chx_speckle.py 文件源码

def poisson(x,K):    
    '''Poisson distribution function.
    K is  average photon counts    
    In case of low intensity, the beam behavors like particle and
    the probability density of photon, P(x), satify this poisson function.
    '''
    K = float(K)    
    Pk = np.exp(-K)*power(K,x)/gamma(x+1)
    return Pk