The use of PCA on a 64x64 Matrix

Hi,

I'm new to image processing, and am having trouble fitting my head
around some topics, this algorithm in particular.

I have an image, which has been converted into a 64x64 matrix (each
value being the brightness of the pixel at that spot).

For the principal component analysis, I have first totted up the values
of all the pixels, and then divided by 64 * 64, giving me the mean
value of the pixels. I then took thbis value away from the values of
all the pixels.

Is this right? Much of the literature I read referred to N column
vectors, and finding the mean for each column vector. In my case this
would mean I had 64 vectors.

My next step was to calculate the Covariance matrix, by C = M *
M(transposed). This was easy enough. I then calculated the eigenvectors
using JAMA.

However, my main problem is that I have a 64 * 64 matrix of
eigenvectors. My aim was to have 2d eigenvectors, so I could find the
principal component, and then from this, theta.

Can anyone correct me where I'm going wrong? Many thanks.

.

Relevant Pages

  • Re: The use of PCA on a 64x64 Matrix
    ... > value of the pixels. ... and finding the mean for each column vector. ... the covariance matrix is 4096 x 4096. ... I then calculated the eigenvectors ...
    (comp.graphics.algorithms)
  • Re: identifying yoghurt jars
    ... So just to convert from RGB to HSV, then eliminate pixels with low S ... feature extraction, shape, shift invariant, scale invariant, rotation ... As regards image processing equivalents of Numerical ... segmentation; I'd tend to attempt grey-level based segmentation ...
    (sci.image.processing)
  • Re: Desperately needing direction with saving images under different compression/quality schemes
    ... KB's and open it in ms paint, then save it without making any changes ... further changes to pixels, maybe just a few bytes of changes in headers ... but thats it). ... background is not in image processing, i am not sure what these changes ...
    (sci.image.processing)
  • Re: Specific area inside of an image
    ... SO what this all boils down to is that I need to find an area ... inside of this circle that has 16 pixels of the same value touching ... Well, conceptually doesn't seem that difficult--what there is in later versions of ML or toolboxes associated w/ image processing that might simplify the coding I've no clue as image processing isn't my bag, but... ...
    (comp.soft-sys.matlab)
  • Re: Determining row of pixels among a group that has the max number of pixels above a threshold
    ... It consists of 30 groups of 1x10 pixels. ... I know image processing software but not the hardware. ... who can design you a custom ASIC chip. ...
    (sci.image.processing)