Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for adjusting confidence scores of image labels for images. In one aspect, a method includes accessing images stored in an image data store, the images being associated with respective sets of labels, the labels describing content depicted in the image and having a respective confidence score that is a measure of confidence that the label accurately describes the content depicted in the image; selecting a first image from the images and determining for each of the other images and independent of the labels, a proximity score that is a measure of a relatedness of the other image to the first image; and adjusting the set of labels associated with the first image based on the respective proximity scores of the other images and the confidence scores of the labels of the other images.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for classifying images. In one aspect, a method includes receiving training samples for a particular data dimension. Each training sample specifies a training value for the data dimension and a measure of relevance between the training sample and a phrase. A value range is determined for the data dimension. The value range is segmented into two or more segments. A predictive model is trained for each segment. The predictive model for each segment is trained to predict an output based on an input value that is within the segment. A classification sample specifying an input value is received. A classification output is computed based on the input value, the predictive model for the segment in which the input value is included, and the predictive model for an adjacent segment.

Abstract: Methods, systems and apparatus for refining image relevance models. In general, one aspect of the subject matter described in this specification can be implemented in methods that include re-training an image relevance model by generating a first re-trained model based on content feature values of first images of a first portion of training images in a set of training images, receiving, from the first re-trained model, image relevance scores for second images of a second portion of the set of training images, removing, from the set of training images, some of the second images identified as outlier images for which the image relevance score received from the first re-trained model is below a threshold score, and generating a second re-trained model based on content feature values of the first images of the first portion and the second images of the second portion that remain following removal of the outlier images.

Abstract: Methods, systems and apparatus for assigning labels to images. In general, in one aspect, a method includes determining, for an image, a first set of labels, each label being determined to be indicative of subject matter of the image based on content feature values of the image, for each label in the first set of labels, determining a second set of labels, each label in the second set of labels determined to be semantically related to the label in the first set of labels, assigning a score to each label in the second sets of labels, and based on the scores assigned to each label in the second sets of labels, assigning one or more of the labels in the second sets of labels to the image.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for adjusting confidence scores of image labels for images. In one aspect, a method includes accessing images stored in an image data store, the images being associated with respective sets of labels, the labels describing content depicted in the image and having a respective confidence score that is a measure of confidence that the label accurately describes the content depicted in the image; selecting a first image from the images and determining for each of the other images and independent of the labels, a proximity score that is a measure of a relatedness of the other image to the first image; and adjusting the set of labels associated with the first image based on the respective proximity scores of the other images and the confidence scores of the labels of the other images.