two_bin.py

import cv2
import numpy as np
from matplotlib import pyplot as plt

def get_pixel(img, center, x, y):
    new_value = 0
    try:
        if img[x][y] >= center:
            new_value = 1
    except:
        pass
    return new_value

def calculated_pixel(img, x, y):
    center = img[x][y]
    left = get_pixel(img, center, x, y-1)    
    right = get_pixel(img, center, x, y+1)
    if left>right:
        return 100
    else:
        return 200

def show_output(output_list):
    output_list_len = len(output_list)
    figure = plt.figure()
    for i in range(output_list_len):
        current_dict = output_list[i]
        current_img = current_dict["img"]
        current_xlabel = current_dict["xlabel"]
        current_ylabel = current_dict["ylabel"]
        current_xtick = current_dict["xtick"]
        current_ytick = current_dict["ytick"]
        current_title = current_dict["title"]
        current_type = current_dict["type"]
        current_plot = figure.add_subplot(1, output_list_len, i+1)            
        if current_type == "gray":
            current_plot.imshow(current_img, cmap = plt.get_cmap('gray'))
            current_plot.set_title(current_title)
            current_plot.set_xticks(current_xtick)
            current_plot.set_yticks(current_ytick)
            current_plot.set_xlabel(current_xlabel)
            current_plot.set_ylabel(current_ylabel)
        elif current_type == "histogram":
            current_plot.plot(current_img, color = "black")
            current_plot.set_xlim([0,260])
            current_plot.set_title(current_title)
            current_plot.set_xlabel(current_xlabel)
            current_plot.set_ylabel(current_ylabel)            
            ytick_list = [int(i) for i in current_plot.get_yticks()]
            current_plot.set_yticklabels(ytick_list,rotation = 90)

    plt.show()
    
def main():
    image_file = 'lenna.jpg'
    img_bgr = cv2.imread(image_file)
    height, width, channel = img_bgr.shape
    img_gray = cv2.cvtColor(img_bgr, cv2.COLOR_BGR2GRAY)
    
    img_two_bin = np.zeros((height, width,3), np.uint8)
    for i in range(0, height):
        for j in range(0, width):
             img_two_bin[i, j] = calculated_pixel(img_gray, i, j)
    hist_two_bin = cv2.calcHist([img_two_bin], [0], None, [256], [0, 256])
    output_list = []
    output_list.append({
        "img": img_gray,
        "xlabel": "",
        "ylabel": "",
        "xtick": [],
        "ytick": [],
        "title": "Gray Image",
        "type": "gray"        
    })
    output_list.append({
        "img": img_two_bin,
        "xlabel": "",
        "ylabel": "",
        "xtick": [],
        "ytick": [],
        "title": "Two Bin Image",
        "type": "gray"
    })    
    output_list.append({
        "img": hist_two_bin,
        "xlabel": "Bins",
        "ylabel": "Number of pixels",
        "xtick": None,
        "ytick": None,
        "title": "Histogram(Two Bin)",
        "type": "histogram"
    })

    show_output(output_list)
                             
    cv2.waitKey(0)
    cv2.destroyAllWindows()
    print("Two bin Program is finished")

if __name__ == '__main__':
    main()