Tham khảo tài liệu 'humanoid robots human-like machines part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Visual Attention and Distributed Processing of Visual Information for the Control of Humanoid Robots 431 Figure 4. Target fixations as a function of top-down influence. A 30 second image sequence was run through the system with different influence settings. The attended object is fairly salient by itself with 37 of fixations when using the bottom-up saliency system only. The top-down system is able to rapidly boost this ratio with almost 85 of all fixations when 2 is at Finally a new conspicuity map is computed by adding the weighted top-down and bottom-up conspicuity maps Jj t XMj t 1-X Jj t . Thus the relative importance of bottom-up and top-down saliency processing is determined by the parameter 2. In Figure 3 2 was used and Mj were initially set to zero i. e. Mj 0 0. We ran a series of tests to check the effects of top-down biasing. A short image sequence of about 30 seconds depicting an object teddy bear being moved around was used as input to the system. In these experiments the system used color opponency and intensity as low-level features and did not generate saccades. The shifts in current region of interest were recorded note that the saccades that would be performed are selected from a subset of these covert attentional shifts. The top-down system was primed with a vector roughly matching the brightness and color space position of the target object. Given proper weighting factors the locations selected by FeatureGate are close to the intended target with high probability. On the other hand by keeping the bottom-up cue in the system we ensure that very salient areas will be attended even if they don t match the feature vector. Tests were run with all settings equal except for the parameter 2 specifying the influence of the top-down system relative to the bottom-up saliency. The data generated is presented in Table 1. We tested the system from 0 influence only the bottom-up system active to 100 only the top-down system used . Fewer saccades are .
