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Fun

Image Analyst
Last activity 44 分钟前

MATLAB Ornament

Christmas season is underway at my house:

(Sorry - the ornament is not available at the MathWorks Merch Shop -- I made it with a 3-D printer.)

Ideas

Image Analyst
Last activity 2024-11-7，18:43

It would be nice to have a function to shade between two curves. This is a common question asked on Answers and there are some File Exchange entries on it but it's such a common thing to want to do I think there should be a built in function for it. I'm thinking of something like

plotsWithShading(x1, y1, 'r-', x2, y2, 'b-', 'ShadingColor', [.7, .5, .3], 'Opacity', 0.5);

So we can specify the coordinates of the two curves, and the shading color to be used, and its opacity, and it would shade the region between the two curves where the x ranges overlap. Other options should also be accepted, like line with, line style, markers or not, etc. Perhaps all those options could be put into a structure as fields, like

plotsWithShading(x1, y1, options1, x2, y2, options2, 'ShadingColor', [.7, .5, .3], 'Opacity', 0.5);

the shading options could also (optionally) be a structure. I know it can be done with a series of other functions like patch or fill, but it's kind of tricky and not obvious as we can see from the number of questions about how to do it.

Does anyone else think this would be a convenient function to add?

Books

Image Analyst
Last activity 2024-11-8，21:02

My favorite image processing books

My favorite image processing book is The Image Processing Handbook by John Russ. It shows a wide variety of examples of algorithms from a wide variety of image sources and techniques. It's light on math so it's easy to read. You can find both hardcover and eBooks on Amazon.com Image Processing Handbook

There is also a Book by Steve Eddins, former leader of the image processing team at Mathworks. Has MATLAB code with it. Digital Image Processing Using MATLAB

You might also want to look at the free online book http://szeliski.org/Book/

Fun

Image Analyst
Last activity 2024-8-12

Rope around the earth

Imagine that the earth is a perfect sphere with a radius of 6371000 meters and there is a rope tightly wrapped around the equator. With one line of MATLAB code determine how much the rope will be lifted above the surface if you cut it and insert a 1 meter segment of rope into it (and then expand the whole rope back into a circle again, of course).

Tips & Tricks

Image Analyst
Last activity 2024-8-10

Setting the Microsoft Azure Information Protection label

Does your company or organization require that all your Word Documents and Excel workbooks be labeled with a Microsoft Azure Information Protection label or else they can't be saved? These are the labels that are right below the tool ribbon that apply a category label such as "Public", "Business Use", or "Highly Restricted". If so, you can either

Create and save a "template file" with the desired label and then call copyfile to make a copy of that file and then write your results to the new copy, or
If using Windows you can create and/or open the file using ActiveX and then apply the desired label from your MATLAB program's code.

For #1 you can do

copyfile(templateFileName, newDataFileName);
writematrix(myData, newDataFileName);

If the template has the AIP label applied to it, then the copy will also inherit the same label.

For #2, here is a demo for how to apply the code using ActiveX.

% Test to set the Microsoft Azure Information Protection label on an Excel workbook.
% Reference support article:
% https://www.mathworks.com/matlabcentral/answers/1901140-why-does-azure-information-protection-popup-pause-the-matlab-script-when-i-use-actxserver?s_tid=ta_ans_results
clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format compact;
% Define your workbook file name.
excelFullFileName = fullfile(pwd, '\testAIP.xlsx');
% Make sure it exists.  Open Excel as an ActiveX server if it does.
if isfile(excelFullFileName)
    % If the workbook exists, launch Excel as an ActiveX server.
    Excel = actxserver('Excel.Application');
    Excel.visible = true; % Make the server visible.
    fprintf('Excel opened successfully.\n');
    fprintf('Your workbook file exists:\n"%s".\nAbout to try to open it.\n', excelFullFileName);
    % Open up the existing workbook named in the variable fullFileName.
    Excel.Workbooks.Open(excelFullFileName);
    fprintf('Excel opened file successfully.\n');
else
    % File does not exist.  Alert the user.
    warningMessage = sprintf('File does not exist:\n\n"%s"\n', excelFullFileName);
    fprintf('%s\n', warningMessage);
    errordlg(warningMessage);
    return;
end
% If we get here, the workbook file exists and has been opened by Excel.
% Ask Excel for the Microsoft Azure Information Protection (AIP) label of the workbook we just opened.
label = Excel.ActiveWorkbook.SensitivityLabel.GetLabel 
% See if there is a label already.  If not, these will be null:
existingLabelID = label.LabelId 
existingLabelName = label.LabelName 
% Create a label.
label = Excel.ActiveWorkbook.SensitivityLabel.CreateLabelInfo 
label.LabelId = "a518e53f-798e-43aa-978d-c3fda1f3a682";
label.LabelName = "Business Use";
% Assign the label to the workbook.
fprintf('Setting Microsoft Azure Information Protection to "Business Use", GUID of a518e53f-798e-43aa-978d-c3fda1f3a682\n');
Excel.ActiveWorkbook.SensitivityLabel.SetLabel(label, label);
% Save this workbook with the new AIP setting we just created.
Excel.ActiveWorkbook.Save;
% Shut down Excel.
Excel.ActiveWorkbook.Close;
Excel.Quit;
% Excel is now closed down.  Delete the variable from the MATLAB workspace.
clear Excel;
% Now check to see if the AIP label has been set 
% by opening up the file in Excel and looking at the AIP banner.
winopen(excelFullFileName)

Note that there is a line in there that gets an AIP label from the existing workbook, if there is one at all. If there is not one, you can set one. But to determine what the proper LabelId (that crazy long hexadecimal number) should be, you will probably need to open an existing document that already has the label that you want set (applied to it) and then read that label with this line:

label = Excel.ActiveWorkbook.SensitivityLabel.GetLabel

Fun

Image Analyst
Last activity 2024-5-17

Puzzle challenge - distance to horizon

In one line of MATLAB code, compute how far you can see at the seashore. In otherwords, how far away is the horizon from your eyes? You can assume you know your height and the diameter or radius of the earth.

Tips & Tricks

Image Analyst
Last activity 2024-2-29

Trick to enlarge a matrix by padding it with zeros.

To enlarge an array with more rows and/or columns, you can set the lower right index to zero. This will pad the matrix with zeros.

m = rand(2, 3) % Initial matrix is 2 rows by 3 columns
mCopy = m;
% Now make it 2 rows by 5 columns
m(2, 5) = 0
m = mCopy; % Go back to original matrix.
% Now make it 3 rows by 3 columns
m(3, 3) = 0
m = mCopy; % Go back to original matrix.
% Now make it 3 rows by 7 columns
m(3, 7) = 0