Image processing using generative graphical models

An image processing computer system comprising one or more computers programmed to process an image comprising a plurality of pixels, the one or more computers comprising at least one processor arranged to execute one or more computer programs and computer memory accessible by the one or more processors for storing variables allocated to one or more nodes of a hierarchical image model representing the image,

• the computer memory storing the hierarchical image model wherein:
• in a first layer of the hierarchical image model each observed pixel of the image is allocated to one or more input nodes of the first layer,
• a set of the one or more input nodes is assigned to a hidden node of a second layer representing a part or subpart of the image in the second layer, to create a subtree for the hidden node, in which the hidden node is a parent node and the one or more input nodes are child nodes;
• and
• a duplicate set of input nodes of the first layer is assigned to a duplicate of the hidden node in the second layer representing the same part or sub part of the image, thereby forming a dense latent tree in which the subtree is duplicated such that no child node has multiple parents in the dense latent tree yet all parent-child relationships between the first and second layer are represented;
• and
• the at least one processor coupled to access the memory to assign variables to the one or more input nodes, the hidden node and the duplicate node and recurringly modifying the variables to process the image.