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connectedComponents: warning free version

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Jason Newton 2012-08-24 23:57:17 -07:00
parent 4d059e9e5b
commit 45b4f4f32b
3 changed files with 384 additions and 18 deletions
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5
modules/imgproc/include/opencv2/imgproc/imgproc.hpp
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@ -1091,6 +1091,11 @@ enum { TM_SQDIFF=0, TM_SQDIFF_NORMED=1, TM_CCORR=2, TM_CCORR_NORMED=3, TM_CCOEFF
CV_EXPORTS_W void matchTemplate( InputArray image, InputArray templ,
OutputArray result, int method );
//! computes the connected components labeled image of boolean image I with 4 or 8 way connectivity - returns N, the total
//number of labels [0, N-1] where 0 represents the background label.
CV_EXPORTS_W uint64_t connectedComponents(Mat &L, const Mat &I, int connectivity = 8);
//! mode of the contour retrieval algorithm
enum
{

365
modules/imgproc/src/connectedcomponents.cpp Normal file
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@ -0,0 +1,365 @@
/*M///////////////////////////////////////////////////////////////////////////////////////
//
// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
//
// By downloading, copying, installing or using the software you agree to this license.
// If you do not agree to this license, do not download, install,
// copy or use the software.
//
//
// Intel License Agreement
// For Open Source Computer Vision Library
//
// Copyright (C) 2000, Intel Corporation, all rights reserved.
// Third party copyrights are property of their respective owners.
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
// * Redistribution's of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// * Redistribution's in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// * The name of Intel Corporation may not be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// This software is provided by the copyright holders and contributors "as is" and
// any express or implied warranties, including, but not limited to, the implied
// warranties of merchantability and fitness for a particular purpose are disclaimed.
// In no event shall the Intel Corporation or contributors be liable for any direct,
// indirect, incidental, special, exemplary, or consequential damages
// (including, but not limited to, procurement of substitute goods or services;
// loss of use, data, or profits; or business interruption) however caused
// and on any theory of liability, whether in contract, strict liability,
// or tort (including negligence or otherwise) arising in any way out of
// the use of this software, even if advised of the possibility of such damage.
//
// 2011 Jason Newton <nevion@gmail.com>
//M*/
//
#include "precomp.hpp"
namespace cv{
namespace connectedcomponents{
using std::vector;
//Find the root of the tree of node i
template<typename LabelT>
inline static
LabelT findRoot(const vector<LabelT> &P, LabelT i){
LabelT root = i;
while(P[root] < root){
root = P[root];
}
return root;
}
//Make all nodes in the path of node i point to root
template<typename LabelT>
inline static
void setRoot(vector<LabelT> &P, LabelT i, LabelT root){
while(P[i] < i){
LabelT j = P[i];
P[i] = root;
i = j;
}
P[i] = root;
}
//Find the root of the tree of the node i and compress the path in the process
template<typename LabelT>
inline static
LabelT find(vector<LabelT> &P, LabelT i){
LabelT root = findRoot(P, i);
setRoot(P, i, root);
return root;
}
//unite the two trees containing nodes i and j and return the new root
template<typename LabelT>
inline static
LabelT set_union(vector<LabelT> &P, LabelT i, LabelT j){
LabelT root = findRoot(P, i);
if(i != j){
LabelT rootj = findRoot(P, j);
if(root > rootj){
