unknown image format on axes in MATLAB

I'm working on CBIR, in my GUI I've 6 axes one for query image 5 for resulted images. For displaying images on axes my code is

    function displayResults(filename,hObject, eventdata, handles)
    % Open 'filename' file... for reading...
    fid = fopen(filename);
    for N=6:1:10
        imagename = fgetl(fid);
        if ~ischar(imagename), break, end       % Meaning: End of File...
        x=imread(imagename);
        axes(handles.(sprintf('axes%d', N)));
        imshow(x)
        xlabel(imagename);  
    end
    fclose(fid);

and calling function is in pushbutton function Texture_Callback(hObject, eventdata, handles). calling function is

displayResults('textureResults.txt',hObject, eventdata, handles);

before pressing pushbutton http://s1273.photobucket.com/user/Chethan_tv/media/fig5_zps64ca6452.jpg.html?sort=3&o=1

after pressing pushbutton http://s1273.photobucket.com/user/Chethan_tv/media/fig5_zps98c96f8f.jpg.html?sort=3&o=0

What just happened to image quality?

Before using above code i was getting clear images, but that was not a GUI window, instead just a figure window. any thing wrong in called function?

[Walter Roberson]

Try

ax = handles.(sprintf('axes%d', N));
imshow(x, 'Parent', ax);
xlabel(ax, imagename);

[Chethan]

imshow(x, 'Parent', ax); results in same clarity. However i used image(x, 'Parent', ax); and this resulted in http://s1273.photobucket.com/user/Chethan_tv/media/fig_zpsa48de802.jpg.html?sort=3&o=0 what had happened to quality of other images?

[Walter Roberson]

Hmmm... As an experiment, after the assignment to "ax", add

hold(ax, 'off')

[Chethan]

well, that resulted in same output. As you said i added hold(ax, 'off') after the assignment to "ax" i.e., above image(x, 'Parent', ax);. . and it didn't work. How can i remove those map values(x and y axis values)?

[Image Analyst]

Not sure what "map values(x and y axis values)" are - I didn't see any axis values or tick marks, but if you have some there now, just say "axis off" to get rid of them. If you have a colorbar, you can say

colormap(gray(256));
colorbar off;

to get rid of the colorbar and go back to a normal display.

Answer 1

[Image Analyst]

Can you plot the histogram in one of those axes so I can look at it. Here's a snippet of code:

% Let's compute and display the histogram.
[pixelCount, grayLevels] = imhist(grayImage);
bar(pixelCount);
grid on;
title('Histogram of original image', 'FontSize', fontSize);
xlim([0 grayLevels(end)]); % Scale x axis manually.

Then see if the histogram (pixelCount) ends around mid-100s and then is all zeros until there is a big spike at element #256.

[Chethan]

Well i tried above code without title('Histogram of original image', 'FontSize', fontSize); because i got an error

 _Undefined function or variable 'fontSize'.

    Error in ==> Fig5>displayResults at 103
    title('Histogram of original image', 'FontSize', fontSize);

    Error in ==> Fig5>Texture_Callback at 150
        displayResults('textureResults.txt',hObject, eventdata, handles);

    Error in ==> gui_mainfcn at 96
        feval(varargin{:});
_

this results in http://s1273.photobucket.com/user/Chethan_tv/media/fig_zps1457488f.jpg.html

where, figure1 window is histogram of first clear image and figure2 window is of second distorted image.

[Image Analyst]

So, define it. Or just use a constant, like 14 or something. Or just get rid of it altogether. There are any number of ways to fix that.

title('Histogram of original image', 'FontSize', 14);

And your link didn't work, but I fixed it. But I don't see any bright white specks in your image there. It looks fine to me.

[Chethan]

But for my query image, all 5 results should be clear. before using this code i was getting good clarity images.

Now only first image is good, what happened to other 4?

http://s1273.photobucket.com/user/Chethan_tv/media/fig_zpsa48de802.jpg.html?sort=3&o=0

Histogram count results in

http://s1273.photobucket.com/user/Chethan_tv/media/123_zps4604a16d.jpg.html

where, figure1 window is histogram of first clear image and figure2 window is of second distorted image.

[Image Analyst]

Upload the original images so I can check. Right now, I don't want screenshots anymore - I want the original 5 images.

[Chethan]

OK http://s1273.photobucket.com/user/Chethan_tv/media/figure_zps326033c2.jpg.html

This result i got using

    function displayResults(filename, header)

    figure('Position',[200 100 700 400], 'MenuBar', 'none', 'Name', header, 'Resize', 'off', 'NumberTitle', 'off');

    % Open 'filename' file... for reading...
    fid = fopen(filename);
    i = 1;                  % Subplot index on the figure...
    while 1
        imagename = fgetl(fid);
        if ~ischar(imagename), break, end       % Meaning: End of File...    
        [x, map] = imread(imagename);
        subplot(2,5,i);
        subimage(x, map);
        xlabel(imagename);
        i = i + 1;
    end
    fclose(fid);

since i want to display images in my GUI i changed my code. In my GUI i should get all images like this in mentioned axes.

[Image Analyst]

Upload the original images so I can check. Right now, I don't want screenshots anymore - I want the original 5 images.

[Chethan]

Sorry

<http://s1273.photobucket.com/user/Chethan_tv/media/DSC00947_zps342d216d.png.html?sort=3&o=3> <http://s1273.photobucket.com/user/Chethan_tv/media/DSC00946_zpsefc05a47.png.html?sort=3&o=4> <http://s1273.photobucket.com/user/Chethan_tv/media/DSC00938_zps1cc4bf1d.png.html?sort=3&o=5> <http://s1273.photobucket.com/user/Chethan_tv/media/DSC00948_zps69b8a267.png.html?sort=3&o=2> <http://s1273.photobucket.com/user/Chethan_tv/media/DSC00950_zps7601ccbb.png.html?sort=3&o=1>

[Image Analyst]

They appear to be indexed images so you need to display using the colormap. And you cannot do image analysis on those image values. Also, the first two values of the colormap look messed up for some reason. Perhaps you misunderstood something when you saved/created the image.

[Chethan]

No, my question is if i use separate figure window i'll get correct output, but if i use GUI as you can see in above links few images are not clear. why is it so?

[Image Analyst]

I don't know, but I'd attack the root cause - that the images are indexed images with a screwed up colormap instead of a normal grayscale image. Who created these images in the first place?

[Chethan]

I only created images, with a purpose. For my CBIR code i need bitmap image of bit depth 8. So using photoshop software i created these images and my database is full of this type of images.

In photoshop: image>mode>indexed color and 8-bit/channel, finally i saved it as .bmp format

[Image Analyst]

Why did you do that? Why did you not use grayscale? (They were saved as PNG, which is good though, better than BMP, so at least you did something right.)

[Chethan]

Anyways finally i got good clarity output. simply i changed final image to RGB, then i displayed

    [x,map]=imread(imagename);
        rgb=ind2rgb(x,map);
        ax = handles.(sprintf('axes%d', N));
        hold(ax, 'off');
        image(rgb, 'Parent', ax);

Thank you for your guidance.