使用python将Quickbird 影像作为参考影像,用二次多项式实现高景(SV1)影像的相对配准,配准使用对应的同名点分别在两个txt中,用一部分同名点用来拟合二次多项式并计算内精度,剩余同名点对计算外精度,并绘制同名点匹配的情况
时间: 2024-03-07 18:49:54 浏览: 89
好的,这是一个关于遥感影像配准的问题,需要用到Python的一些库和算法。首先,需要安装GDAL库,用于读取和处理遥感影像数据。然后,我们可以使用OpenCV库实现同名点的匹配和绘制。最后,可以使用Scipy库中的optimize函数拟合二次多项式,并计算内外精度。
以下是大致的代码框架:
```python
import cv2
import numpy as np
from osgeo import gdal
from scipy.optimize import curve_fit
def read_image(filename):
dataset = gdal.Open(filename)
image = dataset.ReadAsArray().astype(np.float32)
return image
def match_points(image1, image2, points1, points2):
# 使用SIFT算法进行特征点提取和匹配
sift = cv2.SIFT_create()
keypoints1, descriptors1 = sift.detectAndCompute(image1, None)
keypoints2, descriptors2 = sift.detectAndCompute(image2, None)
matcher = cv2.BFMatcher()
matches = matcher.knnMatch(descriptors1, descriptors2, k=2)
good_matches = []
for m, n in matches:
if m.distance < 0.75 * n.distance:
good_matches.append(m)
# 使用RANSAC算法计算变换矩阵
src_points = np.float32([keypoints1[m.queryIdx].pt for m in good_matches]).reshape(-1, 1, 2)
dst_points = np.float32([keypoints2[m.trainIdx].pt for m in good_matches]).reshape(-1, 1, 2)
M, mask = cv2.findHomography(src_points, dst_points, cv2.RANSAC, 5.0)
# 根据匹配点对筛选同名点
src_points = []
dst_points = []
for i in range(len(points1)):
x1, y1 = points1[i]
x2, y2 = points2[i]
src_point = np.array([x1, y1, 1])
dst_point = np.dot(M, src_point)
dst_point /= dst_point[2]
src_points.append([x1, y1])
dst_points.append([dst_point[0], dst_point[1]])
return np.array(src_points), np.array(dst_points)
def quadratic_function(x, a, b, c):
return a * x[0] ** 2 + b * x[1] ** 2 + c * x[0] * x[1]
def fit_quadratic_function(points):
# 使用Scipy库的optimize函数拟合二次多项式
x = points[:, :2].T
y = points[:, 2:].T
popt, pcov = curve_fit(quadratic_function, x, y)
return popt
def compute_accuracy(points, popt):
# 计算内外精度
x = points[:, :2].T
y = points[:, 2:].T
y_fit = quadratic_function(x, *popt)
residual = y - y_fit
RMSE = np.sqrt(np.mean(residual ** 2))
return RMSE
# 读取Quickbird影像和高景(SV1)影像
quickbird = read_image('quickbird.tif')
sv1 = read_image('sv1.tif')
# 读取同名点文件
points1 = np.loadtxt('points1.txt')
points2 = np.loadtxt('points2.txt')
# 进行同名点匹配
src_points, dst_points = match_points(quickbird, sv1, points1, points2)
# 将同名点坐标和像元值组成二维数组
points = np.hstack([src_points, dst_points])
# 使用一部分同名点拟合二次多项式,并计算内精度
n = len(points) // 2
popt = fit_quadratic_function(points[:n])
RMSE_internal = compute_accuracy(points[:n], popt)
# 使用剩余同名点计算外精度
RMSE_external = compute_accuracy(points[n:], popt)
# 绘制同名点匹配情况
img_match = cv2.drawMatches(quickbird, keypoints1, sv1, keypoints2, good_matches, None)
cv2.imshow('Matched points', img_match)
cv2.waitKey(0)
cv2.destroyAllWindows()
```
需要注意的是,这只是一个大致的代码框架,具体实现还需要根据实际情况进行调整和优化。
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