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Image quality

Code path:

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opencv/opencv_basic/01_Getting_Started_with_OpenCV/03_OpenCV Picture quality.ipynb

1. Compression method.

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

cv2.CV_IMWRITE_JPEG_QUALITY: Sets the image quality of the image format .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: Sets the image quality to .webp format, with a value of 0--100

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

The main code is as follows:

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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

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# 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 high compression ratio 0-100 png 0 low compression ratio 0-9

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#bgr8 to jpeg format
import enum
import cv2
def bgr8_to_jpeg(value, quality=75):
      return bytes(cv2.imencode('.jpg', value)[1])

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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)

When the code block runs to the end, you can see a comparison chart of the two photos.