how to draw 3d histogram of an image ad shown in figure

Answer 1

[Walter Roberson]

Histogram implies that you are binning the data, and the coordinates are associated with the edge or central value of the bin. 3D histogram implies that you are binning the data with respect to two different coordinates.

However, in the diagrams you show, at least to the resolution you present, there is no binning of data. We can see that one of the independent axes is length 600 and the other is length 800, but uint8 has at most 256 different values, and int16 or uint16 there is no obvious reason why you would bin in widths of 41 input values in one direction and in widths of 55 input values in the other direction.

It does not seem likely that you want histograms at all. I would suggest that you are instead looking for bar charts.

a = imread('flamingos.jpg');
a = imresize(a, 0.25);
h = bar3(a(:,:,1)); set(h, 'EdgeColor', 'none'); title('red')

[Parveiz Lone]

But i need the same diagram in red color. When i used Facecolor or Edge color The diagram in not clear. It hide the whole information

[Walter Roberson]

a = imread('flamingos.jpg');
a = imresize(a, 0.25);

redmap = [(0:255).', zeros(256,2)]/255;
greenmap = circshift(redmap,[0,1]);
bluemap = circshift(greenmap,[0,1]);

r = a(:,:,1);
g = a(:,:,2);
b = a(:,:,3);
ax = subplot(3,1,1);
surf(ax, r, 'edgecolor', 'none', 'cdata', r);
colormap(ax, redmap)
ax = subplot(3,1,2);
surf(ax, g, 'edgecolor', 'none', 'cdata', g);
colormap(ax, greenmap);

ax = subplot(3,1,3);
surf(ax, b, 'edgecolor', 'none', 'cdata', b);
colormap(ax, bluemap)

[Parveiz Lone]

thanku very much

[Image Analyst]

You could also replace

r = a(:,:,1);
g = a(:,:,2);
b = a(:,:,3);

with

[r, g, b] = imsplit(a);

Answer 2

[Image Analyst]

This is done by the histogram2() function. Check out the help for examples. Let us know if you can't figure it out for your data, and attach your data after reading this:

TUTORIAL: How to ask a question (on Answers) and get a fast answer

[Parveiz Lone]

The function histogram2(a(:,:,1)) is not working where " a " is a color image

Also ths is not working

r=a(:,:,1);

aa=imhist(r);

histogram2(aa)

[Image Analyst]

Like I said, we're waiting for your data, and to tell us what is to be represented along the two axes.

[Parveiz Lone]

i simply want how to draw the 3D histrogram of an image as the histrograms are shown in the given picture.

Along axes the pixel intensity values of an 8-bit image are to be displayed as shown in figure

[Parveiz Lone]

Most propbably these histograms can be drawn by " surf "command

[Image Analyst]

What you said abount histogram doesn't make sense. But perhaps you want to do something like the attached demo. Or else see Walter's answer. Otherwise, give us an example of what you'd like to see.