gray_projectionsT_gray_projectionsgray_projectionsGrayProjectionsGrayProjections (Operator)

Name

gray_projectionsT_gray_projectionsgray_projectionsGrayProjectionsGrayProjections — Calculate horizontal and vertical gray-value projections.

Signature

Description

gray_projectionsgray_projectionsgray_projectionsGrayProjectionsGrayProjections calculates the horizontal and vertical gray-value projections, i.e., the mean values in the horizontal and vertical direction of the gray values of the input image ImageImageImageImageimage within the input region RegionRegionRegionRegionregion.

If ModeModeModeModemode = 'simple'"simple""simple""simple""simple" is selected the projection is performed in the direction of the coordinate axes of the image, i.e.:

                                      ----
                                      \
    HorProjection(r)  =  1/n(r+r')    /    Image(r+r',c+c')
                                      ----
                                   (r+r',c+c') in Region

                                      ----
                                      \
    VertProjection(c) =  1/n(c+c')    /    Image(r+r',c+c')
                                      ----
                                   (r+r',c+c') in Region

Here, (r',c') denotes the upper left corner of the smallest enclosing axis-parallel rectangle of the input region (see smallest_rectangle1smallest_rectangle1smallest_rectangle1SmallestRectangle1SmallestRectangle1), and n(x) denotes the number of region points in the corresponding row r+r' or column c+c'. Hence, the horizontal projection returns a one-dimensional function that reflects the vertical gray value changes. Likewise, the vertical projection returns a function that reflects the horizontal gray value changes.

If ModeModeModeModemode = 'rectangle'"rectangle""rectangle""rectangle""rectangle"is selected the projection is performed in the direction of the major axes of the smallest enclosing rectangle of arbitrary orientation of the input region (see smallest_rectangle2smallest_rectangle2smallest_rectangle2SmallestRectangle2SmallestRectangle2). Here, the horizontal projection direction corresponds to the larger axis, while the vertical direction corresponds to the smaller axis. In this mode, all gray values within the smallest enclosing rectangle of arbitrary orientation of the input region are used to compute the projections.

Parallelization

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Processed without parallelization.

Parameters

Module

1D Metrology