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7. Picture Cut

Image cutting first reads the image, then obtains the pixel region from the array. In the code below, the rectangular region is X: 300-500 Y: 500-700. Note that the image size is 800*800, so the selected area should not exceed this resolution.

Code path:

~/dofbot_opencv/scripts/2.Transform/02_cut_pic.ipynb

​x
import cv2
img = cv2.imread('yahboom.jpg', 1)
dst = img[500:700,300:500]  # Here select rectangular area X: 300-500 Y: 500-700
#cv2.imshow('image',dst)
​
#cv2.waitKey(0)

Below, the JupyterLab widget displays a comparison of the two compressed images

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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])

Below is the before and after image comparison:

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import ipywidgets.widgets as widgets
image_widget1 = widgets.Image(format='jpg', )
image_widget2 = widgets.Image(format='jpg', )
# display the container in this cell's output
display(image_widget1)
display(image_widget2)
img1 = cv2.imread('yahboom.jpg',1)
​
image_widget1.value = bgr8_to_jpeg(img1)  # original image
image_widget2.value = bgr8_to_jpeg(dst)   # cropped image

After the program runs, you can see that part of the image has been cropped out.