Computer Vision News - June 2016

retrieval. This technology was successively converted to the computer vision area by applying the same method on the features discovered in the image. Bag of Visual Words allows us to identify and classify a video by comparing visual histograms, where the technique of PCA (Principal Component Analysis) helps us find the most common factors and make a match faster. The procedure is parallel to that used in creating word histograms, which are traced according to word frequency in a text: visual clues is represented in a histogram according to its presence among the features of that video. In fact, the ease of the classification task depends on the subject at hand : it might be quite simple to detect sports played on snow or grass, but other subjects lacking a distinct visual appearance will be more difficult to identify. It is worth noting that advertisers might want to exclude adult content from their choice of subjects. Filters based on colors and motion detection are very successful in sorting out and eliminating adult videos in order to fulfil that request too. The video classification system can also use other keys found in the images: for instance, it might detect texts in the wild, pass them to the OCR engine and finally get some keywords which might give precious clues regarding the subject of the video . In the same way, logo detection might serve as a useful tool to shed additional light on the video at hand. Computer Vision News Project 31 “ How to determine the content of a video, especially when the uploader did not define any video tags ”