Open Source Computer Vision Library https://opencv.org/
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#!/usr/bin/env python
'''
Lucas-Kanade homography tracker test
===============================
Uses goodFeaturesToTrack for track initialization and back-tracking for match verification
between frames. Finds homography between reference and current views.
'''
# Python 2/3 compatibility
from __future__ import print_function
import numpy as np
import cv2
#local modules
from tst_scene_render import TestSceneRender
from tests_common import NewOpenCVTests, isPointInRect
lk_params = dict( winSize = (19, 19),
maxLevel = 2,
criteria = (cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, 10, 0.03))
feature_params = dict( maxCorners = 1000,
qualityLevel = 0.01,
minDistance = 8,
blockSize = 19 )
def checkedTrace(img0, img1, p0, back_threshold = 1.0):
p1, st, err = cv2.calcOpticalFlowPyrLK(img0, img1, p0, None, **lk_params)
p0r, st, err = cv2.calcOpticalFlowPyrLK(img1, img0, p1, None, **lk_params)
d = abs(p0-p0r).reshape(-1, 2).max(-1)
status = d < back_threshold
return p1, status
class lk_homography_test(NewOpenCVTests):
render = None
framesCounter = 0
frame = frame0 = None
p0 = None
p1 = None
gray0 = gray1 = None
numFeaturesInRectOnStart = 0
def test_lk_homography(self):
self.render = TestSceneRender(self.get_sample('samples/data/graf1.png'),
self.get_sample('samples/data/box.png'), noise = 0.1, speed = 1.0)
frame = self.render.getNextFrame()
frame_gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
self.frame0 = frame.copy()
self.p0 = cv2.goodFeaturesToTrack(frame_gray, **feature_params)
isForegroundHomographyFound = False
if self.p0 is not None:
self.p1 = self.p0
self.gray0 = frame_gray
self.gray1 = frame_gray
currRect = self.render.getCurrentRect()
for (x,y) in self.p0[:,0]:
if isPointInRect((x,y), currRect):
self.numFeaturesInRectOnStart += 1
while self.framesCounter < 200:
self.framesCounter += 1
frame = self.render.getNextFrame()
frame_gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
if self.p0 is not None:
p2, trace_status = checkedTrace(self.gray1, frame_gray, self.p1)
self.p1 = p2[trace_status].copy()
self.p0 = self.p0[trace_status].copy()
self.gray1 = frame_gray
if len(self.p0) < 4:
self.p0 = None
continue
H, status = cv2.findHomography(self.p0, self.p1, cv2.RANSAC, 5.0)
goodPointsInRect = 0
goodPointsOutsideRect = 0
for (x0, y0), (x1, y1), good in zip(self.p0[:,0], self.p1[:,0], status[:,0]):
if good:
if isPointInRect((x1,y1), self.render.getCurrentRect()):
goodPointsInRect += 1
else: goodPointsOutsideRect += 1
if goodPointsOutsideRect < goodPointsInRect:
isForegroundHomographyFound = True
self.assertGreater(float(goodPointsInRect) / (self.numFeaturesInRectOnStart + 1), 0.6)
else:
p = cv2.goodFeaturesToTrack(frame_gray, **feature_params)
self.assertEqual(isForegroundHomographyFound, True)