当我们想要提取Region时，图像处理后，往往存在几个类似的Region，此时，需要根据Region的一些特殊特征，来选择指定的Region。
求Region指定特征值：region_features(Regions : : Features : Value)
根据特征值选择区域：select_shape(Regions : SelectedRegions : Features, Operation, Min, Max : )
Region特征一览：
| 特征 | 英 | 译 | 备注 |
| area | Area of the object | 对象的面积 | |
| row | Row index of the center | 中心点的行坐标 | |
| column | Column index of the center | 中心点的列坐标 | |
| width | Width of the region | 区域的宽度 | |
| height | Height of the region | 区域的高度 | |
| row1 | Row index of upper left corner | 左上角行坐标 | |
| column1 | Column index of upper left corner | 左上角列坐标 | |
| row2 | Row index of lower right corner | 右下角行坐标 | |
| column2 | Column index of lower right corner | 右下角列坐标 | |
| circularity | Circularity | 圆度 | 0~1 |
| compactness | Compactness | 紧密度 | 0~1 |
| contlength | Total length of contour | 轮廓线总长 | |
| convexity | Convexity | 凸性 | |
| rectangularity | Rectangularity | 矩形度 | 0~1 |
| ra | Main radius of the equivalent ellipse | 等效椭圆长轴半径长度 | |
| rb | Secondary radius of the equivalent ellipse | 等效椭圆短轴半径长度 | |
| phi | Orientation of the equivalent ellipse | 等效椭圆方向 | |
| anisometry | Anisometry | 椭圆参数，Ra/Rb长轴与短轴的比值 | |
| bulkiness | Bulkiness | 椭圆参数，蓬松度π*Ra*Rb/A | |
| struct_factor | Structur Factor | 椭圆参数，Anisometry*Bulkiness-1 | |
| outer_radius | Radius of smallest surrounding circle | 最小外接圆半径 | |
| inner_radius | Radius of largest inner circle | 最大内接圆半径 | |
| inner_width | Width of the largest axis-parallel rectangle that fits into the region | 最大内接矩形宽度 | |
| inner_height | Height of the largest axis-parallel rectangle that fits into the region | 最大内接矩形高度 | |
| dist_mean | Mean distance from the region border to the center | 区域边界到中心的平均距离 | |
| dist_deviation | Deviation of the distance from the region border from the center | 区域边界到中心距离的偏差 | |
| roundness | Roundness | 圆度，与circularity计算方法不同 | |
| num_sides | Number of polygon sides | 多边形边数 | |
| connect_num | Number of connection components | 连通数 | |
| holes_num | Number of holes | 区域内洞数 | |
| area_holes | Area of the holes of the object | 所有洞的面积 | |
| max_diameter | Maximum diameter of the region | 最大直径 | |
| orientation | Orientation of the region | 区域方向 | |
| euler_number | Euler number | 欧拉数，即连通数和洞数的差 | |
| rect2_phi | Orientation of the smallest surrounding rectangle | 最小外接矩形的方向 | |
| rect2_len1 | Half the length of the smallest surrounding rectangle | 最小外接矩形长度的一半？？ | smallest_rectangle2 |
| rect2_len2 | Half the width of the smallest surrounding rectangle | 最小外接矩形宽度的一半 | |
| moments_m11 | Geometric moments of the region | 几何矩 | |
| moments_m20 | Geometric moments of the region | 几何矩 | |
| moments_m02 | Geometric moments of the region | 几何矩 | |
| moments_ia | Geometric moments of the region | 几何矩 | |
| moments_ib | Geometric moments of the region | 几何矩 | |
| moments_m11_invar | Geometric moments of the region | 几何矩 | |
| moments_m20_invar | Geometric moments of the region | 几何矩 | |
| moments_m02_invar | Geometric moments of the region | 几何矩 | |
| moments_phi1 | Geometric moments of the region | 几何矩 | |
| moments_phi2 | Geometric moments of the region | 几何矩 | |
| moments_m21 | Geometric moments of the region | 几何矩 | |
| moments_m12 | Geometric moments of the region | 几何矩 | |
| moments_m03 | Geometric moments of the region | 几何矩 | |
| moments_m30 | Geometric moments of the region | 几何矩 | |
| moments_m21_invar | Geometric moments of the region | 几何矩 | |
| moments_m12_invar | Geometric moments of the region | 几何矩 | |
| moments_m03_invar | Geometric moments of the region | 几何矩 | |
| moments_m30_invar | Geometric moments of the region | 几何矩 | |
| moments_i1 | Geometric moments of the region | 几何矩 | |
| moments_i2 | Geometric moments of the region | 几何矩 | |
| moments_i3 | Geometric moments of the region | 几何矩 | |
| moments_i4 | Geometric moments of the region | 几何矩 | |
| moments_psi1 | Geometric moments of the region | 几何矩 | |
| moments_psi2 | Geometric moments of the region | 几何矩 | |
| moments_psi3 | Geometric moments of the region | 几何矩 | |
| moments_psi4 | Geometric moments of the region | 几何矩 |