1 FINGER ART Sean Liu Grace Li October 31, 2008 PROPOSAL Introduction In our project, we will simulate the act of painting. The user will wear a special glove with LEDs, which will enable a camera to track the motion and gestures of the user’s hand. As the user “paints”, the system will calculate the location, velocity, and angle of the hands, which translate into variations in virtual brushes. Additionally, the system also incorporates painting effects such as color mixing, paint splatter, and brush saturation. The goal is to simulate a real painting experience. Our project is composed of two parts: the video interface and the paint canvas synthesis. The video interface takes movements from the user’s hands and identifies the position of the virtual paintbrush, the velocity with which it is moving, and the orientation or angle of the user’s hands. These three pieces of information are then passed to the paint canvas synthesis. The paint canvas synthesis system takes in the position, speed, and orientation data and selects a brush, color, saturation, and surrounding splatter around the brush. These selections are translated into pixel color assignments, which add to what the user has already painted. Functionality In order to understand the how the painting occurs; one must first understand how we model the paint, palette, and paintbrush. The paint is represented using three 5-bit binary numbers to encode RGB color, and an additional 3-bit number to encode the saturation level. The screen is divided into two sections – the canvas and palette. If the system identifies that the user’s brush is over the palette section, then paint is absorbed onto the brush. If the user’s brush is over the canvas section, then paint is deposited on the canvas. The palette contains a set of primary colors, which the user can absorb at various saturations to mix and match paints. Finally, the user’s hands represent a paintbrush, which will be the instrument for depositing the paint onto the canvas and picking it up from the palette. The paintbrush is represented as a line of blobs, and the line can have very different orientations. Each blob has a core zone of high saturation surrounded by a zone of lower saturation, which represents the spreading out of the paint. Where the paintbrush touches the canvas, the core blobs of the brush deposit color on the canvas at the user hand location. When the paintbrush moves, each place that is rests upon will have paint deposited in the area of the lines of blobs. The makeup of the paintbrush from different kinds of blobs comes from the velocity of the2 brush. The faster the paintbrush, the narrower and more randomized the blobs, and the slower the brush, the finer and more well defined the blobs. There will be a finite amount of paint on the paintbrush, and as the paintbrush is moved, paint is deposited onto the canvas, and less paint remains on the paintbrush. This simulates the real effect observed in painting, where long strokes gradually deposit reduced amounts of paint. We represent this effect by gradually decreasing the saturation of the color deposited. Eventually, when the paintbrush has deposited all of its paint on the canvas, there will no longer be any paint on the paintbrush, and paint will no longer be deposited onto the canvas. The palette will serve as the location where the user can pick up more paint. There will be sections for the three primary colors, sections for both black and white so that the user can make their chosen color both darker and lighter, and a section where the user can clean off all color from their paintbrush. How much of a certain color is picked up by the paintbrush and the saturation of that color are directly proportional to the time that the paintbrush touches the color. System Usage In this section, we will describe the different user interactions that are possible with the system and how the different user actions translate to painting. The user should be able to do the following things: • Determine the position and velocity of the paintbrush • Determine the orientation of their paintbrush • Touch their paintbrush to the canvas to start painting • Lift their paintbrush from the canvas to stop painting • Pick up different amounts of paint from different colors on the palette • Mix colors • Clean their paintbrush The user will wear a glove which has two LEDs attached. One will be attached to the index finger and the other will be attached to the thumb. The midpoint of the two LEDs will determine the center of the paintbrush. Using the movement of their hand, the user will be able to determine the velocity of the paintbrush by changing the position of their hand. Orientation of the paintbrush will be determined by the relative positions of the two LEDs. The line between the two LEDs on the user’s index finger and thumb is used as the orientation of the paintbrush. In order to touch the paintbrush to the canvas, the user will blink the LED twice and the system will know to start painting. Then, when the user again blinks the LED twice, the system will know that it should stop painting. To acquire paint on the brush, the user will position their index finger over the patch of paint on the palette and move their finger in a circular motion. Then, to clean the paintbrush off, the user will move their index finger in a circular motion over the cleaning area of the palette.3 Module Definitions Here we will discuss overviews of the modules in the system. Figure 1 gives a block diagram identifying the modules in the system. Conceptually we can divide the system into two main parts. The first part consists of the Video Capture, Gesture recognizer, and Intention modules. The second part consists of the Painter, Saturation, Color Generator, and Display modules. The Game Pixel Generator and Scorer are areas for potential expansion. Video Capture ZBT 800x600 Gesture Recognizer Brush Generator Painter Display Saturation Intention Color Gen Scorer ZBT Game Pixel Generator CameraButton Debouncer Monitor Frame 800x600 x1,y2 velocity enable Core brush px saturation color selected color pixel addr add, subtract frame expected color of px Display location of game gesture User score Frame 800x600 10 10 color saturation 15 3 15 3 15 x2,y2 current pixel midpt Figure 1: Modules of the Finger Paint system Part 1: Video Capture,
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