def make_pixel_lut(self, dims):
"""
Generate an x and y image which maps the array indices into
floating point array indices (to be corrected for pixel size later)
returns
FIXME - check they are the right way around
add some sort of known splinefile testcase
"""
# Cache the value in case of multiple calls
if self.pixel_lut is None:
x_im = numpy.outer(range(dims[0]), numpy.ones(dims[1]))
y_im = numpy.outer(numpy.ones(dims[0]), range(dims[1]))
# xcor is tck2
x_im = numpy.add(
x_im,
bisplev.bisplev(range(dims[1]), range(dims[0]), self.tck2).T,
x_im)
# ycor is tck1
y_im = numpy.add(
y_im,
bisplev.bisplev(range(dims[1]), range(dims[0]), self.tck1).T,
y_im)
self.pixel_lut = x_im, y_im
return self.pixel_lut
def correct(self, xin, yin):
"""
Transform x,y in raw image coordinates into x,y of an
idealised image. Returns a tuple (x,y), expects a
pair of floats as arguments
"""
if self.orientation == "edf":
xcor = xin + bisplev.bisplev(yin, xin, self.tck2)
ycor = yin + bisplev.bisplev(yin, xin, self.tck1)
else:
# fit2d does a flip
raise Exception("Spline orientations must be edf, convert "
"your image to edf and remake the spline")
# Unreachable code - we no longer accept this complexity
# it means the spline file for ImageD11 bruker images
# is not the same as for fit2d.
xpos = self.xmax - xin
xcor = xin - bisplev.bisplev(yin, xpos, self.tck2)
ycor = yin + bisplev.bisplev(yin, xpos, self.tck1)
return xcor, ycor
def distort(self, xin, yin):
"""
Distort a pair of points xnew, ynew to find where they
would be in a raw image
Iterative algorithm...
"""
yold = yin - bisplev.bisplev(yin, xin, self.tck1)
xold = xin - bisplev.bisplev(yin, xin, self.tck2)
# First guess, assumes distortion is constant
ytmp = yin - bisplev.bisplev(yold, xold, self.tck1)
xtmp = xin - bisplev.bisplev(yold, xold, self.tck2)
# Second guess should be better
error = math.sqrt((xtmp - xold) * (xtmp - xold) + (ytmp - yold) *
(ytmp - yold))
ntries = 0
while error > self.tolerance:
ntries = ntries + 1
xold = xtmp
yold = ytmp
ytmp = yin - bisplev.bisplev(yold, xold, self.tck1)
xtmp = xin - bisplev.bisplev(yold, xold, self.tck2)
error = math.sqrt((xtmp - xold) * (xtmp - xold) + (ytmp - yold) *
(ytmp - yold))
# print error,xold,x,yold,y
if ntries == 10:
raise Exception("Error getting the inverse spline to converge")
return xtmp, ytmp