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[求助]
请教如何用matlab识别出一张曲线图上最高点对应的X,Y轴坐标 已有14人参与
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对于一张jpg图（例如下图），没有原始的数据，对于图中曲线，如何用matlab识别出最高点对应的X,Y轴坐标呢？我有很多这样的图，所以能编出程序或写出代码自动识别就好了，然后将坐标输出，请问谁有什么想法或者谁会吗？ ref.jpg |
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【答案】应助回帖
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lqshn: 金币+1, ★有帮助 2015-06-16 13:15:36
lqshn: 金币+1, ★有帮助 2015-06-16 13:15:36
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试试泰勒公式， 渐近线， 高数课本里学过， 可以模拟各种曲线的坐标， 或者还有其他方法， 具体的记不清了。 这其实不仅是编程，更多的是对数学建模的理解和方法的选择， 你可以找个学数学的专业人士讨论一下， 肯定会有收获。 至于图像的扫描和像素的识别， 编程方面没有什么大的难度， 每个JPG 像素都是一个数值的形式储存的， 对像素颜色数值进行分析就是了（个人想法，没试过）。windows 或c++ 或java 都有自己的类库 专门做图像分析和处理的，是一些DLL 类库， 直接拿来用就是了。一下是一个java例程，图片处理的， Below is the syntax highlighted version of Picture.java from § Standard Libraries. Here is the Javadoc. /************************************************************************* * Compilation: javac Picture.java * Execution: java Picture imagename * * Data type for manipulating individual pixels of an image. The original * image can be read from a file in jpg, gif, or png format, or the * user can create a blank image of a given size. Includes methods for * displaying the image in a window on the screen or saving to a file. * * % java Picture mandrill.jpg * * Remarks * ------- * - pixel (x, y) is column x and row y, where (0, 0) is upper left * * - see also GrayPicture.java for a grayscale version * *************************************************************************/ import java.awt.Color; import java.awt.FileDialog; import java.awt.Toolkit; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException; import java.net.URL; import javax.imageio.ImageIO; import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; import javax.swing.KeyStroke; /** * This class provides methods for manipulating individual pixels of * an image. The original image can be read from a <tt>.jpg</tt>, <tt>.gif</tt>, * or <tt>.png</tt> file or the user can create a blank image of a given size. * This class includes methods for displaying the image in a window on * the screen or saving it to a file. * <p> * Pixel (<em>x</em>, <em>y</em>  is column <em>x</em> and row <em>y</em>.* By default, the origin (0, 0) is upper left, which is a common convention * in image processing. * The method <tt>setOriginLowerLeft()</tt> change the origin to the lower left. * <p> * For additional documentation, see * <a href="http://introcs.cs.princeton.edu/31datatype">Section 3.1</a> of * <i>Introduction to Programming in Java: An Interdisciplinary Approach</i> * by Robert Sedgewick and Kevin Wayne. * * @author Robert Sedgewick * @author Kevin Wayne */ public final class Picture implements ActionListener { private BufferedImage image; // the rasterized image private JFrame frame; // on-screen view private String filename; // name of file private boolean isOriginUpperLeft = true; // location of origin private final int width, height; // width and height /** * Initializes a blank <tt>width</tt>-by-<tt>height</tt> picture, with <tt>width</tt> columns * and <tt>height</tt> rows, where each pixel is black. */ public Picture(int width, int height) { if (width < 0) throw new IllegalArgumentException("width must be nonnegative" ;if (height < 0) throw new IllegalArgumentException("height must be nonnegative" ;this.width = width; this.height = height; image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // set to TYPE_INT_ARGB to support transparency filename = width + "-by-" + height; } /** * Initializes a new picture that is a deep copy of <tt>picture</tt>. */ public Picture(Picture picture) { width = picture.width(); height = picture.height(); image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); filename = picture.filename; for (int col = 0; col < width(); col++) for (int row = 0; row < height(); row++) image.setRGB(col, row, picture.get(col, row).getRGB()); } /** * Initializes a picture by reading in a .png, .gif, or .jpg from * the given filename or URL name. */ public Picture(String filename) { this.filename = filename; try { // try to read from file in working directory File file = new File(filename); if (file.isFile()) { image = ImageIO.read(file); } // now try to read from file in same directory as this .class file else { URL url = getClass().getResource(filename); if (url == null) { url = new URL(filename); } image = ImageIO.read(url); } width = image.getWidth(null); height = image.getHeight(null); } catch (IOException e) { // e.printStackTrace(); throw new RuntimeException("Could not open file: " + filename); } } /** * Initializes a picture by reading in a .png, .gif, or .jpg from a File. */ public Picture(File file) { try { image = ImageIO.read(file); } catch (IOException e) { e.printStackTrace(); throw new RuntimeException("Could not open file: " + file); } if (image == null) { throw new RuntimeException("Invalid image file: " + file); } width = image.getWidth(null); height = image.getHeight(null); filename = file.getName(); } /** * Returns a JLabel