Image Data Preprocessing

Converting Image Data

• The brightness value of the image data pixel of each number is converted into vector data and used.

from PIL import Image
import numpy as np

img = Image.open('zero_image.png').convert('L')

width, height = img.size

img_pixels = []

for y in range(height):
    for x in range(width):
        img_pixels.append(img.getpixel((x, y)))
        
print(img_pixels)

[255, 255, 170, 34, 102, 238, 255, 255, 255, 255, 34, 0, 85, 0, 170, 255, 255, 204, 0, 221, 255, 68, 119, 255, 255, 187, 51, 255, 255, 119, 119, 255, 255, 170, 119, 255, 255, 102, 119, 255, 255, 187, 68, 255, 238, 51, 136, 255, 255, 221, 17, 170, 85, 51, 255, 255, 255, 255, 153, 34, 85, 255, 255, 255]

from sklearn import datasets
from sklearn import metrics
from sklearn.ensemble import RandomForestClassifier

digits = datasets.load_digits()
n_samples = len(digits.images)
data = digits.images.reshape((n_samples, -1))

model = RandomForestClassifier(n_estimators = 10)
model.fit(data[:n_samples // 2], digits.target[:n_samples // 2])

expected = digits.target[n_samples // 2:]
predicted = model.predict(data[n_samples // 2:])

print(metrics.classification_report(expected, predicted))

              precision    recall  f1-score   support

           0       0.90      0.98      0.93        88
           1       0.84      0.88      0.86        91
           2       0.89      0.88      0.89        86
           3       0.88      0.87      0.87        91
           4       0.90      0.83      0.86        92
           5       0.78      0.86      0.82        91
           6       0.91      0.93      0.92        91
           7       0.91      0.92      0.92        89
           8       0.83      0.68      0.75        88
           9       0.81      0.83      0.82        92

    accuracy                           0.87       899
   macro avg       0.87      0.87      0.86       899
weighted avg       0.87      0.87      0.86       899

참고문헌

• 秋庭伸也 et al. 머신러닝 도감 : 그림으로 공부하는 머신러닝 알고리즘 17 / 아키바 신야, 스기야마 아세이, 데라다 마나부 [공] 지음 ; 이중민 옮김, 2019.