I think I can shed some light on these values:
Coef Variation:
This is differently computed depending on the unit of the data:
if (unit != null && unit.contains("intensity")) {
final double m = valueSum / sampleCount;
final double m2 = sqrSum / sampleCount;
cv = Math.sqrt(m2 - m*m) / m;
} else {
final double m4 = power4Sum / sampleCount;
final double m2 = sqrSum / sampleCount;
cv = Math.sqrt(m4 - m2*m2) / m2;
}
The code can be found here: snap-engine/SummaryStxOp.java
Background information: Coefficient of variation - Wikipedia
ENL:
if (unit != null && unit.contains("intensity")) {
final double m = valueSum / sampleCount;
final double m2 = sqrSum / sampleCount;
final double mm = m*m;
enl = mm / (m2 - mm);
} else {
final double m4 = power4Sum / sampleCount;
final double m2 = sqrSum / sampleCount;
final double m2m2 = m2*m2;
enl = m2m2 / (m4 - m2m2);
}
The code can be found here: snap-engine/SummaryStxOp.java
Background information: Estimation of the Equivalent Number of Looks in Polarimetric Synthetic Aperture Radar Imagery | IEEE Journals & Magazine | IEEE Xplore
Max error:
This is actually the bin size.
The code can be found here: snap-desktop/StatisticsPanel.java