Face sub-space determination

A method of determining face sub-spaces, the method comprising:

• a. generating a first series of initial images in which a first predetermined facial property is modified,
• b. generating a second series of initial images in which a second predetermined facial property is modified,
• c. coding each series of images according to the variance of the images to obtain an estimated sub-space for each facial property,
• d. concatenating the sub-spaces to provide a single over-exhaustive space,
• e. approximating each image of the first and second series on the over-exhaustive space to obtain approximated versions of each image on each estimated property sub-space,
• f. generating overall approximated versions of each image on the whole over-exhaustive space,
• g. comparing the overall approximated version of each image with the initial image to determine an error value for each image,
• h. sub-dividing the error value for each image into a sub-error for each estimated property sub-space in proportion to the variance of that sub-space,
• i. combining each sub-error for each image with the approximated version of that image on the estimated property sub-space, to obtain a new approximated version in the property sub-space for each image,
• j. coding the new approximated versions of the images according to their variance to obtain new estimated sub-spaces.