【特征提取】MultiBlock-LBP特征

MB-LBP特征，注意区分是Multi-block LBP还是MultiScale Block LBP,区别是是否使用了多尺度方法。其中Multiscale Block LBP，来源于论文，中科院的人发明的，opencv源码在Traincascade级联目标训练检测中的LBP特征使用的就是MultiScale Block LBP。 

 generateFeatures

void CvLBPEvaluator::generateFeatures()
{
    int offset = winSize.width + 1;
    for( int x = 0; x < winSize.width; x++ )
        for( int y = 0; y < winSize.height; y++ )
            for( int w = 1; w <= winSize.width / 3; w++ )
                for( int h = 1; h <= winSize.height / 3; h++ )
                    if ( (x+3*w <= winSize.width) && (y+3*h <= winSize.height) )
                        features.push_back( Feature(offset, x, y, w, h ) );
    numFeatures = (int)features.size();
}

Feature

CvLBPEvaluator::Feature::Feature( int offset, int x, int y, int _blockWidth, int _blockHeight )
{
    Rect tr = rect = cvRect(x, y, _blockWidth, _blockHeight);
    CV_SUM_OFFSETS( p[0], p[1], p[4], p[5], tr, offset )
    tr.x += 2*rect.width;
    CV_SUM_OFFSETS( p[2], p[3], p[6], p[7], tr, offset )
    tr.y +=2*rect.height;
    CV_SUM_OFFSETS( p[10], p[11], p[14], p[15], tr, offset )
    tr.x -= 2*rect.width;
    CV_SUM_OFFSETS( p[8], p[9], p[12], p[13], tr, offset )
}

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