examine

# examine - function examine(ballMovieFilename) % EXAMINE % *...

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function examine(ballMovieFilename) % EXAMINE % ******* % This function loads the specified avi movie to measure the trajectory of an % object that moves across the frame. The object should be light-colored on a black background. % The function outputs a text file and generates quick plots, using pixels and frames as units. f % Begin by clearing the console and the output variables. clc; clear x y area; c % Set constants. FRAME_WIDTH = 640; % Pixels. FRAME_HEIGHT = 480; % Pixels. TIME_TICK = 1; % Spacing of time ticks, in seconds. MIN_BALL_AREA = 200; % Area in pixels^2 required for an object to be considered the ball. MAX_VELOCITY = 100; % Maximum velocity to illustrate on plots, in pixels/frame. M % Define sentinel values. NO_OBJECTS = -1; % No objects were located in frame. OBJECT_TOO_SMALL = -2; % No objects over the minimum ball area were found. OBJECT_AT_EDGE = -3; % The object's bounding box is touching the edge of the frame. f % Print a banner. banner = sprintf('\nMEAM 147: Introduction to Mechanics Lab\nUniversity of Pennsylvania\nProfessor K. J. Kuchenbecker\n\n'); disp(banner); clear banner; d % Load the specified avi movie file. disp(['Loading "' ballMovieFilename '" . . .']); ballMovie = aviread(ballMovieFilename); disp(['Done loading "' ballMovieFilename '"']); d % Now tell the user the number of frames in this movie and store in a variable. nFrames = length(ballMovie); disp([sprintf('\n') 'This movie contains ' num2str(nFrames) ' frames.']) d % Now load the camera calibration and tell the user about it. load camera_calibration; disp([sprintf('\n') 'Using a camera view calibration of ' num2str(CAMERA_VIEW_HEIGHT_M) ' m tall and ' num2str(CAMERA_VIEW_WIDTH_M) ' m wide,\n shooting at ' num2str(CAMERA_FRAME_RATE_FPS) ' fps.']) w % Make a time vector. t = (0:(1/CAMERA_FRAME_RATE_FPS):((nFrames-1)/CAMERA_FRAME_RATE_FPS))';

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## examine - function examine(ballMovieFilename) % EXAMINE % *...

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