CAJ | 학술논문

针对常用的旋转投影车牌倾斜检测算法检测精度不高和计算量大的问题,提出一种基于投影坐标p次方差及粒子群的车牌倾斜检测方法.根据边缘点水平投影纵坐标值的最小p次方差准则确定车牌的倾斜角,以提高车牌倾斜检测精度;然后利用改进的带极值扰动简化粒子群算法寻找或直接计算最优倾斜角,以降低检测时间.通过实验研究了p取不同值时对车牌倾斜检测误差和运行时间的影响,并与Hough变换法、旋转投影法及主成分分析法进行了性能比较.结果表明:当p→∞时,文中方法检测精确度最高,而p=2时运算速度最快.该方法已成功地应用于的"智能停车场"系统中.
침대상용적선전투영차패경사검측산법검측정도불고화계산량대적문제,제출일충기우투영좌표p차방차급입자군적차패경사검측방법.근거변연점수평투영종좌표치적최소p차방차준칙학정차패적경사각,이제고차패경사검측정도;연후이용개진적대겁치우동간화입자군산법심조혹직접계산최우경사각,이강저검측시간.통과실험연구료p취불동치시대차패경사검측오차화운행시간적영향,병여Hough변환법、선전투영법급주성분분석법진행료성능비교.결과표명:당p→∞시,문중방법검측정학도최고,이p=2시운산속도최쾌.해방법이성공지응용우적"지능정차장"계통중.
The commonly used tilt detection algorithm for license plate based on rotation projection is time consuming besides its insufficiency of detection accuracy. In view of it, a new approach is presented based on the minimum p-th power variance of projection coordinates and particle swarm optimization. Firstly, to further improve detection accuracy, the tilt angle of the license plate is determined based on the minimum p-th power variance of vertical coordinates of the horizontally projected edge points. Then the optimal tilt angle is found by using the extremum disturbed and simple particle swarm optimization algorithm or calculated directly so as to reduce the detection time. Finally, the effects of different p values on the license plate tilt detection error and the running time are experimentally studied and the performance is compared with those of Hough transform method, rotation projection method and principal component analysis method. The experimental results show that, when p→∞, the proposed approach has the highest accuracy, while p=2, the computation is the fastest. The proposed approach has been successfully applied to our " Intelligent Parking" system.