/usr/share/psychtoolbox-3/PsychDemos/VideoTextureExtractionDemo.m is in psychtoolbox-3-common 3.0.9+svn2579.dfsg1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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% Use ARToolkit to track and visualize 3D objects in live-video.
%
% Usage: ARToolkitDemo([lightson = 0][, objtype = 3][, multiMarker = 2])
%
% Minimalistic demo on how to capture video data and use ARToolkit to
% detect and track the rigid position and orientation of markers, then
% visualize corresponding 3D objects on top of video via OpenGL.
%
% Parameters:
%
% multiMarker = If set to 2 (default), track single markers. If set to 1,
% track so called multi markers or composite markers for more robustness
% against occlusion of single markers. A setting of 3 (=1+2) should track
% both types of markers simultaneously, but this doesn't seem to work well
% yet.
%
% History:
% 19.04.2009 mk First prototype written.
global GL;
global sizeMM;
% Running on PTB-3? Hopefully...
AssertOpenGL;
% Size of rendered objects in millimeters:
sizeMM = 40; %#ok<NASGU>
if nargin < 1
lightson = [];
end
if isempty(lightson)
lightson = 0;
end
if nargin < 2
objtype = [];
end
if isempty(objtype)
objtype = 3;
end
try
% No sync tests for this simple demo:
olsync = Screen('Preference', 'SkipSyncTests', 2);
InitializeMatlabOpenGL;
% Open onscreen window for diplay:
screenid = max(Screen('Screens'));
% Size of window: Default to fullscreen:
if objtype ~= 3
roi = CenterRect(1.5 * [0 0 640 480], Screen('Rect',screenid));
else
roi = [];
end
% Use imaging pipeline to flip image horizontally to avoid confusing
% the viewer due to mirror view:
PsychImaging('PrepareConfiguration');
PsychImaging('AddTask', 'General', 'UseFastOffscreenWindows');
PsychImaging('AddTask', 'AllViews', 'FlipHorizontal');
win = PsychImaging('OpenWindow', screenid, 0, roi);
% Open videocapture device: For now we use engine 2, the ARVideo
% engine, to simplify compatibility issues...
imgFormat = [];
engineId = 0;
switch engineId
case 2,
grabber = Screen('OpenVideoCapture', win, 0, [], 5, [], [], [], [], engineId);
case 0,
devid = PsychGetCamIdForSpec('Eye');
grabber = Screen('OpenVideoCapture', win, devid, [], 1, [], [], [], [], engineId);
% imgFormat = 4;
case 1,
grabber = Screen('OpenVideoCapture', win, 0, [0 0 640 480], [], [], [], [], [], engineId);
otherwise
error('Unknown video capture engineId');
end
% Start capture with requested 30 fps:
Screen('StartVideoCapture', grabber, 30, 1);
% Get a single texture that we can query for the image format:
tex = Screen('GetCapturedImage', win, grabber);
[w, h] = Screen('WindowSize', tex) %#ok<NOPRT>
channels = Screen('PixelSize', tex) / 8 %#ok<NOPRT>
% Release texture after query:
Screen('Close', tex);
tex = []; %#ok<NASGU>
% Debug level for tracker:
PsychCV('Verbosity', 3);
% Initialize ARToolkit: Load camera calibration data, assign image size
% and properties for raw video input images:
ardata = [ PsychtoolboxRoot 'PsychDemos/ARToolkitDemoData/' ];
PsychCV('ARRenderSettings', [], [], 2000);
% ON OS/X:
%
% imgFormat == 4 fuer Quicktime 0,4 channel or ARVideo 0,4 channel.
% imgFormat == [] or 7 fuer ARVideo 5 channels (aka 4 channels swizzled).
% imgFormat == [] or 1 fuer Quicktime or ARVideo 3 channels.
% imgFormat == [] or 6 fuer Quicktime 1,2 channels.
% imgFormat == [] fuer Firewire 0,1,2,3,4 channels.
