优化numpy阵列中的元素修改操作

所以我的代码做了一个非常基本的图像处理,把一个字符串存储到一个图像中。

因此,数组现在类似于: [ [ [odd_clr_val,odd_clr_val,odd_clr_vlue] ... ] .... ]

现在我用一个简单的程序把它读回来。

代码如下所示:

from PIL import Image
import numpy as np
import time
#if the value of pixel is:
#Odd = 0 , even = 1
#We make every element odd

img = Image.open('Desktop/test.jpg')

arr = np.array(img)
x,y,z  = np.shape(arr)
count = 0
initial = time.time()

#This nested loop makes every element odd but is very slow and in need to be optimized
for i in range(x):
    for j in range(y):
        count += 1
        k = arr[i][j]
        arr[i][j][0] =  k[0] + int(not(k[0]%2)) # adds 1 if k[i] is odd else 0
        arr[i][j][1] =  k[1] + int(not(k[1]%2))
        arr[i][j][2] =  k[2] + int(not(k[2]%2))

print("Time delta: %f"%(time.time() - initial ))
print("The amount of data you can store in this image is: %d kiBs"%((count*3)/1024))
#every element of this image is odd now

z = input("Enter the string:")

long_array = []
for i in z:
    long_array += list(map(int,list(format(ord(i), '#010b')[2:])))


#everything is in binary now

counter = 0
try:
    for i in range(x):
        for j in range(y):
            k = arr[i][j]

            arr[i][j][0] = k[0] if not(long_array[counter]) else k[0]+1
            counter += 1

            arr[i][j][1] = k[1] if not(long_array[counter]) else k[1]+1
            counter += 1

            arr[i][j][2] = k[2] if not(long_array[counter]) else k[2]+1
            counter += 1
except IndexError:
    print("Done")
except:
    print("An unidentified error occured!")

image = Image.fromarray(arr)

image.show()

image.save("secret.png")

我的问题 我无法优化代码的上循环,因为它需要16秒才能完成(使用800x600x3图片矩阵)。另外,我的代码的下循环比上循环快得多。

那么,有没有一种方法来优化我的上循环使用一些numpy魔术?