1 图像对齐
std::for_each(ref_frame->seg_fts_.begin(), ref_frame->seg_fts_.end(), [&](plsvo::Feature* i){ LineFeat* seg = static_cast<LineFeat*>(i); total_length += seg->length; });
计算一帧线特征的累积长度
int max_num_seg_samples = std::ceil( total_length / patch_size_ );
计算得到线特征的最大数量
设置缓存结构以分配优化数据（残留物，jacobians等）
原文：https://www.cnblogs.com/feifanrensheng/p/10637895.html