How to load an image to a figure using uigetfile/imread?

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Hello,
Novice coder here with a question that I am certain there will be an easy answer to - it just escapes me at the moment...
I am simply trying to display an image that I select from my PC's location, in a figure for further analysis. I actually have the analysis code working, but the problem I am having is that when I use uigetfile to provide the 'file look-up', I can navigate to the file, get the figure to launch, but the image then doesn't write to the figure. My code thus far is:
[filename, pathname] = uigetfile(...
{'*.jpg; *.JPG; *.jpeg; *.JPEG; *.img; *.IMG; *.tif; *.TIF; *.tiff, *.TIFF','Supported Files (*.jpg,*.img,*.tiff,)'; ...
'*.jpg','jpg Files (*.jpg)';...
'*.JPG','JPG Files (*.JPG)';...
'*.jpeg','jpeg Files (*.jpeg)';...
'*.JPEG','JPEG Files (*.JPEG)';...
'*.img','img Files (*.img)';...
'*.IMG','IMG Files (*.IMG)';...
'*.tif','tif Files (*.tif)';...
'*.TIF','TIF Files (*.TIF)';...
'*.tiff','tiff Files (*.tiff)';...
'*.TIFF','TIFF Files (*.TIFF)'},...
'MultiSelect', 'on');
% Error check - if no filename there is an error
if isequal(filename,0)
error(' Load Error: No files selected! Load cancelled.')
else
end
% launch the figure box
figure
imagefilename = imgfile(filename,pathname);
c = imread(imagefilename);
image(c)
axis image
grid on
I'm certain the problem is the bit after I launch the figure, but I have tried several different combinations of syntax, but just cant get it right.
Could anyone offer some wizardry to put me right please?
Best regards,
10B.

Accepted Answer

Image Analyst
Image Analyst on 7 Aug 2015
I think you want fullfile() instead of imgfile().
% Have user browse for a file, from a specified "starting folder."
% For convenience in browsing, set a starting folder from which to browse.
startingFolder = 'C:\Program Files\MATLAB';
if ~exist(startingFolder, 'dir')
% If that folder doesn't exist, just start in the current folder.
startingFolder = pwd;
end
% Get the name of the file that the user wants to use.
defaultFileName = fullfile(startingFolder, '*.*');
[baseFileName, folder] = uigetfile(defaultFileName, 'Select a file');
if baseFileName == 0
% User clicked the Cancel button.
return;
end
fullFileName = fullfile(folder, baseFileName)
myImage = imread(fullFileName);
imshow(myImage);
  6 Comments
Image Analyst
Image Analyst on 10 Aug 2015
"grid on" sort of makes grid lines over the image but they're dotted and hard to see. If you want nice, high-contrast, solid color lines over the image, you should use line():
% Make horizontal lines every 50 rows.
hold on;
for row = 1 : 50 : rows
line([1, columns], [row, row], 'Color', 'r');
end
% Make vertical lines every 75 columns.
for col = 1 : 75 : columns
line([col, col], [1, rows], 'Color', 'r');
end
10B
10B on 11 Aug 2015
Yes, thats a good suggestion - the dotted lines aren't great TBH, which is why I put them in white. I have tried to use your last bit of code, but I'm running into errors.
I leave axis on and remove grid on like this:
fullFileName = fullfile(folder, baseFileName);
myImage = imread(fullFileName);
imshow(myImage);
axis on;
hold on;
for row = 1 : 50 : rows
line([1, columns], [row, row], 'Color', 'r');
end
% Make vertical lines every 75 columns.
for col = 1 : 75 : columns
line([col, col], [1, rows], 'Color', 'r');
end
but unfortunately, it doesn't add the solid lines over the image. I have also tried different combinations of with the grid, without the axis etc. and all no joy as it throws the following error:
"Undefined function or variable 'rows'.
Error in Untitled7 (line 27) for row = 1 : 50 : rows"
I also tried to put the rows in single quote and enclose that section in parenthesis like this:
hold on;
for row = (1 : 50 : 'rows')
line([1, columns], [row, row], 'Color', 'r');
but that simply threw another error:
"For colon operator with char operands, first and last operands must be char.
Undefined function or variable 'rows'."
The Doc Help on rows/columns doesn't really address what this problem may be - other then to say rows/columns are unassigned variables. Sorry to ask again, but do you have another insight on this problem?

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More Answers (1)

Rafael Lozano
Rafael Lozano on 26 Aug 2020
This was very usefull for me, thaks to all!

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