Convert between Python tuple and list：
a = (1, 2) # a is a tuple
b = list(a) # b is a list
c = tuple(b) # c is a tuple
Convert between Python tuple, list and NumPy 1D array
a = (1, 2) # a is a tuple
b = np.array(a) # b is an numpy array
c = tuple(b) # c is a tuple
a = [1, 2] # a is a python array
b = np.array(a) # b is a numpy array
c = list(b) # c is a python list
Convert between NumPy 2D array and NumPy matrix
a = numpy.ndarray([2,3]) # create 2x3 array
m1 = numpy.asmatrix(a) # does not create new matrix, m1 refers to the same memory as a
m2 = numpy.matrix(a) # creates new matrix and copies content
b1 = numpy.asarray(m2) # does not create array, b1 refers to the same emory as m2
b2 = numpy.array(m2) # creates new array and copies content
Read/Write Images with OpenCV
image = cv.LoadImage(“ponzo.jpg”)
cv.SaveImage(“out.png”, image)
Read/Write Images with PIL
image = Image.open(“ponzo.jpg”)
image.save(“out.jpg”)
Read/Write Images with PyOpenCV
mat = pyopencv.imread(“ponzo.jpg”)
pyopencv.imwrite(“out.png”, mat)
Convert between OpenCV image and PIL image
# color image
cimg = cv.LoadImage("ponzo.jpg", cv.CV_LOAD_IMAGE_COLOR) # cimg is a OpenCV image
pimg = Image.fromstring("RGB", cv.GetSize(cimg), cimg.tostring()) # pimg is a PIL image
cimg2 = cv.CreateImageHeader(pimg.size, cv.IPL_DEPTH_8U, 3) # cimg2 is a OpenCV image
cv.SetData(cimg2, pimg.tostring())
Note: OpenCV stores color image in BGR format. So, the converted PIL image is also in BGR-format. The standard PIL image is stored in RGB format.
#### gray image
```python
cimg = cv.LoadImage("ponzo.jpg", cv.CV_LOAD_IMAGE_GRAYSCALE) # cimg is a OpenCV image
Convert between PIL image and NumPy ndarray
image = Image.open(“ponzo.jpg”) # image is a PIL image
array = numpy.array(image) # array is a numpy array
image2 = Image.fromarray(array) # image2 is a PIL image
Convert between PIL image and PyOpenCV matrix
image = Image.open(“ponzo.jpg”) # image is a PIL image
mat = pyopencv.Mat.from_pil_image(image) # mat is a PyOpenCV matrix
image2 = mat.to_pil_image() # image2 is a PIL image
Convert between OpenCV image and NumPy ndarray
cimg = cv.LoadImage("ponzo.jpg", cv.CV_LOAD_IMAGE_COLOR) # cimg is a OpenCV image
pimg = Image.fromstring("RGB", cv.GetSize(cimg), cimg.tostring()) # pimg is a PIL image
array = numpy.array(pimg) # array is a numpy array
pimg2 = cv.fromarray(array) # pimg2 is a OpenCV image
还可以参考这样形式的代码：
PIL.Image转换成OpenCV格式：
import cv2
from PIL import Image
import numpy
image = Image.open("plane.jpg")
image.show()
img = cv2.cvtColor(numpy.asarray(image),cv2.COLOR_RGB2BGR)
cv2.imshow("OpenCV",img)
cv2.waitKey()
OpenCV转换成PIL.Image格式：
import cv2
from PIL import Image
import numpy
img = cv2.imread("plane.jpg")
cv2.imshow("OpenCV",img)
image = Image.fromarray(cv2.cvtColor(img,cv2.COLOR_BGR2RGB))
image.show()
cv2.waitKey()
