checkerboard.py
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00032 
00033 import numpy
00034 from numpy import matrix, vsplit, sin, cos, reshape
00035 import rospy
00036 
00037 param_names = ['spacing_x', 'spacing_y']
00038 
00039 class Checkerboard:
00040     '''
00041     Primitive for generating 3D points of a checkerboard.
00042     '''
00043 
00044     # Dictionary with four elems
00045     #  num_x:   number of internal corners along x axis (Not configurable)
00046     #  num_y:   number of internal corners along y axis (Not configurable)
00047     #  width_x: spacing between corners along x direction
00048     #  width_y: spacing between corners along y direction
00049     def __init__(self, config = {'corners_x': 2,
00050                                  'corners_y': 2,
00051                                  'spacing_x': .10,
00052                                  'spacing_y': .10} ):
00053         rospy.logdebug('Initializing Checkerboard')
00054         self._corners_x = config['corners_x']
00055         self._corners_y = config['corners_y']
00056 
00057         param_vec = reshape( matrix([ config['spacing_x'], config['spacing_y'] ], float), (-1,1))
00058         self.inflate(param_vec)
00059 
00060     def calc_free(self, free_config):
00061         return [free_config[x] == 1 for x in param_names]
00062 
00063     def params_to_config(self, param_vec):
00064         return { 'corners_x' : self._corners_x,
00065                  'corners_y' : self._corners_y,
00066                  'spacing_x' : float(param_vec[0,0]),
00067                  'spacing_y' : float(param_vec[1,0]) }
00068 
00069     # Convert column vector of params into config
00070     def inflate(self, param_vec):
00071         self._spacing_x = param_vec[0,0]
00072         self._spacing_y = param_vec[1,0]
00073 
00074     # Return column vector of config
00075     def deflate(self):
00076         param_vec = reshape(matrix( [self._spacing_x, self._spacing_y], float ), (-1,1))
00077         return param_vec
00078 
00079     # Returns # of params needed for inflation & deflation
00080     def get_length(self):
00081         return len(param_names)
00082 
00083     # Generate the 3D points associated with all the corners of the checkerboard
00084     # returns - 4xN numpy matrix with all the points (in homogenous coords)
00085     def generate_points(self):
00086         N = self._corners_x * self._corners_y
00087         pts = matrix(numpy.zeros((4,N), float))
00088         for y in range(0,self._corners_y):
00089             for x in range(0,self._corners_x):
00090                 n = y*self._corners_x + x
00091                 pts[:,n] = numpy.matrix([ [x * self._spacing_x],
00092                                           [y * self._spacing_y],
00093                                           [0],
00094                                           [1] ])
00095         return pts
00096 
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calibration_estimation
Author(s): Vijay Pradeep, Michael Ferguson
autogenerated on Thu Aug 15 2013 10:15:40