Obviousness

US patent 7292261 (hereinafter "the '261 patent") describes a "virtual reality camera" that integrates panoramic image creation and interactive viewing capabilities directly into the camera device. The patent aims to address limitations of prior art, such as the need for a separate computer for stitching and viewing panoramic images in the field.

Under 35 U.S.C. § 103, a patent claim is considered obvious if the differences between the claimed invention and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art (POSITA) in the relevant field. The analysis requires identifying prior art references, establishing a motivation to combine them, and demonstrating that the combination would have yielded the claimed invention with a reasonable expectation of success. The priority date for the '261 patent is August 20, 1999.

The '261 patent's "Background of the Invention" section explicitly lays out several prior art elements and their associated problems, which can be leveraged for an obviousness analysis. The "Summary of the Invention" provides several statements that serve as representative claims for this analysis.

Here are combinations of prior art references that would render key aspects of the '261 patent's claims obvious, along with the motivation for a POSITA to combine them:

Obviousness Analysis

1. Claiming a Camera with In-Camera Panoramic Image Combining (Representative Claim: "a camera comprising... combining circuitry for at least partially combining the first frame and the second frame into a panoramic image.")

• Prior Art Elements:

  • Digital cameras with acquisition circuitry for acquiring frames are well-known [BACKGROUND].
  • Panoramic images up to 360° in extent are known [BACKGROUND].
  • The process of "panoramic content creation" by capturing multiple photos and subsequently running a "stitching" application on a computer to combine them into a single panoramic image is explicitly described as prior art. An example cited is the assignee's PhotoVista® software [BACKGROUND].
  • Known problems include the necessity for a photographer to "take a computer with him in the field" which can be "burdensome," and the inability to "create and view the panoramic image while in the field" [BACKGROUND].

• Motivation to Combine:

  • A person having ordinary skill in the art in digital camera design and image processing, recognizing the well-documented burden and inconvenience of requiring a separate computer in the field for creating panoramic images, would be strongly motivated to integrate the known functionality of computer-based "stitching" applications (like PhotoVista®) directly into a digital camera. The explicit problem statement in the background ("One disadvantage is that the photographer needs to take a computer with him in the field") serves as a clear motivation for a POSITA to move the processing capability from an external computer to the camera itself. This combination would lead directly to a camera with internal combining circuitry to produce a panoramic image, solving a known problem in the art.

2. Claiming a Camera with Viewfinder Compositing for Alignment Assistance (Representative Claim: "a camera including... a viewfinder displaying the second field of view... and displaying at least a portion of the first field of view at least partially composited with the second field of view.")

• Prior Art Elements:

  • Digital cameras include camera lenses, acquisition circuitry, and viewfinders [FIG. 1, BACKGROUND].
  • Prior art recognizes the difficulty for a photographer to "accurately align adjacent fields of view" when rotating a camera, especially handheld [BACKGROUND].
  • Mechanical aids for alignment, such as tripod brackets with "equi-spaced notches" (e.g., Kaidan KiWi™ tripod head) and "spirit levels," are known [BACKGROUND].
  • Techniques for "compositing images" are known, explicitly referencing assignee's co-pending application U.S. Ser. No. 08/922,732, filed on Sep. 3, 1997 [Detailed Description "Blending" section].
  • Perspective correction for adjusting image elements based on camera rotation is described [Detailed Description "Acquisition Stage", Equations 3 & 4].

• Motivation to Combine:

  • A POSITA in digital camera engineering, aiming to improve the accuracy and ease of capturing successive frames for panoramic images, particularly given the acknowledged difficulty of precise alignment, would be motivated to enhance the camera's existing viewfinder. While mechanical aids (like notched tripod heads) exist, a visual, real-time aid would offer a more intuitive and direct method. By combining the camera's viewfinder capabilities with known image compositing techniques and applying perspective correction (which is a standard image manipulation task when accounting for camera rotation), a POSITA would find it obvious to display a portion of a previously captured frame (with adjusted perspective) composited onto the live view of the current field in the viewfinder. This provides immediate visual feedback to the photographer for accurate alignment, directly addressing the prior art's stated difficulty with alignment. The patent itself states this feature "assists the photographer in accurately aligning adjacent fields of view" [Summary].

3. Claiming a Camera with In-Camera Interactive Panoramic Playback (Representative Claim: "a camera including... a memory for storing data for a panoramic image, a display for displaying at least a portion of the panoramic image, and display control circuitry for selecting a portion of the panoramic image to display.")

