Image Analysis - second order moments - ellipticities

AI Thread Summary
The discussion centers on calculating ellipticities and orientation angles of images using their second order moments of inertia. The user seeks clarification on performing the summation involved in this calculation, specifically how to define the x and y values. It is noted that x and y represent the coordinates of each point within the image matrix, corresponding to the indices of the matrix elements (column and row). A crucial step is defining the region of interest within the image, which can be achieved by setting a condition, such as a grayscale intensity threshold, to isolate specific features like bright spots. The provided source offers some guidance, but the user remains uncertain about the practical application of the summation process.
Miss_Astro
Messages
15
Reaction score
0
There seems to be a good source here:

http://www.cs.cf.ac.uk/Dave/AI2/node194.html


But my problem is understanding the summation. What I am trying to do is calculate ellipticites and orientation angles of images using their second order moments of inertia.


My images are in matrix form with values depicting the greyscale of the image. Do you know what I would actually do? The above source is helpful but I am stuck on the actual summation and what would be use as x and y values.
 
Technology news on Phys.org
x and y are the coordinates of each point within the region, so in your case it would be the index of the matrix elements (column, row).

But first you have to define the region that is part of the object. You have to set some kind of condition that defines the region. For example, it could be a grayscale intensity threshold if you are looking for bright spots.
 
Thread 'Is this public key encryption?'

Thread 'Is this public key encryption?'

I've tried to intuit public key encryption but never quite managed. But this seems to wrap it up in a bow. This seems to be a very elegant way of transmitting a message publicly that only the sender and receiver can decipher. Is this how PKE works? No, it cant be. In the above case, the requester knows the target's "secret" key - because they have his ID, and therefore knows his birthdate.
View full post »
Thread 'Project Documentation'

Thread 'Project Documentation'

Trying to package up a small bank account manager project that I have been tempering on for a while. One that is certainly worth something to me. Although I have created methods to whip up quick documents with all fields and properties. I would like something better to reference in order to express the mechanical functions. It is unclear to me about any standardized format for code documentation that exists. I have tried object orientated diagrams with shapes to try and express the...
View full post »

Similar threads

Stargazing Astro Image Stacking (optimize DSS image stacking and post processing)
Replies
43
Views
11K
MATLAB Bilinear spline interpolation MATLAB using MESHGRID and SURF
Replies
2
Views
3K
I What would a calculus author have to say on ##\int r^2dm##?
Replies
11
Views
2K
I Fundamental matrix of a second order 2x2 system of ODEs
Replies
2
Views
4K
Second Moment of Area calculation?
Replies
4
Views
5K
Engineering Question - Calculating Coefficients for 2nd Order Transient Analysis
Replies
2
Views
1K
Python Invert a matrix from a 4D array : equivalence or difference with indexes
Replies
2
Views
2K
Classification of a second order partial differential equation
Replies
5
Views
2K
Fourier Transform, Discrete Forier Transform image processing
Replies
3
Views
3K
Expressing Elliptic Orbitals As Speed Functions.
Replies
2
Views
1K

Hot Threads

Recent Insights

Back
Top