Table 1 Summary of parameters belonging to first- and second-order texture features33-35
From: Characterizing MRI features of rectal cancers with different KRAS status
Texture feature | Histogram (n=9) | Run-length matrix (n=5) | Grey-level co-occurrence matrix (n=11) |
|---|---|---|---|
Level/Order | First order | Second order | Second order |
Description | Histogram where x-axis represents pixel/voxel gray level and y-axis represents frequency of occurrence | Adjacent or consecutive pixels/voxels of a single gray level in a given direction | How often pairs of pixels with specific values in a specified spatial range occur in an image |
Parameters | Mean | Short run-length emphasis | Angular second moment |
standard deviation | Long run-length emphasis | Contrast | |
skewness | Run-length non-uniformity | Correlation | |
Kurtosis | Grey-level non-uniformity | Sum of squares | |
Perc.1% | Fraction of image in runs | Inverse difference moment | |
Perc.10% | Â | Sum average | |
Perc.50% | Â | Sum variance | |
Perc.90% | Â | Sum entropy | |
Perc.99% | Â | Entropy | |
| Â | Â | Difference variance | |
| Â | Â | Difference entropy |