setting image position centered

I have an image in the figure as shown above.

I want to display region of interest (white portion) at the center of the figure window (align centered position-registration). How can I do it?

Please explain. Thank you.

Answer 1

[Image Analyst]

Try using regionprops to get the centroid, then imtranslate to shift it to the center of the image:

rgbImage = imread('image.png');
subplot(2, 1, 1);
imshow(rgbImage)
axis('on', 'image')

% Get binary image from the RGB image the poster attached.
binaryImage = rgbImage(:, :, 1) > 128;

% Find centroid.
props = regionprops(binaryImage, 'Centroid')

% Translate the image.
xt = props.Centroid(1)
yt = props.Centroid(2)
% Get center of image
[rows, columns, numberOfColorChannels] = size(binaryImage)
xc = columns/2;
yc = rows/2;
deltax = xc - xt
deltay = yc - yt
hold on;
plot(xt, yt, 'r+', 'LineWidth', 2, 'MarkerSize', 60);
centeredImage = imtranslate(rgbImage,[deltax deltay],'FillValues', 0);
subplot(2, 1, 2);
imshow(centeredImage)
axis('on', 'image')
% Draw center lines.
xline(xc, 'LineWidth', 2, 'Color', 'r');
yline(yc, 'LineWidth', 2, 'Color', 'r');

[image-pro]

Field reference for multiple structure elements that is followed by more reference blocks is an error.

Error in centre (line 13)

xt = props.Centroid(1);

[Walter Roberson]

That would be an error if there is more than one region in the image, but the image were asked to deal with only has one region. If there could be more than one region then the question is not well defined: what should be centered if there are multiple regions? The largest region? The centroid of the centroids of all the regions? The center of mass?

[image-pro]

What will be the code to define centroid of all regions and multiple regions?

[Walter Roberson]

c = vertcat(props.Centroid);
cc = mean(c, 1);

cc will now be the unweighted centroid of the centroids. This would be different than the centroid of the occupied portions of the image.

To get the centroid over the entire image use

props = regionprops( double(binaryImage), 'Centroid')

[image-pro]

Undefined function or variable 'xline'.

Error in centre (line 29)

xline(xc, 'LineWidth', 2, 'Color', 'r');

[Image Analyst]

You must have a really old version. Those are optional. They just put red crosshairs over the image. You can just delete those lines.

[image-pro]

The output in second image is not translated(shifted in centered position). why?

[Image Analyst]

Loooks like you have a huge white frame around your blobs. Why? It also looks like your image has a black caption atop the image. Why? Are these screenshots of an entire figure rather than a binary image you got from a photo?

[image-pro]

Thanks a lot Image Analyst you solved my problem. Thanks