22. An apparatus for determining a person's response to a retail element, based on the person's facial expression and shopping behavior, comprising: a) at least a first means for capturing images that captures first input images, b) at least a control and processing system that performs the following steps of: detecting and tracking a face from the first input images, estimating two-dimensional and three-dimensional pose of the face, localizing facial features, estimating gaze direction of the person using the two-dimensional and three-dimensional poses and the positions of the facial features and changes in affective state of the person by extracting emotion-sensitive features, c) at least a second means for capturing images that captures second input images, d) the control and processing system that performs the following steps of: detecting and tracking the person from the second input images producing a trajectory of the person, and estimating body orientation, identifying the shopping behaviors of the person toward the retail element, utilizing position and the body orientation of the person relative to the retail element, and determining intermediate responses and end response of the person to the retail element by analyzing the changes in affective states and interest, in the context of the shopping behavior, and e) at least a means for video interface that connects the first means for capturing images and the second means for capturing images to the control and processing system, wherein the shopping behaviors include showing interest, engagement, interaction, or purchasing.
22. An apparatus for determining a person's response to a retail element, based on the person's facial expression and shopping behavior, comprising: a) at least a first means for capturing images that captures first input images, b) at least a control and processing system that performs the following steps of: detecting and tracking a face from the first input images, estimating two-dimensional and three-dimensional pose of the face, localizing facial features, estimating gaze direction of the person using the two-dimensional and three-dimensional poses and the positions of the facial features and changes in affective state of the person by extracting emotion-sensitive features, c) at least a second means for capturing images that captures second input images, d) the control and processing system that performs the following steps of: detecting and tracking the person from the second input images producing a trajectory of the person, and estimating body orientation, identifying the shopping behaviors of the person toward the retail element, utilizing position and the body orientation of the person relative to the retail element, and determining intermediate responses and end response of the person to the retail element by analyzing the changes in affective states and interest, in the context of the shopping behavior, and e) at least a means for video interface that connects the first means for capturing images and the second means for capturing images to the control and processing system, wherein the shopping behaviors include showing interest, engagement, interaction, or purchasing. 24. The apparatus according to claim 22 , wherein the apparatus further comprises means for training a plurality of second machines for localizing facial features in the face.