stsci.convolve.iraf

1 import numpy as num 2 3 """This module defines the function frame() which creates 4 a framed copy of an input array with the boundary pixels 5 defined according to the IRAF boundary modes: 'nearest', 6 'reflect', 'wrap', and 'constant.' 7 """ 8

9 -def frame_nearest(a, shape, cval=None):

10 11 """frame_nearest creates an oversized copy of 'a' with new 'shape' 12 and the contents of 'a' in the center. The boundary pixels are 13 copied from the nearest edge pixel in 'a'. 14 15 >>> a = num.arange(16) 16 >>> a.shape=(4,4) 17 >>> frame_nearest(a, (8,8)) 18 array([[ 0, 0, 0, 1, 2, 3, 3, 3], 19 [ 0, 0, 0, 1, 2, 3, 3, 3], 20 [ 0, 0, 0, 1, 2, 3, 3, 3], 21 [ 4, 4, 4, 5, 6, 7, 7, 7], 22 [ 8, 8, 8, 9, 10, 11, 11, 11], 23 [12, 12, 12, 13, 14, 15, 15, 15], 24 [12, 12, 12, 13, 14, 15, 15, 15], 25 [12, 12, 12, 13, 14, 15, 15, 15]]) 26 27 """ 28 29 b = num.zeros(shape, dtype=a.dtype) 30 delta = (num.array(b.shape) - num.array(a.shape)) 31 dy = delta[0] // 2 32 dx = delta[1] // 2 33 my = a.shape[0] + dy 34 mx = a.shape[1] + dx 35 36 b[dy:my, dx:mx] = a # center 37 b[:dy,dx:mx] = a[0:1,:] # top 38 b[my:,dx:mx] = a[-1:,:] # bottom 39 b[dy:my, :dx] = a[:, 0:1] # left 40 b[dy:my, mx:] = a[:, -1:] # right 41 b[:dy, :dx] = a[0,0] # topleft 42 b[:dy, mx:] = a[0,-1] # topright 43 b[my:, :dx] = a[-1, 0] # bottomleft 44 b[my:, mx:] = a[-1, -1] # bottomright 45 46 return b

47

48 -def frame_reflect(a, shape, cval=None):

49 50 """frame_reflect creates an oversized copy of 'a' with new 'shape' 51 and the contents of 'a' in the center. The boundary pixels are 52 reflected from the nearest edge pixels in 'a'. 53 54 >>> a = num.arange(16) 55 >>> a.shape = (4,4) 56 >>> frame_reflect(a, (8,8)) 57 array([[ 5, 4, 4, 5, 6, 7, 7, 6], 58 [ 1, 0, 0, 1, 2, 3, 3, 2], 59 [ 1, 0, 0, 1, 2, 3, 3, 2], 60 [ 5, 4, 4, 5, 6, 7, 7, 6], 61 [ 9, 8, 8, 9, 10, 11, 11, 10], 62 [13, 12, 12, 13, 14, 15, 15, 14], 63 [13, 12, 12, 13, 14, 15, 15, 14], 64 [ 9, 8, 8, 9, 10, 11, 11, 10]]) 65 """ 66 67 b = num.zeros(shape, dtype=a.dtype) 68 delta = (num.array(b.shape) - num.array(a.shape)) 69 dy = delta[0] // 2 70 dx = delta[1] // 2 71 my = a.shape[0] + dy 72 mx = a.shape[1] + dx 73 sy = delta[0] - dy 74 sx = delta[1] - dx 75 76 b[dy:my, dx:mx] = a # center 77 b[:dy,dx:mx] = a[:dy,:][::-1,:] # top 78 b[my:,dx:mx] = a[-sy:,:][::-1,:] # bottom 79 b[dy:my,:dx] = a[:,:dx][:,::-1] # left 80 b[dy:my,mx:] = a[:,-sx:][:,::-1] # right 81 b[:dy,:dx] = a[:dy,:dx][::-1,::-1] # topleft 82 b[:dy,mx:] = a[:dy,-sx:][::-1,::-1] # topright 83 b[my:,:dx] = a[-sy:,:dx][::-1,::-1] # bottomleft 84 b[my:,mx:] = a[-sy:,-sx:][::-1,::-1] # bottomright 85 return b

86

87 -def frame_wrap(a, shape, cval=None):

