% [threshold,crop] = TestImageRecognition(file,frame,minsize,rotate)
%
% Function for finding and testing the correct image recognition
% parameters.
%
% Input parameters:
%   file = Video file
%   frame = Number of test frame. Choose any frame where you can see the
%           droplet.
%   minsize = Minimum area that is recognized as a droplet in pixels (e.g. 
%             100)
%   rotate = Video rotation angle (deg). Used to straighten skewed videos.
%
% Output parameters:
%   threshold = Threshold for black-and-white conversion (0..1)
%   crop = Amount video is cropped from bottom. 


function [threshold,crop]=TestImageRecognition(file,frame,minsize,rotate)
% This script is not relevant for writing the report, but it might be
% interesting. Probably not.

% Open video
video=VideoReader(file);
org=read(video, frame);  %Original image is also needed
image=org;

% Rotate image if needed
if rotate ~= 0
    temp=imrotate(image,rotate);
    % White border instead of black
    rotationmask = ~imrotate(true(size(image)),rotate);
    temp(rotationmask&~imclearborder(rotationmask)) = 255;
    image=temp;
end

width=size(image,2);
height=size(image,1);

% Convert to grayscale
imgray=rgb2gray(image);

% Interactive thresholding by Brandon Kuczenski
disp('Adjust the threshold for black-and-white conversion and select "done".');
threshold=thresh_tool(imgray,colormap('gray'));
threshold=threshold/255;
BW = im2bw(imgray,threshold);
disp(['Threshold = ' num2str(threshold)]);

% Interactive cropping
disp('Crop the image (only lower limit matters) so that substrate is left out. Double click inside cropped area when done.');
h=figure; 
set(h,'Position',[200 500  width*6 height*3]);
axes('position',[0  0  .5  1])
[~,cropcoordinates]=imcrop(BW);
crop=height-(cropcoordinates(2)+cropcoordinates(4));
crop=round(crop);
disp([num2str(crop) ' pixels cropped.']);

% Try to find droplet x-coordinate
axes('position',[0.5  crop/height  .5  (height-crop)/height]);
test=ImageRecognition(org,minsize,threshold,crop,rotate,1);

if test > 0
    disp('Single object found. Position showed in red.');
elseif test == -1
        disp('Droplet not found! Try decreasing "minsize".')
    else
        disp('Several "droplets" found! Try increasing "minsize".')
end
end