关键词：可视化；众包；图表；文本；认知模型
摘 要：In order to modify charts, we need access to the locations of the marks in the chart and the underlying data. We present algorithms that automatically extract this information from raster bar and pie charts that obey some common assumptions. Using a corpus of images drawn from the web, these algorithms successfully extract marks from 79% of bar charts and 62% of pie charts, and from these charts they successfully extract the data from 71% of bar charts and 64% of pie charts. We then present an application that uses the extracted marks and data to present a gallery of redesigns. Next, we tackle the problem of customizing existing visualizations to best support a viewer’s goal. We introduce graphical overlays—visual elements that are layered onto charts to facilitate a larger set of chart reading tasks.