1. A computer-implemented method, comprising: under the control of one or more computer systems configured with executable instructions, capturing, using a camera of a computing device, a first image including a first representation of an object; identifying, in the first image, a plurality of first feature points corresponding to the first representation of the object; analyzing, using at least one processor of the computing device, each combination of four feature points in the plurality of first feature points, each said combination having a local coordinate system defined by a first pair of the four feature points and a first geometric relationship defined by relative coordinates of a second pair of the four feature points to the local coordinate system; identifying at least one subset of the first geometric relationships determined to be representative of the object in the first image; storing information for the at least one subset as entries in a geometric descriptor table; determining that a first subset of the first geometric relationships matches a second subset of the first geometric relationships; omitting at least one of the first subset of the first geometric relationships or the second subset of the first geometric relationships from entry into the geometric descriptor table; capturing, using the camera of the computing device, a second image including a second representation of the object; identifying, in the second image, a plurality of second feature points corresponding to the second representation of the object; analyzing, using the at least one processor of the computing device, each combination of four feature points in the plurality of second feature points, each said combination having a local coordinate system defined by a first pair of the four feature points and a second geometric relationship defined by relative coordinates of a second pair of the four feature points to the local coordinate system; comparing each of the second geometric relationships for the second image to the entries stored in the geometric descriptor table for the first image; and determining at least one of a presence or an approximate location of the object in the second image in response to identifying at least one second geometric relationship matching at least one entry in the geometric descriptor table to within an allowable deviation.