View Full Version : gabor patch - matplotlib vizard problem

12-02-2014, 08:52 AM
Hello everyone,

just having troubles with a little class that makes a little gabor patch using some math, matplotlib, and vizmatplot. I would like to rotate the gabor patch (actually looks more like a bar) by pressing keys (left and right arrow) and update this every time a key was pressed.

However, "repainting" the gabor takes soooo much time... Has anyone some insight into what I am doing wrong and how to speed this up?

Many thanks in advance and kind regards!

import matplotlib, sys
import matplotlib.backends.backend_agg as agg
import pylab, math

import numpy as np
import matplotlib.pyplot as plt
import matplotlib.cm as cm

import random, viz, vizmatplot, vizact


class GaborPatch():
""" http://www.science-emergence.com/ImageProcessing/ImageProcessingPython/PlotGaborFilterMatplotlib/"""
def __init__(self):
self.F = 0.0
self.ANGLE = 90
self.theta = math.radians(self.ANGLE) # Converts angle x from degrees to radians.
self.sigma_x = 1.0
self.sigma_y = 30.0
self.radius = 100

self.M = np.zeros((self.radius*2, self.radius*2))
# viz.ON or viz.OFF

def onSensorDown(self, key):
if key == viz.KEY_RIGHT:
self.ANGLE += 10
if key == viz.KEY_LEFT:
self.ANGLE -= 10

def ChangeBase(self, x, y, theta):
self.x_theta = x * math.cos(self.theta) + y * math.sin(self.theta)
self.y_theta = y * math.cos(self.theta) - x * math.sin(self.theta)
return self.x_theta, self.y_theta

def GaborFunction(self, x, y, theta, f, sigma_x, sigma_y):
r1 = self.ChangeBase(x, y, theta)[0] / sigma_x
r2 = self.ChangeBase(x, y, theta)[1] / sigma_y
arg = - 0.5 * (r1**2 + r2**2)
return math.exp(arg) * math.cos(2*math.pi*f*self.ChangeBase(x, y, theta)[0])

def Gabor(self):
self.theta = math.radians(self.ANGLE)
x = -float(self.radius)
for i in range(self.radius*2):
y = -float(self.radius)
for j in range(self.radius*2):
self.M[i, j] = self.GaborFunction(x, y, self.theta, self.F, self.sigma_x, self.sigma_y)
y = y + 1
x = x + 1
# Normalization from 0 to 255
self.M[:, :] = ((self.M[:, :] - self.M.min()) * 255) / (self.M.max() - self.M.min())


def Plot(self):
# Create a figure with size 8 x 8 inches, resolution 80 dots per inch and
# set color of drawing background to black = 'k'
self.fig = pylab.figure(figsize=[8, 8], dpi=100, facecolor='k')
# gca stands for 'get current axis'
self.ax = self.fig.gca()
plt.imshow(self.M, cmap=cm.Greys_r)
#enable rendering of plot by passing the pyplot figure to vizmatplot
matplot = vizmatplot.Show(self.fig)
#enable display of draw rate
matplot.showDrawRate(viz.OFF) # viz.ON or viz.OFF

def main():
patch = GaborPatch()
viz.callback(viz.KEYDOWN_EVENT, patch.onSensorDown)

12-02-2014, 08:57 AM
sorry, the code needs the vizmatplot.py file that can be downloaded here in order to work: