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Hello guys,
I want to convert Python code to VB.net or Java
Plz help me
The code is for calculating Zernike moments
import numpy as np
from math import atan2
from numpy import cos, sin, conjugate, sqrt
def _slow_zernike_poly(Y,X,n,l):
def _polar(r,theta):
x = r * cos(theta)
y = r * sin(theta)
return 1.*x+1.j*y
def _factorial(n):
if n == 0: return 1.
return n * _factorial(n - 1)
y,x = Y[0],X[0]
vxy = np.zeros(Y.size, dtype=complex)
index = 0
for x,y in zip(X,Y):
Vnl = 0.
for m in range( int( (n-l)//2 ) + 1 ):
Vnl += (-1.)**m * _factorial(n-m) / \
( _factorial(m) * _factorial((n - 2*m + l) // 2) * _factorial((n - 2*m - l) // 2) ) * \
( sqrt(x*x + y*y)**(n - 2*m) * _polar(1.0, l*atan2(y,x)) )
vxy[index] = Vnl
index = index + 1
return vxy
def zernike_reconstruct(img, radius, D, cof):
idx = np.ones(img.shape)
cofy,cofx = cof
cofy = float(cofy)
cofx = float(cofx)
radius = float(radius)
Y,X = np.where(idx > 0)
P = img[Y,X].ravel()
Yn = ( (Y -cofy)/radius).ravel()
Xn = ( (X -cofx)/radius).ravel()
k = (np.sqrt(Xn**2 + Yn**2) <= 1.)
frac_center = np.array(P[k], np.double)
Yn = Yn[k]
Xn = Xn[k]
frac_center = frac_center.ravel()
# in the discrete case, the normalization factor is not pi but the number of pixels within the unit disk
npix = float(frac_center.size)
reconstr = np.zeros(img.size, dtype=complex)
accum = np.zeros(Yn.size, dtype=complex)
for n in range(D+1):
for l in range(n+1):
if (n-l)%2 == 0:
# get the zernike polynomial
vxy = _slow_zernike_poly(Yn, Xn, float(n), float(l))
# project the image onto the polynomial and calculate the moment
a = sum(frac_center * conjugate(vxy)) * (n + 1)/npix
# reconstruct
accum += a * vxy
reconstr[k] = accum
return reconstr
if __name__ == '__main__':
import cv2
import pylab as pl
from matplotlib import cm
D = 12
img = cv2.imread('fl.bmp', 0)
rows, cols = img.shape
radius = cols//2 if rows > cols else rows//2
reconst = zernike_reconstruct(img, radius, D, (rows/2., cols/2.))
reconst = reconst.reshape(img.shape)
pl.figure(1)
pl.imshow(img, cmap=cm.jet, origin = 'upper')
pl.figure(2)
pl.imshow(reconst.real, cmap=cm.jet, origin = 'upper')
I want to convert Python code to VB.net or Java
Plz help me
The code is for calculating Zernike moments
import numpy as np
from math import atan2
from numpy import cos, sin, conjugate, sqrt
def _slow_zernike_poly(Y,X,n,l):
def _polar(r,theta):
x = r * cos(theta)
y = r * sin(theta)
return 1.*x+1.j*y
def _factorial(n):
if n == 0: return 1.
return n * _factorial(n - 1)
y,x = Y[0],X[0]
vxy = np.zeros(Y.size, dtype=complex)
index = 0
for x,y in zip(X,Y):
Vnl = 0.
for m in range( int( (n-l)//2 ) + 1 ):
Vnl += (-1.)**m * _factorial(n-m) / \
( _factorial(m) * _factorial((n - 2*m + l) // 2) * _factorial((n - 2*m - l) // 2) ) * \
( sqrt(x*x + y*y)**(n - 2*m) * _polar(1.0, l*atan2(y,x)) )
vxy[index] = Vnl
index = index + 1
return vxy
def zernike_reconstruct(img, radius, D, cof):
idx = np.ones(img.shape)
cofy,cofx = cof
cofy = float(cofy)
cofx = float(cofx)
radius = float(radius)
Y,X = np.where(idx > 0)
P = img[Y,X].ravel()
Yn = ( (Y -cofy)/radius).ravel()
Xn = ( (X -cofx)/radius).ravel()
k = (np.sqrt(Xn**2 + Yn**2) <= 1.)
frac_center = np.array(P[k], np.double)
Yn = Yn[k]
Xn = Xn[k]
frac_center = frac_center.ravel()
# in the discrete case, the normalization factor is not pi but the number of pixels within the unit disk
npix = float(frac_center.size)
reconstr = np.zeros(img.size, dtype=complex)
accum = np.zeros(Yn.size, dtype=complex)
for n in range(D+1):
for l in range(n+1):
if (n-l)%2 == 0:
# get the zernike polynomial
vxy = _slow_zernike_poly(Yn, Xn, float(n), float(l))
# project the image onto the polynomial and calculate the moment
a = sum(frac_center * conjugate(vxy)) * (n + 1)/npix
# reconstruct
accum += a * vxy
reconstr[k] = accum
return reconstr
if __name__ == '__main__':
import cv2
import pylab as pl
from matplotlib import cm
D = 12
img = cv2.imread('fl.bmp', 0)
rows, cols = img.shape
radius = cols//2 if rows > cols else rows//2
reconst = zernike_reconstruct(img, radius, D, (rows/2., cols/2.))
reconst = reconst.reshape(img.shape)
pl.figure(1)
pl.imshow(img, cmap=cm.jet, origin = 'upper')
pl.figure(2)
pl.imshow(reconst.real, cmap=cm.jet, origin = 'upper')