Rotation and chunking of [Python + OpenCV] Images

In the work of image processing, scripting language is used more, in recent years, with the development of Python, script programming becomes more easily accessible. With Open Source Library OpenCV, Python can be used to do some image processing work, here are two simple examples of actual image processing.

Header files to be introduced:

Import cv2
import numpy
Import math
Import string
import os

Image rotation Code:

# rotate (): Rotate image
# return:rotated Image Object
def rotate (
	img,  #image matrix
	angle #angle o F rotation
	):
	
	height = img.shape[0]
	width = img.shape[1]
	
	if angle%180 = = 0:
		scale = 1
	elif angle %90 = 0:
		scale = float (max (height, width))/min (height, width)
	else:
		scale = math.sqrt (POW (height,2) + Pow (width,2))/min (height, width)
	
	#print ' scale%f\n '%scale
		
	rotatemat = cv2.getrotationmatrix2d (WIDTH/2, HEIGHT/2), angle, scale)
	rotateimg = Cv2.warpaffine (img, Rotatemat, (width, height))
	#cv2. Imshow (' Rotateimg ', rotateimg)
	#cv2. Waitkey (0) return
	
	rotateimg #rotated image

Image chunking Code:

# split (): Split image into patches, and save them
# Return:null
def split (
	img,    #image matrix
	ratio,  #patch_length/image_length
	N,      #number of patches per line
	dstpath #destination path
	):
	Height = img.shape[0]
	width = img.shape[1]
	#cv2. Imshow (Imgpath, img)
	pheight = Int (ratio*height)
	Pheightinterval = (height-pheight)/(n-1)
	
	#print ' pheight:%d\n '%pheight 
	#print ' pheightinterval:%d\n '% Pheightinterval
	
	pWidth = Int (ratio*width)
	pwidthinterval = (width-pwidth)/(n-1)
	
	#print ' pWidth:%d\n ' %pwidth 
	#print ' pwidthinterval:%d\n '%pwidthinterval
	
	cnt = 1 for
	i in range (n): to
		J in range (N): 
  x = Pwidthinterval * I
			y = pheightinterval * J
			
			#print ' x:%d\n '%x
			#print ' y:%d\n '%y
			
			patch = img [Y:y+pheight, X:x+pwidth,:]
			Cv2.imwrite (dstpath+ ' _%d '%cnt+ '. jpg ', patch);
			CNT + + 1
			#cv2. Imshow (' Patch ', patch)
			#cv2. Waitkey (0)