root = rootj;
}
setRoot(P, j, root);
}
setRoot(P, i, root);
return root;
}
//Flatten the Union Find tree and relabel the components
template<typename LabelT>
inline static
LabelT flattenL(vector<LabelT> &P){
LabelT k = 1;
for(size_t i = 1; i < P.size(); ++i){
if(P[i] < i){
P[i] = P[P[i]];
}else{
P[i] = k; k = k + 1;
}
}
return k;
}
////Flatten the Union Find tree - inconsistent labels
//void flatten(int P[], int size){
// for(int i = 1; i < size; ++i){
// P[i] = P[P[i]];
// }
//}
const int G4[2][2] = {{-1, 0}, {0, -1}};//b, d neighborhoods
const int G8[4][2] = {{-1, -1}, {-1, 0}, {-1, 1}, {0, -1}};//a, b, c, d neighborhoods
//Based on "Two Strategies to Speed up Connected Components Algorithms", the SAUF (Scan array union find) variant
//using decision trees
//Kesheng Wu, et al
template<typename LabelT, typename PixelT, int connectivity = 8>
struct LabelingImpl{
LabelT operator()(Mat &L, const Mat &I){
const int rows = L.rows;
const int cols = L.cols;
size_t nPixels = size_t(rows) * cols;
vector<LabelT> P; P.push_back(0);
LabelT l = 1;
//scanning phase
for(int r_i = 0; r_i < rows; ++r_i){
for(int c_i = 0; c_i < cols; ++c_i){
if(!I.at<PixelT>(r_i, c_i)){
L.at<LabelT>(r_i, c_i) = 0;
continue;
}
if(connectivity == 8){
const int a = 0;
const int b = 1;
const int c = 2;
const int d = 3;
bool T[4];
for(size_t i = 0; i < 4; ++i){
int gr = r_i + G8[i][0];
int gc = c_i + G8[i][1];
T[i] = false;
if(gr >= 0 && gr < rows && gc >= 0 && gc < cols){
if(I.at<PixelT>(gr, gc)){
T[i] = true;
}
}
}
//decision tree
if(T[b]){
//copy(b)
L.at<LabelT>(r_i, c_i) = L.at<LabelT>(r_i + G8[b][0], c_i + G8[b][1]);
}else{//not b
if(T[c]){
if(T[a]){
//copy(c, a)
L.at<LabelT>(r_i, c_i) = set_union(P, L.at<LabelT>(r_i + G8[c][0], c_i + G8[c][1]), L.at<LabelT>(r_i + G8[a][0], c_i + G8[a][1]));
}else{
if(T[d]){
//copy(c, d)
L.at<LabelT>(r_i, c_i) = set_union(P, L.at<LabelT>(r_i + G8[c][0], c_i + G8[c][1]), L.at<LabelT>(r_i + G8[d][0], c_i + G8[d][1]));
}else{
//copy(c)
L.at<LabelT>(r_i, c_i) = L.at<LabelT>(r_i + G8[c][0], c_i + G8[c][1]);
}
}
}else{//not c
if(T[a]){
//copy(a)
L.at<LabelT>(r_i, c_i) = L.at<LabelT>(r_i + G8[a][0], c_i + G8[a][1]);
}else{
if(T[d]){
//copy(d)
L.at<LabelT>(r_i, c_i) = L.at<LabelT>(r_i + G8[d][0], c_i + G8[d][1]);
}else{
//new label
L.at<LabelT>(r_i, c_i) = l;
P.push_back(l);//P[l] = l;
l = l + 1;
}
}
}
}
}else{
//B & D only
const int b = 0;
const int d = 1;
assert(connectivity == 4);
bool T[2];
for(size_t i = 0; i < 2; ++i){
int gr = r_i + G4[i][0];
int gc = c_i + G4[i][1];
T[i] = false;
if(gr >= 0 && gr < rows && gc >= 0 && gc < cols){
if(I.at<PixelT>(gr, gc)){
T[i] = true;
}
}
}
if(T[b]){
if(T[d]){
//copy(d, b)
L.at<LabelT>(r_i, c_i) = set_union(P, L.at<LabelT>(r_i + G4[d][0], c_i + G4[d][1]), L.at<LabelT>(r_i + G4[b][0], c_i + G4[b][1]));
}else{
//copy(b)
L.at<LabelT>(r_i, c_i) = L.at<LabelT>(r_i + G4[b][0], c_i + G4[b][1]);
}
}else{
if(T[d]){
//copy(d)
L.at<LabelT>(r_i, c_i) = L.at<LabelT>(r_i + G4[d][0], c_i + G4[d][1]);
}else{
//new label
L.at<LabelT>(r_i, c_i) = l;
P.push_back(l);//P[l] = l;
l = l + 1;
}
}
}
}
}
//analysis
LabelT nLabels = flattenL(P);
//assign final labels
for(size_t r = 0; r < rows; ++r){
for(size_t c = 0; c < cols; ++c){
L.at<LabelT>(r, c) = P[L.at<LabelT>(r, c)];
}
}
return nLabels;
}//End function LabelingImpl operator()
};//End struct LabelingImpl
}//end namespace connectedcomponents
//L's type must have an appropriate depth for the number of pixels in I
uint64_t connectedComponents(Mat &L, const Mat &I, int connectivity){
CV_Assert(L.rows == I.rows);
CV_Assert(L.cols == I.cols);
CV_Assert(L.channels() == 1 && I.channels() == 1);
CV_Assert(connectivity == 8 || connectivity == 4);
int lDepth = L.depth();
int iDepth = I.depth();
using connectedcomponents::LabelingImpl;
//warn if L's depth is not sufficient?
