In this paper, we propose a two-stage foreground propagation that uses clues to adapt to the environment and detect moving objects in a non-stationary camera. The first stage creates a weight matrix to instantaneously regulate the background model by responding to clues from frame differencing and background subtraction. The regulated background model is less affected by inaccurate motion compensation. In the second stage, an iterative approach is taken to refine the threshold for each pixel location by initially using pixels with high foreground probability as clues. Foreground regions detected from the refined threshold are less likely to be false detections and capture true object regions with completeness. Experimental results showed that the two-stage foreground propagation had significantly higher recall with comparable precision and outperformed other methods.

As kids encounter food advertisements, it is important that they be able to critically evaluate the message's claims, the healthiness of the promoted product and their desire for it. To explore how technology might help kids develop these skills, we created an online forum called TalkBack that encourages children to critically analyze the messaging in food ads and their attitudes towards marketed foods. We evaluated TalkBack with twenty-eight middle school students in a summer camp program. We discuss how participants appeared to project and protect their sense of self through their interaction with TalkBack. We also describe the limited analytic depth of their forum contributions and suggest directions for HCI research that attempts to encourage critical thinking and health promotion in adolescents.