How can I read handles data in opc callback function

Hi! I am writing an OPC callback function in matlab! I have a trouble that my OPC callback function can not read the handles data, but the other button callback function can read it. What is the error, please help me, m code is: try handles.data = addgroup(handles.da); handles.dataIDS = {cambien1}; handles.data_itm = additem(handles.data,handles.dataIDS); guidata(hObject, handles); set(handles.data,'DataChangeFcn',{@Data_Group_Callback,handles},'UpdateRate',0); end my Data_Group_Callback function if(handles.data_itm.value==1) axes(handles.capture); vid=handles.vid; pause(3); data=getsnapshot(vid); imshow(data); savename = strcat('doan' ,'hinh', '.jpg'); imwrite(data,savename); x = get(handles.x,'value'); if x==1

axes(handles.processing); RBG = imread('doanhinh.jpg'); bw = imsubtract(RBG(:,:,1), rgb2gray(RBG)); % Convert the resulting grayscale image into a binary image. bw = im2bw(bw,0.18); % Remove all those pixels less than 300px bw = bwareaopen(bw,30);...... my button call back is function red_Callback(hObject, eventdata, handles) % hObject handle to red (see GCBO) % eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) handles.x=1; guidata(hObject,handles); can not use the handles.x in the function Data_Group_Callback(hObject, eventdata, handles)