How many vlad model are?

The term "Vlad model" can refer to various contexts, such as the VLAD (Vector of Locally Aggregated Descriptors) model in computer vision or different models named Vlad in other domains. If you're asking about the VLAD model in computer vision, it is a method for aggregating local features into a compact representation, typically used for image classification and retrieval. Please specify the context if you're referring to a different "Vlad model."