Method and apparatus for computing motion tracking parameters

• US 6,750,900 B1
• Filed: 07/23/1998
• Issued: 06/15/2004
• Est. Priority Date: 07/23/1998
• Status: Expired due to Fees

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Cok, David R.
• Primary Examiner(s): DIEP, NHON THANH
• Application Number:
  US09/121,171
• Time in Patent Office: 2,154 Days
• Field of Search: H04/N.5225, 348/169, 348/170, 348/171, 348/172, 348/161, 369/44.28, 369/44.29, 369/53.28, 367/134
• US Class Current: 348/169
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments
• CPC Class Codes: G06T 7/33 using feature-based methods
• CPC Class Codes: G11B 27/031 Electronic editing of digitised analogue information signals, e.g. audio or video signals
• CPC Class Codes: H04N 5/144 Movement detection for video coding H04N19/503; analysis of motion in general G06T7/20

Abstract

A method and apparatus is provided for efficient computing of perspective transformation motion tracking parameters in a sequence of images. More specifically, a set of initial positions for N points defined as (xi yi) for i=1 to N corresponding to at least one input image in a sequence of images are defined. The initial positions are preferably chosen based on image features having good edge and corner definitions. A set of mapping parameters are then generated using a matrix processor to solve linearized equations that define a set of final positions. The mapping parameters are then applied to the initial positions to define the set of final positions.

Claims

1. A method for efficient determination and computing of perspective transformation motion tracking parameters in a sequence of images comprising:

defining a set of initial positions for N points defined as (xi yi) for i=1 to N corresponding to at least one input image in said sequence of images;

generating a set of mapping parameters using a matrix processor to solve a set of linearized equations; and

applying the set of mapping parameters to the initial positions to define a set of final positions.

2. A method as claimed in claim 1, wherein the mapping parameters correspond to a perspective transformation having eight parameters (a, b, c, d, e, f, g, h) and relate to the initial and final positions as defined by the following non-linear equations:

3. A method as claimed in claim 2, wherein the step of generating a set of mapping parameters includes solving the following linearized equations:

4. A method as claimed in claim 3, wherein the linearized equations are solved using the perspective matrix equation of FIG. 1.

5. A method as claimed in claim 1, wherein the step of generating a set of mapping parameters includes:

a.) fixing initial values of g and h

b.) determining best values of (a, b, c, d, e, f) by solving the following matrix equations;

6. An apparatus for efficient determination and computing of perspective transformation motion tracking parameters in a sequence of images comprising:

means for defining a set of initial positions for N points defined as (xi yi) for i=1 to N corresponding to at least one input image in said sequence of images;

means for generating a set of perspective mapping parameters by solving linearized equations; and

means for applying the set of mapping parameters to the initial positions to define a set of final positions.