im2dhist 0.1.0.6

Calculate two dimensional histogram of a given image.

im2dhist

This small piece of code is intended to help researchers, especially in field of image processing, to easily calculate two dimensional histogram of a given image.

How it works

A moving window of w*w moves through out the given image, and as its center places on each pixel, number of encounters with same and other brightness intensities is counted seperately. This package basically outputs a normalized two dimensional numpy array of brightness intensity encounters.

Installation

Run the following to install:

pip install im2dhist

Usage

from im2dhist import im2dhist
import cv2
import numpy as np
from mpl_toolkits import mplot3d
import matplotlib.pyplot as plt

def main():
    image_name = 'Plane.jpg'
    image = cv2.imread(image_name)
    # converts rgb image to gray
    gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

    # 2*w_neighboring+1 is width of the square window around each pixel, when counting neiboring pixels
    # calculate 2 dimensional histogram of gray_image
    v_image_2DHisteq = im2dhist(gray_image, w_neighboring=6, showProgress = True)

    # plots 2D-Histogram
    [K, _] = v_image_2DHisteq.shape
    x = np.outer(np.arange(0, K), np.ones(K))
    y = x.copy().T 
    # ln-ing v_image_2DHisteq makes its details more prominent.
    Hist2D_ln = v_image_2DHisteq.copy()
    Hist2D_ln[np.where(Hist2D_ln<=0)] = 1e-15
    z = np.log(Hist2D_ln)
    fig = plt.figure()
    ax = plt.axes(projection='3d')
    ax.plot_surface(x, y, z,cmap='viridis', edgecolor='none')
    ax.set_title(f'2D-Histogram of {image_name}')
    plt.show()
if __name__ == '__main__': main()

Showcase

This is a sample image Two dimensional histogram of the sample image