OpenCV中CascadeClassifier类实现多尺度检测源码解析

「爱情、让人受尽委屈。」 2022-08-06 01:26 213阅读 0赞

级联分类器检测类CascadeClassifier，在2.4.5版本中使用Adaboost的方法+LBP、HOG、HAAR进行目标检测，加载的是使用traincascade进行训练的分类器

class CV\_EXPORTS\_W CascadeClassifier

public:

CV\_WRAP CascadeClassifier(); // 无参数构造函数，new自动调用该函数分配初试内存

CV\_WRAP CascadeClassifier( const string& filename ); // 带参数构造函数，参数为XML的绝对名称

virtual ~CascadeClassifier(); // 析构函数，无需关心

CV\_WRAP virtual bool empty() const; // 是否导入参数，只创建了该对象而没有加载或者加载失败时都是空的

CV\_WRAP bool load( const string& filename ); // 加载分类器，参数为XML的绝对名称，函数内部调用read读取新格式的分类器，读取成功后直接返回，读取失败后调用cvLoad读取旧格式的分类器，读取成功返回true，否则返回false

virtual bool read( const FileNode& node ); // load内部调用read解析XML中的内容，也可以自己创建节点然后调用Read即可，但是该函数只能读取新格式的分类器，不能读取旧格式的分类器

// 多尺度检测函数

CV\_WRAP virtual void detectMultiScale( const Mat& image, // 图像，cvarrtoMat实现IplImage转换为Mat，必须为8位，内部可自行转换为灰度图像

CV\_OUT vector<Rect>& objects, // 输出矩形，注意vector不是线程安全的

double scaleFactor=1.1, // 缩放比例，必须大于1

int minNeighbors=3, // 合并窗口时最小neighbor，每个候选矩阵至少包含的附近元素个数

int flags=0, // 检测标记，只对旧格式的分类器有效，与 cvHaarDetectObjects的参数flags相同， 默认为0，可能的取值为CV\_HAAR\_DO\_CANNY\_PRUNING(CANNY边缘检测)、CV\_HAAR\_SCALE\_IMAGE(缩放图像)、CV\_HAAR\_FIND\_BIGGEST\_OBJECT(寻找最大的目标)、 CV\_HAAR\_DO\_ROUGH\_SEARCH(做粗略搜索)；如果寻找最大的目标就不能缩放图像，也不能CANNY边缘检测

Size minSize=Size(), // 最小检测目标

Size maxSize=Size() ); // 最大检测目标

// 最好不要在这里设置最大最小，可能会影响合并的效果，因此可以在检测完毕后自行判断结果是否满足要求

CV\_WRAP virtual void detectMultiScale( const Mat& image,

CV\_OUT vector<Rect>& objects,

vector<int>& rejectLevels,

vector<double>& levelWeights,

double scaleFactor=1.1,

int minNeighbors=3, int flags=0,

Size minSize=Size(),

Size maxSize=Size(),

bool outputRejectLevels=false );

// 上述参数多了rejectLevels和levelWeights以及 outputRejectLevels参数，只有在 outputRejectLevels为true的时候才可能输出前两个参数

// 还有就是在使用旧分类器的时候必须设置flags为 CV\_HAAR\_SCALE\_IMAGE，可以通过haarcascade\_frontalface\_alt.xml检测人脸尝试

bool isOldFormatCascade() const; // 是否是旧格式的分类器

virtual Size getOriginalWindowSize() const; // 初始检测窗口大小，也就是训练的窗口

int getFeatureType() const; // 获取特征类型

bool setImage( const Mat& ); // 设置图像，计算图像的积分图

virtual int runAt( Ptr<FeatureEvaluator>& feval, Point pt, double& weight ); // 计算某检测窗口是否为目标

