Changeset - 6aace8f39e75
[Not reviewed]
default
0 2 1
Laman - 6 years ago 2019-03-04 19:29:53

detecting board diagonals with RANSAC
3 files changed with 86 insertions and 4 deletions:
0 comments (0 inline, 0 general)
exp/board_detect.py
Show inline comments
 
import sys
 

	
 
sys.path.append("../src")
 

	
 
import os
 
import math
 
import random
 
import itertools
 
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
 
from ransac import DiagonalRansac
 
from annotations import DataFile,computeBoundingBox
 
from hough import show,prepareEdgeImg,HoughTransform
 
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)
 
	wood=[193,165,116]
 
	(centers,distortion)=scipy.cluster.vq.kmeans(arr,3)
 
	log.debug("k-means centers: %s",centers)
 
	(black,empty,white)=sorted(centers,key=sum)
 
	if np.linalg.norm(black)>np.linalg.norm(black-wood):
 
		black=None
 
	if np.linalg.norm(white-[255,255,255])>np.linalg.norm(white-wood):
 
		white=None
 
	log.debug("black, white: %s, %s",black,white)
 
	return (black,white,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,"accepted and rejected stones")
 
	return res
 

	
 

	
 
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
 
		(black,white,colors)=self._sampleColors(rect)
 
		quantized=quantize(rect,colors)
 
		gray=cv.cvtColor(rect,cv.COLOR_BGR2GRAY)
 
		edges=cv.Canny(gray,70,130)
 
		show(edges,"edges")
 
		quantized=quantized & (255-cv.cvtColor(edges,cv.COLOR_GRAY2BGR))
 
		show(quantized,"quantized, edges separated")
 

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

	
 
		# detect lines from edges and stones
 
		edgeImg=prepareEdgeImg(rect)
 
		hough=HoughTransform(edgeImg)
 
		stonesImg=np.zeros((self._rectH,self._rectW),np.uint8)
 
		for (point,c) in stones:
 
			cv.circle(stonesImg,(int(point.x),int(point.y)),2,255,-1)
 

	
 
		show(stonesImg,"detected stones")
 
		hough.update(stonesImg,10)
 
		lines=hough.extract()
 

	
 
		linesImg=np.copy(rect)
 
		for line in itertools.chain(*lines):
 
			self._drawLine(linesImg,line)
 
		show(linesImg,"detected lines")
 

	
 
		# # rectify the image
 
		matrix=self._computeTransformationMatrix(lines[0][0],lines[0][-1],lines[1][0],lines[1][-1])
 
		transformed=cv.warpPerspective(rect,matrix,(self._rectW,self._rectH))
 

	
 
		# determine precise board edges
 
		intersections=[]
 
		for p in lines[0]:
 
			for q in lines[1]:
 
				intersections.append(p.intersect(q))
 
		sack=DiagonalRansac(intersections,19)
 
		diagonals=sack.extract(10,2000)
 
		log.debug("diagonals candidates: %s",diagonals)
 
		for line in diagonals:
 
			self._drawLine(linesImg,line,[0,255,255])
 
		show(linesImg,"diagonals candidates")
 

	
 
	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,black,white):
 
		(h,w)=quantized.shape[:2]
 
		mask=self._maskStones(quantized,black,white)
 
		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,black,white):
 
		unit=np.array([1,1,1],dtype=np.uint8)
 
		if black is not None:
 
			maskB=cv.inRange(quantized,black-unit,black+unit)
 

	
 
			distTransform=cv.distanceTransform(maskB,cv.DIST_L2,5)
 
			maskB=cv.inRange(distTransform,6,20)
 
			show(maskB,"black areas")
 
		else: maskB=np.zeros(quantized.shape[:2],dtype=np.uint8)
 

	
 
		if white is not None:
 
			maskW=cv.inRange(quantized,white-unit,white+unit)
 
			distTransform=cv.distanceTransform(maskW,cv.DIST_L2,5)
 
			maskW=cv.inRange(distTransform,6,20)
 
			show(maskW,"white areas")
 
		else: maskW=np.zeros(quantized.shape[:2],dtype=np.uint8)
 

	
 
		stones=cv.bitwise_or(maskB,maskW)
 
		show(stones,"black and white areas")
 
		return stones
 

	
 
	def _computeTransformationMatrix(self,p,q,r,s): # p || q, r || s
 
		(a,b,c,d)=Corners([p.intersect(r),p.intersect(s),q.intersect(r),q.intersect(s)]) # 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,"rectified image")
 

	
 
		return matrix
 

	
 
	def _drawLine(self,img,line):
 
	def _drawLine(self,img,line,color=None):
 
		if not color: color=[0,255,0]
 
		(h,w)=img.shape[:2]
 
		corners=[EPoint(0,0),EPoint(w,0),EPoint(0,h),EPoint(w,h)] # NW NE SW SE
 
		borders=[
 
			[Line.fromPoints(corners[0],corners[1]), Line.fromPoints(corners[2],corners[3])], # N S
 
