MATLAB: Reading an image from path stored in a text file using IMREAD

image processing

I want to use imread() for reading an image by giving the path stored in a text file, given as input argument. I get an error saying Error in ==> imread at 199 if (strfind(filename, '://'))

WHAT SHALL BE DONE TO GET IT THROUGH?

the code is

fid=fopen('d:/output.txt','r'); data_line = fgetl(fid); data_line [a b] = strread(data_line, '%s %s', 'delimiter', ','); fclose(fid);

% where a and b are the paths i.e d:\pic\image_3.bmp and d:\pic\image_2.bmp

m1 = imread(a); m2 = imread(b);

Best Answer

fid=fopen('d:/output.txt','r');
data_line = textscan('%s%s', 1, 'delimiter', ',');
fclose(fid);
a = data_line{1}{1}; b = data_line{1}{2};  %I think

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MATLAB: How to export the pixel value of an jpg image to a .txt file

You forgot to mention, if you have imported the JPG already. And you did not specify the format of the txt file. While writing the pixel values is trivial, the re-creation of the image requires the dimensions also.

img = imread('YourImage.jpg');
fid = fopen('YourImage.txt', 'w');
if fid == -1, error('Cannot open file'); end
fprintf(fid, '%d %d %d ', size(img));  % Assuming it is an RGB image
fprintf(fid, '%g ', img(:));
fclose(fid);

The re-import:

fid = fopen('YourImage.txt', 'r');
if fid == -1, error('Cannot open file'); end
ImgSize = fscanf(fid, '%d %d %d ', 3);
ImgData = fscanf(fid, '%g ', Inf);
Img     = reshape(ImgData, ImgSize);
fclose(fid);

The file will be shorter, if you convert the floating point values to integers before writing:

ImgInt = round(Img * 255);

and a corresponding back-transformation after the reading.

BTW. Are you really sure that this is useful? imread seems to be more convenient.

MATLAB: How to let ‘textscan’ stop when read an empty line

instead of reading the whole block of data using textscan, I tried to read it into a cell line by line. Textscan will stop when hits the empty line.

Code:

           while (~feof(fid_t))
                temp1 = fgetl(fid_t);
                if isempty(temp1) 
                    break; 
                end
                   inputtext=textscan(temp1, formatstring,...
                'delimiter',',')
                   temp_out=[inputtext{:}];
                  Data(end+1,:)=temp_out;
           end

and it works finally. It is still not an effective way, but it works. any suggestion?

Best Answer

Related Solutions

MATLAB: How to export the pixel value of an jpg image to a .txt file

MATLAB: How to let ‘textscan’ stop when read an empty line

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