// 保存强分类器数据

class Data

public:

struct CV\_EXPORTS DTreeNode // 节点

int featureIdx; // 对应的特征编号

float threshold; // for ordered features only 节点阈值

int left; // 左子树

int right; // 右子树

\};

struct CV\_EXPORTS DTree // 弱分类器

int nodeCount; // 弱分类器中节点个数

\};

struct CV\_EXPORTS Stage // 强分类器

int first; // 在classifier中的起始位置

int ntrees; // 该强分类器中的弱分类器数

float threshold; // 强分类器阈值

\};

bool read(const FileNode &node); // 读取强分类器

bool isStumpBased; // 是否只有树桩

int stageType; // BOOST，boostType:GAB、RAB等

int featureType; // HAAR、HOG、LBP

int ncategories; // maxCatCount，LBP为256，其余为0

Size origWinSize;

vector<Stage> stages;

vector<DTree> classifiers;

vector<DTreeNode> nodes;

vector<float> leaves;

vector<int> subsets;

\};

Data data;

Ptr<FeatureEvaluator> featureEvaluator;

Ptr<CvHaarClassifierCascade> oldCascade;

// 关于mask这块参考《OpenCV目标检测之MaskGenerator》

public:

class CV\_EXPORTS MaskGenerator

public:

virtual ~MaskGenerator() \{\}

virtual cv::Mat generateMask(const cv::Mat& src)=0;

virtual void initializeMask(const cv::Mat& /\*src\*/) \{\};

\};

void setMaskGenerator(Ptr<MaskGenerator> maskGenerator);

Ptr<MaskGenerator> getMaskGenerator();

void setFaceDetectionMaskGenerator();

protected:

Ptr<MaskGenerator> maskGenerator;

注意：当在不同的分类器之间切换的时候，需要手动释放，因为read内部没有释放上一次读取的分类器数据！

关于新旧格式的分类器参考《OpenCV存储解读之Adaboost分类器》

使用CascadeClassifier检测目标的过程

1) load分类器并调用empty函数检测是否load成功

// 读取stages

bool CascadeClassifier::Data::read(const FileNode &root)

static const float THRESHOLD\_EPS = 1e-5f;

// load stage params

string stageTypeStr = (string)root\[CC\_STAGE\_TYPE\];

if( stageTypeStr == CC\_BOOST )

stageType = BOOST;

else

return false;

printf("stageType: %s\\n", stageTypeStr.c\_str());

string featureTypeStr = (string)root\[CC\_FEATURE\_TYPE\];

if( featureTypeStr == CC\_HAAR )

featureType = FeatureEvaluator::HAAR;

else if( featureTypeStr == CC\_LBP )

featureType = FeatureEvaluator::LBP;

else if( featureTypeStr == CC\_HOG )

featureType = FeatureEvaluator::HOG;

else

return false;

printf("featureType: %s\\n", featureTypeStr.c\_str());

origWinSize.width = (int)root\[CC\_WIDTH\];

origWinSize.height = (int)root\[CC\_HEIGHT\];

CV\_Assert( origWinSize.height > 0 && origWinSize.width > 0 );

isStumpBased = (int)(root\[CC\_STAGE\_PARAMS\]\[CC\_MAX\_DEPTH\]) == 1 ? true : false;

printf("stumpBased: %d\\n", isStumpBased);

// load feature params

FileNode fn = root\[CC\_FEATURE\_PARAMS\];

if( fn.empty() )

return false;

// LBP的maxCatCount=256，其余特征都等于0

ncategories = fn\[CC\_MAX\_CAT\_COUNT\]; // ncategories=256/0

int subsetSize = (ncategories + 31)/32,// subsetSize=8/0 // 强制类型转换取整，不是四舍五入

nodeStep = 3 + ( ncategories>0 ? subsetSize : 1 ); //每组数值个数，nodeStep=11/4

printf("subsetSize: %d, nodeStep: %d\\n", subsetSize, nodeStep);

// load stages

fn = root\[CC\_STAGES\];

if( fn.empty() )

return false;

stages.reserve(fn.size());

classifiers.clear();

nodes.clear();

FileNodeIterator it = fn.begin(), it\_end = fn.end();

for( int si = 0; it != it\_end; si++, ++it )

