your code has

stretched_CIR = decorrstretch(truecolor, 'Tol', 0.1);
figure
%img1 = imshow(stretched_CIR);
%title('CIR after Decorrelation Stretch');
%A property of color infrared composites is that they look red in areas with a high vegetation (chlorophyll) density. Notice that the Bois de Boulogne park is red in the CIR composite, which is consistent with its green appearance in the decorrelation-stretched truecolor composite.
img1 = imread(stretched_CIR);

We see from https://www.mathworks.com/help/images/ref/decorrstretch.html that [...] and returns the result in S. S has the same size and class as A [...]

Your array truecolor is numeric, so your result stretched_CIR is numeric. But then you try to imread() from that numeric array.

It is not clear to me why you are not just using

img1 = stretched_CIR;

[Surya Gnyawali]

%img1 = imread(stretched_CIR); img1 = stretched_CIR; imh = imshow(img1); % Create a mask using freehand ROI %img1 = imwrite(img1, truecolor); imshow(img1); h = imfreehand; m = createMask(h, imh); %delete(h) % Extract individual color channels r = img1(:,:,1); g = img1(:,:,2); b = img1(:,:,3); % Get sum of intensity of each channel r_s = sum(r(m)); g_s = sum(g(m)); b_s = sum(b(m)); % Calculate percentage of intensity of each color r_p = r_s / (r_s + g_s + b_s) * 100; g_p = g_s / (r_s + g_s + b_s) * 100; b_p = b_s / (r_s + g_s + b_s) * 100;

Answer 2

[Surya Gnyawali]

imwrite(stretched_CIR, truecolor);

why this part still give me error: img1 = imwrite(stretched_CIR, truecolor); Error using imwrite Too many output arguments.

[Walter Roberson]

imwrite() never returns anything.

If you want the data from the image, then

img1 = stretched_CIR;

will do it -- or at most

img1 = im2uint8(stretched_CIR);

If you have a particular reason for wanting to write the image to a file and read back from the file, then use an imwrite() / imread() pair. But remember that stretched_CIR is not a file name!

[Surya Gnyawali]

img1 = stretched_CIR; imh = imshow(img1); % Create a mask using freehand ROI img1 = imwrite(img1, truecolor); imshow(img1); h = imfreehand; m = createMask(h, imh); %delete(h) % Extract individual color channels r = img1(:,:,1); g = img1(:,:,2); b = img1(:,:,3); % Get sum of intensity of each channel r_s = sum(r(m)); g_s = sum(g(m)); b_s = sum(b(m)); % Calculate percentage of intensity of each color r_p = r_s / (r_s + g_s + b_s) * 100; g_p = g_s / (r_s + g_s + b_s) * 100; b_p = b_s / (r_s + g_s + b_s) * 100;

I want to fix this part of the code and get the intensity of each channel. Need help please

The error I got is as below after I draw freehand ROI

Error using iptcheckhandle (line 54) Function IMROI expected its second input argument, h_im, to be a valid handle to a single graphics object.

Error in imroi/parseInputsForCreateMask (line 106) iptcheckhandle(h_im,{'image'},'imroi','h_im',2)

Error in imroi/createMask (line 258) [obj,h_im] = parseInputsForCreateMask(varargin{:});

[Surya Gnyawali]

img1 = stretched_CIR;

This part of your help did work. The rest of it is not. Need help[. I appreciat3e your help. Can you help me how to give credit to someone like you because you are helping?