numpy批量iou

  

   

    

     

    
    

     

      import random
     
    
   

    

     

    
    

     

      import time
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      import numpy as np
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      """
     
    
   

    

     

    
    

     

      #单个iou
     
    
   

    

     

    
    

     

      """
     
    
   

    

     

    
    

     

      def compute_iou2(rec1, rec2):
     
    
   

    

     

    
    

     

          areas1 = (rec1[3] - rec1[1]) * (rec1[2] - rec1[0])
     
    
   

    

     

    
    

     

          areas2 = (rec2[3] - rec2[1]) * (rec2[2] - rec2[0])
     
    
   

    

     

    
    

     

          left = max(rec1[1],rec2[1])
     
    
   

    

     

    
    

     

          right = min(rec1[3],rec2[3])
     
    
   

    

     

    
    

     

          top = max(rec1[0], rec2[0])
     
    
   

    

     

    
    

     

          bottom = min(rec1[2], rec2[2])
     
    
   

    

     

    
    

     

          w = max(0, right-left)
     
    
   

    

     

    
    

     

          h = max(0, bottom-top)
     
    
   

    

     

    
    

     
    return w*h/(areas2+areas1-w*h)
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      def Ious(bbox, gt):
     
    
   

    

     

    
    

     
    assert bbox.shape[0]>0, 'bbox len must>0'
     
    
   

    

     

    
    

     
    assert gt.shape[0]>0, 'bbox len must>0'
     
    
   

    

     

    
    

     
    """
     
    
   

    

     

    
    

     

       :param bbox: (n, 4)
     
    
   

    

     

    
    

     

       :param gt: (m, 4)
     
    
   

    

     

    
    

     

       :return: (n, m)
     
    
   

    

     

    
    

     

       numpy 广播机制 从后向前对齐。 维度为1 的可以重复等价为任意维度
     
    
   

    

     

    
    

     

       eg: (4,3,2) (3,2) (3,2)会扩充为(4,3,2)
     
    
   

    

     

    
    

     

       (4,1,2) (3,2) (4,1,2) 扩充为(4, 3, 2) (3, 2)扩充为(4, 3,2) 扩充的方法为重复
     
    
   

    

     

    
    

     

       广播会在numpy的函数 如sum, maximun等函数中进行
     
    
   

    

     

    
    

     

       """
     
    
   

    

     

    
    

     

          lt = np.maximum(bbox[:, None, :2], gt[:, :2])  # left_top (x, y)
     
    
   

    

     

    
    

     

          rb = np.minimum(bbox[:, None, 2:], gt[:, 2:])  # right_bottom (x, y)
     
    
   

    

     

    
    

     

          wh = np.maximum(rb - lt , 0)                # inter_area (w, h)
     
    
   

    

     

    
    

     

          inter_areas = wh[:, :, 0] * wh[:, :, 1]        # shape: (n, m)
     
    
   

    

     

    
    

     

          box_areas = (bbox[:, 2] - bbox[:, 0] ) * (bbox[:, 3] - bbox[:, 1] )
     
    
   

    

     

    
    

     

          gt_areas = (gt[:, 2] - gt[:, 0] ) * (gt[:, 3] - gt[:, 1] )
     
    
   

    

     

    
    

     

          IoU = inter_areas / (box_areas[:, None] + gt_areas - inter_areas)
     
    
   

    

     

    
    

     
    return IoU
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

      if __name__ == '__main__':
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

          data_a=[[1,1,3,3]]
     
    
   

    

     

    
    

     

          data_a=[]
     
    
   

    

     

    
    

     

          data_b=[[1,1,2,2],[2,2,4,4],[1,1,3,3],[3,3,4,4]]
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

          ious= Ious(np.array(data_a), np.array(data_b))
     
    
   

    

     

    
    

     
    print('IoU res')
     
    
   

    

     

    
    

     
    print(ious.max())
     
    
   

    

     

    
    

     
 
     
    
   

    

     

    
    

     

          ious=[]
     
    
   

    

     

    
    

     

          start = time.time()
     
    
   

    

     

    
    

     
    for data in data_b:
     
    
   

    

     

    
    

     

              iou = compute_iou2(data_a[0], data)
     
    
   

    

     

    
    

     

              ious.append(iou)
     
    
   

    

     

    
    

     
    print('compute_iou2 res')
     
    
   

    

     

    
    

     
    print(ious)
     
    
  
 

文章来源: blog.csdn.net，作者：AI视觉网奇，版权归原作者所有，如需转载，请联系作者。

原文链接：blog.csdn.net/jacke121/article/details/121526711