Method

Description

Color based techniques

Considering only pixel values. Color features based on different color spaces (RGB, HSI/HSV), histograms.

Texture based techniques

Considering spatial relations between pixels. Co-occurrence matrices, homogenous texture descriptors.

Contour based techniques

Focusing on edge, contour and boundary detection.

Segmentation

Dividing images into meaningful regions based on criteria.

Combination of various techniques

1) Thresholding methods—Classifiers.

2) Pre-processing/post processing images.

­ Dark regions removed.

­ Over illuminated regions removed.

­ Eliminate small detections.

­ Color histogram adaptations Divide picture into smaller parts.