Wb. Mikhael et A. Ramaswamy, APPLICATION OF MULTITRANSFORMS FOR LOSSY IMAGE REPRESENTATION, IEEE transactions on circuits and systems. 2, Analog and digital signal processing, 41(6), 1994, pp. 431-434
The multitransform technique is applied for lossy image representation
. The image is first divided into smaller non-overlapping submages. Ea
ch subimage is resolved into two dimensional (2-D) subsignals, which a
re then compactly represented in a particular transform domain. This l
eads to an efficient representation of the subimage by superimposing t
he dominant coefficients corresponding to each subsignal. An adaptive
algorithm in conjunction with an optimization strategy are developed t
o minimize the difference between the original and the reconstructed s
ubimage. Extensive simulations verify that, for a given number of reta
ined coefficients, the combination of the DCT and Haar transforms yiel
ds a more compact representation than using DCT or Haar alone.