Comments on: Image overlay using transparency http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/ Steve Eddins manages the Image & Geospatial development team at The MathWorks and coauthored Digital Image Processing Using MATLAB. He writes here about image processing concepts, algorithm implementations, and MATLAB. Sat, 11 Feb 2012 18:27:50 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Alex http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24793 Alex Fri, 13 Jan 2012 05:05:11 +0000 http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24793 Hey, never mind! I just needed to try one more thing, I did, and it works like charm! Matlab is awesome! Thanks for you blog!! It was the key! Hey, never mind! I just needed to try one more thing, I did, and it works like charm! Matlab is awesome! Thanks for you blog!! It was the key!

]]> By: Alex http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24791 Alex Fri, 13 Jan 2012 02:26:12 +0000 http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24791 Not sure if to say Dear Steve because when I was reading all those posts Dear Steve, Steve, ..... the Bruce Almighty movie came to mind. =) I have a question and I am not sure if even possible (although I think in Matlab everything is possible). I am working in augmented reality and I am trying to exactly what you explained here vey well. However, I noticed you use hold on and off and lose the handle of the first image. In augmented reality you have a "video" on real time of your environment (which would be the first image in your problem here but changing every few miliseconds) and basically I want to overlay icons (which would be your second image here in your problem) on real time and at the same time those icons should be using an AlphaData per pixel of 0.5 and they don't change or update as the video does. They should stay there. How I am getting the video? I have a webcam and I am using a timer function to display at a given rate. To update the image (I am using image not imshow), I use the property CData. When I run the program it doesn't show the icon I am intending to see on top of the time-variant picture/video. For the icon I created the object, got the handle, and then update inside the timer right after I update the video. I have been trying to find a way around to make it work but I was actually wondering if it was even possible because I did a search in google and nobody have tried or commented about this topic. Am I in the right track at least? Entertaining blog. Thanks! Not sure if to say Dear Steve because when I was reading all those posts Dear Steve, Steve, ….. the Bruce Almighty movie came to mind. =)

I have a question and I am not sure if even possible (although I think in Matlab everything is possible). I am working in augmented reality and I am trying to exactly what you explained here vey well. However, I noticed you use hold on and off and lose the handle of the first image. In augmented reality you have a “video” on real time of your environment (which would be the first image in your problem here but changing every few miliseconds) and basically I want to overlay icons (which would be your second image here in your problem) on real time and at the same time those icons should be using an AlphaData per pixel of 0.5 and they don’t change or update as the video does. They should stay there. How I am getting the video? I have a webcam and I am using a timer function to display at a given rate. To update the image (I am using image not imshow), I use the property CData. When I run the program it doesn’t show the icon I am intending to see on top of the time-variant picture/video. For the icon I created the object, got the handle, and then update inside the timer right after I update the video. I have been trying to find a way around to make it work but I was actually wondering if it was even possible because I did a search in google and nobody have tried or commented about this topic. Am I in the right track at least?

Entertaining blog. Thanks!

]]> By: Steve Eddins http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24766 Steve Eddins Thu, 29 Dec 2011 13:21:37 +0000 http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24766 Matteo—Handle Graphics image objects don't display unless the axes is in a 2-D view. Try instead texture-mapping the data onto a flat surface object. Matteo—Handle Graphics image objects don’t display unless the axes is in a 2-D view. Try instead texture-mapping the data onto a flat surface object.

