Changeset - 7df1503a4ca6
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Laman - 6 years ago 2019-01-25 20:05:40

computing transformation matrix
1 file changed with 44 insertions and 3 deletions:
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exp/board_detect.py
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import sys
 

	
 
sys.path.append("../src")
 

	
 
import os
 
import math
 
import random
 
import logging as log
 

	
 
import cv2 as cv
 
import numpy as np
 
import scipy.cluster
 
import scipy.ndimage
 
import scipy.signal
 

	
 
from geometry import Line, point2lineDistance
 
from polar_hough import PolarHough
 
from annotations import DataFile,computeBoundingBox
 
from hough import show
 
from analyzer.epoint import EPoint
 
from analyzer.corners import Corners
 

	
 
random.seed(361)
 
log.basicConfig(level=log.DEBUG,format="%(message)s")
 

	
 

	
 
def kmeans(img):
 
	arr=np.reshape(img,(-1,3)).astype(np.float)
 
	colors=np.array([[0,0,0],[255,255,255],[193,165,116]],np.float)
 
	log.debug(colors)
 
	(centers,distortion)=scipy.cluster.vq.kmeans(arr,colors)
 
	log.debug("k-means centers: %s",centers)
 
	return centers
 

	
 

	
 
def quantize(img,centers):
 
	origShape=img.shape
 
	data=np.reshape(img,(-1,3))
 
	(keys,dists)=scipy.cluster.vq.vq(data,centers)
 
	pixels=np.array([centers[k] for k in keys],dtype=np.uint8).reshape(origShape)
 
	return pixels
 

	
 

	
 
def filterStones(contours,bwImg,stoneDims):
 
	contourImg=cv.cvtColor(bwImg,cv.COLOR_GRAY2BGR)
 
	res=[]
 
	for (i,c) in enumerate(contours):
 
		keep=True
 
		moments=cv.moments(c)
 
		center=(moments["m10"]/(moments["m00"] or 1), moments["m01"]/(moments["m00"] or 1))
 
		area=cv.contourArea(c)
 
		(x,y,w,h)=cv.boundingRect(c)
 
		if w>stoneDims[0] or h>stoneDims[1]*1.5 or w<2 or h<2:
 
			cv.drawMarker(contourImg,tuple(map(int,center)),(0,0,255),cv.MARKER_TILTED_CROSS,12)
 
			keep=False
 
		coverage1=area/(w*h or 1)
 
		hull=cv.convexHull(c)
 
		coverage2=area/(cv.contourArea(hull) or 1)
 
		if coverage2<0.8:
 
			cv.drawMarker(contourImg,tuple(map(int,center)),(0,127,255),cv.MARKER_DIAMOND,12)
 
			keep=False
 
		if keep:
 
			res.append((EPoint(*center),c))
 
			cv.drawMarker(contourImg,tuple(map(int,center)),(255,0,0),cv.MARKER_CROSS)
 
	log.debug("accepted: %s",len(res))
 
	log.debug("rejected: %s",len(contours)-len(res))
 
	show(contourImg)
 
	return res
 

	
 

	
 
def groupLines(points,minCount,tolerance):
 
	random.shuffle(points)
 
	sample=points[:57]
 
	for (i,a) in enumerate(sample):
 
		for (j,b) in enumerate(sample):
 
			if j<=i: continue
 
			ab=Line(a,b)
 
			for c in points:
 
				if c is a or c is b: continue
 
				if point2lineDistance(a,b,c)<=tolerance:
 
					ab.points.add(c)
 
			if len(ab.points)>=minCount:
 
				yield ab
 

	
 

	
 
class BoardDetector:
 
	def __init__(self,annotationsPath):
 
		self._annotations=DataFile(annotationsPath)
 

	
 
		self._rectW=0
 
		self._rectH=0
 
		self._rect=None
 

	
 
	def __call__(self,img,filename):
 
		# approximately detect the board
 
		(h,w)=img.shape[:2]
 
		log.debug("image dimensions: %s x %s",w,h)
 
		show(img,filename)
 
		(x1,y1,x2,y2)=self._detectRough(img,filename)
 
		rect=img[y1:y2,x1:x2]
 
		self._rectW=x2-x1
 
		self._rectH=y2-y1
 
		self._rect=rect
 

	
 
		# quantize colors
 
		colors=self._sampleColors(rect)
 
		quantized=quantize(rect,colors)
 
		show(quantized,filename)
 

	
 
		# detect black and white stones
 
		stones=self._detectStones(quantized,colors)
 

	
 
		# detect lines passing through the stones
 
		lines=self._constructLines(stones)
 

	
 
		# detect vanishing points of the lines
 
		vanish=self._detectVanishingPoints(lines,EPoint(w//2-x1, h//2-y1))
 
		imgCenter=EPoint(w//2-x1, h//2-y1)
 
		vanish=self._detectVanishingPoints(lines,imgCenter)
 
		(a,b,c,d)=(p-EPoint(x1,y1) for p in self._annotations[filename][0])
 
		(p,q,r,s)=(Line(a,b),Line(b,c),Line(c,d),Line(d,a))
 
		v1=p.intersect(r)
 
		v2=q.intersect(s)
 
		log.debug("true vanishing points: %s ~ %s, %s ~ %s",v1,v1.toPolar(imgCenter),v2,v2.toPolar(imgCenter))
 

	
 
		# rectify the image
 
		matrix=self._computeTransformationMatrix(vanish,lines)
 
		transformed=cv.warpPerspective(rect,matrix,(self._rectW,self._rectH))
 

	
 
		# determine precise board edges
 

	
 
	def _detectRough(self,img,filename):
 
		corners=self._annotations[filename][0]
 
		(x1,y1,x2,y2)=computeBoundingBox(corners)
 
		log.debug("bounding box: (%s,%s) - (%s,%s)",x1,y1,x2,y2)
 
		return (x1,y1,x2,y2)
 

	
 
	def _sampleColors(self,rect):
 
		(h,w)=rect.shape[:2]
 
		minirect=rect[h//4:3*h//4, w//4:3*w//4]
 
		return kmeans(minirect)
 

	
 
	def _detectStones(self,quantized,colors):
 
		(h,w)=quantized.shape[:2]
 
		mask=self._maskStones(quantized,colors)
 
		stoneDims=(w/19,h/19)
 
		log.debug("stone dims: %s - %s",tuple(x/2 for x in stoneDims),stoneDims)
 

	
 
		(contours,hierarchy)=cv.findContours(mask,cv.RETR_LIST,cv.CHAIN_APPROX_SIMPLE)
 
		stoneLocs=filterStones(contours,mask,stoneDims)
 

	
 
		return stoneLocs
 

	
 
	def _maskStones(self,quantized,colors):
 
		unit=np.array([1,1,1],dtype=np.uint8)
 
		kernel=np.ones((3,3),np.uint8)
 
		maskB=cv.inRange(quantized,colors[0]-unit,colors[0]+unit)
 
		maskB=cv.morphologyEx(maskB,cv.MORPH_OPEN,kernel,iterations=1)
 
		maskB=cv.erode(maskB,kernel,iterations=4)
 
		maskB=cv.erode(maskB,kernel,iterations=3)
 
		# distTransform = cv.distanceTransform(maskB,cv.DIST_L2,5)
 
		# maskB=cv.inRange(distTransform,6,10)
 
		show(maskB)
 
		maskW=cv.inRange(quantized,colors[1]-unit,colors[1]+unit)
 
		maskW=cv.erode(maskW,kernel,iterations=3)
 
		maskW=cv.morphologyEx(maskW,cv.MORPH_OPEN,kernel,iterations=1)
 
		maskW=cv.erode(maskW,kernel,iterations=2)
 
		show(maskW)
 
		stones=cv.bitwise_or(maskB,maskW)
 
		show(stones)
 
		return stones
 

	
 
	def _constructLines(self,stoneLocs):
 
		lineDict=dict()
 
		minCount=min(max(math.sqrt(len(stoneLocs))-4,3),7)
 
		log.debug("min count: %s",minCount)
 
