gray_features — Calculates gray value features for a set of regions.
gray_features has a set of regions
(Regions) as input. For each of these regions the
features (Features) are calculated and returned in Value.
Possible values for Features:
 'area': Gray value volume of region
(see area_center_gray)
 'row': Row index of the center of gravity
(see area_center_gray)
 'column': Column index of the center of gravity
(see area_center_gray)
 'ra': Major axis of equivalent ellipse
(see elliptic_axis_gray)
 'rb': Minor axis of equivalent ellipse
(see elliptic_axis_gray)
 'phi': Orientation of equivalent ellipse
(see elliptic_axis_gray)
 'min': Minimum gray value
(see min_max_gray)
 'max': Maximum gray value
(see min_max_gray)
 'median': Median gray value
(see min_max_gray, with Percent=50)
 'mean':Mean gray value (see intensity)
 'deviation': Deviation of gray values
(see intensity)
 'plane_deviation':  Deviation from the approximating plane
(see plane_deviation)
 'anisotropy': Anisotropy
(see entropy_gray)
 'entropy': Entropy
(see entropy_gray)
 'fuzzy_entropy': Fuzzy entropy of region
(see fuzzy_entropy, with a fuzzy function from
Apar=0 to Cpar=255)
 'fuzzy_perimeter': Fuzzy perimeter of region
(see fuzzy_perimeter, with a fuzzy function from
Apar=0 to Cpar=255)
 'moments_row': Mixed moments along a row
(see moments_gray_plane)
 'moments_column': Mixed moments along a column
(see moments_gray_plane)
 'alpha': Approximating plane, parameter Alpha
(see moments_gray_plane)
 'beta': Approximating plane, parameter Beta
(see moments_gray_plane)
Several features are processed in the order in which they are entered.
Note that the operator gray_features only considers
the given Regions and ignores any previously set domain
of the input image Image.
Regions (input_object)  region-array → object
Regions to be examined.
Image (input_object)  singlechannelimage → object (byte / direction / cyclic / int1 / int2 / uint2 / int4 / real)
Gray value image.
Features (input_control)  string(-array) →  (string)
Names of the features.
Default value: 'mean'
List of values: 'alpha', 'anisotropy', 'area', 'beta', 'column', 'deviation', 'entropy', 'fuzzy_entropy', 'fuzzy_perimeter', 'max', 'mean', 'median', 'min', 'moments_column', 'moments_row', 'phi', 'plane_deviation', 'ra', 'rb', 'row'
Value (output_control)  real(-array) →  (real)
Values of the features.
If F is the area of the region and N the number of features the runtime complexity is O(F * N).
The operator gray_features returns the value 2 (H_MSG_TRUE) if the
input image has the defined gray values and the parameters are
correct. If necessary an exception is raised.
connection, 
mean_image, 
entropy_image, 
sobel_amp, 
median_separate
select_gray, 
shape_trans, 
reduce_domain, 
count_obj
select_gray, 
deviation_image, 
entropy_gray, 
intensity, 
mean_image, 
min_max_gray, 
select_obj
Foundation