FileNode fns = \*it;

Stage stage;

stage.threshold = (float)fns\[CC\_STAGE\_THRESHOLD\] - THRESHOLD\_EPS;

fns = fns\[CC\_WEAK\_CLASSIFIERS\];

if(fns.empty())

return false;

stage.ntrees = (int)fns.size();

stage.first = (int)classifiers.size();

printf("stage %d: ntrees: %d, first: %d\\n", si, stage.ntrees, stage.first);

stages.push\_back(stage);

classifiers.reserve(stages\[si\].first + stages\[si\].ntrees);

FileNodeIterator it1 = fns.begin(), it1\_end = fns.end();

for( ; it1 != it1\_end; ++it1 ) // weak trees

FileNode fnw = \*it1;

FileNode internalNodes = fnw\[CC\_INTERNAL\_NODES\];

FileNode leafValues = fnw\[CC\_LEAF\_VALUES\];

if( internalNodes.empty() || leafValues.empty() )

return false;

// 弱分类器中的节点

DTree tree;

tree.nodeCount = (int)internalNodes.size()/nodeStep;

classifiers.push\_back(tree);

nodes.reserve(nodes.size() + tree.nodeCount);

leaves.reserve(leaves.size() + leafValues.size());

if( subsetSize > 0 ) // 针对LBP

subsets.reserve(subsets.size() + tree.nodeCount\*subsetSize);

FileNodeIterator internalNodesIter = internalNodes.begin(), internalNodesEnd = internalNodes.end();

// 保存每一个node

for( ; internalNodesIter != internalNodesEnd; ) // nodes

DTreeNode node;

node.left = (int)\*internalNodesIter; ++internalNodesIter;

node.right = (int)\*internalNodesIter; ++internalNodesIter;

node.featureIdx = (int)\*internalNodesIter; ++internalNodesIter;

// 针对LBP，获取8个数值

if( subsetSize > 0 )

for( int j = 0; j < subsetSize; j++, ++internalNodesIter )

subsets.push\_back((int)\*internalNodesIter);

node.threshold = 0.f;

else

node.threshold = (float)\*internalNodesIter; ++internalNodesIter;

nodes.push\_back(node);

// 保存叶子节点

internalNodesIter = leafValues.begin(), internalNodesEnd = leafValues.end();

for( ; internalNodesIter != internalNodesEnd; ++internalNodesIter ) // leaves

leaves.push\_back((float)\*internalNodesIter);

return true;

// 读取stages与features

bool CascadeClassifier::read(const FileNode& root)

// load stages

if( !data.read(root) )

return false;

// load features，参考 《图像特征->XXX特征之OpenCV-估计》

featureEvaluator = FeatureEvaluator::create(data.featureType);

FileNode fn = root\[CC\_FEATURES\];

if( fn.empty() )

return false;

return featureEvaluator->read(fn);

// 外部调用的函数

bool CascadeClassifier::load(const string& filename)

oldCascade.release();

data = Data();

featureEvaluator.release();

// 读取新格式的分类器

FileStorage fs(filename, FileStorage::READ);

if( !fs.isOpened() )

return false;

if( read(fs.getFirstTopLevelNode()) )

return true;

fs.release();

// 读取新格式失败则读取旧格式的分类器

oldCascade = Ptr<CvHaarClassifierCascade>((CvHaarClassifierCascade\*)cvLoad(filename.c\_str(), 0, 0, 0));

return !oldCascade.empty();

2) 调用detectMultiScale函数进行多尺度检测，该函数可以使用老分类器进行检测也可以使用新分类器进行检测

2.1 如果load的为旧格式的分类器则使用cvHaarDetectObjectsForROC进行检测，flags参数只对旧格式的分类器有效，参考《OpenCV函数解读之cvHaarDetectObjects》

if( isOldFormatCascade() )

MemStorage storage(cvCreateMemStorage(0));

CvMat \_image = image;

