cvnumpyconvert.py

"""opencv <-> numpy array conversion

from http://opencv.willowgarage.com/wiki/PythonInterface/"""
import cv
import numpy as np
def cv2array(im):
  depth2dtype = {
        cv.IPL_DEPTH_8U: 'uint8',
        cv.IPL_DEPTH_8S: 'int8',
        cv.IPL_DEPTH_16U: 'uint16',
        cv.IPL_DEPTH_16S: 'int16',
        cv.IPL_DEPTH_32S: 'int32',
        cv.IPL_DEPTH_32F: 'float32',
        cv.IPL_DEPTH_64F: 'float64',
    }

  arrdtype=im.depth
  a = np.fromstring(
         im.tostring(),
         dtype=depth2dtype[im.depth],
         count=im.width*im.height*im.nChannels)
  a.shape = (im.height,im.width,im.nChannels)
  return a

def array2cv(a):
  dtype2depth = {
        'uint8':   cv.IPL_DEPTH_8U,
        'int8':    cv.IPL_DEPTH_8S,
        'uint16':  cv.IPL_DEPTH_16U,
        'int16':   cv.IPL_DEPTH_16S,
        'int32':   cv.IPL_DEPTH_32S,
        'float32': cv.IPL_DEPTH_32F,
        'float64': cv.IPL_DEPTH_64F,
    }
  try:
    nChannels = a.shape[2]
  except:
    nChannels = 1
  cv_im = cv.CreateImageHeader((a.shape[1],a.shape[0]),
          dtype2depth[str(a.dtype)],
          nChannels)
  cv.SetData(cv_im, a.tostring(),
             a.dtype.itemsize*nChannels*a.shape[1])
  return cv_im