• Prior Art Elements:

  • Digital cameras possess internal memory for storing image data and displays (e.g., viewfinder displays) for viewing images [FIG. 1].
  • "Digital panoramic images can be archived on Internet servers, for access by remote clients" [BACKGROUND].
  • "Client viewer software enables users to interactively view panoramic images by navigating through the panorama" on a "client computer video display." This includes functionality for shifting (panning) and changing magnification (zooming) [BACKGROUND].
  • A known problem is that the "photographer cannot see the quality of his panoramic image while in the field" [BACKGROUND].

• Motivation to Combine:

  • Given the obviousness of creating a panoramic image directly within the camera (as argued in point 1), a POSITA would naturally seek to address the concomitant problem of enabling the photographer to review the quality of that image immediately in the field. Since "client viewer software" already provided interactive viewing (panning, zooming) of panoramic images on external computer displays, it would be an obvious design choice for a POSITA to adapt and integrate this known interactive display functionality onto the camera's existing display using its internal memory and control circuitry. This provides immediate feedback to the photographer, directly solving the problem of not being able to assess image quality until returning to a computer.

4. Claiming Specific Image Combining Methods (Representative Claim: "a method for combining a first frame and a second frame, including the steps of determining horizontal and vertical offsets... summing absolute values of color differences... determining brightness and contrast parameters for chromatically aligning... and generating a panoramic image, including the step of compositing a portion of the second frame onto a portion of the first frame...")

• Prior Art Elements:

  • "Stitching" applications (e.g., PhotoVista® software) are known to combine digital photos into panoramic images [BACKGROUND]. Such applications inherently perform spatial alignment, chromatic alignment, and compositing.
  • Techniques for "blending images" are known, with a specific reference to assignee's co-pending application U.S. Ser. No. 08/922,732, which "describes techniques for blending images" and the '261 patent elaborates on using "brightness and contrast parameters" [Detailed Description "Blending" section].
  • The "sum of absolute differences (SAD)" is presented in the '261 patent as a known "measure of the error" for aligning frames [Detailed Description "Motion estimation" section, Equation 8], indicating its common use in image processing for determining spatial offsets.

• Motivation to Combine:

  • A POSITA developing or implementing image stitching functionality, whether in software or hardware, would routinely employ well-established image processing algorithms for spatial and chromatic alignment, and compositing. The steps described in the claim (determining offsets using sum of absolute differences, adjusting brightness and contrast for chromatic alignment, and compositing) represent standard and known techniques in the field of image stitching. The patent itself refers to its assignee's prior application for blending techniques and discusses SAD as a method for error measurement without claiming its novelty. Therefore, applying these known algorithmic components from existing stitching software (like PhotoVista®) and image processing literature (like U.S. Ser. No. 08/922,732) to the task of in-camera panoramic image creation would be an obvious engineering choice for a POSITA.

5. Claiming an In-Place Texture Mapping Method (Representative Claim: "a method for converting an image stored in a buffer... from a first coordinate system, to a corresponding image stored in the buffer... in a second coordinate system... including the steps of computing color values... storing the computed color values in the buffer at the pixel locations along the axis...")

• Prior Art Elements:

  • Panoramic images are "typically texture mapped into a suitable surface geometry, such as a cylindrical or a spherical geometry," implying that the non-linear transformation from rectilinear to cylindrical coordinates is known [BACKGROUND, Detailed Description "Texture Mapping" section, Equations 5 & 6].
  • The use of memory buffers for storing image data is fundamental in computer graphics and image processing [Detailed Description "Texture Mapping" section].
  • The concept of "in-place processing" to reduce memory requirements is a known optimization technique in computer science and embedded systems programming [Detailed Description "Texture Mapping" section states "in-place processing is advantageous in that it reduces memory requirements"].

• Motivation to Combine:

  • When porting computationally intensive image transformations, such as texture mapping from rectilinear to cylindrical coordinates (which is known prior art for panoramic image creation), to memory-constrained embedded systems like digital cameras, a POSITA would be strongly motivated to employ memory-efficient algorithms. The technique of performing operations "in-place"—that is, writing transformed data back into the same memory buffer as the source data to avoid allocating a duplicate buffer—is a fundamental and well-known optimization strategy in computer science to conserve memory resources. Applying this known optimization to the known texture mapping transformation for panoramic images would be an obvious engineering implementation for a POSITA facing memory limitations in a camera environment. The patent explicitly states this as an advantage: "in-place processing is advantageous in that it reduces memory requirements, since separate memory buffers are not required for both the rectilinear and the cylindrical data" [Detailed Description "Texture Mapping"].

In summary, the '261 patent details a camera that integrates several functionalities, each of which, when considered in light of the prior art explicitly discussed within the patent, would have been obvious to a person of ordinary skill in the art. The motivation stems from well-known problems in panoramic photography (the need for a computer in the field, difficulty in alignment, inability to immediately review) and the logical application of existing image processing techniques and hardware optimization strategies to solve these problems within a camera device.