			[Line.fromPoints(corners[0],corners[2]), Line.fromPoints(corners[1],corners[3])] # W E
 
		]
 

	
 
		(a,b)=(line.intersect(borders[0][0]), line.intersect(borders[0][1]))
 
		log.debug("%s %s",line,(a,b))
 
		if not a or not b:
 
			(a,b)=(line.intersect(borders[1][0]), line.intersect(borders[1][1]))
 
			log.debug("* %s %s",line,(a,b))
 
		if any(abs(x)>10**5 for x in [*a,*b]):
 
			log.debug("ignored")
 
			return
 
		cv.line(img,(int(a.x),int(a.y)),(int(b.x),int(b.y)),[0,255,0])
 
		cv.line(img,(int(a.x),int(a.y)),(int(b.x),int(b.y)),color)
 

	
 

	
 
if __name__=="__main__":
 
	detector=BoardDetector(sys.argv[2])
 
	filepath=sys.argv[1]
 
	filename=os.path.basename(filepath)
 
	img=cv.imread(filepath)
 
	detector(img,filename)
exp/hough.py
Show inline comments
 
import sys
 
sys.path.append("../src")
 

	
 
import math
 
from datetime import datetime
 
import logging as log
 

	
 
import numpy as np
 
import scipy.optimize
 
import scipy.signal
 
import cv2 as cv
 

	
 
from geometry import EPoint,Line
 

	
 
DEBUG=True
 

	
 

	
 
class LineBag:
 
	def __init__(self):
 
		self._lines=[]
 

	
 
	def put(self,score,alpha,beta,peaks):
 
		self._lines.append((score,alpha,beta,peaks))
 

	
 
	def pull(self,count):
 
		self._lines.sort(reverse=True)
 
		res=[]
 
		for (score,alpha,beta,peaks) in self._lines:
 
			if any(abs(alpha-gamma)<10 and abs(beta-delta)<10 for (_,gamma,delta,_) in res): continue
 
			# avoid intersecting lines
 
			if any((beta-delta)!=0 and (alpha-gamma)/(beta-delta)<0 for (_,gamma,delta,_) in res): continue
 
			res.append((score,alpha,beta,peaks))
 
			if len(res)>=count: break
 
		return res
 

	
 

	
 
class HoughTransform:
 
	"""Find line sequences with Hough transform.
 

	
 
	Uses usual image coordinates on input and output, with [0,0] in the upper left corner and [height-1,width-1] in the lower right.
 
	However, internally it uses the usual cartesian coordinates, centered at the image center. [-w/2,-h/2] in the upper left and [w/2,h/2] in the lower right."""
 
	def __init__(self,img):
 
		self._angleBandwidth=30 # degrees
 

	
 
		(h,w)=img.shape[:2]
 
		self._diagLen=int(np.sqrt(h**2+w**2))+1
 
		self._center=(w//2,h//2)
 
		self._acc=np.zeros((180,self._diagLen),dtype=np.int32)
 

	
 
		self.update(img)
 

	
 
	def extract(self):
 
		img=self._createImg()
 
		self.show(img)
 
		lines=self._detectLines()
 
		res=[]
 
		i=0
 
		for (score,alpha,beta,peaks) in lines:
 
			log.debug("score: %s",score)
 
			log.debug("alpha, beta: %s, %s",alpha,beta)
 
			self._drawLine(img,alpha,beta,peaks,i)
 

	
 
			res.append([])
 
			keys=self._readLineKeys(alpha,beta)
 
			for k in peaks:
 
				(alphaDeg,d)=keys[k]
 
				line=Line(alphaDeg*math.pi/180,d-self._diagLen//2)
 
				res[-1].append(self._transformOutput(line))
 
			res[-1].sort(key=lambda line: line.d)
 
			res[-1].sort(key=lambda line: line.d if line.alpha<math.pi else -line.d)
 
			i+=1
 

	
 
		self.show(img)
 
		return res
 

	
 
	def update(self,img,weight=1):
 
		start=datetime.now().timestamp()
 
		for (r,row) in enumerate(img):
 
			for (c,pix) in enumerate(row):
 
				if pix==0: continue
 
				for alphaDeg in range(0,180):
 
					d=self._computeDist(c,r,alphaDeg)+self._diagLen//2
 
					self._acc[(alphaDeg,d)]+=weight
 
		log.debug("Hough updated in %s s",round(datetime.now().timestamp()-start,3))
 

	
 
	def show(self,img=None):
 
		if img is None: img=self._createImg()
 
		show(img,"Hough transform accumulator")
 

	
 
	def _computeDist(self,x,y,alphaDeg):
 
		alphaRad=alphaDeg*math.pi/180
 
		(x0,y0)=self._center
 
		(dx,dy)=(x-x0,y0-y)
 
		d=dx*math.cos(alphaRad)+dy*math.sin(alphaRad)
 
		return round(d)
 

	
 
	def _detectLines(self):
 
		bag=LineBag()
 
		for alpha in range(0,180+60,2):
 
			for beta in range(max(alpha-60,0),min(alpha+60,180+60),2):
 
				accLine=[self._acc[key] for key in self._readLineKeys(alpha,beta)]
 
