GUI - Error when trying to program the second slide bar for the upper limit for variable hue in image processing (lower limit succeeded)

Question

S. 2021-11-29

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1598299-gui-error-when-trying-to-program-the-second-slide-bar-for-the-upper-limit-for-variable-hue-in-imag

编辑： S. 2021-12-2

42.jpg

I am trying to implement two sliders - one for the lower limit and one for the upper limit - for an image processing project I am doing myself. I am trying to seperate fruits from the background by using a range of the hue value. I succeeded to implement one slider, the one for the lower limit. However, when I add the code of the second slider for the upper limit unfortunately I get the following error:

Error using uicontrol

Incorrect number of input arguments

Can someone help me with it?

RGB_Image_Re = imread('42.jpg');
%Shifting color model
HSV_B = rgb2hsv(RGB_Image_Re); 
%Color seperation
hImage = HSV_B(:, :, 1);
f = figure(1);
ax = axes('Parent',f,'position',[0.13 0.39 0.77 0.54]);
%Initial values
Hue_min = 0;
Hue_max = 1;
%Slider for the lower limit of hue 
Hmin_Slider = uicontrol('Parent',f,'Style','slider','Position',[81,54,419,23],...
'value', Hue_min, 'min',0, 'max',0.5, 'Callback', @(es, ed)Slider(RGB_Image_Re, hImage, es.Value));
% % Add a text uicontrol to label the slider.
% txt_Hmin = uicontrol('Style','text',...
%      'unit','normalized',...
%                'position',[81,55,419,24],...
%      'String','Fitting Parameter "H_min"');
%Slider for the upper limit of hue 
Hmax_Slider = uicontrol('Parent',f,'Style','slide','Position',[81,54.1,419,23],...
'value', Hue_max, 'min',0,51, 'max',1, 'Callback', @(es, ed)Slider(RGB_Image_Re, hImage, es.Value));
% 
% % Add a text uicontrol to label the slider.
% txt_Hmax = uicontrol('Style','text',...
%      'unit','normalized',...
%                'position',[81,60,419,24],...
%      'String','Fitting Parameter "H_max"');
 
function Slider(RGB_Image_Re, hImage, Hue_min, Hue_max)
mask = (hImage >= Hue_min) & (hImage <= Hue_max);
% Create variable masked image (output) based on RGB image (input).
maskedRGBImage = RGB_Image_Re;
% Set background pixels (i.e. leaves, sky, logs) where the mask is false to
% black color [0,0,0]
maskedRGBImage(repmat(~mask,[1 1 3])) = 0;
imshow(maskedRGBImage);
title('Initial color seperation: fruit');
end

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Rik 2021-11-29

I have deleted the duplicate post as a comment on another thread. Please do not post your question in multiple places.

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Answer 1

Rik 2021-11-29

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https://ww2.mathworks.cn/matlabcentral/answers/1598299-gui-error-when-trying-to-program-the-second-slide-bar-for-the-upper-limit-for-variable-hue-in-imag#answer_842819

在 MATLAB Online 中打开

Your syntax doesn't match up. In your callback definition you have only 3 inputs, but your function assumes 4. I would suggest storing all handles and data in guidata and retrieving it in the callback.

You should also always use explicit handles to graphics objects. You also might consider using imshow only during initialisation, and then only setting the CData property of the image object it returns. That will be much faster.

h=struct; %put all handles and data in this struct
h.f=f;
%Slider for the lower limit of hue 
h.min_Slider = uicontrol('Parent',f,'Style','slider', ...
    'Units','Pixels','Position',[81,54,419,23],...
    'value', Hue_min, 'min',0, 'max',0.5,...
    'Callback', @Slider);
h.max_Slider = uicontrol('Parent',f,'Style','slider',... 
    ...                           %this was missing an r
    'Units','Pixels','Position',[81,54.1,419,23],...
    'value', Hue_max, 'min',0.51, 'max',1,...
    ...                   %this was 0,51
    'Callback', @Slider);
guidata(h,h.f)
function Slider(hObj,eventdata)
h=guidata(hObj);
RGB_Image_Re=h.RGB_Image_Re;
hImage=h.hImage;
Hue_minh.min_Slider.Value;
Hue_max=h.max_Slider.Value;
mask = (hImage >= Hue_min) & (hImage <= Hue_max);
% Create variable masked image (output) based on RGB image (input).
maskedRGBImage = RGB_Image_Re;
% Set background pixels (i.e. leaves, sky, logs) where the mask is false to
% black color [0,0,0]
maskedRGBImage(repmat(~mask,[1 1 3])) = 0;
imshow(maskedRGBImage,'Parent',h.ax);
title(h.ax,'Initial color seperation: fruit');
end

