【opencv】指定宽或高按比例缩放图片 & 拼接图片

指定宽或高按比例缩放图片

import cv2

def resize_by_ratio(image, width=None, height=None, inter=cv2.INTER_AREA):
    img_new_size = None
    (h, w) = image.shape[:2] # 获得高度和宽度
    if width is None and height is None: # 如果输入的宽度和高度都为空
        return image # 直接返回原图
    if width is None: 
        h_ratio = height / float(h) # 输入高度 / 原始高度 得到比率
        img_new_size = (int(w * h_ratio), height) # 将宽度缩放同样的比例
    else:
        w_ratio = width / float(w)
        img_new_size = (width, int(h * w_ratio))
    resized = cv2.resize(image, img_new_size, interpolation=inter)
    return resized

# 绘图显示函数
def cv_show(img):
    cv2.imshow('name',img)
    cv2.waitKey(0) # 按任意键 终止窗口
    cv2.destroyAllWindows()

img = cv2.imread('img1.jpeg')
img = resize_by_ratio(img,width=300)
# cv_show(img)
cv2.imwrite('img2_new.jpg',img)

拼接图片

img1 = cv2.imread('start.png')
img2 = cv2.imread('record.png')
img3 = cv2.imread('end.png')
img = np.hstack((img1,img2,img3))
cv_show(img)