| Statistical Model | ||
---|---|---|---|
First-order | Second-order | Higher-order | |
Meaning | Frequency distribution of pixel/voxel gray-values without considering their spatial orientation [45]. | Spatial distribution of pixel/voxel gray-levels in relation to their relative positions [46] | Characterizing images based on a unique interaction between the pixels/voxels that constitute the image [25]. |
Computation method | Histogram from which several texture features can be derived | Texture features obtained from the joint probability distribution of neighboring pixels | Mathematical algorithms that evaluate pixel intensities in relation to their neighboring pixels |
Examples | mean gray-level intensity, uniformity, entropy, standard deviation, skewness, kurtosis | GLCM, GLRLM | NGTDM, NSZM, wavelet, and Gabor transform |