containing this picture, for embedding in a JPanel, * JFrame or other GUI widget. * @return the <tt>JLabel</tt> */ public JLabel getJLabel() { if (image == null) { return null; } // no image available ImageIcon icon = new ImageIcon(image); return new JLabel(icon); } /** * Sets the origin to be the upper left pixel. This is the default. */ public void setOriginUpperLeft() { isOriginUpperLeft = true; } /** * Sets the origin to be the lower left pixel. */ public void setOriginLowerLeft() { isOriginUpperLeft = false; } /** * Displays the picture in a window on the screen. */ public void show() { // create the GUI for viewing the image if needed if (frame == null) { frame = new JFrame(); JMenuBar menuBar = new JMenuBar(); JMenu menu = new JMenu("File" ;menuBar.add(menu); JMenuItem menuItem1 = new JMenuItem(" Save... " ;menuItem1.addActionListener(this); menuItem1.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S, Toolkit.getDefaultToolkit().getMenuShortcutKeyMask())); menu.add(menuItem1); frame.setJMenuBar(menuBar); frame.setContentPane(getJLabel()); // f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); frame.setTitle(filename); frame.setResizable(false); frame.pack(); frame.setVisible(true); } // draw frame.repaint(); } /** * Returns the height of the picture. * @return the height of the picture (in pixels) */ public int height() { return height; } /** * Returns the width of the picture. * @return the width of the picture (in pixels) */ public int width() { return width; } /** * Returns the color of pixel (<tt>col</tt>, <tt>row</tt> .* @return the color of pixel (<tt>col</tt>, <tt>row</tt> * @throws IndexOutOfBoundsException unless both 0 ≤ <tt>col</tt> < <tt>width</tt> * and 0 ≤ <tt>row</tt> < <tt>height</tt> */ public Color get(int col, int row) { if (col < 0 || col >= width()) throw new IndexOutOfBoundsException("col must be between 0 and " + (width()-1)); if (row < 0 || row >= height()) throw new IndexOutOfBoundsException("row must be between 0 and " + (height()-1)); if (isOriginUpperLeft) return new Color(image.getRGB(col, row)); else return new Color(image.getRGB(col, height - row - 1)); } /** * Sets the color of pixel (<tt>col</tt>, <tt>row</tt> to given color.* @throws IndexOutOfBoundsException unless both 0 ≤ <tt>col</tt> < <tt>width</tt> * and 0 ≤ <tt>row</tt> < <tt>height</tt> * @throws NullPointerException if <tt>color</tt> is <tt>null</tt> */ public void set(int col, int row, Color color) { if (col < 0 || col >= width()) throw new IndexOutOfBoundsException("col must be between 0 and " + (width()-1)); if (row < 0 || row >= height()) throw new IndexOutOfBoundsException("row must be between 0 and " + (height()-1)); if (color == null) throw new NullPointerException("can't set Color to null" ;if (isOriginUpperLeft) image.setRGB(col, row, color.getRGB()); else image.setRGB(col, height - row - 1, color.getRGB()); } /** * Is this Picture equal to obj? * @return <tt>true</tt> if this picture is the same dimension as <tt>obj</tt> * and if all pixels have the same color */ public boolean equals(Object obj) { if (obj == this) return true; if (obj == null) return false; if (obj.getClass() != this.getClass()) return false; Picture that = (Picture) obj; if (this.width() != that.width()) return false; if (this.height() != that.height()) return false; for (int col = 0; col < width(); col++) for (int row = 0; row < height(); row++) if (!this.get(col, row).equals(that.get(col, row))) return false; return true; } /** * Saves the picture to a file in a standard image format. * The filetype must be .png or .jpg. */ public void save(String name) { save(new File(name)); } /** * Saves the picture to a file in a standard image format. */ public void save(File file) { this.filename = file.getName(); if (frame != null) { frame.setTitle(filename); } String suffix = filename.substring(filename.lastIndexOf('.') + 1); suffix = suffix.toLowerCase(); if (suffix.equals("jpg" || suffix.equals("png") {try { ImageIO.write(image, suffix, file); } catch (IOException e) { e.printStackTrace(); } } else { System.out.println("Error: filename must end in .jpg or .png" ;} } /** * Opens a save dialog box when the user selects "Save As" from the menu. */ public void actionPerformed(ActionEvent e) { FileDialog chooser = new FileDialog(frame, "Use a .png or .jpg extension", FileDialog.SAVE); chooser.setVisible(true); if (chooser.getFile() != null) { save(chooser.getDirectory() + File.separator + chooser.getFile()); } } /** * Tests this <tt>Picture</tt> data type. Reads a picture specified by the command-line argument, * and shows it in a window on the screen. */ public static void main(String[] args) { Picture picture = new Picture(args[0]); System.out.printf("%d-by-%d\n", picture.width(), picture.height()); picture.show(); } } |
7楼2015-04-05 01:46:34
WanderingHeart
铁杆木虫 (著名写手)
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2楼2015-04-03 16:50:54
3楼2015-04-03 18:35:38
WanderingHeart
铁杆木虫 (著名写手)
- 应助: 90 (初中生)
- 金币: 13890.8
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- 专业: 凝聚态物性 II ：电子结构
4楼2015-04-03 22:25:36