CvSeq\* \_objects = cvHaarDetectObjectsForROC( &\_image, oldCascade, storage, rejectLevels, levelWeights, scaleFactor,

minNeighbors, flags, minObjectSize, maxObjectSize, outputRejectLevels );

vector<CvAvgComp> vecAvgComp;

Seq<CvAvgComp>(\_objects).copyTo(vecAvgComp);

objects.resize(vecAvgComp.size());

std::transform(vecAvgComp.begin(), vecAvgComp.end(), objects.begin(), getRect());

return;

2.2 新格式分类器多尺度检测

for( double factor = 1; ; factor \*= scaleFactor )

Size originalWindowSize = getOriginalWindowSize();

Size windowSize( cvRound(originalWindowSize.width\*factor), cvRound(originalWindowSize.height\*factor) );

Size scaledImageSize( cvRound( grayImage.cols/factor ), cvRound( grayImage.rows/factor ) );

Size processingRectSize( scaledImageSize.width-originalWindowSize.width + 1, scaledImageSize.height-originalWindowSize.height + 1 );

if( processingRectSize.width <= 0 || processingRectSize.height <= 0 )

break;

if( windowSize.width > maxObjectSize.width || windowSize.height > maxObjectSize.height )

break;

if( windowSize.width < minObjectSize.width || windowSize.height < minObjectSize.height )

continue;

// 缩放图像

Mat scaledImage( scaledImageSize, CV\_8U, imageBuffer.data );

resize( grayImage, scaledImage, scaledImageSize, 0, 0, CV\_INTER\_LINEAR );

// 计算步长

int yStep;

if( getFeatureType() == cv::FeatureEvaluator::HOG )

yStep = 4;

else

yStep = factor > 2. ? 1 : 2;

// 并行个数以及大小，按照列进行并行处理

int stripCount, stripSize;

// 是否采用TBB进行优化

\#ifdef HAVE\_TBB

const int PTS\_PER\_THREAD = 1000;

stripCount = ((processingRectSize.width/yStep)\*(processingRectSize.height + yStep-1)/yStep + PTS\_PER\_THREAD/2)/PTS\_PER\_THREAD;

stripCount = std::min(std::max(stripCount, 1), 100);

stripSize = (((processingRectSize.height + stripCount - 1)/stripCount + yStep-1)/yStep)\*yStep;

\#else

stripCount = 1;

stripSize = processingRectSize.height;

\#endif

// 调用单尺度检测函数进行检测

if( !detectSingleScale( scaledImage, stripCount, processingRectSize, stripSize, yStep, factor, candidates,

rejectLevels, levelWeights, outputRejectLevels ) )

break;

2.3 合并检测结果

objects.resize(candidates.size());

std::copy(candidates.begin(), candidates.end(), objects.begin());

if( outputRejectLevels )

groupRectangles( objects, rejectLevels, levelWeights, minNeighbors, GROUP\_EPS );

else

groupRectangles( objects, minNeighbors, GROUP\_EPS );

单尺度检测函数流程

2.2.1 根据所载入的特征计算积分图、积分直方图等

// 计算当前图像的积分图，参考《图像特征->XXX特征之OpenCV-估计》

if( !featureEvaluator->setImage( image, data.origWinSize ) )

return false;

2.2.2 根据是否输出检测级数并行目标检测

vector<Rect> candidatesVector;

vector<int> rejectLevels;

vector<double> levelWeights;

Mutex mtx;

if( outputRejectLevels )

parallel\_for\_(Range(0, stripCount), CascadeClassifierInvoker( \*this, processingRectSize, stripSize, yStep, factor,

candidatesVector, rejectLevels, levelWeights, true, currentMask, &mtx));

levels.insert( levels.end(), rejectLevels.begin(), rejectLevels.end() );

weights.insert( weights.end(), levelWeights.begin(), levelWeights.end() );

else

parallel\_for\_(Range(0, stripCount), CascadeClassifierInvoker( \*this, processingRectSize, stripSize, yStep, factor,

candidatesVector, rejectLevels, levelWeights, false, currentMask, &mtx));

candidates.insert( candidates.end(), candidatesVector.begin(), candidatesVector.end() );

