Welcome to DOFBOT-Ultra repository

Image Quality

Code path:

~/dofbot_opencv/scripts/1.OpenCV_basic/03_quality_pic.ipynb

1. Compression method.

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

cv2.CV_IMWRITE_JPEG_QUALITY: Sets the image quality for .jpeg or .jpg format, with a value range of 0---100 (larger value means higher quality), default is 95

cv2.CV_IMWRITE_WEBP_QUALITY: Sets the image quality for .webp format, with a value range of 0--100

cv2.CV_IMWRITE_PNG_COMPRESSION: Sets the compression ratio for .png format, with a value range of 0--9 (larger value means higher compression), default is 3

Main code:

xxxxxxxxxx
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 high compression 0-100     png 0 low compression 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 eachother
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)

After the code block runs, you can see a comparison of the two images.