Perspective improvement for image and video applications

• US 8,494,224 B2
• Filed: 03/07/2011
• Issued: 07/23/2013
• Est. Priority Date: 04/25/2006
• Status: Expired due to Fees

• Current Assignee: Motorola Mobility LLC (Lenovo Group Ltd.)
• Original Assignee: Motorola Mobility LLC (Lenovo Group Ltd.)
• Inventors: Super, Boaz J., Augustine, Bruce A., Crenshaw, James E., Groat, Evan A., Theims, Michael S.
• Primary Examiner(s): Chu, Randolph I
• Application Number:
  US13/041,486
• Publication Number:
  US 20110169986A1
• Time in Patent Office: 869 Days
• Field of Search: None
• US Class Current: 382/106
• CPC Class Codes: G06V 10/247 by affine transforms, e.g. correction due to perspective effects; Quadrilaterals, e.g. trapezoids
• CPC Class Codes: G06V 40/161 Detection; Localisation; Normalisation

Abstract

A system and method for reducing distance-based distortion in a camera image of an object, where the distanced-based distortion is due to differences in distance from the camera to different parts of the object. In one approach, the distortion is reduced by estimating distances to different parts of the object and then generating a reprojected image of the object dependent upon the estimated distances and upon a virtual viewpoint that is more distant than the camera from the object. In a further approach, the image is warped such that points in the image match corresponding points in one or more stored templates. In a still further approach, if excessive distortion is present in the image, the camera zoom is increased and a magnified image is displayed, prompting a person to move farther from the camera thereby reducing the distortion.

Claims

1. A method for reducing distance-based distortion in an image of an object, the image being captured by a camera, where the distance-based distortion is due to differences in distance from the camera to different parts of the object, the method comprising:

for each template of at least one template of the object, a camera determining a set of parameters that relate points in the image to corresponding points in the template of the object;

selecting by the camera from the set of parameters for each of the at least one template, the set of parameters that results in the best match between the image and the corresponding template; and

warping, by the camera, the image using the selected set of parameters.

2. A method in accordance with claim 1, wherein the at least one template of the object comprise a plurality of views of the object.

3. A method in accordance with claim 1, wherein the object is a face and wherein the image comprises an image from a sequence of video images.

6. A method in accordance with claim 1, wherein the object is a face and wherein the image comprises an image from a sequence of video images.

4. A method for reducing distortion in an image of a face, the image being captured by a camera, the method comprising:

storing a template of a face;

determining a set of parameters that relate the image to the template of the face;

selecting parameters that results in the best match between the image and the corresponding template;

warping the image using the selected set of parameters; and

transmitting the warped image from a video phone or webcam.

5. A method in accordance with claim 4, wherein the template of the face comprises a plurality of views of the face.