Convert image pixels to XYZ-coordinates (3D plot)

2022 10 23
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更新时间：2022 10 26
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0 个投票

Hello everyone,
I want to extend the following code:
Im = imread('./Images/Plot.png');
figure(1);
imshow(Im);
CoordinateMatrix = pic2points(Im);
scatter(CoordinateMatrix (:,1), CoordinateMatrix (:,2),'.');
figure(2);
so that:
- be able to display multiple images in the same graph (the images are in the "Images" folder that has been created; an example of an image is the one attached)
- display the graph in 3D (and not in 2D as in this case)

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Alberto Acri
Alberto Acri 2022-10-23
编辑：Alberto Acri 2022-10-23
I changed the code in the following way but it only allows me to see a transformed figure with "pic2point".
myFolder = 'C:\Users\Alberto\Downloads\pic2points\Images';
if ~isdir(myFolder)
errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
uiwait(warndlg(errorMessage));
return;
end
filePattern = fullfile(myFolder, '*.png');
jpegFiles = dir(filePattern);
for k = 1:length(jpegFiles)
baseFileName = jpegFiles(k).name;
fullFileName = fullfile(myFolder, baseFileName);
fprintf(1, 'Now reading %s\n', fullFileName);
imageArray = imread(fullFileName);
% figure();
imshow(imageArray); % Display image.
drawnow; % Force display to update immediately.
figure(1);
CoordinateMatrix = pic2points(imageArray);
scatter(CoordinateMatrix (:,1), CoordinateMatrix (:,2),'.');
figure(2);
end
Alberto Acri
Alberto Acri 2022-10-23
I would like to open the images obtained at the end of the "pic2points" function into a single three-dimensional image.

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Image Analyst
Image Analyst 2022-10-23

0 个投票

Try this:
myFolder = 'C:\Users\Alberto\Downloads\pic2points\Images';
if ~isfolder(myFolder)
errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
uiwait(warndlg(errorMessage));
return;
end
filePattern = fullfile(myFolder, '*.png');
imageFiles = dir(filePattern);
for k = 1:length(imageFiles)
baseFileName = imageFiles(k).name;
fullFileName = fullfile(myFolder, baseFileName);
fprintf('Now reading %s\n', fullFileName);
imageArray = imread(fullFileName);
CoordinateMatrix = pic2points(imageArray);
scatter(CoordinateMatrix(:, 1), CoordinateMatrix(:, 2), '.');
hold on;
end
fprintf('Done!\n');

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Alberto Acri
Alberto Acri 2022-10-23
OK, thanks for the help @Image Analyst. With your code I can correctly display the images separately.
Is it possible to display all the images I got in the same figure? Possibly with three dimensional visualization?
Image Analyst
Image Analyst 2022-10-23
I'm not exactly sure what z is. Maybe k? If so use plot3
Instead of
scatter(CoordinateMatrix(:, 1), CoordinateMatrix(:, 2), '.');
try
z = k * ones(size(CoordinateMatrix, 1), 1);
plot3(CoordinateMatrix(:, 1), CoordinateMatrix(:, 2), z, '.');
Or see the attached demo.
Alberto Acri
Alberto Acri 2022-10-24
编辑：Alberto Acri 2022-10-24
Okay, the code works!
Is it also possible to put the created images in one plot3? As in attached figure.
Image Analyst
Image Analyst 2022-10-24
Everything should already be in the same axes. Nothing in my code creates a new axes or figure window.
Plus I also use "hold on" so it will just overwrite (add on) the additional plot curves to the existing axes.
Alberto Acri
Alberto Acri 2022-10-25
I tried running the code again. I display the figures (.png) in separate images (plot3). I would like to "merge" them all into a single image as in the figure shown in the demo.
Image Analyst
Image Analyst 2022-10-25
Attach your script and 3 of your input images.
If you have any more questions, then attach your data and code to read it in with the paperclip icon after you read this:
TUTORIAL: How to ask a question (on Answers) and get a fast answer
Alberto Acri
Alberto Acri 2022-10-25
Here is the code and 4 figures attached:
myFolder = 'C:\Users\Alberto\Downloads\pic2points\Images';
if ~isfolder(myFolder)
errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
uiwait(warndlg(errorMessage));
return;
end
filePattern = fullfile(myFolder, '*.png');
imageFiles = dir(filePattern);
for k = 1:length(imageFiles)
baseFileName = imageFiles(k).name;
fullFileName = fullfile(myFolder, baseFileName);
fprintf('Now reading %s\n', fullFileName);
imageArray = imread(fullFileName);
CoordinateMatrix = pic2points(imageArray);
% scatter(CoordinateMatrix(:, 1), CoordinateMatrix(:, 2), '.');
z = k * ones(size(CoordinateMatrix, 1), 1);
plot3(CoordinateMatrix(:, 1), CoordinateMatrix(:, 2), z, '.');
hold on
end
Image Analyst
Image Analyst 2022-10-25
Try this
clc; % Clear the command window.
fprintf('Beginning to run %s.m ...\n', mfilename);
close all; % Close all figures (except those of imtool.)
clearvars;
workspace; % Make sure the workspace panel is showing.
format short g;
format compact;
myFolder = pwd; %'C:\Users\Alberto\Downloads\pic2points\Images';
if ~isfolder(myFolder)
errorMessage = sprintf('Error: The following folder does not exist:\n%s', myFolder);
uiwait(warndlg(errorMessage));
return;
end
filePattern = fullfile(myFolder, '*.png');
imageFiles = dir(filePattern);
hFig3 = figure('Name', '3D Plot', 'NumberTitle', 'off');
for k = 1:length(imageFiles)
baseFileName = imageFiles(k).name;
fullFileName = fullfile(myFolder, baseFileName);
fprintf('Now reading %s\n', fullFileName);
imageArray = imread(fullFileName);
drawnow;
% Call pic2points. This will open a new figure.
CoordinateMatrix = pic2points(imageArray);
% Switch to the figure for the 3-D plotting:
figure(hFig3);
% scatter(CoordinateMatrix(:, 1), CoordinateMatrix(:, 2), '.');
z = k * ones(size(CoordinateMatrix, 1), 1);
plot3(CoordinateMatrix(:, 1), CoordinateMatrix(:, 2), z, '.');
hold on
drawnow;
end
grid on;
hFig3.WindowState = 'maximized';
fprintf('Done running %s.m.\n', mfilename);
Alberto Acri
Alberto Acri 2022-10-26
OK, the code works.
Last clarification. Is it possible to apply the same color for all figures? And is it possible to change the position of each figure on the Z axis? In the graph: the first figure is placed on the plane with Z=1, the second figure on the plane with Z=2, etc. That is, a step=1 is imposed. I would like to define at which step to place the images.
Image Analyst
Image Analyst 2022-10-26
Yes, just specify the color in plot3(), for example if you want blue:
plot3(CoordinateMatrix(:, 1), CoordinateMatrix(:, 2), z, 'b.');
Since it answered your question, could you please click the "Accept this answer" link?
Thanks in advance. 🙂
Alberto Acri
Alberto Acri 2022-10-26
Thank you @Image Analyst! I will make another post to see if it is possible to set a step value to my liking.

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