Upscaling of an image refers to enlarging the size of an image.

圖像放大是指放大圖像的大小。

In this program, we will be using two functions of OpenCV-python (cv2) module.. let's see their syntax and descriptions first

在此程序中，我們將使用OpenCV-python(cv2)模塊的兩個函數。.讓我們首先查看它們的語法和描述。

1) imread():
It takes an absolute path/relative path of your image file as an argument and returns its corresponding image matrix.

1)imread()：
它以圖像文件的絕對路徑/相對路徑作為參數，并返回其對應的圖像矩陣。

If flag value is:

如果標志值為：

• 1: Loads a color image.

  1 ：加載彩色圖像。

• 0: Loads image in grayscale mode.

  0 ：以灰度模式加載圖像。

• -1: Loads image as such including alpha channel.

  -1 ：加載圖像，包括alpha通道。

If the flag value is not given then show the original image, which path is given.

如果未給出標志值，則顯示原始圖像，并給出哪個路徑。

2) imshow():
It takes window name and image matrix as an argument in order to display an image in a display window with a specified window name.

2)imshow()：
它以窗口名稱和圖像矩陣為參數，以便在具有指定窗口名稱的顯示窗口中顯示圖像。

Also In this program, we will be using one function of numpy module.

同樣在此程序中，我們將使用numpy模塊的一個功能。

median(): It takes array and returns the median of the array .

平均()：它接受array并返回array的中位數。

Also, in this program we are using the concept of array slicing

另外，在此程序中，我們使用數組切片的概念

Let, A is 1-d array:
A[start:stop:step]

設A為一維數組：
A [開始：停止：步驟]

1. start: Starting number of the sequence.

   start：序列的起始編號。

2. stop: Generate numbers up to, but not including this number.

   停止：生成不超過此數字的數字，但不包括此數字。

3. step: Difference between each number in the sequence.

   步驟：序列中每個數字之間的差。

Example:

例：

    A = [1,2,3,4,5,6,7,8,9,10]
print(A[ 1: 5])
Output:
[2,3,4,5]

用于在Python中放大灰度圖像的Python程序 (Python program for upscaling the grayscale image in Python)

# open-cv library is installed as cv2 in python
# import cv2 library into this program
import cv2
# import numpy as np name
import numpy as np
# read an image using imread() function of cv2
# we have to  pass only the path of the image
img = cv2.imread(r'C:/Users/user/Desktop/pic6.jpg',0)
# displaying the image using imshow() function of cv2
# In this : 1st argument is name of the frame
# 2nd argument is the image matrix
cv2.imshow('original image',img)
# upscaling code
# Upscaling the image x,y times along row and column
x,y = 2, 2
# here image is of class 'uint8', the range of values  
# that each colour component can have is [0 - 255]
# create a zero matrix of order of x,y times
# of previous image of 3-dimensions
upscale_img = np.zeros((x*img.shape[0],y*img.shape[1]),np.uint8)
i, m = 0, 0
while m < img.shape[0] :
j, n = 0, 0
while n < img.shape[1]:
# We assign pixel value from original image matrix to the
# new upscaling image matrix in alternate rows and columns
upscale_img[i, j] = img[m, n]
# increment j by y times
j += y
# increment n by one
n += 1
# increment m by one
m += 1
# increment i by x times
i += x
cv2.imshow('upscaling image',upscale_img)

Output

輸出量

翻譯自: https://www.includehelp.com/python/upscaling-the-grayscale-image.aspx