if(lDepth == CV_8U){
if(iDepth == CV_8U || iDepth == CV_8S){
if(connectivity == 4){
return (uint64_t) LabelingImpl<uint8_t, uint8_t, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<uint8_t, uint8_t, 8>()(L, I);
}
}else if(iDepth == CV_16U || iDepth == CV_16S){
if(connectivity == 4){
return (uint64_t) LabelingImpl<uint8_t, uint16_t, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<uint8_t, uint16_t, 8>()(L, I);
}
}else if(iDepth == CV_32S){
if(connectivity == 4){
return (uint64_t) LabelingImpl<uint8_t, int32_t, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<uint8_t, int32_t, 8>()(L, I);
}
}else if(iDepth == CV_32F){
if(connectivity == 4){
return (uint64_t) LabelingImpl<uint8_t, float, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<uint8_t, float, 8>()(L, I);
}
}else if(iDepth == CV_64F){
if(connectivity == 4){
return (uint64_t) LabelingImpl<uint8_t, double, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<uint8_t, double, 8>()(L, I);
}
}
}else if(lDepth == CV_16U){
if(iDepth == CV_8U || iDepth == CV_8S){
if(connectivity == 4){
return (uint64_t) LabelingImpl<uint16_t, uint8_t, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<uint16_t, uint8_t, 8>()(L, I);
}
}else if(iDepth == CV_16U || iDepth == CV_16S){
if(connectivity == 4){
return (uint64_t) LabelingImpl<uint16_t, uint16_t, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<uint16_t, uint16_t, 8>()(L, I);
}
}else if(iDepth == CV_32S){
if(connectivity == 4){
return (uint64_t) LabelingImpl<uint16_t, int32_t, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<uint16_t, int32_t, 8>()(L, I);
}
}else if(iDepth == CV_32F){
if(connectivity == 4){
return (uint64_t) LabelingImpl<uint16_t, float, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<uint16_t, float, 8>()(L, I);
}
}else if(iDepth == CV_64F){
if(connectivity == 4){
return (uint64_t) LabelingImpl<uint16_t, double, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<uint16_t, double, 8>()(L, I);
}
}
}else if(lDepth == CV_32S){
if(iDepth == CV_8U || iDepth == CV_8S){
if(connectivity == 4){
return (uint64_t) LabelingImpl<int32_t, uint8_t, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<int32_t, uint8_t, 8>()(L, I);
}
}else if(iDepth == CV_16U || iDepth == CV_16S){
if(connectivity == 4){
return (uint64_t) LabelingImpl<int32_t, uint16_t, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<int32_t, uint16_t, 8>()(L, I);
}
}else if(iDepth == CV_32S){
if(connectivity == 4){
return (uint64_t) LabelingImpl<int32_t, int32_t, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<int32_t, int32_t, 8>()(L, I);
}
}else if(iDepth == CV_32F){
if(connectivity == 4){
return (uint64_t) LabelingImpl<int32_t, float, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<int32_t, float, 8>()(L, I);
}
}else if(iDepth == CV_64F){
if(connectivity == 4){
return (uint64_t) LabelingImpl<int32_t, double, 4>()(L, I);
}else{
return (uint64_t) LabelingImpl<int32_t, double, 8>()(L, I);
}
}
}
CV_Error(CV_StsUnsupportedFormat, "unsupported label/image type");
return -1;
}
}

30
samples/cpp/connected_components.cpp
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@ -11,23 +11,19 @@ int threshval = 100;
static void on_trackbar(int, void*)
{
Mat bw = threshval < 128 ? (img < threshval) : (img > threshval);
vector<vector<Point> > contours;
vector<Vec4i> hierarchy;
findContours( bw, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE );
Mat dst = Mat::zeros(img.size(), CV_8UC3);
if( !contours.empty() && !hierarchy.empty() )
{
// iterate through all the top-level contours,
// draw each connected component with its own random color
int idx = 0;
for( ; idx >= 0; idx = hierarchy[idx][0] )
{
Scalar color( (rand()&255), (rand()&255), (rand()&255) );
drawContours( dst, contours, idx, color, CV_FILLED, 8, hierarchy );
Mat labelImage(img.size(), CV_32S);
int nLabels = connectedComponents(labelImage, bw, 8);
Vec3b colors[nLabels];
colors[0] = Vec3b(0, 0, 0);//background
for(int label = 1; label < nLabels; ++label){
colors[label] = Vec3b( (rand()&255), (rand()&255), (rand()&255) );
}
Mat dst(img.size(), CV_8UC3);
for(int r = 0; r < dst.rows; ++r){
for(int c = 0; c < dst.cols; ++c){
int label = labelImage.at<int>(r, c);
Vec3b &pixel = dst.at<Vec3b>(r, c);
pixel = colors[label];
}
}