4.Open Source CV image quality

The code was run on jupyterlab

1. Compression method

cv2.imwrite('yahboomTest.jpg', img, [cv2.IMWRITE_JPEG_QUALITY, 50])

cv2.CV_IMWRITE_JPEG_QUALITY: Set the image quality of the image format to .jpeg or .jpg, the value is 0---100 (the larger the value, the higher the quality), the default is 95

cv2.CV_IMWRITE_WEBP_QUALITY: Set the image format to .webp format image quality, the value is 0--100

cv2.CV_IMWRITE_PNG_COMPRESSION: Set the compression ratio of .png format, the value is 0--9 (the larger the value, the greater the compression ratio), the default is 3

​x
import cv2

img = cv2.imread('yahboom.jpg',1)

cv2.imwrite('yahboomTest.jpg', img, [cv2.IMWRITE_JPEG_QUALITY, 50])

#1M 100k 10k 0-100 Lossy compression

xxxxxxxxxx
# 1 lossless 2 transparency attribute

import cv2

img = cv2.imread('yahboom.jpg',1)

cv2.imwrite('yahboomTest.png', img, [cv2.IMWRITE_PNG_COMPRESSION,0])

# jpg 0 compression ratio higher 0-100 png 0 compression ratio lower 0-9

xxxxxxxxxx
#bgr8 to jpeg format

import enum

import cv2


def bgr8_to_jpeg(value, quality=75):

     return bytes(cv2.imencode('.jpg', value)[1])

xxxxxxxxxx
import ipywidgets.widgets as widgets

image_widget1 = widgets.Image(format='jpg', )

image_widget2 = widgets.Image(format='jpg', )

# create a horizontal box container to place the image widget next to each other

image_container = widgets.HBox([image_widget1, image_widget2])


# display the container in this cell's output

display(image_container)

img1 = cv2.imread('yahboomTest.jpg',1)

img2 = cv2.imread('yahboomTest.png',1)

image_widget1.value = bgr8_to_jpeg(img1)

image_widget2.value = bgr8_to_jpeg(img2)