Optitrak + Projector touch table/surface

Calibration with Tracking Tools

note: if you are using the laptop setup in room 3108, make sure that the dongle for Tracking Tools is not plugged in when starting up the computer.

To calibrate the optitrak for use with the touch table, make sure that the Tracking tools dongle is plugged in. Then start Tracking Tools from the desktop.

In general, you will follow these steps in order to calibrate:

1. Use the wand to register the area of interest
2. Use the plane to set the ground plane
3. If using trackables, create trackable objects
4. Set the data to stream out (for reading into matlab)

Step-by-step calibration guide

1. Open Tracking Tools and select "Perform Calibration"

2. Change Illumination Type from "Strobe IR" to "Continuous"

3. Clear the table of the reflective equipment (e.g., finger ball, wand, ground plane) and make sure that there are no bright lights registered in the software. If there are, find their source on or around the table and remove them so that the cameras images are all dark. Once this is the case move on to step 4.

As a last resort if there are any lights registered that can't be removed, you can block out that area in the corresponding camera with a mask. To do so, use the masking tools to e.g., draw a circle on top of the light. You can use the unblock all button to remove masks if you need to adjust or start again. Once all lights are masked, move on to step 4.

Click on "Start Wanding" and sweep the wand over the table's surface, making sure to focus your sweeps on the area just above the table top.

Matlab scripts

Function: Setting the optitrak plane in matlab

In place of the matlab code for reading in optitrak data, the following matlab function can be used to:

1. read in data sent from the optitrak system, and furthermore
2. set the table top plane, as understood by the Optitrak, into variables for reference in matlab, and
3. transform the native coordinate system of the optitrak (x z y) into another, possibly more familiar coordinate system (x y z).

This function will return:

This function should be called before opening a main window with psychtoolbox.

function [touch_plane_info, client] = opti_setup_touch_plane_srt

%This gives an error (freezes) if the NET assembly is already loaded.  In
%that case you need to quit Matlab and start over

if ~IsAssemblyAdded('NatNetML')  
	Opti = NET.addAssembly('C:\Users\Jim Enns\Documents\MATLAB\NatNetSDK2.2\NatNetSDK\lib\NatNetML.dll');
end

client = NatNetML.NatNetClientML(1);
%client.Initialize('142.103.0.167','142.103.0.167');
client.Initialize('142.103.251.175','142.103.251.175');
data = client.GetLastFrameOfData;
	

reply = 'N';
while ~strcmpi(reply,'Y')
	
	answer = {};
	while isempty(answer)        
		prompt={'Pixel Coords: '};
		name='Lower Left Corner';
		numlines=[1,35]; %this width allows for title to be seen
		defaultanswer={'[0 768]'};
		answer=inputdlg(prompt,name,numlines,defaultanswer);

		%convert from string to number data for output variables
		if ~isempty(answer)
			OriginPixelCoords = str2num(answer{1});
		end
	end

	pDataDest = [data.OtherMarkers(1).x data.OtherMarkers(1).z data.OtherMarkers(1).y];
	
	Question = {'LOWER LEFT pre coordinate transform:'...
		...
		'Marker 1: ' num2str(pDataDest(1:3))...
		...
		'Accept?'...
		};
	ButtonName = questdlg(Question, 'Data Check', 'Yes', 'No', 'Quit', 'Yes');

	switch ButtonName
		case 'Yes'
			orig_pos = pDataDest;
			reply = 'Y';
		case 'No'
			reply = 'N';
		case 'Quit'
			%quit opto too?
			%need to pass quit flag so this actually works?
			transform_info = [];
			clear all; close all; Screen('CloseAll'); 
			disp('*** Exiting Program ***');
			return
	end

end

%take a point on +ve x axis
reply='N';
while ~strcmpi(reply,'Y')

	answer = {};
	while isempty(answer)        
		prompt={'Pixel Coords: '};
		name='Lower Right Corner';
		numlines=[1,35]; %this width allows for title to be seen
		defaultanswer={'[1024 768]'};
		answer=inputdlg(prompt,name,numlines,defaultanswer);

		%convert from string to number data for output variables
		if ~isempty(answer)
			XAxisPixelCoords = str2num(answer{1});
		end
	end


	 pDataDest = [data.OtherMarkers(1).x data.OtherMarkers(1).z data.OtherMarkers(1).y];
	
	Question = {'LOWER RIGHT pre coordinate transform:'...
		...
		'Marker 1: ' num2str(pDataDest(1:3))...
		...
		'Accept?'...
		};
	ButtonName = questdlg(Question, 'Data Check', 'Yes', 'No', 'Quit', 'Yes');

	switch ButtonName
		case 'Yes'
			x_axis = pDataDest;
			reply = 'Y';
		case 'No'
			reply = 'N';
		case 'Quit'
			%quit opto too?
			%need to pass quit flag so this actually works?
			clear all; close all; Screen('CloseAll'); 
			disp('*** Exiting Program ***');
			return
	end
end