[imgbuffer, projectionMatrix, debugimagebuffer] = PsychCV('ARInitialize', [ardata 'camera_para.dat'], w, h, channels, imgFormat); %#ok<NASGU>
% [templateMatchingInColor, imageProcessingFullSized, imageProcessingIdeal, trackingWithPCA] = PsychCV('ARTrackerSettings')
% Single markers by default:
if nargin < 3
multiMarker = 2;
end
% Load our (multi-)marker(s):
% Need to cd() into marker directory, as some paths inside the marker
% config files are coded relative to working directory :-(
olddir = pwd;
try
marker = [];
if bitand(multiMarker, 2)
cd(ardata);
% marker(end+1) = PsychCV('ARLoadMarker', 'patt.sample2', 0, 40);
% marker(end+1) = PsychCV('ARLoadMarker', 'patt.hiro', 0);
marker(end+1) = PsychCV('ARLoadMarker', 'patt.kanji', 0, 40);
end
if bitand(multiMarker, 1)
cd([ ardata 'multi/' ]);
marker(end+1) = PsychCV('ARLoadMarker', 'marker.dat', 1); %#ok<NASGU>
end
catch
end
cd(olddir);
if objtype == 3
% Setup our 3D dense OpenGL head model for mirroring -- Our "Avatar":
MFHeadmodel('Initialize', win);
% Enable lighting model for head rendering:
MFHeadmodel('SetLighting', 0);
% Load OBJ's and initialize morph & render engine:
CGHeadModelFile = 'CGHeadModels/TwentySevenCGKeyExpressions/TwentySevenCGKeyExpressions.mat';
ExpressionsCount = MFHeadmodel('LoadModels', sprintf('%s%s', MFData, CGHeadModelFile)); %#ok<NASGU>
% Compute nonrigid facial expression morph for this frame:
morphWeights = 1;
MFHeadmodel('MorphHead', morphWeights);
texprops = MFHeadmodel('GetModelTextureProperties') %#ok<NOPRT>
texResolution = texprops.texResolution;
texSize = max(texResolution);
texCoordMin = texprops.texCoordMin;
texCoordMax = texprops.texCoordMax;
texSize = 512;
texScale = texSize / max(texResolution);
texCoordMin = [0, 0];
texCoordMax = [texSize, texSize];
texResolution = [texSize, texSize];
else
texSize = 512;
texCoordMin = [0, 0];
texCoordMax = [texSize, texSize];
texResolution = [texSize, texSize];
end
% zThreshold may need tweaking for depth range of object:
zThreshold = 0.000001;
callbackEvalString = 'glCallList(gld);';
context = moglExtractTexture('CreateContext', win, [0 0 w h], texCoordMin, texCoordMax, texResolution, zThreshold);
context = moglExtractTexture('SetRenderCallback', context, callbackEvalString);
% Setup OpenGL 3D rendering for our simple test:
Screen('BeginOpenGL', win);
% Enable lighting and depth-test:
glColor3f(1,1,1);
if lightson
glEnable(GL.LIGHTING);
end
glEnable(GL.LIGHT0);
glEnable(GL.DEPTH_TEST);
% Set projection matrix to one provided by ARToolkit:
glMatrixMode(GL.PROJECTION);
glLoadIdentity;
glLoadMatrixd(projectionMatrix);
% Init modelview matrix to identity: Will be overwritten, reloaded on
% each object draw operation by modelview matrix from ARToolkit:
glMatrixMode(GL.MODELVIEW);
glLoadIdentity;
% Position lightsource:
glLightfv(GL.LIGHT0,GL.POSITION,[ 1 2 3 0 ]);
% Define background clearcolor etc.:
glClearColor(0,0,0,0);
glClear;
% Absolutely crucial that alpha blending is "off"!
glDisable(GL.BLEND);
% Build display list with static texture extraction 3D object:
gld = glGenLists(1);
glNewList(gld, GL.COMPILE);
texmin = 0.00;
texmax = 1.00;
glPushMatrix;
switch(objtype)
case 1,
glTranslated(-sizeMM/2, -sizeMM/2, 0);
glTranslated(0, -sizeMM, 0);
glBegin(GL.QUADS);
glTexCoord2f(texmin, texmin);
glVertex2f(0.0, 0.0);
glTexCoord2f(texmin, texmax);
glVertex2f(0.0, 1.0 * sizeMM);
glTexCoord2f(texmax, texmax);
glVertex2f(1.0 * sizeMM, 1.0 * sizeMM);
glTexCoord2f(texmax, texmin);
glVertex2f(1.0 * sizeMM, 0.0);
glEnd;
case 2,
glTranslated(-sizeMM/2, -sizeMM/2, 0);
mysphere = gluNewQuadric;
gluQuadricTexture(mysphere, GL.TRUE);
glMatrixMode(GL.TEXTURE);
glPushMatrix;
glLoadIdentity;
glScaled(texSize, texSize, 1);
gluSphere(mysphere, sizeMM, 100, 100);
glPopMatrix;
glMatrixMode(GL.MODELVIEW);
gluDeleteQuadric(mysphere);
case 3,
glTranslated(0, 1*sizeMM, 0);
glRotated(180, 0, 0, 1);
glMatrixMode(GL.TEXTURE);
glPushMatrix;
glLoadIdentity;
glScaled(texScale, texScale, 1);
moglmorpher('render');
glPopMatrix;
glMatrixMode(GL.MODELVIEW);
end
glPopMatrix;
glEndList;
% OpenGL 3D setup done:
Screen('EndOpenGL', win);
% Shutdown head renderer: We can release the MFHeadmodels ressources
