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Image reading and display

1. Image reading:

img = cv2.imread('yahboom.jpg', 0) The first parameter is the path to the image, and the second parameter is how to read the image.

cv2.IMREAD_UNCHANGED: keep the original format unchanged, -1;

cv2.IMREAD_GRAYSCALE: reads the image in grayscale mode, which can be represented by 0;

cv2.IMREAD_COLOR: Read in a color image, which can be represented by 1; the default value

cv2.IMREAD_UNCHANGED: Reads an image and includes its alpha channel, which can be represented by 2.

2. Image display

cv.imshow('frame', frame): Opens a window named frame and displays frame data (image/video data)

Parameter meaning:

The first parameter indicates the name of the window to be opened.

The second parameter indicates the image to be displayed

2.1、Code and actual effect display

Source code path:

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opencv/opencv_basic/01_Getting_Started_with_OpenCV/01_OpenCVImage reading and display.ipynb

Main code:

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import cv2
img = cv2.imread('yahboom.jpg', 1)
# cv2.imshow('image', img) #This line can only be executed by the command line py file, and a video window will pop up
# cv2.waitKey (0)
#bgr8 to jpeg format
import enum
import cv2
def bgr8_to_jpeg(value, quality=75):
return bytes(cv2.imencode('.jpg', value)[1])
# The image component in jupyterLab displays the read image
import ipywidgets.widgets as widgets
image_widget = widgets.Image(format='jpg', width=800, height=800)
display(image_widget)
image_widget.value = bgr8_to_jpeg(img)

After running the code block, you can see the following interface, the image has been read out