图像随机裁剪

import cv2
import numpy as np
np.random.seed(0)
#IoU
def iou(a, b):
    area_a=(a[2]-a[0])*(a[3]-a[1])
    area_b=(b[2]-b[0])*(b[3]-b[1])
    iou_x1=np.maximum(a[0],b[0])
    iou_y1=np.maximum(a[1],b[1])
    iou_x2=np.minimum(a[2],b[2])
    iou_y2=np.minimum(a[3],b[3])
    #IoU宽度
    iou_w=iou_x2-iou_x1
    #IoU高度
    iou_h=iou_y2-iou_y1
    #IoU面积
    area_iou=iou_w*iou_h
    iou=area_iou/(area_a+area_b-area_iou)
    return iou
#图像裁剪
def crop_bbox(img,gt,Crop_N=200,L=60,th=0.5):
    H,W,C=img.shape
    for i in range(Crop_N):
        x1=np.random.randint(W-L)
        y1=np.random.randint(H-L)
        x2=x1+L
        y2=y1+L
        crop=np.array((x1,y1,x2,y2))
        _iou=iou(gt,crop)
        #标签
        if _iou>=th:
            cv.rectangle(img,(x1,y1),(x2,y2),(0,0,255),1)
            label=1
        else:
            cv.rectangle(img,(x1,y1),(x2,y2),(255,0,0),1)
            label=0
    return img
img=cv2.imread("C:/Users/xpp/Desktop/Lena.png")
cv2.imshow("original",img)
img1=img.copy()
gt=np.array((87,51,169,113),dtype=np.float32)
img=crop_bbox(img,gt,Crop_N=100,L=60,th=0.6)
cv2.rectangle(img,(gt[0],gt[1]),(gt[2],gt[3]),(0,255,0),1)
cv2.rectangle(img1,(gt[0],gt[1]),(gt[2],gt[3]),(0,255,0),1)
cv2.imshow("result01",img1)
cv2.imshow("result02",img)
cv2.imwrite("C:/Users/xpp/Desktop/result3.png",img)
cv2.waitKey(0)
cv2.destroyAllWindows()