Spoof detection by estimating subject motion from captured image frames

A method comprising:

• receiving, at one or more processing devices, a first image and a second image, wherein the first image represents a first relative location of an image acquisition device with respect to a first subject, and the second image represents a second relative location, different from the first relative location, of the image acquisition device with respect to the first subject;
• determining, by the one or more processing devices and using the first image and the second image, a first total relative displacement of the first subject with respect to the image acquisition device between a time of capture of the first image and a time of capture of the second image;
• determining, based on sensor data associated with one or more sensors associated with the image acquisition device, motion information associated with the image acquisition device;
• determining, based on (i) the first total relative displacement and (ii) the motion information associated with the image acquisition device, a motion of the first subject;
• in response to determining that the motion of the first subject is below a threshold, determining that the first subject is an alternative representation of a live person;
• and
• responsive to determining that the first subject is an alternative representation of a live person, preventing access to a system.

A system comprising:

• an image acquisition device that captures a first sequence of images of a first subject over a time period in which relative locations of the image acquisition device with respect to the first subject varies;
• and
• an image analysis engine comprising one or more processing devices, the image analysis engine configured to:
• receive the first sequence of images,
• select a first image and a second image from the first sequence of images, wherein the first image represents a first relative location of the image acquisition device with respect to the first subject, and the second image represents a second relative location, different from the first relative location, of the image acquisition device with respect to the first subject,
• determine, using the first image and the second image, a first total relative displacement of the first subject with respect to the image acquisition device between a time of capture of the first image and a time of capture of the second image,
• determine, based on sensor data associated with one or more sensors associated with the image acquisition device, motion information associated with the image acquisition device,
• determining, based on (i) the first total relative displacement and (ii) the motion information associated with the image acquisition device, a motion of the first subject,
• in response to determining that the motion of the first subject is below a threshold, determine that the first subject is an alternative representation of a live person, and
• responsive to determining that the first subject is an alternative representation of a live person, prevent access to a system.

One or more non-transitory machine-readable storage devices having encoded thereon computer readable instructions for causing one or more processing devices to perform operations comprising:

• obtaining a first sequence of images of a first subject captured by an image acquisition device over a time period in which relative locations of the image acquisition device with respect to the first subject varies;
• selecting a first image and a second image from the first sequence of images, wherein the first image represents a first relative location of the image acquisition device with respect to the first subject, and the second image represents a second relative location, different from the first relative location, of the image acquisition device with respect to the first subject;
• determining, using the first image and the second image, a first total relative displacement of the first subject with respect to the image acquisition device between a time of capture of the first image and a time of capture of the second image;
• determining, based on sensor data associated with one or more sensors associated with the image acquisition device, motion information associated with the image acquisition device;
• determining, based on (i) the first total relative displacement and (ii) the motion information associated with the image acquisition device, a motion of the first subject;
• in response to determining that the motion of the first subject is below a threshold, determining that the first subject is an alternative representation of a live person;
• and
• responsive to determining that the first subject is an alternative representation of a live person, preventing access to a system.