Question

In matlab I have a 128 by n matrix, which we can call

[A B C]

where each letter is an 128 by 1 matrix.

So what I want to do is concat the above matrix with another matrix,

[A~ D E].

Where A~ is similar in its values to A.
What I want to get as the result of the concat would be:

[A B C D E],

where A~ is omitted.

What is the best way to do this? Note that I do not know beforehand that A~ is similar.

To clarify, my problem is how would I determine if two columns are similar? By similar I mean where between two columns, many of the row values are close in value.

Maybe an illustration would help as well

Vector A: [1  2   3 4 5 6 7 8   9]'
           |  |   | | | | | |   | 
Vector B: [20 2.4 4 5 0 7 7 7.6 10]' 

where there are some instances where the values are completely different, but for the most part the values are close. I don’t have a defined threshold for this, but ideally it would be something that I could experiment with.

Answer 1

To solve this, a matching algorithm called vl_ubcmatch can be used.

[matches, scores] = vl_ubcmatch(da, db) ; For each descriptor in da,
vl_ubcmatch finds the closest descriptor in db (as measured by the L2
norm of the difference between them). The index of the original match
and the closest descriptor is stored in each column of matches and the
distance between the pair is stored in scores.

source:
http://www.vlfeat.org/overview/sift.html

Thus, the solution is to find the matched columns with the highest scores and eliminate them before concatenating.