如何使用 OpenCV-Python 访问图像的像素？
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How do I access the pixels of an image using OpenCV-Python?
提问by Harini Subhakar
I want to know how to loop through all pixels of an image. I tried this:
我想知道如何遍历图像的所有像素。我试过这个：
import cv2
import numpy as np
x = np.random.randint(0,5,(500,500))
img = cv2.imread('D:\Project\Capture1.jpg',0)
p = img.shape
print p
rows,cols = img.shape
for i in range(rows):
for j in range(cols):
k = x[i,j]
print k
It prints a vertical set of numbers which is not in the form of an array. I am also getting an array out of bounds exception. Please suggest a method.
它打印一组不是数组形式的垂直数字。我也得到一个数组越界异常。请提出一种方法。
回答by user3590169
The vertical array are the RGB (Reg, Green, Blue) channel values for the image. If you want a single value for the pixel you may want to convert the image to grayscale first. It really depends on your application and what you want to do with the image, converting to grayscale is just one approach.
垂直阵列是图像的 RGB（Reg、Green、Blue）通道值。如果您想要像素的单个值，您可能需要先将图像转换为灰度。这实际上取决于您的应用程序以及您想对图像做什么，转换为灰度只是一种方法。
To convert to grayscale
转换为灰度
grayImg = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
Some basic operations are shown in the documentation
文档中显示了一些基本操作
回答by Rohit Salunke
Access specific pixel in Python
在 Python 中访问特定像素
import cv2
image = cv2.imread("sample.jpg")
pixel= image[200, 550]
print pixel
output:[ 73 89 102]
输出：[ 73 89 102]
回答by Roxanne
I don't see what's the purpose of your x variable. You don't need it.
我不明白你的 x 变量的目的是什么。你不需要它。
Simply use:
只需使用：
img = cv2.imread('D:\Project\Capture1.jpg',0)
rows,cols = img.shape
for i in range(rows):
for j in range(cols):
k = img[i,j]
print k
which will print indeed a vertical set of numbers. If you want to modify the values of the pixels use img.itemset(). http://docs.opencv.org/3.0-beta/doc/py_tutorials/py_core/py_basic_ops/py_basic_ops.html
这将确实打印一组垂直的数字。如果要修改像素的值，请使用img.itemset(). http://docs.opencv.org/3.0-beta/doc/py_tutorials/py_core/py_basic_ops/py_basic_ops.html
If you want to print the whole array then use print(img)
如果要打印整个数组，请使用 print(img)
回答by Be'ezrat Hashem
Try this:
尝试这个：
import numpy as np
import Image
image = Image.open("example.png")
image_data = np.asarray(image)
for i in range(len(image_data)):
for j in range(len(image_data[0])):
print(image_data[i][j]) # this row prints an array of RGB color for each pixel in the image
回答by Ebenezer James Valdez
import cv2
import numpy as np
image = cv2.imread('C:/Users/Asus/Desktop/test.jpg', cv2.IMREAD_COLOR)
for x in range (1,480):
for y in range (1,640):
pixel = image[x,y]
print pixel
回答by paparoch
you are reading image in gray scale
你正在阅读灰度图像
img = cv2.imread('D:\Project\Capture1.jpg',0)
img = cv2.imread('D:\Project\Capture1.jpg',0)
here you will only get intencity
在这里你只会得到强度
回答by Anon George
This code will give you the pixel values in an array 'k'by going through loop.
此代码将通过循环为您提供数组“k”中的像素值。
import cv2
import numpy as np
img = cv2.imread('sample.jpg',0)
rows,cols = img.shape
k = []
for i in range(rows):
for j in range(cols):
k.append(img[i,j])
print k
回答by Vivek Ananthan
Accessing using array index will be slow with a numpy array.
使用数组索引访问 numpy 数组会很慢。
You can use the item()method for access and itemsetfor performing changes.
您可以使用该item()方法进行访问和itemset执行更改。
For example
例如
for i in range(0,img.shape[0]):
for j in range(0,img.shape[1]):
pixel = img.item(i, j)
print pixel
回答by Muskan Agarwal
You can do this
你可以这样做
for (int y = 0; y<im.rows; y++)
{
for (int x = 0; x<im.cols; x++)
{
Vec3b color = im.at<Vec3b>(Point(x, y));
//you can print color this has the pixel value
}
}
回答by Mahmut Ayd?n
import cv2
import numpy as np
imagename = "capure.jpg"
img = cv2.imread(imagename, 0) # 0 params, for gray image
height, width = img.shape[:2] # image height and width
print(img) # all image pixels value in array
print(img[10, 10]) # one pixel value in 10,10 coordinate
for y in range(height):
for x in range(width):
print(img[y,x], end = "\t")
print("\t")