CascadeClassifierInvoker函数的operator()实现具体的检测过程

// 对于没有并行时range.start=0,range.end=1

void operator()(const Range& range) const

Ptr<FeatureEvaluator> evaluator = classifier->featureEvaluator->clone();

Size winSize(cvRound(classifier->data.origWinSize.width \* scalingFactor),

cvRound(classifier->data.origWinSize.height \* scalingFactor));

// strip=processingRectSize.height

int y1 = range.start \* stripSize; // 0

int y2 = min(range.end \* stripSize, processingRectSize.height); // processSizeRect.height也就是可以处理的高度，已经减去窗口高度

for( int y = y1; y < y2; y += yStep )

for( int x = 0; x < processingRectSize.width; x += yStep )

if ( (!mask.empty()) && (mask.at<uchar>(Point(x,y))==0)) \{

continue;

// result=1表示通过了所有的分类器 <=0表示失败的级数

// gypWeight表示返回的阈值

double gypWeight;

int result = classifier->runAt(evaluator, Point(x, y), gypWeight);

// 输出LOG

\#if defined (LOG\_CASCADE\_STATISTIC)

logger.setPoint(Point(x, y), result);

\#endif

// 当返回级数的时候可以最后三个分类器不通过

if( rejectLevels )

if( result == 1 )

result = -(int)classifier->data.stages.size();

// 可以最后三个分类器不通过

if( classifier->data.stages.size() + result < 4 )

mtx->lock();

rectangles->push\_back(Rect(cvRound(x\*scalingFactor), cvRound(y\*scalingFactor), winSize.width, winSize.height));

rejectLevels->push\_back(-result);

levelWeights->push\_back(gypWeight);

mtx->unlock();

// 不返回级数的时候通过所有的分类器才保存起来

else if( result > 0 )

mtx->lock();

rectangles->push\_back(Rect(cvRound(x\*scalingFactor), cvRound(y\*scalingFactor),

winSize.width, winSize.height));

mtx->unlock();

// 如果一级都没有通过那么加大搜索步长

if( result == 0 )

x += yStep;

runAt函数实现某一检测窗口的检测

int CascadeClassifier::runAt( Ptr<FeatureEvaluator>& evaluator, Point pt, double& weight )

CV\_Assert( oldCascade.empty() );

assert( data.featureType == FeatureEvaluator::HAAR ||

data.featureType == FeatureEvaluator::LBP ||

data.featureType == FeatureEvaluator::HOG );

// 设置某一点处的特征，参考 《图像特征->XXX特征之OpenCV-估计》

if( !evaluator->setWindow(pt) )

return -1;

// 如果为树桩，没有树枝

if( data.isStumpBased )

if( data.featureType == FeatureEvaluator::HAAR )

return predictOrderedStump<HaarEvaluator>( \*this, evaluator, weight );

else if( data.featureType == FeatureEvaluator::LBP )

return predictCategoricalStump<LBPEvaluator>( \*this, evaluator, weight );

else if( data.featureType == FeatureEvaluator::HOG )

return predictOrderedStump<HOGEvaluator>( \*this, evaluator, weight );

else

return -2;

// 每个弱分类器不止一个node

else

if( data.featureType == FeatureEvaluator::HAAR )

return predictOrdered<HaarEvaluator>( \*this, evaluator, weight );

else if( data.featureType == FeatureEvaluator::LBP )

return predictCategorical<LBPEvaluator>( \*this, evaluator, weight );

else if( data.featureType == FeatureEvaluator::HOG )

return predictOrdered<HOGEvaluator>( \*this, evaluator, weight );

else

return -2;

predictOrdered\*函数实现判断当前检测窗口的判断

// HAAR与HOG特征的多node检测

template<class FEval>

inline int predictOrdered( CascadeClassifier& cascade, Ptr<FeatureEvaluator> &\_featureEvaluator, double& sum )

int nstages = (int)cascade.data.stages.size();

int nodeOfs = 0, leafOfs = 0;

