在Python中使用旋转矩阵旋转图像

Question

所以我试图创建一个代码，可以通过实现旋转矩阵使用Python逆时针旋转图像。这段代码应该逆时针旋转图像，但是为什么它要顺时针旋转图像呢?

import math
import numpy as np
from PIL import Image
img = Image.open('squidward.jpg')
Im = np.array(img)
angle = 30
# Define the most occuring variables
angle=math.radians(angle)                               #converting degrees to radians
cosine=math.cos(angle)
sine=math.sin(angle)
height=Im.shape[0]                                   #define the height of the image
width=Im.shape[1]                                    #define the width of the image
# Define the height and width of the new image that is to be formed
new_height  = round(abs(Im.shape[0]*cosine)+abs(Im.shape[1]*sine))+1
new_width  = round(abs(Im.shape[1]*cosine)+abs(Im.shape[0]*sine))+1
# define another image variable of dimensions of new_height and new _column filled with zeros
Rot_Im=np.zeros((new_height,new_width,Im.shape[2]))
# Find the centre of the image about which we have to rotate the image
original_centre_height   = round(((Im.shape[0]+1)/2)-1)    #with respect to the original image
original_centre_width    = round(((Im.shape[1]+1)/2)-1)    #with respect to the original image
# Find the centre of the new image that will be obtained
new_centre_height= round((((new_height)+1)/2)-1)        #with respect to the new image
new_centre_width= round((((new_width)+1)/2)-1)          #with respect to the new image
for i in range(height):
for j in range(width):
#co-ordinates of pixel with respect to the centre of original image
y0=Im.shape[0]-1-i-original_centre_height                   
x0=Im.shape[1]-1-j-original_centre_width

#co-ordinate of pixel with respect to the rotated image
new_y0=round(x0*sine+y0*cosine)
new_x0=round(x0*cosine-y0*sine)
'''since image will be rotated the centre will change too, 
so to adust to that we will need to change new_x and new_y with respect to the new centre'''
new_y0=new_centre_height-new_y0
new_x0=new_centre_width-new_x0
# adding if check to prevent any errors in the processing
if 0 <= new_x0 < new_width and 0 <= new_y0 < new_height and new_x0>=0 and new_y0>=0:
Rot_Im[new_y0,new_x0,:]=Im[i,j,:]                          #writing the pixels to the new destination in the output image
pil_img=Image.fromarray((Rot_Im).astype(np.uint8))                       # converting array to image
pil_img.save("rotated_image.png")                                                 # saving the image

Answer 1

按-30表示逆时针。我想你会得到答案的，但我想已经太晚了。