Method _createPath

utils/motionblur.py:111–231

[summary] creates a motion blur path with the given intensity. [description] Proceede in 5 steps 1. Get a random number of random step sizes 2. For each step get a random angle 3. combine steps and angles into a sequence of increments 4. create

(self)

        self.kernel_is_generated = False

    def _createPath(self):
        """[summary]
        creates a motion blur path with the given intensity.
        [description]
        Proceede in 5 steps
        1. Get a random number of random step sizes
        2. For each step get a random angle
        3. combine steps and angles into a sequence of increments
        4. create path out of increments
        5. translate path to fit the kernel dimensions

        NOTE: "random" means random but might depend on the given intensity
        """

        # first we find the lengths of the motion blur steps
        def getSteps():
            """[summary]
            Here we calculate the length of the steps taken by
            the motion blur
            [description]
            We want a higher intensity lead to a longer total motion
            blur path and more different steps along the way.

            Hence we sample

            MAX_PATH_LEN =[U(0,1) + U(0, intensity^2)] * diagonal * 0.75

            and each step: beta(1, 30) * (1 - self.INTENSITY + eps) * diagonal)
            """

            # getting max length of blur motion
            self.MAX_PATH_LEN = 0.75 * self.DIAGONAL * \
                (uniform() + uniform(0, self.INTENSITY**2))

            # getting step
            steps = []

            while sum(steps) < self.MAX_PATH_LEN:

                # sample next step
                step = beta(1, 30) * (1 - self.INTENSITY + eps) * self.DIAGONAL
                if step < self.MAX_PATH_LEN:
                    steps.append(step)

            # note the steps and the total number of steps
            self.NUM_STEPS = len(steps)
            self.STEPS = np.asarray(steps)

        def getAngles():
            """[summary]
            Gets an angle for each step
            [description]
            The maximal angle should be larger the more
            intense the motion is. So we sample it from a
            U(0, intensity * pi)

            We sample "jitter" from a beta(2,20) which is the probability
            that the next angle has a different sign than the previous one.