Function rectangle

Synopse

Create a binary rectangle image.

g = rectangle(s, r, c)
- g: Image.
- s: Image. [rows cols], output image dimensions.
- r: Double. [rrows ccols], rectangle image dimensions.
- c: Image. [row0 col0], center of the rectangle.

Description

Creates a binary image with dimensions given by s, rectangle dimensions given by r and center given by c. The pixels inside the rectangle are one and outside zero.



In [1]:

    
import numpy as np

def rectangle(s, r, c):

    rows,  cols  = s[0], s[1]
    rrows, rcols = r[0], r[1]
    rr0,   cc0   = c[0], c[1]
    rr, cc = np.meshgrid(np.arange(rows), np.arange(cols), indexing='ij')

    min_row, max_row = rr0-rrows//2, rr0+rrows//2
    min_col, max_col = cc0-rcols//2, cc0+rcols//2

    g1 = (min_row <= rr) & (max_row > rr)
    g2 = (min_col <= cc) & (max_col > cc)

    g = g1 & g2
    return g

Examples



In [1]:

    
testing = (__name__ == "__main__")
if testing:
    ! jupyter nbconvert --to python rectangle.ipynb
    import numpy as np
    import sys,os
    ia898path = os.path.abspath('../../')
    if ia898path not in sys.path:
        sys.path.append(ia898path)
    import ia898.src as ia









    



[NbConvertApp] Converting notebook rectangle.ipynb to python
[NbConvertApp] Writing 1808 bytes to rectangle.py

Example 1



In [2]:

    
if testing:
    F = ia.rectangle([7,9], [3,2], [3,4])
    print(F)









    



[[False False False False False False False False False]
 [False False False False False False False False False]
 [False False False  True  True False False False False]
 [False False False  True  True False False False False]
 [False False False False False False False False False]
 [False False False False False False False False False]
 [False False False False False False False False False]]

Example 2



In [3]:

    
if testing:
    F = ia.rectangle([200,300], [90,120], [70,120])
    ia.adshow(ia.normalize(F))

Equation

\begin{equation} g(x,y)=\begin{cases} 1, & \text{if } x_\text{min} \leq x < x_\text{max} \text{ and } y_\text{min} \leq y < y_\text{max}.\\ 0, & \text{otherwise}. \end{cases} \end{equation}

Contributions

Lucas de Vasconcellos Teixeira, 1st semester 2017