图像不变局部特征研究及应用

图像不变局部特征是新近兴起的一类图像特征，基于不变局部特征的图像表示是计算机视觉的热点研究问题，在理论研究和实际应用上都具有重要意义。本论文针对图像不变局部特征的原理特性及应用展开研究：（1）当今流行的不变局部特征检测和描述方法；（2）局部特征组织方式；（3）基于局部不变特征的摄像机运动检测方法；（4）基于局部特征组合的目标模型及识别方法。 深入研究了当今流行的不变局部特征检测子，重点分析了其提取原理、特征结构、不变性阶次、精确度等特性，在此基础上对多种检测子进行比较分析，得出各自的适用范围，并总结出在具体应用环境下的特征选择原则。 针对视频分析中摄像机运动检测的具体应用，提出一种基于尺度不变局部特征的摄像机运动检测方法。该方法选取尺度不变局部特征，采用无序特征集合的方式表示图像帧，通过帧间局部特征的匹配，提出归一化软投票的方法鲁棒地估计特征匹配对的位置、尺度的变化，并根据各变化值和投票数的特点识别出摄像机的运动类型。该方法简单、鲁棒，满足了摄像机运动检测的处理速度和准确性需求。 针对基于局部特征的目标表示和识别问题，研究分析现有两种模型bag-of-words和part-based的优缺点，将二者结合，提出一种局部特征组合的目标表示模型和相应的识别算法。该方法在半局部区域内的特征同时进行外观描述和空间位置编码，并用数据挖掘中的频繁项挖掘技术自动提取出表征目标的特征组合，作为子模型。目标模型由一系列子模型构成，子模型的数量及每个子模型中包含的部件数目均自动从训练集中发现，是完全目标自适应的。所提方法克服了bag-of-words方法表达的精确性不足、part-based方法训练速度过慢的缺点，在识别问题上得到了较好的总体性能。

聋童与正常儿童中文阅读信息加工过程的比较研究

Based upon the experiments showing three traits of Chinese characters as stimulus, the comparison has been made between the hearing-impaired and normal children in RT functions for the judgment involved in the verbal recording. The results show that the function of semantic code is more strongly correlated with recognition of Chinese character than the phonetic code and graphic code for both the hearing-impaired and normal children. For hearing-impaired children, a direct access that a semantic code is produced directly from the graphic code is observed. However, for normal children the strategly of grapheme-phoneme conversion rules to interpret the meaning of words is used. It's shown that no significant differences of mental processing has been found between the hearing-impaired and normal children. Perhaps both the direct access and the grapheme-phoneme conversion form a comprehensive information procession activating each other. In reading Chinese character, the hearing-impaired and normal children is significantly effected by stroke under and character frequency. It is found that the normal children have more depth processing in reading Chinese sentences than the hearing-impaired children.