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Rik 2021-11-30

在 MATLAB Online 中打开

I showed in my answer what I mean: I used 'Parent',ax when calling imshow. That way you make sure that the image will show up where you expect it to be, even if the user clicked on other figures and axes.

If you use h_im=imshow(___); that will return the handle to an image object, just like f=figure; returns the handle to a figure object. You can set values to it, just like you can with the Value property of your sliders.

As for your last question you will need to change your setup to achieve that.

At the start of your callback function you should check if the two values are the correct way around. I would suggest setting the Userdata property of each slider:

h.min_Slider = uicontrol('Parent',f,'Style','slider', ...
    'Userdata','min');
h.max_Slider = uicontrol('Parent',f,'Style','slider',... 
    'Userdata','min');

That way you can determine with hObj.Userdata which slider is currently changing. If this is your intention, you should probably set the min and max values to 0 and 1 for both. Currently the value of your min slider can't be above the value of the max slider.

As for 0.50 <= x <= 0.12: this is a common mathematical syntax, but it doesn't work like this in Matlab. You need 0.50 <= x && x <= 0.12 instead.

S. 2021-11-30

在 MATLAB Online 中打开

Okay, I misunderstood the set() function. However, I am still quite confused about your function story, because most of the GUI problems online where in the format of script and internal function.

Do you suggest something like this? (it doesn't work yet, but more for my understanding, because I am doubting if this is what you meant)

%%Function file
function guidata = myGUI(hImage, RGB_Image_Re)
h=struct; %put all handles and data in this struct
h.RGB_Image_Re = RGB_Image_Re;
h.f = figure(1);
h.ax = axes('Parent',h.f,'position',[0.13 0.39 0.77 0.54]);
h.h_im = imshow(h.RGB_Image_Re,'Parent',h.ax);
title(h.ax,'Initial color seperation: fruit');
%Initial values
Hue_min = 0;
Hue_max = 1;
%Slider for the lower limit of hue 
h.min_Slider = uicontrol('Parent',f,'Style','slider', ...
    'Units','Pixels','Position',[81,54,419,23],...
    'value', Hue_min, 'min',0, 'max',1,...
    'Callback', @Slider);
h.max_Slider = uicontrol('Parent',f,'Style','slider',... 
    'Units','Pixels','Position',[81,54.1,419,23],...
    'value', Hue_max, 'min',0, 'max',1,...
    'Callback', @Slider);
guidata(h,h.f)
end
%%Main file
[guidata] = myGUI(hImage, RGB_Image_Re)

%Function file
function Slider(hObj,eventdata)
h=guidata(hObj);
Hue_minh.min_Slider.Value;
Hue_max=h.max_Slider.Value;
mask = (hImage >= Hue_min) & (hImage <= Hue_max);
% Create variable masked image (output) based on RGB image (input).
maskedRGBImage = RGB_Image_Re;
% Set background pixels (i.e. leaves, sky, logs) where the mask is false to
% black color [0,0,0]
maskedRGBImage(repmat(~mask,[1 1 3])) = 0;
set(h.h_im, 'CData', maskedRGBImage);
end

Rik 2021-12-1

在 MATLAB Online 中打开

In general I don't make GUIs with output variables. However, you can use uiwait or waitfor in your main GUI function:

function output = myGUI(hImage, RGB_Image_Re)
% create the GUI
uicontrol(___)
guidata(h,h.f)
% Wait for the 'confirm' button.
uiwait(h.f);
% This allows user interaction with the GUI, but otherwise the execution of
% this function is paused.
h=guidata(h.f);%reload data
output= %the values of the sliders?
end
function Slider(hObj,~)
end
function ConfirmButtonCallback(hObj,~)
uiresume(gcbf) %gcbf is the parent figure of hObj
end

As for your error: you need to make sure to save all data you may need to the h struct, then store it to the figure with guidata. The important thing to remember is that guidata(h,h.f) will store the data, and h=guidata(___); will load the data.

