Function hadamard

Synopse

Hadamard Transform.

F = iahadamard(f)
- Output:
  - F: Image.
- Input:
  - f: Image.

Function code



In [1]:

    
import numpy as np

def hadamard(f):
    import ia898.src as ia
    f = np.asarray(f).astype(np.float64)
    if len(f.shape) == 1: f = f[:, newaxis]
    (m, n) = f.shape
    A = ia.hadamardmatrix(m)
    if (n == 1):
        F = np.dot(A, f)
    else:
        B = ia.hadamardmatrix(n)
        F = np.dot(np.dot(A, f), np.transpose(B))
    return F

Examples

Example 1



In [2]:

    
testing = (__name__ == "__main__")

if testing:
    ! jupyter nbconvert --to python hadamard.ipynb
    import numpy as np
    import sys,os
    import matplotlib.image as mpimg
    ia898path = os.path.abspath('../../')
    if ia898path not in sys.path:
        sys.path.append(ia898path)
    import ia898.src as ia









    



[NbConvertApp] Converting notebook hadamard.ipynb to python
[NbConvertApp] Writing 1348 bytes to hadamard.py



In [3]:

    
if testing:
    f = mpimg.imread('../data/cameraman.tif')
    F = ia.hadamard(f)
    nb = ia.nbshow(2)
    nb.nbshow(f)
    nb.nbshow(ia.normalize(np.log(abs(F)+1)))
    nb.nbshow()

Measuring time:



In [ ]:

    
if testing:
    f = mpimg.imread('../data/cameraman.tif')
    print('Computational time is:')
    %timeit ia.hadamard(f)









    



Computational time is:



In [ ]: