话不多说，先看图，这是导入一张图后运行的效果。

在此函数中，左图是灰度图加上colorBar后的彩色效果图，右图是二值化后的图，下面是可调节阈值的灰度直方图。

左上角的按钮是回归初始状态，右上角的按钮是结束阈值调整并记录该阈值和所得的二值化图像。

该函数先计算一个自适应阈值，若你不满意可以拉动灰度直方图的阈值灰色竖线左右移动，图像就会根据你的阈值选择变化。

很好用的一个工具，下面放代码。

 

function [level,bw] = thresh_tool(im,cmap,defaultLevel) %mainfunction%THRESH_TOOL  Interactively select intensity level for image thresholding.%   THRESH_TOOL launches a GUI (graphical user interface) for thresholding%   an intensity input image, IM. IM is displayed in the top left corner. A%   colorbar and IM's histogram are displayed on the bottom. A line on the%   histogram indicates the current threshold level. A binary image is%   displayed in the top right based on the selected level.  To change the%   level, click and drag the line. The output image updates automatically.%%   There are two ways to use this tool.%%Mode 1 - nonblocking behavior:%   THRESH_TOOL(IM) launches GUI tool.  You can continue using the MATLAB%   Desktop.  Since no results are needed, the function does not block%   execution of other commands.%%   THRESH_TOOL(IM,CMAP) allows the user to specify the colormap, CMAP.  If%   not specified, the default colormap is used.%%   THRESH_TOOL(IM,CMAP,DEFAULTLEVEL) allows the user to specify the%   default threshold level. If not specified, DEFAULTLEVEL is determined%   by GRAYTHRESH. Valid values for DEFAULTLEVEL must be consistent with%   the data type of IM for integer intensity images: uint8 [0,255], uint16%   [0,65535], int16 [-32768,32767].%%   Example%       x = imread('rice.png');%       thresh_tool(x)          %no return value, so MATLAB keeps running%%Mode 2 - blocking behavior:%   LEVEL = THRESH_TOOL(...) returns the user selected level, LEVEL, and%   MATLAB waits for the result before proceeding.  This blocking behavior%   mode allows the tool to be inserted into an image processing algorithm%   to support an automated workflow.%%   [LEVEL,BW] = THRESH_TOOL(...) also returns the thresholded binary %   output image, BW.%%   Example%       x = imread('rice.png');%       lev = thresh_tool(x)    %MATLAB waits for GUI tool to finish%%See also COLORMAP, GRAYTHRESH, IM2BW.if ndims(im)== 3     im = rgb2gray(im); end%defensive programmingerror(nargchk(1,3,nargin))error(nargoutchk(0,2,nargout))%validate defaultLevel within rangeif nargin>2 %uer specified DEFAULTLEVEL  dataType = class(im);  switch dataType    case 'uint8','uint16','int16'      if defaultLevel
        
         intmax(dataType)        error(['Specified DEFAULTLEVEL outside class range for ' dataType])      elseif defaultLevel
         
          max(im(:))        error('Specified DEFAULTLEVEL outside data range for IM')      end    case 'double','single'      %okay, do nothing    otherwise      error(['Unsupport image type ' dataType])  end %switchendmax_colors=1000;    %practical limit%calculate bins centerscolor_range = double(limits(im));if isa(im,'uint8') %special case [0 255]  color_range = [0 255];  num_colors = 256;  di = 1;elseif isinteger(im)  %try direct indices first  num_colors = diff(color_range)+1;  if num_colors
          