		for line in groupLines([point for (point,contour) in stoneLocs],minCount,2):
 
			key=line.getSortedPoints()
 
			if key in lineDict: # we already have a line with the same incident points
 
				continue
 
			lineDict[line.getSortedPoints()]=line
 
			obsolete=set()
 
			for ab in lineDict.values():
 
				if ab is line: continue
 
				if line.points<ab.points: # == impossible
 
					del lineDict[key]
 
					break
 
				if ab.points<line.points:
 
					obsolete.add(ab.getSortedPoints())
 
			for key in obsolete: del lineDict[key]
 
		log.debug("valid lines: %s",len(lineDict))
 
		lines=sorted(lineDict.values(), key=lambda ab: len(ab.points), reverse=True)
 

	
 
		# visualize
 
		linesImg=cv.cvtColor(np.zeros((self._rectH,self._rectW),np.uint8),cv.COLOR_GRAY2BGR)
 
		cv.drawContours(linesImg,[c for (point,c) in stoneLocs],-1,(255,255,255),-1)
 
		for (p,c) in stoneLocs:
 
			cv.drawMarker(linesImg,(int(p.x),int(p.y)),(255,0,0),cv.MARKER_CROSS)
 
		for line in lines:
 
			points=line.getSortedPoints()
 
			(xa,ya)=points[0]
 
			(xb,yb)=points[-1]
 
			cv.line(linesImg,(int(xa),int(ya)),(int(xb),int(yb)),(255,255,0),1)
 
		show(linesImg)
 

	
 
		return lines
 

	
 
	def _detectVanishingPoints(self,lines,imgCenter):
 
		polarHough=PolarHough(math.pi/180,10)
 
		for (i,ab) in enumerate(lines):
 
			for cd in lines[i+1:]:
 
				point=ab.intersect(cd)
 
				if 0<=point.x<=self._rectW and 0<=point.y<=self._rectH: continue
 
				log.debug("%s -> %s",point,point.toPolar(imgCenter))
 
				polarHough.put(point.toPolar(imgCenter))
 
		vanish=[EPoint.fromPolar(p,imgCenter) for p in polarHough.extract(2)]
 
		log.debug(vanish)
 
		return vanish
 

	
 
	def _computeTransformationMatrix(self,vanish,lines):
 
		(v1,v2)=vanish
 
		(p,r)=sorted(lines,key=lambda p: point2lineDistance(p.a,p.b,v1))[:2]
 
		(q,s)=sorted(lines,key=lambda p: point2lineDistance(p.a,p.b,v2))[:2]
 
		(a,b,c,d)=Corners([p.intersect(q),q.intersect(r),r.intersect(s),s.intersect(p)]) # canonize the abcd order
 
		a_=EPoint(b.x,min(a.y,d.y))
 
		b_=EPoint(b.x,max(b.y,c.y))
 
		c_=EPoint(c.x,max(b.y,c.y))
 
		d_=EPoint(c.x,min(a.y,d.y))
 
		abcd=[list(point) for point in (a,b,c,d)]
 
		abcd_=[list(point) for point in (a_,b_,c_,d_)]
 
		log.debug("abcd: %s ->",(a,b,c,d))
 
		log.debug("-> abcd_: %s",(a_,b_,c_,d_))
 
		matrix=cv.getPerspectiveTransform(np.float32(abcd),np.float32(abcd_))
 
		log.debug("transformation matrix: %s",matrix)
 

	
 
		rect=np.copy(self._rect)
 
		for point in (a,b,c,d):
 
			cv.drawMarker(rect,(int(point.x),int(point.y)),(0,255,255),cv.MARKER_TILTED_CROSS)
 
		show(rect)
 
		transformed=cv.warpPerspective(rect,matrix,(self._rectW,self._rectH))
 
		show(transformed)
 

	
 
		return matrix
 

	
 

	
 
if __name__=="__main__":
 
	detector=BoardDetector(sys.argv[2])
 
	filepath=sys.argv[1]
 
	filename=os.path.basename(filepath)
 
	img=cv.imread(filepath)
 
	detector(img,filename)
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