opencv通过拉伸关键点对齐两个图像

Question

我有两张照片

图像1（对象）：

没有标记关键点的原始图像：

图2为白色图片（500x500）

在图1和图2中，我标记了关键点。我想按关键点对齐图像2上的图像1。因此，目标是使两个关键点与拉伸、缩放和变换图像重叠2。

这是我的关键点（csv文件）。图像1中的图像1和图像2的坐标是x和y。

object1_x,object1_y,image_x,image_y
0,0,80,137
286,0,409,42
286,198,416,390
174,198,331,384
158,116,291,119
0,97,111,311

如何使用opencv和python实现这一点？因此，结果图像应如下所示（没有红点，红点仅用于演示关键点）：

Answer 1

从第一组关键点提取3个索引集，当从两组关键点索引时，这些关键点将形成三角形。使用索引，我们可以从两组关键点获得相应的三角形，从而可以逐个三角形构建扭曲图像三角形（有关更多详细信息，请参阅使用OpenCV将一个三角形扭曲到另一个三角形）：

image1.png（附加点）：

image2.png（附加点）：

结果（有加分）

import cv2
import numpy as np

def triangles(points):
    points = np.where(points, points, 1)
    subdiv = cv2.Subdiv2D((*points.min(0), *points.max(0)))
    subdiv.insert(list(points))
    for pts in subdiv.getTriangleList().reshape(-1, 3, 2):
        yield [np.where(np.all(points == pt, 1))[0][0] for pt in pts]

def crop(img, pts):
    x, y, w, h = cv2.boundingRect(pts)
    img_cropped = img[y: y + h, x: x + w]
    pts[:, 0] -= x
    pts[:, 1] -= y
    return img_cropped, pts

def warp(img1, img2, pts1, pts2): 
    for indices in triangles(pts1):
        img1_cropped, triangle1 = crop(img1, pts1[indices])
        img2_cropped, triangle2 = crop(img2, pts2[indices])
        transform = cv2.getAffineTransform(np.float32(triangle1), np.float32(triangle2))
        img2_warped = cv2.warpAffine(img1_cropped, transform, img2_cropped.shape[:2][::-1], None, cv2.INTER_LINEAR, cv2.BORDER_REFLECT_101)
        mask = np.zeros_like(img2_cropped)
        cv2.fillConvexPoly(mask, np.int32(triangle2), (1, 1, 1), 16, 0)
        img2_cropped *= 1 - mask
        img2_cropped += img2_warped * mask

img1 = cv2.imread("image1.png")
img2 = cv2.imread("image2.png")

pts1 = np.array([[0, 0], [286, 0], [286, 198], [174, 198], [158, 116], [0, 97]])
pts2 = np.array([[80, 37], [409, 42], [416, 390], [331, 384], [291, 119], [111, 311]])

warp(img1, img2, pts1, pts2)

for pt in pts2:
    cv2.circle(img2, tuple(pt), 15, (0, 0, 255), -1)

cv2.imshow("Original", img1)
cv2.imshow("Transformed", img2)
cv2.waitKey(0)
cv2.destroyAllWindows()

1. 导入必要的库：

import cv2
import numpy as np

def triangles(points):
    points = np.where(points, points, 1)
    subdiv = cv2.Subdiv2D((*points.min(0), *points.max(0)))
    subdiv.insert(list(points))
    for pts in subdiv.getTriangleList().reshape(-1, 3, 2):
        yield [np.where(np.all(points == pt, 1))[0][0] for pt in pts]

def crop(img, pts):
    x, y, w, h = cv2.boundingRect(pts)
    img_cropped = img[y: y + h, x: x + w]
    pts[:, 0] -= x
    pts[:, 1] -= y
    return img_cropped, pts

def warp(img1, img2, pts1, pts2): 
    for indices in triangles(pts1):
        img1_cropped, triangle1 = crop(img1, pts1[indices])
        img2_cropped, triangle2 = crop(img2, pts2[indices])
        transform = cv2.getAffineTransform(np.float32(triangle1), np.float32(triangle2))
        img2_warped = cv2.warpAffine(img1_cropped, transform, img2_cropped.shape[:2][::-1], None, cv2.INTER_LINEAR, cv2.BORDER_REFLECT_101)
        mask = np.zeros_like(img2_cropped)
        cv2.fillConvexPoly(mask, np.int32(triangle2), (1, 1, 1), 16, 0)
        img2_cropped *= 1 - mask
        img2_cropped += img2_warped * mask

img1 = cv2.imread("image1.png")
img2 = cv2.imread("image2.png")

pts1 = np.array([[0, 0], [286, 0], [286, 198], [174, 198], [158, 116], [0, 97]])
pts2 = np.array([[80, 37], [409, 42], [416, 390], [331, 384], [291, 119], [111, 311]])

warp(img1, img2, pts1, pts2)

for pt in pts2:
    cv2.circle(img2, tuple(pt), 15, (0, 0, 255), -1)

cv2.imshow("Original", img1)
cv2.imshow("Transformed", img2)
cv2.waitKey(0)
cv2.destroyAllWindows()