# 视觉信息的处理方式

## 自底向上（Bottom-up）方式

In general, semantics concerns the extraction of meaning from data. Semantic vision seeks to understand not only what objects are present in an image but, perhaps even more importantly, the relationship between those objects.
In semantic vision, an image is typically segmented into regions of interest. Each segment is allocated a classification so that all pixels in an image are assigned a class (e.g. car, road, footpath, person, tree, sky).
Contextual relationships provide important cues for understanding a scene.

## 自顶向下（Top-down）方式

1. 车牌都是长方形的
2. 长方形的位置，大小，形状，款和高符合一定的比例
3. 长方形中的像素具有两种高对比度的色调