pil example threshold function (snippet)

Python pil example 'threshold function'

Functions in program:

• def threshold(imageArray):

Modules used in program:

• import time
• import matplotlib.pyplot as plt
• import numpy as np

python threshold function

Python pil example: threshold function

import numpy as np
import matplotlib.pyplot as plt
import time
from PIL import Image

def threshold(imageArray):
    balAr = []
    newAr = imageArray
    from statistics import mean
    for eachRow in imageArray:
        for eachPix in eachRow:
            avg = mean(eachPix[:3])
            balAr.append(avg)
    balance = mean(balAr)

    for eachRow in newAr:
        for eachPix in eachRow:
            if mean(eachPix[:3]) > balance :
                eachPix[0] = 255
                eachPix[1] = 255
                eachPix[2] = 255
                eachPix[3] = 255
            else:
                eachPix[0] = 0
                eachPix[1] = 0
                eachPix[2] = 0
                eachPix[3] = 255
    return newAr        

i1 = Image.open('images/dot.png')
i1_ar = np.array(i1)
i1_ar = threshold(i1_ar)

i2 = Image.open('images/numbers/0.1.png')
i2_ar = np.array(i2)
i2_ar = threshold(i2_ar)

i3 = Image.open('images/numbers/y0.5.png')
i3_ar = np.array(i3)
i3_ar = threshold(i3_ar)

i4 = Image.open('images/dotndot.png')
i4_ar = np.array(i4)
i4_ar = threshold(i4_ar)

fig = plt.figure()

ax1 = plt.subplot2grid((8,6),(0,0),rowspan = 4,colspan = 3)
ax2 = plt.subplot2grid((8,6),(4,0),rowspan = 4,colspan = 3)
ax3 = plt.subplot2grid((8,6),(0,3),rowspan = 4,colspan = 3)
ax4 = plt.subplot2grid((8,6),(4,3),rowspan = 4,colspan = 3)

ax1.imshow(i1_ar)
ax2.imshow(i2_ar)
ax3.imshow(i3_ar)
ax4.imshow(i4_ar)

plt.show()

Python links

• Learn Python: https://pythonbasics.org/
• Python Tutorial: https://pythonprogramminglanguage.com