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feature_homography.py:

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building descriptor index on target capture
simple AR experiment (work in progress)
pull/5/head
Alexander Mordvintsev 13 years ago
parent cf04fed369
commit 72a4f1924d
1 changed files with 79 additions and 51 deletions
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  1. 130
      samples/python2/feature_homography.py

130
samples/python2/feature_homography.py
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@ -19,11 +19,8 @@ import numpy as np
import cv2
import video
import common
from operator import attrgetter
def get_size(a):
h, w = a.shape[:2]
return w, h
from collections import namedtuple
from common import getsize
FLANN_INDEX_KDTREE = 1
@ -33,12 +30,29 @@ flann_params= dict(algorithm = FLANN_INDEX_LSH,
key_size = 12, # 20
multi_probe_level = 1) #2
MIN_MATCH_COUNT = 10
ar_verts = np.float32([[0, 0, 0], [0, 1, 0], [1, 1, 0], [1, 0, 0],
[0, 0, 1], [0, 1, 1], [1, 1, 1], [1, 0, 1],
[0.5, 0.5, 2]])
ar_edges = [(0, 1), (1, 2), (2, 3), (3, 0),
(4, 5), (5, 6), (6, 7), (7, 4),
(0, 4), (1, 5), (2, 6), (3, 7),
(4, 8), (5, 8), (6, 8), (7, 8)]
def draw_keypoints(vis, keypoints, color = (0, 255, 255)):
for kp in keypoints:
x, y = kp.pt
cv2.circle(vis, (int(x), int(y)), 2, color)
class App:
def __init__(self, src):
self.cap = video.create_capture(src)
self.frame = None
self.paused = False
self.ref_frame = None
self.detector = cv2.ORB( nfeatures = 1000 )
@ -47,19 +61,18 @@ class App:
cv2.namedWindow('plane')
self.rect_sel = common.RectSelector('plane', self.on_rect)
self.frame = None
def match_frames(self):
if len(self.frame_desc) < MIN_MATCH_COUNT or len(self.frame_desc) < MIN_MATCH_COUNT:
return
raw_matches = self.matcher.knnMatch(self.ref_descs, trainDescriptors = self.frame_desc, k = 2)
raw_matches = self.matcher.knnMatch(self.frame_desc, k = 2)
p0, p1 = [], []
for m in raw_matches:
if len(m) == 2 and m[0].distance < m[1].distance * 0.75:
m = m[0]
p0.append( self.ref_points[m.queryIdx].pt )
p1.append( self.frame_points[m.trainIdx].pt )
p0.append( self.ref_points[m.trainIdx].pt ) # queryIdx
p1.append( self.frame_points[m.queryIdx].pt )
p0, p1 = np.float32((p0, p1))
if len(p0) < MIN_MATCH_COUNT:
return
@ -72,44 +85,31 @@ class App:
return p0, p1, H
def on_frame(self, frame):
if self.frame is None or not self.rect_sel.dragging:
self.frame = frame = np.fliplr(frame).copy()
self.frame_points, self.frame_desc = self.detector.detectAndCompute(self.frame, None)
if self.frame_desc is None: # detectAndCompute returns descs=None if not keypoints found
self.frame_desc = []
else:
self.ref_frame = None
w, h = get_size(self.frame)
vis = np.zeros((h, w*2, 3), np.uint8)
vis[:h,:w] = self.frame
self.rect_sel.draw(vis)
for kp in self.frame_points:
x, y = kp.pt
cv2.circle(vis, (int(x), int(y)), 2, (0, 255, 255))
if self.ref_frame is not None:
vis[:h,w:] = self.ref_frame
x0, y0, x1, y1 = self.ref_rect
cv2.rectangle(vis, (x0+w, y0), (x1+w, y1), (0, 255, 0), 2)
for kp in self.ref_points:
x, y = kp.pt
cv2.circle(vis, (int(x+w), int(y)), 2, (0, 255, 255))
match = self.match_frames()
if match is not None:
p0, p1, H = match
for (x0, y0), (x1, y1) in zip(np.int32(p0), np.int32(p1)):
cv2.line(vis, (x0+w, y0), (x1, y1), (0, 255, 0))
x0, y0, x1, y1 = self.ref_rect
corners = np.float32([[x0, y0], [x1, y0], [x1, y1], [x0, y1]])
corners = np.int32( cv2.perspectiveTransform(corners.reshape(1, -1, 2), H) )
cv2.polylines(vis, [corners], True, (255, 255, 255), 2)
cv2.imshow('plane', vis)
def on_frame(self, vis):
match = self.match_frames()
if match is None:
return
w, h = getsize(self.frame)
p0, p1, H = match
for (x0, y0), (x1, y1) in zip(np.int32(p0), np.int32(p1)):
cv2.line(vis, (x0+w, y0), (x1, y1), (0, 255, 0))
x0, y0, x1, y1 = self.ref_rect
corners0 = np.float32([[x0, y0], [x1, y0], [x1, y1], [x0, y1]])
img_corners = cv2.perspectiveTransform(corners0.reshape(1, -1, 2), H)
cv2.polylines(vis, [np.int32(img_corners)], True, (255, 255, 255), 2)
corners3d = np.hstack([corners0, np.zeros((4, 1), np.float32)])
fx = 0.9
K = np.float64([[fx*w, 0, 0.5*(w-1)],
[0, fx*w, 0.5*(h-1)],
[0.0,0.0, 1.0]])
dist_coef = np.zeros(4)
ret, rvec, tvec = cv2.solvePnP(corners3d, img_corners, K, dist_coef)
verts = ar_verts * [(x1-x0), (y1-y0), -(x1-x0)*0.3] + (x0, y0, 0)
verts = cv2.projectPoints(verts, rvec, tvec, K, dist_coef)[0].reshape(-1, 2)
for i, j in ar_edges:
(x0, y0), (x1, y1) = verts[i], verts[j]
cv2.line(vis, (int(x0), int(y0)), (int(x1), int(y1)), (255, 255, 0), 2)
def on_rect(self, rect):
x0, y0, x1, y1 = rect
@ -123,11 +123,39 @@ class App:
descs.append(desc)
self.ref_points, self.ref_descs = points, np.uint8(descs)
self.matcher.clear()
self.matcher.add([self.ref_descs])
def run(self):
while True:
ret, frame = self.cap.read()
self.on_frame(frame)
playing = not self.paused and not self.rect_sel.dragging
if playing or self.frame is None:
ret, frame = self.cap.read()
if not ret:
break
self.frame = np.fliplr(frame).copy()
self.frame_points, self.frame_desc = self.detector.detectAndCompute(self.frame, None)
if self.frame_desc is None: # detectAndCompute returns descs=None if not keypoints found
self.frame_desc = []
w, h = getsize(self.frame)
vis = np.zeros((h, w*2, 3), np.uint8)
vis[:h,:w] = self.frame
if self.ref_frame is not None:
vis[:h,w:] = self.ref_frame
x0, y0, x1, y1 = self.ref_rect
cv2.rectangle(vis, (x0+w, y0), (x1+w, y1), (0, 255, 0), 2)
draw_keypoints(vis[:,w:], self.ref_points)
draw_keypoints(vis, self.frame_points)
if playing and self.ref_frame is not None:
self.on_frame(vis)
self.rect_sel.draw(vis)
cv2.imshow('plane', vis)
ch = cv2.waitKey(1)
if ch == ord(' '):
self.paused = not self.paused
if ch == 27:
break
@ -136,5 +164,5 @@ if __name__ == '__main__':
import sys
try: video_src = sys.argv[1]
except: video_src = '0'
except: video_src = 0
App(video_src).run()

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