% here already, because we only need 1 static "neutral expression"
% shape, which we stored conveniently into a GL display list above :-)
MFHeadmodel('Shutdown');
% Init segmentation gain to 50% of avg image intensity:
gain = 0.5;
SetMouse(gain * Screen('WindowSize', win)/2, 100);
count = 0;
t=GetSecs;
KbReleaseWait;
inImage = [];
texBuffer = [];
doExtract = 0;
buttons = [0 0 0];
% Run tracking and viz loop until keypress:
while ~buttons(2)
% Update image segmentation gain from horizontal mouse position:
[xm, ym, buttons] = GetMouse;
gain = 2 * xm / Screen('WindowSize', win);
if xm == 0 && ym == 0
break;
end
if buttons(1) && ~oldbuttons
doExtract = 1 - doExtract;
end
oldbuttons = buttons(1);
% Retrieve next captured image. The 'waitforImage=2' waits for a
% new image, but disables texture creation, so 'dummy' is actually
% an empty handle. The 'specialMode'=4 flag requests video data to
% be put into the PsychCV() memory buffer referenced by
% 'imgbuffer'. 'imgIntensity' returns the average image intensity -
% Useful for computing an adaptive image segmentation threshold:
[inImage pts nrdropped imgIntensity] = Screen('GetCapturedImage', win, grabber, 1, inImage, 4, imgbuffer);
% Define dynamic threshold for image segmentation:
thresh = max(min(imgIntensity * gain, 254), 1);
% ARToolkit processing:
detectedMarkers = PsychCV('ARDetectMarkers', [], thresh);
% Visualize detected objects in 3D mode:
Screen('BeginOpenGL', win);
% Clear z-buffer for proper occlusion handling:
glClear(GL.DEPTH_BUFFER_BIT);
% Render current video image as backdrop:
PsychCV('ARRenderImage');
% For each candidate marker do...
for i=1:length(detectedMarkers)
% i'th candidate detected reliably?
merr = detectedMarkers(i).MatchError;
if merr < realmax
% Yes: Draw 3D object corresponding to i'th pattern:
mpos = detectedMarkers(i).ModelViewMatrix(1:3, 4);
statusTxt = sprintf('POS X = %04f Y = %04f Z = %04f', mpos(1), mpos(2), mpos(3));
DrawFormattedText(win, statusTxt, 'center', 0, [255 0 0], [], 1);
% Setup rigid position and orientation via 4x4 xform matrix:
glLoadMatrixd(detectedMarkers(i).ModelViewMatrix);
if doExtract
% Perform texture extraction pass from input video image:
[texBuffer, texId, texTarget] = moglExtractTexture('Extract', context, inImage, 0);
else
% Perform regular render pass:
if isempty(texBuffer)
glCallList(gld);
end
end
% Rerender:
if ~isempty(texBuffer)
if objtype ~= 3
glTranslatef(2.2*sizeMM, 0, 0);
end
glEnable(texTarget);
glBindTexture(texTarget, texId);
glCallList(gld);
glBindTexture(texTarget, 0);
glDisable(texTarget);
end
end
end
% Done with objects:
Screen('EndOpenGL', win);
if doExtract && ~isempty(texBuffer)
% Draw extracted texture:
% Screen('DrawTexture', win, texBuffer);
end
% if ~isempty(texBuffer)
% % Close previously extracted texture:
% Screen('Close', texBuffer);
% texBuffer = [];
% end
% Show updated image at next retrace:
Screen('Flip', win, 0, 0, 1);
% Next tracking loop iteration...
count = count + 1;
end;
telapsed = GetSecs - t;
moglExtractTexture('DestroyContext', context);
% Shutdown head renderer:
MFHeadmodel('Shutdown');
% Stop capture, close engine and onscreen window:
Screen('StopVideoCapture', grabber);
Screen('CloseVideoCapture', grabber);
Screen('CloseAll');
% Shutdown tracker:
PsychCV('ARShutdown');
% Stats...
avgfps = count / telapsed %#ok<NOPRT,NASGU>
catch
Screen('CloseAll');
PsychCV('ARShutdown');
end;
% Restore sync settings:
Screen('Preference', 'SkipSyncTests', olsync);
return
end
function MCalib = computeRigidXForm(MTarget, MHandle)
TTarget = MTarget(1:3, 4);
RTarget = MTarget(1:3, 1:3);
% Tinverse is the 4x4 translation matrix with the negated
% (inverted) T ranslation vector of the tracking target:
Tinverse = diag([1 1 1 1]);
Tinverse(1:3, 4) = -TTarget;
% Rinverse is the transpose (==inverse) of the tracking targets
% rotation matrix RTarget, extended to a 4x4 matrix:
Rinverse = diag([1 1 1 1]);
Rinverse(1:3, 1:3) = transpose(RTarget);
% Build final inverse transformation:
MTargetInverse = Rinverse * Tinverse;
% Build combined forward transformation:
MCalib = MTargetInverse * MHandle;
return;
end
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