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Navigator                   3.1 Image Capture This portion of the interface has been implemented using the Java Media Framework (JMF). Among other things, JMF provides the programming interface to capture video from particular hardware. In our case, we have used a Sun Video Plus (PCI) capture board in a Sun Blade 1000 hardware environment. The external video source is a wireless analog camera that is directly attached to the Video Capture board. Even though the hardware supports video capture at a rate up to 30 frames per second, some of these frames are lost in the process of displaying them in the Java Interface. The effective capture thus drops to about 20 to 25 frames per second. The Image Capture frame includes a method for capturing an image at a given time, i.e. a snapshot, which returns an image in the Java Image format. This method will be used from several other frames. Figure 1.3: Image Capture Frame 3.2 Color Chooser Before unleashing the fury, the operator must define the color relationship between the line and the background. The color chooser provides some functionality that aids the operator to this end. The frame is split into a specific color matcher and a gross color matcher. For the specific color matcher, the operator takes a snapshot from the Image Capture Frame, then outlines all areas that roughly correspond to the line using a Rectangular Region Selection tool. From the union of all these rectangular regions, the frame computes the lowest and highest color values for red, green, and blue, respectively. The 6 emerging values are then used as a template for reducing the 24-bit color capture to 2 colors: white line and black background. This particular tool captures precise border lines, given only one image. However, because lighting may change somewhat throughout the environment, this tool does not provide the margin of color fades from line to background. For this reason, we have included a gross color matcher, which is divided into 6 sliders. Three of these sliders represent the lower bounds for red, green, and blue; the other three represent the upper bounds. The operator may use these color sliders to adjust the border between line and background so as to obtain a more flexible setting. In any case, however, line color may always occur in the background, depending on the floor's condition and the transmission quality of the wireless camera. Certain fuzz is automatically detected, as will be explained later. Figure 1.4: Color Chooser Frame Click to enlarge