Creating the ball

The design ideas for the ball and testing suggested that the ball should be yellow, to ensure that it stands out against the background of the game board, the video image of the players.

The ball has the same diameter (in pixels) as the height of the paddle, to keep continuity and for aesthetic purposes. A small white rectangle has been added to the yellow ball to create a pseudo 3D effect and add detail to the ball.

The ball has been coded to move only within the borders of the game board. This required some mathematical work, to calculate the velocity of the ball, it's projected position from an initial state to the next during one time step, the distance the ball travels in the x and y axis in a single time step and when it should rebound from the border, accounting for the radius of the ball.

Image Processing

I've started to code the game by working on the image processing needed to capture the video signal from the web-cam, turning this into a binary Hue and Saturation image and also creating a flipped copy of the video image in it's original state.

The binary image is used to calculate the weighted-centroid of the bright pink colour of an AIBO ball. The AIBO ball is being used during development, whilst I wait for the larger pink gym ball to arrive.

The copy of the video image has been flipped and will used as the background for the game board, so that players can see themselves, as well as the gym ball. The players will be able to see that the way in which they move the gym ball has an effect on the paddle used in the game.