Halcon图像识别——单个字符提取

**代码功能：**选取图片中字符信息并提取出来
**关键算子：**阈值分割（threshold()）、形态学闭运算（closing_circle()）、连接域（connection()）、求交运算（intersection()）

*关闭当前窗口
dev_close_window ()
*新建窗口，窗口句柄WindowHandle可用于后面的划矩形区域算子
dev_open_window (0, 0, 512, 512, 'black', WindowHandle)
*打开目录并选取图片，图片赋予变量Selection
dev_open_file_dialog ('read_image', 'default', 'default', Selection)
*读取图片，并赋予变量Image
read_image (Image, Selection)
*将图片转换成灰度图，并赋予变量GrayImage
rgb1_to_gray (Image, GrayImage)
*阈值划分，选取字符所在区域的阈值区间，即参数中（128, 255）
threshold (GrayImage, Region, 128, 255)
*闭运算，即对所选区域进行膨胀—腐蚀运算，运算半径为1.5
closing_circle (Region, RegionOpening, 1.5)
*将运算后区域进行连接域操作
connection (RegionOpening, ConnectedRegions)
*框选出需要的字符
draw_rectangle1 (WindowHandle, Row1, Column1, Row2, Column2)
*获取所框选的字符区域
gen_rectangle1 (Rectangle, Row1, Column1, Row2, Column2)
*对阈值划分的区域与框选的区域求交，即所得字符
intersection (Rectangle, Region, RegionIntersection)

/手动分割线

//
// File generated by HDevelop for HALCON/.NET (C#) Version 18.05
//
//  This file is intended to be used with the HDevelopTemplate or
//  HDevelopTemplateWPF projects located under %HALCONEXAMPLES%\c#

using System;
using HalconDotNet;

public partial class HDevelopExport
{
  public HTuple hv_ExpDefaultWinHandle;

  // Main procedure 
  private void action()
  {


    // Local iconic variables 

    HObject ho_Image, ho_GrayImage, ho_Region;
    HObject ho_RegionOpening, ho_ConnectedRegions, ho_Rectangle;
    HObject ho_RegionIntersection;

    // Local control variables 

    HTuple hv_WindowHandle = new HTuple(), hv_Selection = new HTuple();
    HTuple hv_Row1 = new HTuple(), hv_Column1 = new HTuple();
    HTuple hv_Row2 = new HTuple(), hv_Column2 = new HTuple();
    // Initialize local and output iconic variables 
    HOperatorSet.GenEmptyObj(out ho_Image);
    HOperatorSet.GenEmptyObj(out ho_GrayImage);
    HOperatorSet.GenEmptyObj(out ho_Region);
    HOperatorSet.GenEmptyObj(out ho_RegionOpening);
    HOperatorSet.GenEmptyObj(out ho_ConnectedRegions);
    HOperatorSet.GenEmptyObj(out ho_Rectangle);
    HOperatorSet.GenEmptyObj(out ho_RegionIntersection);
    //关闭当前窗口
    //dev_close_window(...);
    //新建窗口，窗口句柄WindowHandle可用于后面的划矩形区域算子
    //dev_open_window(...);
    //打开目录并选取图片，图片赋予变量Selection
    // dev_open_file_dialog(...); only in hdevelop
    //读取图片，并赋予变量Image
    ho_Image.Dispose();
    HOperatorSet.ReadImage(out ho_Image, hv_Selection);
    //将图片转换成灰度图，并赋予变量GrayImage
    ho_GrayImage.Dispose();
    HOperatorSet.Rgb1ToGray(ho_Image, out ho_GrayImage);
    //阈值划分，选取字符所在区域的阈值区间，即参数中（128, 255）
    ho_Region.Dispose();
    HOperatorSet.Threshold(ho_GrayImage, out ho_Region, 128, 255);
    //闭运算，即对所选区域进行膨胀—腐蚀运算，运算半径为1.5
    ho_RegionOpening.Dispose();
    HOperatorSet.ClosingCircle(ho_Region, out ho_RegionOpening, 1.5);
    //将运算后区域进行连接域操作
    ho_ConnectedRegions.Dispose();
    HOperatorSet.Connection(ho_RegionOpening, out ho_ConnectedRegions);
    //框选出需要的字符
    hv_Row1.Dispose();hv_Column1.Dispose();hv_Row2.Dispose();hv_Column2.Dispose();
    HOperatorSet.DrawRectangle1(hv_ExpDefaultWinHandle, out hv_Row1, out hv_Column1, 
        out hv_Row2, out hv_Column2);
    //获取所框选的字符区域
    ho_Rectangle.Dispose();
    HOperatorSet.GenRectangle1(out ho_Rectangle, hv_Row1, hv_Column1, hv_Row2, hv_Column2);
    //对阈值划分的区域与框选的区域求交，即所得字符
    ho_RegionIntersection.Dispose();
    HOperatorSet.Intersection(ho_Rectangle, ho_Region, out ho_RegionIntersection);

    ho_Image.Dispose();
    ho_GrayImage.Dispose();
    ho_Region.Dispose();
    ho_RegionOpening.Dispose();
    ho_ConnectedRegions.Dispose();
    ho_Rectangle.Dispose();
    ho_RegionIntersection.Dispose();

    hv_WindowHandle.Dispose();
    hv_Selection.Dispose();
    hv_Row1.Dispose();
    hv_Column1.Dispose();
    hv_Row2.Dispose();
    hv_Column2.Dispose();

  }
  public void InitHalcon()
  {
    // Default settings used in HDevelop 
    HOperatorSet.SetSystem("width", 512);
    HOperatorSet.SetSystem("height", 512);
  }

  public void RunHalcon(HTuple Window)
  {
    hv_ExpDefaultWinHandle = Window;
    action();
  }

}