feature_orbslam2.py

"""
* This file is part of PYSLAM 
*
* Copyright (C) 2016-present Luigi Freda <luigi dot freda at gmail dot com> 
*
* PYSLAM 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.
*
* PYSLAM 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 PYSLAM. If not, see <http://www.gnu.org/licenses/>.
"""

import os 
import cv2
import numpy as np

from utils_sys import Printer,getchar

from orbslam2_features import ORBextractor



kVerbose = True   


# interface for pySLAM 
class Orbslam2Feature2D: 
    def __init__(self,num_features=2000, scale_factor=1.2, num_levels=8): 
        print('Using Orbslam2Feature2D')
        self.orb_extractor = ORBextractor(num_features, scale_factor, num_levels)
    
    # extract keypoints 
    def detect(self, img, mask=None):  #mask is fake: it is not considered by the c++ implementation 
        # detect and compute 
        kps_tuples = self.orb_extractor.detect(img)            
        # convert keypoints 
        kps = [cv2.KeyPoint(*kp) for kp in kps_tuples]
        return kps       
    
    def compute(self, img, kps, mask=None):
        Printer.orange('WARNING: you are supposed to call detectAndCompute() for ORB2 instead of compute()')
        Printer.orange('WARNING: ORB2 is recomputing both kps and des on input frame', img.shape)            
        return self.detectAndCompute(img)
        #return kps, np.array([])
        
    def setMaxFeatures(self, num_features): # use the cv2 method name for extractors (see https://docs.opencv.org/4.x/db/d95/classcv_1_1ORB.html#aca471cb82c03b14d3e824e4dcccf90b7)
        self.orb_extractor.SetNumFeatures(num_features) # custom method name for OrbSlam2 python wrapper
        
    # compute both keypoints and descriptors       
    def detectAndCompute(self, img, mask=None): #mask is fake: it is not considered by the c++ implementation 
        # detect and compute 
        kps_tuples, des = self.orb_extractor.detectAndCompute(img)        
        # convert keypoints 
        kps = [cv2.KeyPoint(*kp) for kp in kps_tuples]
        return kps, des