Bounce is an augmented reality installation, allowing the user to interact with the system by throwing balls at a projection on the wall.
It was developed as a student project using OpenFrameworks and the included OpenCV-Addon.
Programming and functionalities are quite prototypical.
What you need:
- experience with OpenFrameworks
In order to compile Bounce you have to:
- download Openframeworks with addons(FAT), compatible to your IDE
- in the OF directory, go to apps/addonsExamples/ and make a copy of allAddonsExample, rename it
- add the source-files from this repository to
- get the media and include it in
The current version is not able to adapt to size change after being compiled.
All buttons and graphics are measured to
1280 x 800, and need to be modified in position and size otherwise.
To change the window's size you need to change the
main.cpp (line 13 and 14).
- use a projector to throw a screen-projection on a wall. The picture needs to be rectangular, no trapezoidal effect.
- than darker the room and than lighter the projection than better.
- it's not necessary that the camera is directly beside the projector.
- make sure that the camera gets the full screen, but few from the surrounding.
- fasten the microphone as near as possible at the projection, directly on the wall, a contact microphone is best.
- test if you get a sound when throwing a ball against the wall.
- use black beanbags or tennisballs in black duct tape.
Windows: When starting the program, a console window is opened and gives you a list of camera devices. Type in the ID of the device you want to use.
MacOS: If you want to choose a device, start from Terminal, otherwise the first available device is chosen.
Linux: not tested
- After the start you see the menu
- Mouseclicking has the same effect as a bounce of a ball.
- You can click or bounce on the buttons to start games or calibration.
- The games start immediately or after the first bounce.
- after the game is finished you see a scores table
- on the left side are all-time highscores, on the right side the scores of the last ten players.
- if you get inserted in the highscores, you have to type in your name.
- the highscores get saved in
game.txtin the bounce directory
After the launch of Bounce it is nessesary to calibrate before the balls get recognised.
- Click on the calibrate button in the menu.
- Now you see the picture of the camera, if not, no camera is available.
- Direct the camera to the screen or projection, the full application window has to be inside the picture.
- click again and the calibration will start, make sure that nothing moves in the image of the camera.
- at first the system tries to see 4 circles, one in each corner.
- then every single cornerposition gets measured from the application.
- after that you can see the audio-plot of the microphone, make some noise and you see an effect.
- now the application is able to recognise balls thrown at the projection, if not read error-handling.
It is also recommended to calibrate while playing.
- SPACE - pauses/proceeds the game
- M - back to menu
- F - fullscreen
- S - open camera settings window
- C - shows/hides the Console (see console)
- 1 to 5 - shows processed images
- 0 - reset calibration
- ESC - end program
used to change specific values (left bottom)
press 'c' to show/hide
use LEFT and RIGHT arrow to navigate between values and UP and DOWN to change the value
screenStoreSize- regulates how much pictures from screen get stored, neccessary because cameraImage and screenImage have temporal difference
camWaitFrames- sets how many frames the system waits from sound to picture, because the microphone is faster than the camera
threshold- sets how high the brightness difference of a pixel has to be at least between camera- and screenImage to be recognised
bangLevel- how much energy-change in the audiosignal a bounce has to make to be recognised, symbolised by the red line at the end of calibration mode
bang of ball not loud enough:
- do the calibration as described, till the audioplots appear.
- throw a ball and see if the audioplot goes above the red line.
- if not change the
bangLevelat the console, till the ballsound is above the red line.
ball not detected:
- after calibration, throw a ball against the wall
- press '5' to see a gray picture from the camera with the ball on it
- if there is no ball on the picture, you have problems with the microphone maybe
- press '3' to see a black picture whera all differences between screen and camera are white
- the ball should be a white blob in this picture
- if there is more white than the ball, increase the threshold in the console
- if there is no white, decrease the treshold in the console, until you see the ball after throwing.
- if the white is not controllable, adapt the lighting of your room.
projector or camera was moved:
- do the calibration once again