FEval& featureEvaluator = (FEval&)\*\_featureEvaluator;

float\* cascadeLeaves = &cascade.data.leaves\[0\];

CascadeClassifier::Data::DTreeNode\* cascadeNodes = &cascade.data.nodes\[0\];

CascadeClassifier::Data::DTree\* cascadeWeaks = &cascade.data.classifiers\[0\];

CascadeClassifier::Data::Stage\* cascadeStages = &cascade.data.stages\[0\];

// 遍历每个强分类器

for( int si = 0; si < nstages; si++ )

CascadeClassifier::Data::Stage& stage = cascadeStages\[si\];

int wi, ntrees = stage.ntrees;

sum = 0;

// 遍历每个弱分类器

for( wi = 0; wi < ntrees; wi++ )

CascadeClassifier::Data::DTree& weak = cascadeWeaks\[stage.first + wi\];

int idx = 0, root = nodeOfs;

// 遍历每个节点

// 选择一个node：root和idx初始化为0，即第一个node

CascadeClassifier::Data::DTreeNode& node = cascadeNodes\[root + idx\];

// 计算当前node特征池编号下的特征值

double val = featureEvaluator(node.featureIdx);

// 如果val小于node阈值则选择左子树，否则选择右子树

idx = val < node.threshold ? node.left : node.right;

\}  while( idx > 0 );

// 累加最终的叶子节点

sum += cascadeLeaves\[leafOfs - idx\];

nodeOfs += weak.nodeCount;

leafOfs += weak.nodeCount + 1;

// 判断所有叶子节点累加和是否小于强分类器阈值，小于强分类器阈值则失败

if( sum < stage.threshold )

return -si;

// 通过了所有的强分类器返回1，否则返回失败的分类器

return 1;

// LBP特征的多node检测

template<class FEval>

inline int predictCategorical( CascadeClassifier& cascade, Ptr<FeatureEvaluator> &\_featureEvaluator, double& sum )

int nstages = (int)cascade.data.stages.size();

int nodeOfs = 0, leafOfs = 0;

FEval& featureEvaluator = (FEval&)\*\_featureEvaluator;

size\_t subsetSize = (cascade.data.ncategories + 31)/32;

int\* cascadeSubsets = &cascade.data.subsets\[0\];

float\* cascadeLeaves = &cascade.data.leaves\[0\];

CascadeClassifier::Data::DTreeNode\* cascadeNodes = &cascade.data.nodes\[0\];

CascadeClassifier::Data::DTree\* cascadeWeaks = &cascade.data.classifiers\[0\];

CascadeClassifier::Data::Stage\* cascadeStages = &cascade.data.stages\[0\];

for(int si = 0; si < nstages; si++ )

CascadeClassifier::Data::Stage& stage = cascadeStages\[si\];

int wi, ntrees = stage.ntrees;

sum = 0;

for( wi = 0; wi < ntrees; wi++ )

CascadeClassifier::Data::DTree& weak = cascadeWeaks\[stage.first + wi\];

int idx = 0, root = nodeOfs;

CascadeClassifier::Data::DTreeNode& node = cascadeNodes\[root + idx\];

// c为0-255之间的数

int c = featureEvaluator(node.featureIdx);

// 获取当前node的subset头位置

const int\* subset = &cascadeSubsets\[(root + idx)\*subsetSize\]; // LBP:subsetSize=8

// 判断选择左子树还是右子树

idx = (subset\[c>>5\] & (1 << (c & 31))) ? node.left : node.right;

// c>>5表示将c右移5位，选择高3位，0-7之间

// c&31表示低5位，1<<(c&31)选择低5位后左移1位

// 将上面的数按位与，如果最后结果不为0表示选择左子树，否则选择右子树

while( idx > 0 );

sum += cascadeLeaves\[leafOfs - idx\];

nodeOfs += weak.nodeCount;

leafOfs += weak.nodeCount + 1;

if( sum < stage.threshold )

return -si;

return 1;

