Hybrid Discrete Wavelet Transform and Gabor Filter Banks Processing for Features Extraction from Biomedical Images

Abstract

A new methodology for automatic feature extraction from biomedical images and subsequent classification is presented. The approach exploits the spatial orientation of high-frequency textural features of the processed image as determined by a two-step process. First, the two-dimensional discrete wavelet transform (DWT) is applied to obtain the HH high-frequency subband image. Then, a Gabor filter bank is applied to the latter at different frequencies and spatial orientations to obtain new Gabor-filtered image whose entropy and uniformity are computed. Finally, the obtained statistics are fed to a support vector machine (SVM) binary classifier. The approach was validated on mammograms, retina, and brain magnetic resonance (MR) images. The obtained classification accuracies show better performance in comparison to common approaches that use only the DWT or Gabor filter banks for feature extraction.

Figure 1

Examples of brain MR images.

Figure 2

Examples of retina images.

Figure 3

Examples of mammograms.

Figure 4

Schematic diagram of the DWT-Gabor approach.

Figure 5

Schematic diagram of the DWT approach.

Figure 6

2D-DWT decomposition of an image.

Figure 7

Analysis of a normal retina.

Figure 8

Analysis of a retina with circinate.