           max_colors %too many levels    num_colors = max_colors;                %practical limit    di = diff(color_range)/(num_colors-1);  endendbin_ctrs = [color_range(1):di:color_range(2)];FmtSpec = ['%.' num2str(ceil(-log10(di))) 'f'];%new figure - interactive GUI tool for level segmentingh_fig = figure;set(h_fig,'ToolBar','Figure')if nargin>1 && isstr(cmap) && strmatch(lower(cmap),'gray')  full_map = gray(num_colors);elseif nargin>1 && isnumeric(cmap) && length(size(cmap))==2 && size(cmap,2)==3  full_map = cmap;else  full_map = jet(num_colors);endsetappdata(h_fig,'im',im)setappdata(h_fig,'FmtSpec',FmtSpec)%top left - input imageh_ax1 = axes('unit','norm','pos',[0.05 0.35 0.4 0.60]);rgb = im2rgb(im,full_map);  function rgb = im2rgb(im,full_map); %nested    %coerce intensities into gray range [0,1]    gray = imadjust(im,[],[0 1]);    %generate indexed image    num_colors = size(full_map,1);    ind = gray2ind(gray,num_colors);    %convert indexed image to RGB    rgb = ind2rgb(ind,full_map);  end %im2rgbimage(rgb), axis image%subimage(im,full_map)axis off, title('Input Image')%top right - segmented (eventually)h_ax2 = axes('unit','norm','pos',[0.55 0.35 0.4 0.60]);axis offsetappdata(h_fig,'h_ax2',h_ax2)%next to bottom - intensity distributionh_hist = axes('unit','norm','pos',[0.05 0.1 0.9 0.2]);n = hist(double(im(:)),bin_ctrs);bar(bin_ctrs,n)axis([color_range limits(n(2:end-1))]) %ignore saturated end scalingset(h_hist,'xtick',[],'ytick',[])title('Intensity Distribution')%very bottom - colorbarh_cbar = axes('unit','norm','pos',[0.05 0.05 0.9 0.05],'tag','thresh_tool_cbar');subimage(color_range,[0.5 1.5],1:num_colors,full_map)set(h_cbar,'ytick',[],'xlim',color_range)axis normalv=version; if str2num(v(1:3))>=7  %link top axes (pan & zoom)  linkaxes([h_ax1 h_ax2])  %link bottom axes (X only - pan & zoom)  linkaxes([h_hist h_cbar],'x')end%colorbar tick locationsset(h_cbar,'xtick',color_range)%threshold level - initial guess (graythresh)if nargin>2 %user specified default level  my_level = defaultLevel;else %graythresh default  lo = double(color_range(1));  hi = double(color_range(2));  norm_im = (double(im)-lo)/(hi-lo);  norm_level = graythresh(norm_im); %GRAYTHRESH assumes DOUBLE range [0,1]  my_level = norm_level*(hi-lo)+lo;end%display level as vertical lineaxes(h_hist)h_lev = vline(my_level,'-');set(h_lev,'LineWidth',2,'color',0.5*[1 1 1],'UserData',my_level)setappdata(h_fig,'h_lev',h_lev)%attach draggable behavior for user to change levelmove_vline(h_lev,@update_plot);axes(h_cbar)y_lim = get(h_cbar,'ylim');% PLACE TEXT LOCATION ON COLORBAR (Laurens)%h_text = text(my_level,mean(y_lim),num2str(round(my_level)));h_text = text(my_level,mean(y_lim),'dummy','HorizontalAlignment','Center');if nargin<2  text_color = 0.5*[1 1 1];else  text_color = 'm';endset(h_text,'FontWeight','Bold','color',text_color,'Tag','cbar_text')movex_text(h_text,my_level)%%%%%%%%%%%%%%%%%%%%%%%%%segmented imagebw = im>my_level;axes(h_ax2)hold onsubimage(bw), axis off, axis ijhold offtitle('Segmented')update_plot%add reset button (resort to initial guess)h_reset = uicontrol('unit','norm','pos',[0.0 0.95 .1 .05]);set(h_reset,'string','Reset','callback',@ResetOriginalLevel)if nargout>0 %return result(s)  h_done = uicontrol('unit','norm','pos',[0.9 0.95 0.1 0.05]);  set(h_done,'string','Done','callback','delete(gcbo)') %better  %inspect(h_fig)  set(h_fig,'WindowStyle','modal')  waitfor(h_done)  if ishandle(h_fig)    h_lev = getappdata(gcf,'h_lev');    level = mean(get(h_lev,'xdata'));    if nargout>1      h_im2 = findobj(h_ax2,'type','image');      bw = logical(rgb2gray(get(h_im2,'cdata')));    end    delete(h_fig)  else    warning('THRESHTOOL:UserAborted','User Aborted - no return value')    level = [];  endendend %thresh_tool (mainfunction)function ResetOriginalLevel(hObject,varargin) %subfunctionh_lev = getappdata(gcf,'h_lev');init_level = get(h_lev,'UserData');set(h_lev,'XData',init_level*[1 1])text_obj = findobj('Type','Text','Tag','cbar_text');movex_text(text_obj,init_level)update_plotend %ResetOriginalLevel (subfunction)function update_plot %subfunctionim = getappdata(gcf,'im');h_lev = getappdata(gcf,'h_lev');my_level = mean(get(h_lev,'xdata'));h_ax2 = getappdata(gcf,'h_ax2');h_im2 = findobj(h_ax2,'type','image');%segmented imagebw = (im>my_level);rgb_version = repmat(double(bw),[1 1 3]);set(h_im2,'cdata',rgb_version)end %update_plot (subfunction)%function rgbsubimage(im,map), error('DISABLED')%----------------------------------------------------------------------function move_vline(handle,DoneFcn) %subfunction%MOVE_VLINE implements horizontal movement of line.%%  Example:%    plot(sin(0:0.1:pi))%    h=vline(1);%    move_vline(h)%%Note: This tools strictly requires MOVEX_TEXT, and isn't much good%      without VLINE by Brandon Kuczenski, available at MATLAB Central.%
           
