Segment objects from measurements using expressions and models.

Parameters

Expression

Write the expression for the segmentation, examples can be found below. The following comparators can be used for the expression:

  • Equals - =

  • And - &

  • Or - |

  • Less than - <

  • Less or equal - <=

  • Larger - >

  • Larger or equal - >=

  • Different from - !=

Model

Select model to apply to the expression.

Min area

The minimum number of pixels for an object to be included.

Max area

The maximum number of pixels for an object to be included.

If 0 no maximum area is defined.

Object filter

Use an expression to further exclude unwanted objects based on shape.

Properties that can be used for the Expression:

  • Area

  • Length

  • Width

  • Circumference

  • Regularity

  • Roundness

  • Angle

  • D1

  • D2

  • X

  • Y

  • MaxBorderDistance

  • BoundingBoxArea

Shrink

Takes away x numbers of pixels at the borders of the objects included in images.

Examples

Using class

Segment object classified to sample class. Expression: class = sample

Using negative

Segment object not classified. Expression: class != none

Band index comparison

Indexing with 1 based index in band list. Expression (B10 > 1.5 or B15 < 2) and B20 <=1.2)

Band names can also be used instead of band numbers in the example the band names are HE and LE. HE > 20 and LE <40

Wavelength number

Using wavelength number. Expression: (W980 > 1.5 or W1024 < 2) & W1200 <= 1.2