Table 3.
Examples of first-order statistics features with their description [23]
| Type of feature | Measure |
|---|---|
| Energy | A measure of the magnitude of voxel values in an image |
| Total Energy | The value of Energy feature scaled by the volume of the voxel in cubic mm |
| Entropy | a measure of the inherent randomness in the gray level intensities of the image |
| Minimum | The lowest intensity present |
| Maximum | The maximum gray level intensity within the region of interest |
| 10th and 90th percentile | The 10th and 90th percentile of the gray level intensity within the region of interest |
| Mean | The average gray level intensity within the region of interest |
| Median | The median gray level intensity within the region of interest |
| Range | The range of gray values in the region of interest |
| Interquartile Range | The range between the 25th and 75th percentile of the image array |
| Mean Absolute Deviation (MAD) | The mean distance of all intensity values from the Mean Value of the image array |
| Robust Mean Absolute Deviation (rMAD) | The mean distance of all intensity values from the Mean Value calculated on the subset of image array with gray levels in between, or equal to the 10th and 90th percentile |
| Root Mean Squared (RMS) | The square-root of the mean of all the squared intensity values |
| Standard Deviation | The amount of variation or dispersion from the Mean Value |
| Skewness | The asymmetry of the distribution of values about the Mean value |
| Kurtosis | a measure of the ‘peakedness’ of the distribution of values in the image region of interest |
| Variance | The mean of the squared distances of each intensity value from the Mean value and a measure of the spread of the distribution about the mean |
| Uniformity | The sum of the squares of each intensity value and a measure of the homogeneity of the image array |