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5. OpenCV pixel operation

3.1. Pixel operation

We can change the pixel color at any position to a new one. Here we first read the image and then assign an area to white.

3.2. Actual effect display

Code path:

/home/pi/Rider-pi_class/4.Open Source CV/A.introduction/Introduction_to_OpenCV/05_OpenCV_Pixel_Ops.ipynb

​x
import cv2
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img = cv2.imread('yahboom.jpg',1)
(b,g,r) = img[100,100]
print(b,g,r)# bgr
#10 100 --- 110 100
i=j=0
for j in range(1,500):
    img[i,j] = (255,255,255)
    for i in range(1,500):
        img[i,j] = (255,255,255)
​
# cv2.imshow('image',img)
# cv2.waitKey(0) #1000 ms

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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 eachother
image_container = widgets.HBox([image_widget1, image_widget2])
​
# display the container in this cell's output
display(image_container)
​
img1 = cv2.imread('yahboom.jpg',1)
​
image_widget1.value = bgr8_to_jpeg(img1)  #Original
image_widget2.value = bgr8_to_jpeg(img)   #After pixel manipulation