convert hex data to viewable image(JPEG) in matlab

i have a hex data of JPEG image from a software called "HxD Editor".The file attached below is the text file of hex characters now, by using that convert back to its original JPEG image in matlab R2018a

fid = fopen('hexdata.txt', 'r');
% Scann the txt file 
img = fscanf(fid, '%x', [256,120]); 
% Close the txt file
fclose(fid);
% restore the image
outImg = reshape(img,[128 128]);
outImg = outImg';
figure, imshow(outImg,[])

[Jan]

• Please post one question per problem only
• See How to format code in the forum
• What does the Hex file contain? The image data only or even the JPEG header and meta data?

[Stephen23]

Duplicate:

https://www.mathworks.com/matlabcentral/answers/408020-convert-hex-data-to-viewable-image-using-matlab-r2018a

https://www.mathworks.com/matlabcentral/answers/404653-how-can-i-convert-hex-data-as-a-text-file-to-viewable-image-jpeg-in-matlab

[Guillaume]

And duplicated again as https://www.mathworks.com/matlabcentral/answers/408047-display-clear-jpeg-image-from-hex-characters-in-matlab-r2018a

Stop asking the same question over and over. This only irritates us.

edit: and again!

Answer 1

[Jan]

Import the HEx data as 8 Bit values:

img = fscanf(fid, '%2x', [256,120])
%                   ^ this matters

You cannot reshape a [256 x 120] array to a [128 x 128] array. Reshaping does not change the number of elements. Maybe you mean imresize? The lack of comments in your code force the readers to guess, what you want to do.

Answer 2

[Guillaume]

Clearly, you have absolutely no idea what you're doing.

A quick search of the first few bytes of your hexadecimal stream reveals that FF D8 FF E0 is typical of the header of a JPEG file. So what you have is simply the whole content of a jpeg file encoded as hexadecimal. Reading that as an array of bytes and hoping it's somehow going to display as an image is never going to work.

The simplest method to decode the image is to resave the stream as a jpeg file and open that the normal way:

fid = fopen('hexdata.txt', 'r');
bindata = fscanf(fid, '%2x');   %read bytes encoded as hexadecimal character
fclose(fid);
fid = fopen('hexdata.jpg', 'w');
fwrite(fid, bindata);    %save bytes to jpeg file
fclose(fid);
img = imread('hexdata.jpg');
imshow(img);

[Sushikshitha C]

Sorry..... and thanks

[Chandler Timm Doloriel]

@Guillaume Is there a way to convert this JPEG hex into RGB888 hex without using the fopen,fwrite?