The main idea of a GUI is that all functions related to the GUI itself are in a single m-file. That m-file should start with a function that creates your GUI (with calls to uicontrol etc). Any callback should probably be in that same file to make things clear. It is fine to only have a wrapper, but you probably need to pass specific variables (stored in guidata), so having the callback function there is probably best.

I would really encourage you to read the thread I linked. I have tried to make it as clear as I can there. You will also find many links to the documentation there. You're already most of the way there.

Rik 2021-12-2

You need to make that confirmation button yourself.

If you would read the documentation you would see that the Position argument can be specified in several units, which is determined by the Unit property. In this case the default is Normalized, meaning that the x is in terms of the width of the parent object and the y is in terms of the height of the parent object.

Most of the follow-up issues so far seem to stem from the point that you don't seem to read the documentation for the functions you're using. If you start reading it yourself you don't have to wait for me to respond.

S. 2021-12-2

编辑：S. 2021-12-2

Yes, I understood the Position, otherwise I wouldn't succeed (at first I didn't understand, but when I read the documentation I succeeded). I think you misunderstood me. I removed that comment.

My main focus is not the GUI. That's why I got confused by the button. I only want the parameters as output.

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Answer 2

yanqi liu 2021-11-30

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1598299-gui-error-when-trying-to-program-the-second-slide-bar-for-the-upper-limit-for-variable-hue-in-imag#answer_843674

编辑：yanqi liu 2021-12-1

在 MATLAB Online 中打开

yes，sir，use Rik method，modify as

clc; clear all; close all;
RGB_Image_Re = imread('https://ww2.mathworks.cn/matlabcentral/answers/uploaded_files/816944/42.jpg');
%Shifting color model
HSV_B = rgb2hsv(RGB_Image_Re); 
%Color seperation
hImage = HSV_B(:, :, 1);
f = figure(1);
ax = axes('Parent',f,'position',[0.13 0.39 0.77 0.54]);
% here use Rik method
h=struct; %put all handles and data in this struct
%Initial values
Hue_min = 0;
Hue_max = 1;
%Slider for the lower limit of hue 
h.min_Slider = uicontrol('Parent',f,'Style','slider', ...
    'Units','Pixels','Position',[81,54,419,23],...
    'value', Hue_min, 'min',0, 'max',0.5);
h.max_Slider = uicontrol('Parent',f,'Style','slider',... 
    ...                           %this was missing an r
    'Units','Pixels','Position',[81,77,419,23],...
    'value', Hue_max, 'min',0.51, 'max',1);
% here modify some code, not use guidata, just use h 
set(h.min_Slider, 'Callback', @(es, ed)Slider(RGB_Image_Re, hImage, h));
set(h.max_Slider, 'Callback', @(es, ed)Slider(RGB_Image_Re, hImage, h));
    
function Slider(RGB_Image_Re, hImage, h)
Hue_min=h.min_Slider.Value;
Hue_max=h.max_Slider.Value;
mask = (hImage >= Hue_min) & (hImage <= Hue_max);
% Create variable masked image (output) based on RGB image (input).
maskedRGBImage = RGB_Image_Re;
% Set background pixels (i.e. leaves, sky, logs) where the mask is false to
% black color [0,0,0]
maskedRGBImage(repmat(mask,[1 1 3])) = 0;
imshow(maskedRGBImage);
title('Initial color seperation: fruit');
end

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S. 2021-12-1

Your method seems to be less lines of code. Why you suggest to use Rick's method?

yanqi liu 2021-12-1

yes，sir，because I refer to some codes

anyway, If you can solve the problem, I wish you every success

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GUI - Error when trying to program the second slide bar for the upper limit for variable hue in image processing (lower limit succeeded)

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