// HAAR与HOG特征的单node检测

template<class FEval>

inline int predictOrderedStump( CascadeClassifier& cascade, Ptr<FeatureEvaluator> &\_featureEvaluator, double& sum )

int nodeOfs = 0, leafOfs = 0;

FEval& featureEvaluator = (FEval&)\*\_featureEvaluator;

float\* cascadeLeaves = &cascade.data.leaves\[0\];

CascadeClassifier::Data::DTreeNode\* cascadeNodes = &cascade.data.nodes\[0\];

CascadeClassifier::Data::Stage\* cascadeStages = &cascade.data.stages\[0\];

int nstages = (int)cascade.data.stages.size();

// 遍历每个强分类器

for( int stageIdx = 0; stageIdx < nstages; stageIdx++ )

CascadeClassifier::Data::Stage& stage = cascadeStages\[stageIdx\];

sum = 0.0;

int ntrees = stage.ntrees;

// 遍历每个弱分类器

for( int i = 0; i < ntrees; i++, nodeOfs++, leafOfs+= 2 )

CascadeClassifier::Data::DTreeNode& node = cascadeNodes\[nodeOfs\];

double value = featureEvaluator(node.featureIdx);

sum += cascadeLeaves\[ value < node.threshold ? leafOfs : leafOfs + 1 \];

if( sum < stage.threshold )

return -stageIdx;

return 1;

// LBP特征的单node检测

template<class FEval>

inline int predictCategoricalStump( CascadeClassifier& cascade, Ptr<FeatureEvaluator> &\_featureEvaluator, double& sum )

int nstages = (int)cascade.data.stages.size();

int nodeOfs = 0, leafOfs = 0;

FEval& featureEvaluator = (FEval&)\*\_featureEvaluator;

size\_t subsetSize = (cascade.data.ncategories + 31)/32;

int\* cascadeSubsets = &cascade.data.subsets\[0\];

float\* cascadeLeaves = &cascade.data.leaves\[0\];

CascadeClassifier::Data::DTreeNode\* cascadeNodes = &cascade.data.nodes\[0\];

CascadeClassifier::Data::Stage\* cascadeStages = &cascade.data.stages\[0\];

\#ifdef HAVE\_TEGRA\_OPTIMIZATION

float tmp = 0; // float accumulator -- float operations are quicker

\#endif

for( int si = 0; si < nstages; si++ )

CascadeClassifier::Data::Stage& stage = cascadeStages\[si\];

int wi, ntrees = stage.ntrees;

\#ifdef HAVE\_TEGRA\_OPTIMIZATION

tmp = 0;

\#else

sum = 0;

\#endif

for( wi = 0; wi < ntrees; wi++ )

CascadeClassifier::Data::DTreeNode& node = cascadeNodes\[nodeOfs\];

int c = featureEvaluator(node.featureIdx);

const int\* subset = &cascadeSubsets\[nodeOfs\*subsetSize\];

\#ifdef HAVE\_TEGRA\_OPTIMIZATION

tmp += cascadeLeaves\[ subset\[c>>5\] & (1 << (c & 31)) ? leafOfs : leafOfs+1\];

\#else

sum += cascadeLeaves\[ subset\[c>>5\] & (1 << (c & 31)) ? leafOfs : leafOfs+1\];

\#endif

nodeOfs++;

leafOfs += 2;

\#ifdef HAVE\_TEGRA\_OPTIMIZATION

if( tmp < stage.threshold ) \{

sum = (double)tmp;

return -si;

\#else

if( sum < stage.threshold )

return -si;

\#endif

\#ifdef HAVE\_TEGRA\_OPTIMIZATION

sum = (double)tmp;

\#endif

return 1;

OpenCV中CascadeClassifier类实现多尺度检测源码解析

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