88 """frame_wrap creates an oversized copy of 'a' with new 'shape' 89 and the contents of 'a' in the center. The boundary pixels are 90 wrapped around to the opposite edge pixels in 'a'. 91 92 >>> a = num.arange(16) 93 >>> a.shape=(4,4) 94 >>> frame_wrap(a, (8,8)) 95 array([[10, 11, 8, 9, 10, 11, 8, 9], 96 [14, 15, 12, 13, 14, 15, 12, 13], 97 [ 2, 3, 0, 1, 2, 3, 0, 1], 98 [ 6, 7, 4, 5, 6, 7, 4, 5], 99 [10, 11, 8, 9, 10, 11, 8, 9], 100 [14, 15, 12, 13, 14, 15, 12, 13], 101 [ 2, 3, 0, 1, 2, 3, 0, 1], 102 [ 6, 7, 4, 5, 6, 7, 4, 5]]) 103 104 """ 105 106 b = num.zeros(shape, dtype=a.dtype) 107 delta = (num.array(b.shape) - num.array(a.shape)) 108 dy = delta[0] // 2 109 dx = delta[1] // 2 110 my = a.shape[0] + dy 111 mx = a.shape[1] + dx 112 sy = delta[0] - dy 113 sx = delta[1] - dx 114 115 b[dy:my, dx:mx] = a # center 116 b[:dy,dx:mx] = a[-dy:,:] # top 117 b[my:,dx:mx] = a[:sy,:] # bottom 118 b[dy:my,:dx] = a[:,-dx:] # left 119 b[dy:my,mx:] = a[:, :sx] # right 120 b[:dy,:dx] = a[-dy:,-dx:] # topleft 121 b[:dy,mx:] = a[-dy:,:sx ] # topright 122 b[my:,:dx] = a[:sy, -dx:] # bottomleft 123 b[my:,mx:] = a[:sy, :sx] # bottomright 124 return b

125

126 -def frame_constant(a, shape, cval=0):

127 """frame_nearest creates an oversized copy of 'a' with new 'shape' 128 and the contents of 'a' in the center. The boundary pixels are 129 copied from the nearest edge pixel in 'a'. 130 131 >>> a = num.arange(16) 132 >>> a.shape=(4,4) 133 >>> frame_constant(a, (8,8), cval=42) 134 array([[42, 42, 42, 42, 42, 42, 42, 42], 135 [42, 42, 42, 42, 42, 42, 42, 42], 136 [42, 42, 0, 1, 2, 3, 42, 42], 137 [42, 42, 4, 5, 6, 7, 42, 42], 138 [42, 42, 8, 9, 10, 11, 42, 42], 139 [42, 42, 12, 13, 14, 15, 42, 42], 140 [42, 42, 42, 42, 42, 42, 42, 42], 141 [42, 42, 42, 42, 42, 42, 42, 42]]) 142 143 """ 144 145 b = num.zeros(shape, dtype=a.dtype) 146 delta = (num.array(b.shape) - num.array(a.shape)) 147 dy = delta[0] // 2 148 dx = delta[1] // 2 149 my = a.shape[0] + dy 150 mx = a.shape[1] + dx 151 152 b[dy:my, dx:mx] = a # center 153 b[:dy,dx:mx] = cval # top 154 b[my:,dx:mx] = cval # bottom 155 b[dy:my, :dx] = cval # left 156 b[dy:my, mx:] = cval # right 157 b[:dy, :dx] = cval # topleft 158 b[:dy, mx:] = cval # topright 159 b[my:, :dx] = cval # bottomleft 160 b[my:, mx:] = cval # bottomright 161 return b

162 163 _frame_dispatch = { "nearest": frame_nearest, 164 "reflect": frame_reflect, 165 "wrap": frame_wrap, 166 "constant" : frame_constant } 167

168 -def frame(a, shape, mode="nearest", cval=0.0):

169 170 """frame creates an oversized copy of 'a' with new 'shape', with 171 extra pixels being supplied according to IRAF boundary mode, 172 'mode'. """ 173 174 try: 175 f = _frame_dispatch[mode] 176 except KeyError: 177 raise ValueError('invalid IRAF boundary mode: "%s"' % mode) 178 179 return f(a, shape, cval)

180

181 -def unframe(a, shape):

182 183 """unframe extracts the center slice of framed array 'a' which had 184 'shape' prior to framing.""" 185 186 delta = num.array(a.shape) - num.array(shape) 187 dy = delta[0]//2 188 dx = delta[1]//2 189 my = shape[0] + dy 190 mx = shape[1] + dx 191 return a[dy:my, dx:mx]

192

193 -def test():

194 import doctest, iraf_frame 195 return doctest.testmod(iraf_frame)

196

Source Code for Module stsci.convolve.iraf_frame