Add anisotropic_diffusion() API

Added anisotropic_diffusion() support from v3.6.0

Author: mlloreda

arrayfire/image.py

@@ -1240,6 +1240,47 @@ def canny(image,
                                      c_uint_t(sobel_window), c_bool_t(is_fast)))
     return output
 
+def anisotropic_diffusion(image, time_step, conductance, iterations, flux_function_type = FLUX.QUADRATIC, diffusion_kind = DIFFUSION.GRAD):
+    """
+    Anisotropic smoothing filter.
+
+    Parameters
+    ----------
+    image: af.Array
+        The input image.
+
+    time_step: scalar.
+        The time step used in solving the diffusion equation.
+
+    conductance:
+        Controls conductance sensitivity in diffusion equation.
+
+    iterations:
+        Number of times the diffusion step is performed.
+
+    flux_function_type:
+        Type of flux function to be used. Available flux functions:
+          - Quadratic (af.FLUX.QUADRATIC)
+          - Exponential (af.FLUX.EXPONENTIAL)
+
+    diffusion_kind:
+        Type of diffusion equatoin to be used. Available diffusion equations:
+          - Gradient diffusion equation (af.DIFFUSION.GRAD)
+          - Modified curvature diffusion equation (af.DIFFUSION.MCDE)
+
+    Returns
+    -------
+    out: af.Array
+        Anisotropically-smoothed output image.
+
+    """
+    out = Array()
+    safe_call(backend.get().
+              af_anisotropic_diffusion(c_pointer(out.arr), image.arr,
+                                       c_float_t(time_step), c_float_t(conductance), c_uint_t(iterations),
+                                       flux_function_type.value, diffusion_kind.value))
+    return out
+
 def is_image_io_available():
     """
     Function to check if the arrayfire library was built with Image IO support.

arrayfire/library.py

@@ -422,6 +422,22 @@ class CANNY_THRESHOLD(_Enum):
     MANUAL = _Enum_Type(0)
     AUTO_OTSU = _Enum_Type(1)
 
+class FLUX(_Enum):
+    """
+    Flux functions
+    """
+    DEFAULT     = _Enum_Type(0)
+    QUADRATIC   = _Enum_Type(1)
+    EXPONENTIAL = _Enum_Type(2)
+
+class DIFFUSION(_Enum):
+    """
+    Diffusion equations
+    """
+    DEFAULT = _Enum_Type(0)
+    GRAD    = _Enum_Type(1)
+    MCDE    = _Enum_Type(2)
+
 _VER_MAJOR_PLACEHOLDER = "__VER_MAJOR__"
 
 def _setup():

arrayfire/tests/simple/image.py

@@ -81,4 +81,6 @@ def simple_image(verbose = False):
     a = af.randu(10, 10)
     b = af.canny(a, low_threshold = 0.2, high_threshold = 0.8)
 
+    display_func(af.anisotropic_diffusion(a, 0.125, 1.0, 64, af.FLUX.QUADRATIC, af.DIFFUSION.GRAD))
+
 _util.tests['image'] = simple_image