]]> By: Matteo http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24755 Matteo Wed, 21 Dec 2011 21:29:11 +0000 http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24755 Hi Steve Is there any way to do this on a surf plot? I am trying to push to 3D the good results I get with this FEX function http://www.mathworks.com/matlabcentral/fileexchange/14157-shaded-pseudo-color I tried the code below but I get same result with last three lines commented off/on Thank you, and happy holidays. Matteo black=cat(3,zeros(size(data)),zeros(size(data)),zeros(size(data))); surf(data,'FaceColor','interp','EdgeColor','none'); colormap(jet);colorbar; set(gca,'YDir','reverse'); view(-18,61); material shiny; axis tight axis equal axis off hold on kk=imagesc(black); hold off set(kk, 'AlphaData', data_slope); Hi Steve

Is there any way to do this on a surf plot?
I am trying to push to 3D the good results I get with this FEX function
http://www.mathworks.com/matlabcentral/fileexchange/14157-shaded-pseudo-color

I tried the code below but I get same result with last three lines commented off/on
Thank you, and happy holidays.

Matteo

black=cat(3,zeros(size(data)),zeros(size(data)),zeros(size(data)));
surf(data,’FaceColor’,'interp’,'EdgeColor’,'none’);
colormap(jet);colorbar;
set(gca,’YDir’,'reverse’);
view(-18,61);
material shiny;
axis tight
axis equal
axis off
hold on
kk=imagesc(black);
hold off
set(kk, ‘AlphaData’, data_slope);

]]> By: Divya http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24582 Divya Sat, 29 Oct 2011 11:53:47 +0000 http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24582 sir actually m doing sign language recognition.m using two gloves for that.one is red and the other is blue.i made seperate programs to segment red hand and blue hand.but when i combine the codes in one program,i hold one segmented image and then show the second one,the second one superimposes on the first one.i am not able to show both both the hands please help me out how to show both hands in one image sir
actually m doing sign language recognition.m using two gloves for that.one is red and the other is blue.i made seperate programs to segment red hand and blue hand.but when i combine the codes in one program,i hold one segmented image and then show the second one,the second one superimposes on the first one.i am not able to show both both the hands
please help me out how to show both hands in one image

]]> By: Steve http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24578 Steve Wed, 26 Oct 2011 16:36:42 +0000 http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24578 Divya—What specific code are you using? Divya—What specific code are you using?

]]> By: Divya http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24569 Divya Sun, 23 Oct 2011 07:59:01 +0000 http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24569 hello steve i liked your program vry much.i have seen your other programs also.i always like your work. in the firs example u superimposed a grayscale image onto a rgb image. i want to superimpose rgb on an rgb image .if i run the same code,its not working.Could you please help me in this. hello steve
i liked your program vry much.i have seen your other programs also.i always like your work.
in the firs example u superimposed a grayscale image onto a rgb image. i want to superimpose rgb on an rgb image .if i run the same code,its not working.Could you please help me in this.

]]> By: Steve http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24496 Steve Wed, 21 Sep 2011 17:24:44 +0000 http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24496 Nishant—That's because the image you downloaded from this web page is in RGB truecolor format rather than grayscale. Convert it to grayscale first. Nishant—That’s because the image you downloaded from this web page is in RGB truecolor format rather than grayscale. Convert it to grayscale first.

]]> By: Nishant http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24490 Nishant Sun, 18 Sep 2011 15:30:25 +0000 http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24490 Hi steve, I have been reading the above post bt I am having the problem that my green matrix is N-by-M-9, for green = cat(3, zeros(size(E)), ones(size(E)), zeros(size(E))); How do i solve this error??? thanx in anticipation Hi steve,
I have been reading the above post bt I am having the problem that my green matrix is N-by-M-9, for
green = cat(3, zeros(size(E)), ones(size(E)), zeros(size(E)));

How do i solve this error???
thanx in anticipation

]]> By: Steve http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24245 Steve Fri, 27 May 2011 12:17:54 +0000 http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/#comment-24245 Waleed—You may have better luck doing the composition calculation directly instead of letting the MATLAB graphics system do it. That will give you direct control over the size. Do a search for "image composition." I'll add this to my list of potential blog topics. Waleed—You may have better luck doing the composition calculation directly instead of letting the MATLAB graphics system do it. That will give you direct control over the size. Do a search for “image composition.” I’ll add this to my list of potential blog topics.

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