椭圆的拟合.doc

F=@(p,x)p(1)*x(:,1).^2+p(2)*x(:,1)+p(3)*x(:,2)+p(4)*x(:,2).^2+p(5); % 离散数据点 x=[2762 1792 2754 1786 2745 1781 2735 1775 2723 1769 2710 1764 2695 1758 2679 1753 2661 1747 2643 1742 2623 1737 2602 1732 2580 1727 2557 1722 2532 1717 2507 1713 2481 1708 2454 1704 2425 1700 2396 1696 2367 1692 2336 1688 2305 1684 2273 1681 2240 1677 2207 1674 2173 1671 2138 1668 2103 1665 2068 1663 2032 1660 1995 1658 1959 1655 1921 1653 1884 1651 1846 1650 1807 1648 1769 1646 1730 1645 1691 1644 1652 1643 1613 1642 1573 1641 1534 1640 1494 1640 1454 1640 1415 1639 1375 1639 1336 1640 1296 1640 1256 1640 1217 1641 1178 1641 1139 1642 1100 1643 1061 1644 1023 1646 985 1647 947 1649 910 1651 873 1652 836 1654 800 1657 764 1659 729 1661 694 1664 660 1667 626 1670 593 1673 561 1676 529 1679 499 1683 468 1686 439 1690 410 1694 383 1698 356 1702 330 1706 305 1711 281 1715 259 1720 237 1725 216 1730 197 1735 179 1740 162 1745 146 1750 132 1756 119 1761 107 1767 97 1773 89 1778 82 1784 76 1790 72 1796 70 1802 69 1808 70 1814 73 1821 77 1827 84 1833 92 1839 102 1845 113 1852 127 1858 143 1864 160 1870 179 1877 201 1883 224 1889 249 1895 276 1900 304 1906 335 1912 367 1917 401 1923 438 1928 475 1933 514 1938 555 1942 598 1947 642 1951 687 1955 734 1959 782 1963 832 1966 882 1970 933 1972 986 1975 1039 1977 1093 1979 1148 1981 1203 1983 1259 1984 1315 1985 1371 1985 1427 1986 1484 1986 1540 1985 1596 1985 1652 1984 1707 1983 1761 1981 1815 1980 1868 1978 1921 1975 1972 1973 2022 1970 2072 1967 2120 1963 2166 1960 2212 1956 2255 1952 2297 1948 2339 1943 2378 1938 2415 1934 2450 1929 2484 1923 2516 1918 2547 1913 2575 1907 2602 1901 2626 1896 2649 1890 2670 1884 2689 1878 2706 1872 2722 1866 2735 1859 2746 1853 2756 1847 2764 1841 2770 1835 2774 1828 2776 1822 2777 1816 2776 1810 2773 1804 2769 1798 ]; p0=[0.005 0.005 0.005 0.005 0.005]; warning off % 拟合系数，最小二乘方法 p=nlinfit(x,zeros(size(x,1),1),F,p0); plot(x(:,1),x(:,2),ro); hold on; xmin=min(x(:,1)); xmax=max(x(:,1)); ymin=min(x(:,2)); ymax=max(x(:,2)