				(peaks,props)=scipy.signal.find_peaks(accLine,prominence=0)
 
				(prominences,peaks)=zip(*sorted(zip(props["prominences"],peaks),reverse=True)[:19])
 
				bag.put(sum(prominences),alpha,beta,peaks)
 
		return bag.pull(2)
 

	
 
	def _readLineKeys(self,alpha,beta):
 
		n=self._diagLen-1
 
		res=[]
 
		for i in range(n+1):
 
			k=round((alpha*(n-i)+beta*i)/n)
 
			if k>=180:
 
				k=k%180
 
				i=n-i
 
			res.append((k,i))
 
		return res
 

	
 
	def _transformOutput(self,line):
 
		(x,y)=self._center
 
		basis=EPoint(-x,y)
 
		shiftedLine=line.shiftBasis(basis)
 
		reflectedLine=Line(math.pi*2-shiftedLine.alpha,shiftedLine.d)
 
		log.debug("%s -> %s",line,reflectedLine)
 
		return reflectedLine
 

	
 
	def _createImg(self):
 
		maxVal=self._acc.max()
 
		arr=np.expand_dims(np.uint8(255*self._acc//maxVal),axis=2)
 
		img=np.concatenate((arr,arr,arr),axis=2)
 

	
 
		(h,w)=img.shape[:2]
 

	
 
		for x in range(0,w,4): # y axis
 
			img[h//2,x]=[255,255,255]
 
		for y in range(0,h,4):
 
			img[y,w//2]=[255,255,255]
 

	
 
		return img
 

	
 
	def _drawLine(self,img,alpha,beta,peaks,colorKey):
 
		colors=[[0,255,255],[255,0,255],[255,255,0]]
 
		color=colors[colorKey]
 
		(h,w)=img.shape[:2]
 
		keys=self._readLineKeys(alpha,beta)
 
		for (y,x) in keys:
 
			if x%3!=0: continue
 
			if y<0 or y>=h: continue
 
			img[y,x]=color
 
		for k in peaks:
 
			(y,x)=keys[k]
 
			cv.drawMarker(img,(x,y),color,cv.MARKER_TILTED_CROSS,8)
 

	
 

	
 
def show(img,filename="x"):
 
	cv.imshow(filename,img)
 
	cv.waitKey(0)
 
	cv.destroyAllWindows()
 

	
 

	
 
def filterVert(edges):
 
	kernel = np.array([[1,0,1],[1,0,1],[1,0,1]],np.uint8)
 
	edges = cv.erode(edges,kernel)
 
	kernel=np.array([[0,1,0],[0,1,0],[0,1,0]],np.uint8)
 
	edges=cv.dilate(edges,kernel)
 
	return edges
 

	
exp/ransac.py
Show inline comments
 
new file 100644
 
import random
 

	
 
from geometry import Line
 

	
 

	
 
class LineBag:
 
	def __init__(self,capacity):
 
		self._capacity=capacity
 
		self._bag=[]
 

	
 
	def put(self,item):
 
		# early abort
 
		if self._bag and item>self._bag[-1]: return
 

	
 
		(v,p)=item
 
		# mostly filter duplicates
 
		for (i,(vi,pi)) in enumerate(self._bag):
 
			if abs(p.alpha-pi.alpha)<0.02 and abs(p.d-pi.d)<5:
 
				if v<vi: self._bag[i]=item
 
				return
 

	
 
		# add new and remove the last
 
		self._bag.append(item)
 
		self._bag.sort()
 
		if len(self._bag)>self._capacity:
 
			self._bag.pop()
 

	
 
	def pull(self,count=0):
 
		return self._bag[:count] if count else self._bag[:]
 

	
 

	
 
class Ransac:
 
	def __init__(self,points):
 
		self._points=points
 

	
 
	def extract(self,count,iterations):
 
		bag=LineBag(count)
 

	
 
		for i in range(iterations):
 
			line=self._generateLine()
 
			score=self._scoreLine(line)
 
			bag.put((score+random.random()/1000,line))
 

	
 
		return [line for (score,line) in bag.pull()]
 

	
 
	def _generateLine(self):
 
		(a,b)=random.sample(self._points,2)
 
		return Line.fromPoints(a,b)
 

	
 
	def _scoreLine(self,line):
 
		return sum(min(line.distanceTo(p),5) for p in self._points)
 

	
 

	
 
class DiagonalRansac(Ransac):
 
	def __init__(self,points,sideLen):
 
		super().__init__(points)
 
		self._sideLen=sideLen
 

	
 
	def _generateLine(self):
 
		n=len(self._points)
 
		m=self._sideLen
 
		ka=random.randrange(0,n)
 
		kb=ka
 

	
 
		while ka//m==kb//m or ka%m==kb%m:
 
			kb=random.randrange(0,n)
 
		a=self._points[ka]
 
		b=self._points[kb]
 

	
 
		return Line.fromPoints(a,b)
0 comments (0 inline, 0 general)