            % This seems to lock the axes positionset(gcf,'Nextplot','Replace')set(gcf,'DoubleBuffer','on')h_ax=get(handle,'parent');h_fig=get(h_ax,'parent');setappdata(h_fig,'h_vline',handle)if nargin<2, DoneFcn=[]; endsetappdata(h_fig,'DoneFcn',DoneFcn)set(handle,'ButtonDownFcn',@DownFcn)  function DownFcn(hObject,eventdata,varargin) %Nested--%    set(gcf,'WindowButtonMotionFcn',@MoveFcn)           %    set(gcf,'WindowButtonUpFcn',@UpFcn)                 %  end %DownFcn------------------------------------------%  function UpFcn(hObject,eventdata,varargin) %Nested----%    set(gcf,'WindowButtonMotionFcn',[])                 %    DoneFcn=getappdata(hObject,'DoneFcn');              %    if isstr(DoneFcn)                                   %      eval(DoneFcn)                                     %    elseif isa(DoneFcn,'function_handle')               %      feval(DoneFcn)                                    %    end                                                 %  end %UpFcn--------------------------------------------%  function MoveFcn(hObject,eventdata,varargin) %Nested------%    h_vline=getappdata(hObject,'h_vline');                  %    h_ax=get(h_vline,'parent');                             %    cp = get(h_ax,'CurrentPoint');                          %    xpos = cp(1);                                           %    x_range=get(h_ax,'xlim');                               %    if xpos
            
             x_range(2), xpos=x_range(2); end                %    XData = get(h_vline,'XData');                           %    XData(:)=xpos;                                          %    set(h_vline,'xdata',XData)                              %    %update text                                            %    text_obj = findobj('Type','Text','Tag','cbar_text');    %    movex_text(text_obj,xpos)                               %  end %MoveFcn----------------------------------------------%end %move_vline(subfunction)%----------------------------------------------------------------------function [x,y] = limits(a) %subfunction% LIMITS returns min & max values of matrix; else scalar value.%%   [lo,hi]=LIMITS(a) returns LOw and HIgh values respectively.%%   lim=LIMITS(a) returns 1x2 result, where lim = [lo hi] valuesif nargin~=1 | nargout>2 %bogus syntax  error('usage: [lo,hi]=limits(a)')endsiz=size(a);if prod(siz)==1 %scalar  result=a;                         % valueelse %matrix  result=[min(a(:)) max(a(:))];     % limitsendif nargout==1 %composite result  x=result;                         % 1x2 vectorelseif nargout==2 %separate results  x=result(1);                      % two scalars  y=result(2);else %no result  ans=result                        % display answerendend %limits (subfunction)%----------------------------------------------------------------------function movex_text(h_txt,x_pos) %subfunctionFmtSpec=getappdata(get(get(h_txt,'parent'),'parent'),'FmtSpec');msg=sprintf(FmtSpec,x_pos);pos=get(h_txt,'position');pos(1)=x_pos;set(h_txt,'Position',pos,'String',msg)end %movex_text%--------------------------------------------------------------------------------------------------------------function hhh=vline(x,in1,in2) %subfunction% function h=vline(x, linetype, label)% % Draws a vertical line on the current axes at the location specified by 'x'.  Optional arguments are% 'linetype' (default is 'r:') and 'label', which applies a text label to the graph near the line.  The% label appears in the same color as the line.%% The line is held on the current axes, and after plotting the line, the function returns the axes to% its prior hold state.%% The HandleVisibility property of the line object is set to "off", so not only does it not appear on% legends, but it is not findable by using findobj.  Specifying an output argument causes the function to% return a handle to the line, so it can be manipulated or deleted.  Also, the HandleVisibility can be % overridden by setting the root's ShowHiddenHandles property to on.%% h = vline(42,'g','The Answer')%% returns a handle to a green vertical line on the current axes at x=42, and creates a text object on% the current axes, close to the line, which reads "The Answer".%% vline also supports vector inputs to draw multiple lines at once.  For example,%% vline([4 8 12],{'g','r','b'},{'l1','lab2','LABELC'})%% draws three lines with the appropriate labels and colors.% % By Brandon Kuczenski for Kensington Labs.% brandon_kuczenski@kensingtonlabs.com% 8 November 2001% Downloaded 8/7/03 from MATLAB Central% http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=1039&objectType=fileif length(x)>1  % vector input    for I=1:length(x)        switch nargin        case 1            linetype='r:';            label='';        case 2            if ~iscell(in1)                in1={in1};            end            if I>length(in1)                linetype=in1{end};            else                linetype=in1{I};            end            label='';        case 3            if ~iscell(in1)                in1={in1};            end            if ~iscell(in2)                in2={in2};            end            if I>length(in1)                linetype=in1{end};            else                linetype=in1{I};            end            if I>length(in2)                label=in2{end};            else                label=in2{I};            end        end        h(I)=vline(x(I),linetype,label);    endelse    switch nargin    case 1        linetype='r:';        label='';    case 2        linetype=in1;        label='';    case 3        linetype=in1;        label=in2;    end                g=ishold(gca);    hold on    y=get(gca,'ylim');    h=plot([x x],y,linetype);    if length(label)        xx=get(gca,'xlim');        xrange=xx(2)-xx(1);        xunit=(x-xx(1))/xrange;        if xunit<0.8            text(x+0.01*xrange,y(1)+0.1*(y(2)-y(1)),label,'color',get(h,'color'))        else            text(x-.05*xrange,y(1)+0.1*(y(2)-y(1)),label,'color',get(h,'color'))        end    end         if g==0    hold off    end    set(h,'tag','vline','handlevisibility','off')end % elseif nargout    hhh=h;endend %vline (subfunction)