% point on the xy plane
reply='N';
while ~strcmpi(reply,'Y')

	answer = {};
	while isempty(answer)        
		prompt={'Pixel Coords: '};
		name='Upper Left Corner';
		numlines=[1,35]; %this width allows for title to be seen
		defaultanswer={'[0 0]'};
		answer=inputdlg(prompt,name,numlines,defaultanswer);

		%convert from string to number data for output variables
		if ~isempty(answer)
			YAxisPixelCoords = str2num(answer{1});
		end
	end

	 pDataDest = [data.OtherMarkers(1).x data.OtherMarkers(1).z data.OtherMarkers(1).y];
	
	Question = {'UPPER LEFT pre coordinate transform:'...
		...
		'Marker 1: ' num2str(pDataDest(1:3))...
		...
		'Accept?'...
		};
	ButtonName = questdlg(Question, 'Data Check', 'Yes', 'No', 'Quit', 'Yes');

	switch ButtonName
		case 'Yes'
			y_axis = pDataDest;
			reply = 'Y';
		case 'No'
			reply = 'N';
		case 'Quit'
			%quit opto too?
			%need to pass quit flag so this actually works?
			clear all; close all; Screen('CloseAll'); 
			disp('*** Exiting Program ***');
			return
	end
end

% finish the screen rect (event though this is redundant for establishing
% the plane)
reply='N';
while ~strcmpi(reply,'Y')

	answer = {};
	while isempty(answer)        
		prompt={'Pixel Coords: '};
		name='Upper Right Corner';
		numlines=[1,35]; %this width allows for title to be seen
		defaultanswer={'[1024 0]'};
		answer=inputdlg(prompt,name,numlines,defaultanswer);

		%convert from string to number data for output variables
		if ~isempty(answer)
			OppCornerPixelCoords = str2num(answer{1});
		end
	end

	 pDataDest = [data.OtherMarkers(1).x data.OtherMarkers(1).z data.OtherMarkers(1).y];
	
	Question = {'UPPER RIGHT pre coordinate transform:'...
		...
		'Marker 1: ' num2str(pDataDest(1:3))...
		...
		'Accept?'...
		};
	ButtonName = questdlg(Question, 'Data Check', 'Yes', 'No', 'Quit', 'Yes');

	switch ButtonName
		case 'Yes'
			opp_corner = pDataDest;
			reply = 'Y';
		case 'No'
			reply = 'N';
		case 'Quit'
			%quit opto too?
			%need to pass quit flag so this actually works?
			clear all; close all; Screen('CloseAll'); 
			disp('*** Exiting Program ***');
			return
	end
end

%Create the Coordinate Systesm
[T_opto_plane,T_plane_opto]=MakeCoordSystem(orig_pos,x_axis,y_axis);

%Display the new transformed coordinate system
disp('Points in Local Coordinate System are:')
[new_orig]=transform4(T_opto_plane, orig_pos)
[new_x_axis]=transform4(T_opto_plane, x_axis)
[new_y_axis]=transform4(T_opto_plane, y_axis)
[new_opp_corner]=transform4(T_opto_plane, opp_corner)

touch_plane_info.T_opto_plane = double(T_opto_plane);
touch_plane_info.T_plane_opto = double(T_plane_opto); 
touch_plane_info.opto_rect = double([new_orig; new_x_axis; new_y_axis; new_opp_corner]);
touch_plane_info.pixel_rect = double([OriginPixelCoords; XAxisPixelCoords; YAxisPixelCoords; OppCornerPixelCoords]);
touch_plane_info.old_opto_rect = double([orig_pos; x_axis; y_axis; opp_corner]);

%calculate the pixel to opto conversion
mm1 = double((new_x_axis(1) - new_orig(1))/(XAxisPixelCoords(1) - OriginPixelCoords(1)) * 1000);
mm2 = double((new_opp_corner(1) - new_y_axis(1))/(OppCornerPixelCoords(1) - YAxisPixelCoords(1)) * 1000);
mm3 = double(-(new_orig(2) - new_y_axis(2))/(OriginPixelCoords(2) - YAxisPixelCoords(2)) * 1000);
mm4 = double(-(new_x_axis(2) - new_opp_corner(2))/(XAxisPixelCoords(2) - OppCornerPixelCoords(2)) * 1000);
touch_plane_info.mmPerPixel = mean ([mm1 mm2 mm3 mm4]);