particleCharacterization.py 1.63 KB
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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
GEPARD - Gepard-Enabled PARticle Detection
Copyright (C) 2018  Lars Bittrich and Josef Brandt, Leibniz-Institut für 
Polymerforschung Dresden e. V. <bittrich-lars@ipfdd.de>    

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program, see COPYING.  
If not, see <https://www.gnu.org/licenses/>.
"""

import numpy as np
import cv2

def getContourStatsWithPixelScale(cnt, pixelscale):
        long, short, longellipse, shortellipse, area = getContourStats(cnt)
        return long*pixelscale, short*pixelscale, longellipse*pixelscale, shortellipse*pixelscale, area*pixelscale**2

def getContourStats(cnt):
    ##characterize particle
        longellipse, shortellipse = np.nan, np.nan
        
        if cnt.shape[0] >= 5:       ##at least 5 points required for ellipse fitting...
            ellipse = cv2.fitEllipse(cnt)
            shortellipse, longellipse = ellipse[1]

        rect = cv2.minAreaRect(cnt)
        long, short = rect[1]
        if short>long:
            long, short = short, long
        
        area = cv2.contourArea(cnt)
    
        return long, short, longellipse, shortellipse, area