Changes between Version 1 and Version 2 of recipes/PCA/PCA


Ignore:
Timestamp:
Mar 29, 2012, 5:22:41 PM (12 years ago)
Author:
Dave Hunter
Comment:

--

Legend:

Unmodified
Added
Removed
Modified

  • recipes/PCA/PCA

    v1 v2  
    11== PCA ==
     2
     3Unless your dataset is exceptionally large (>400) you will have more dimensions in you dataset than samples. If you need to check, the number of dimensions is twice the number of points in your template (i.e. x and y coordinates in the picture), strictly speaking you can subtract up to 6 as a result of the alignment process but that only works if both you and the stats package understand rank-deficient matrices. In order to reduce that number of dimensions, and reduce the chance of over-fitting we use '''PCA''', fortunately shape PCA is built into Psychomorph in the form of an '''ASM''' (Active Shape Model).
     4
     5[wiki:recipes/PCA/explanation PCA (somewhat) explained] - A long winded incoherent rant on the topic.
     6
     7== The PCA Menu ==
     8[wiki:recipes/PCA/BuildShapePCA Build Shape PCA (ASM)] – Build an Active Shape Model(ASM) from a set of templates[[BR]]
     9[wiki:recipes/PCA/BatchAnalyseShape Batch Analyse Shape] – Analyse a set of templates using an ASM and produce a set of PCA parameters[[BR]]
     10[wiki:recipes/PCA/BatchShapeReconstruct Batch Shape Reconstruct] – Reconstruct a set of templates from a set of PCA parameters using the ASM[[BR]]
     11---[[BR]]
     12[wiki:recipes/PCA/BuildImagePCA Build Image PCI] – Build a Principal Components Image (PCI) model from a set of images[[BR]]
     13[wiki:recipes/PCA/BatchAnalyseImages Batch Analyse Images] – Analyse a set of images uinsg a PCI model and produce a set of PCA parameters[[BR]]
     14[wiki:recipes/PCA/BatchImageReconstruct Batch Image Reconstruct] – Reconstruct a set images from a PCI model and a set of PCA parameters.[[BR]]
     15PCA Options[[BR]]
     16-'''Mask Input Images''' – Mask images prior to bulding PCI model or analysing image sets.[[BR]]
     17-'''Mask Output Images''' – Mask images reconstructed from PCI model.[[BR]]
     18-'''Normalise Images''' – Pre-normalise images before building or analysing PCI model.[[BR]]
     19-'''Save Residual Images'''. – Save residuals from image analysis.[[BR]]
     20
     21
     22[[Image(average.jpg, width=40)]]