Image Analyst

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32,142 total contributions since 2010

Senior Scientist (male/man) and Inventor in one of the world's 10 largest industrial corporations doing image analysis full time. Ph.D. in Optical Sciences specializing in imaging, image processing, and image analysis. 40+ years of military, academic, and (mostly) industrial experience with image analysis programming and algorithm development. Experience designing custom light booths and other imaging systems. Experience with color and monochrome imaging, video analysis, thermal, ultraviolet, hyperspectral, CT, MRI, radiography, profilometry, microscopy, NIR and Raman spectroscopy, etc. on a huge variety of subjects. Member of the Mathworks Community Advisory Board. Be sure to click "View All" in my File Exchange to see ALL of my demos and tutorials: http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

Professional Interests: Image analysis and processing

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Answered
Extract only diagonal elements from matrix
You can do this, where m is your matrix, and v is the vector of extracted values from the x,y locations v = zeros(1, length(X))...

4 hours ago | 0

Answered
How do you find the centroid of a particular Blob?
I think I already did this swinging pendulum panel thing before when you had a video. Not sure why you're posting it again. Bu...

4 hours ago | 0

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How to change the gray level of a 8-bit gray level image to 7, 6, 5-bit gray level image using for loops?
To seqentially reduce the number of "used" bits in an 8 bit image you'd do for k = 1 : 7 grayImage = grayImage / 2; end

5 hours ago | 0

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change the dimension of a cell in a cell array
You almost definitely should not use a cell array for this. They are slow and have lots of overhead. It looks like you can use...

10 hours ago | 0

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Remove duplicate 1s from matrix columns
Mitchell, try this: qq = logical([... 1 0 1 1 1 1 1 0 1 1 1 0 0 0 1]) [rows, columns] = si...

2 days ago | 0

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Generating a range of curves that fit inside a set of fixed limits
Here's an example. Adapt as needed: clc; % Clear the command window. close all; % Close all figures (except those of imto...

2 days ago | 0

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Subtracting XYZ coordinates defined by matrices
"For instance let A correspond to the point cloud corresponding to a sphere and B correspond to a smaller, concentric sphere. Th...

3 days ago | 1

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Is it possible to tell what matlab is "Busy" with?
You might be able to click the pause button and it will stop there, then hopefully if you click continue, it will continue.

3 days ago | 1

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How can I find the max value and location within a matrix
Try this, where m is your matrix maxValue = max(m(:)); rows = find(m == maxValue); % Find all locations where m equals the max...

3 days ago | 1

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Answered
Writing the built in matlab function in simple code(like for loop, etc.)
Jimmy, try this: y=[1 2 3 4]; % First input OccurancesParameter= 5; % second input , it's always unsigned integer number great...

3 days ago | 0

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Answered
Manipulate amplitude without using linspace
Use rescale(): x_t = rescale(x_t, -2, 1);

3 days ago | 1

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Automatic Segmentation of Ultrasound Images?
It's so noisy and ill-defined that I see deep learning using SegNet as your only hope. Otherwise look to the literature: USC A...

3 days ago | 0

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How to detect small white pixels in an image and change their colour
You can use regionfill(), or you can treat them as salt and pepper noise and use my attached demo which uses a modified median f...

3 days ago | 0

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time stamp in video files (image to video file conversion)
If you have the Computer Vision Toolbox, use insertText(). If not, you have to use text() and then getframe() but the image s...

3 days ago | 0

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Answered
draw horizontal lines on edges of a image
Try this: clc; % Clear the command window. close all; % Close all figures (except those of imtool.) clear; % Erase all e...

3 days ago | 0

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Find the Euclidean distance of each pixel from a user-selected pixel in color space and displays scaled images from 0 to the current max distance.
Just do this [x, y] = ginput(1); row = round(y); col = round(x); rp = double(rgbImage(row, col, 1)); gp = double(rgbImage(r...

3 days ago | 0

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Answered
how to convert dicom image to png
I imagine you looked at what map was. Did that not give you any clue as to why it was not 3 columns? What was it? Maybe it's ...

3 days ago | 0

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Purple colour extraction only
Ramdhan: OK, here is a full demo: % Demo by Image Analyst. clc; % Clear the command window. close all; % Close all figur...

3 days ago | 0

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How to automatically obtain upper-left pixel coordinates of one of the 4x4 blocks I obtained splitting an image?
Try indexing: [rows, columns] = size(ca) for col = 1 : columns for row = 1 : rows thisCellContents = ca{row, col...

3 days ago | 0

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Answered
How to extract highest intensity area from a greyscale spectrogram?
You've given no criteria for how those areas are to be determined. You might want to use watershed() or superpixels(). Or use ...

3 days ago | 1

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Answered
Finding longest subvector of equal elements in 5000000 length int-vector.
Here's how I thought of to do it, using regionprops to count the length of each consequtive run of numbers: data = [1,1,1,2,1,1...

4 days ago | 0

Answered
Change font and fontsize in uialert of title and message text?
See attached demos.

4 days ago | 0

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how to calculate area region growing
You accepted an answer, so is it solved already? If not, what is this regiongrowing() function you mentioned? You should just ...

4 days ago | 1

Answered
finding the radii of circles knowing the center of those circles
You can do this: mask = grayImage > 50; % Or whatever props = regionprops(mask, 'Centroid', 'EquivDiameter', 'Area'); allDiam...

4 days ago | 1

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Answered
Purple colour extraction only
Try this: mask = imdilate(redChannel>200, true(5)); %the mask

6 days ago | 0

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Display Folder Browser in MatLab Online?
Try issuing the >> filebrowser command.

6 days ago | 0

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setting the limits for negative values for colormap
What are the values when it crashes: minValue = min(C{g,1}(:,1)) maxValue = max(C{g,1}(:,1)) fprintf('Min = %f, max = %f.\n'...

6 days ago | 0

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Saving full screen multiple figures
Try this: clear all; close all; clc; format long g; format compact; fontSize = 18; fprintf('Beginning to run %s.m ...\n',...

6 days ago | 1

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Answered
How to compare two colors?
JD, I haven't heard back from you so I assume you're having a lot of trouble. Maybe start with this simple script where I compa...

6 days ago | 0

Answered
How to compare two colors?
There are several ways to do this. For example you can use statistical discriminant analysis in RGB color space, like the attac...

6 days ago | 0