Mitsubishi Electric Research Laboratories, Inc.

Mitsubishi Electric Information Technology Center America, Inc (ita)

Sourabh A Niyogi

William T Freeman

To identify an image characteristic, a tree structured code having coding representing each of a plurality of training images is stored in a memory. Coding representing a sample image, not included in the plurality of training images, is compared to the tree structured code to identify the training image coding in the structured tree code closest to the sample image coding. A characteristic of the sample image is identified based upon the training image represented by the closest training image coding.

Identifying images using a tree structure

A method and apparatus are disclosed for determining a direction in which a subject's head is facing. The present invention has particular relevance to monitoring driver conditions in automobiles. By monitoring head positions and motions, the system can estimate driver awareness. Signals or alarms can be activated if the driver does not appear to be aware of driving conditions. The present invention provides a rapid, low cost device for determining pose position, which would be useful in automobiles. A large number of images of various subjects in different poses are stored a memory. The poses are then organized according to tree-structured vector quantization to allow comparison with a sample image of an actual driver. The tree structure is traversed to find a leaf node constituting one of the stored images which is closest to the sample image. The pose of the closest image is outputted as the pose of the sample image. Cropping can be done automatically by including, within the stored images, extra examples which are offset from center. If the closest pose is one that is offset, the cropping window for subsequent sample images is appropriately adjusted in order to maintain the head of the subject close to the center of the cropping window.

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Cambridge, MA, United States of America

Sourabh A Niyogi