contrasts.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-


# TODO import as cv
import cv2
import numpy as np
from .helpers import luminance
from copy import deepcopy

# subclassing numpy ndarray
# Vorgehen: https://docs.scipy.org/doc/numpy/user/basics.subclassing.html
# resize Probleme https://sourceforge.net/p/numpy/mailman/message/12594801/
# andere ownership Probleme könne angeblich mit out= gelöst werden
# "Use __new__ when you need to control the creation of a new instance.
# Use __init__ when you need to control initialization of a new instance."
class View(np.ndarray):
    """Core class for the representation of colour contrasts in Movies
       
       View is the basis class for specific ways to represent colour contrasts.
       It does hold the definitions of contrasts itself. Objects of class View
       subclass the numpy array class and hence inherit numpy methods. However,
       it is not recommended to use functions which manipulate the array in
       terms of structure. In this case some of the additional functions which
       are implemented by this class and its subclasses might not lead to
       reasonable results.

       Attributes:
       TODO Docstring komplettieren und Verfahren überprüfen
       """
    def __new__(cls, frames, input_array=None):
        """instantiates the view class

           instantiation complies with the recommendation for subclassing
           numpy.ndarray

           Parameters
           ----------
           frames : itten.movie.Frames
           input_array : itten.contrasts.View  # TODO wie schaffte np lower case object
           contrast : String  # Modifizieren Channel Integer to String
           frame_step : Int
           savefig : Boolean

           Returns
           -------
           Object : View
               Empty numpy.ndarray of type View
        """
        obj = input_array
        if type(obj) == np.ndarray:
            obj = np.asarray(input_array, dtype=np.uint8).view(cls).copy()
        else:
            input_array = np.zeros((0), dtype=np.uint8)
            obj = np.asarray(input_array).view(cls).copy()
        obj._frames = frames
        obj._contrast = 2
        obj._frame_step = 10
        obj._bins = 256
        return obj

    def __array_finalize__(self, obj):
        if obj is None: return
        self._frames = getattr(obj, '_frames', None)
        self._contrast = getattr(obj, '_contrast', None)
        self._frame_step = getattr(obj, '_frame_step', None)
        self._bins = getattr(obj, '_bins', None)

    def __array_wrap__(self, out_arr, context=None):
        return np.ndarray.__array_wrap__(self, out_arr, context)


# subclassing subclass of numpy http://stackoverflow.com/questions/7342637/how-to-subclass-a-subclass-of-numpy-ndarray
# TODO es gibt noch das Problem, dass numpy nach mehreren Berechnungen von drive eine max recursion Warnung ausgiebt, warum? Brauche ich __del__
class VHistStack(View):
    def __new__(cls, frames, input_array=None):
        """Represents a movie contrast in terms of stacked histograms

           For each defined frame a histogram is calculated and each bin that
           exceeds threshold is considered in the output array

           Parameters
           ----------
           bins : Int
               Number of bins for the calculation of the histogram
           thrsh : Int
               Threshhold defining the number of pixels a bin needs to contain
               to be considered in the result

           Returns
           -------
           Object : VHistStack
               VHistStack is a 2-dimensional numpy array which contains
               the frame number, the bin number and a quantifier which
               represents the relative weight of the bin in the frame
        """

        obj = View.__new__(cls, frames, input_array=input_array)
        obj._threshold = 60000
        return obj

    def __array_finalize__(self, obj):
        if obj is None: return
        View.__array_finalize__(self, obj)
        self._threshold = getattr(obj, '_threshold', None)

    # TODO jetzt ausschließlich mit self numpy rechnen statt mit contrast_points liste
    def populate(self, ctrst=2, frm_stp=10, bins=16, thrsh=60000, start=1, end=0):
        """doc (aus __new__ zusammentragen)
        """

        # set class properties
        self._contrast = ctrst
        self._frame_step = frm_stp
        self._bins = bins
        self._threshold = thrsh
        # TODO dafür müssen erst getters und setters in movie.frames definiert werden
        # slef._frames.start = start
        # slef._frames.end = end

        contrast_points = []
        # pwd list sollte in Frames sein und hier nur durchlaufen werden
        for frm_nr in range(self._frames.start, self._frames.end, self._frame_step):
            pwd = self._frames.folder + self._frames.prefix + str(frm_nr) + '.png'

            img = cv2.imread(pwd)  # BGR

            # TODO Dictionary um Parameter auf Kontrast Funktion zu mappen

            # so wie hier für 2 das ist die Referznimplementierung
            # luminances gibt ein Bild mit den luminanz werten in der
            # 3. Dimension zurück
            if self._contrast == 2:
                luminances = luminance(img)
                hist_value, _ = np.histogram(luminances.flatten(), bins=self._bins, range=(0, 256))
            else:
                img_hsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV_FULL)
                hist_value = cv2.calcHist([img_hsv], [self._contrast], None, [16], [0, 256])

            for bin_index, point in enumerate(hist_value):
                if point > self._threshold:
                    contrast_points.append((frm_nr, bin_index, int(point)))

        contrast_points = np.asarray(contrast_points, np.uint8)
        shape = contrast_points.shape
        self.resize(shape, refcheck=False)
        self[:, :] = contrast_points

        return deepcopy(self)  # TODO does not create a new object