Lukasz - if you want the image from the pre-processing part of the ocr1 function to appear in a specific axes, then pass the axes handle into the function. Just change your function signature to
function [ o_str ] = ocr1(img, preProcImgAxesHandle)
and then when you have the pre-processed image to display, just do
imshow(preProcImg,'Parent', preProcImgAxesHandle);
and the pre-processed image, preProcImg, will be shown on the axes that is represented by the preProcImgAxesHandle handle.
In your GUI, you would call this function as (for example)
ocr1(img,handles.axes18)
Try making the above change and see what happens!
