How Digital Images Hide Invisible Markers to Track Rotation and Scaling
A method for hiding invisible patterns in digital images that allow computers to detect if an image has been rotated or resized, even if the original version is missing.
Original patent title: “Method and apparatus for discerning image distortion by reference to encoded marker signals”
A method for hiding invisible patterns in digital images that allow computers to detect if an image has been rotated or resized, even if the original version is missing. Granted to Digimarc Corp in 2003 with 31 claims and 136 forward citations.
Key facts
Coverage
What does this patent actually cover?
This patent describes a way to embed invisible 'orientation markers' into a digital image. These markers are essentially a specific pattern of energy peaks that appear when the image is analyzed using a mathematical process called a Fourier transform. Because these peaks follow a predictable geometric pattern, a computer can compare the distorted version of an image against the known original pattern to calculate exactly how much it has been rotated or scaled. This allows software to automatically 'undo' these distortions to recover hidden data, such as a copyrightcopyrightLegal protection for original creative works (books, code, art). Automatic at creation. Different from patents, which protect inventions.Read more → watermark, without needing the original, unedited file.
The gap
What does this patent NOT cover?
- Does not cover visible watermarks like logos or text overlays.
- Does not cover methods that require the original, unedited image to calculate distortion.
- Does not cover distortion types other than rotation and scaling, such as perspective warping or cropping.
- Does not cover non-digital image formats or physical analog prints.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The innovation lies in embedding the orientation markers in the spatial frequency domain as a pattern of energy peaks, which remain mathematically discoverable even after the image has been transformed or degraded.
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Digital image watermarking software
Automated copyrightcopyrightLegal protection for original creative works (books, code, art). Automatic at creation. Different from patents, which protect inventions.Read more → enforcement tools
Content authentication systems for digital media
Why it matters
The bigger picture
This technology was foundational for digital rights management and content protection in the early 2000s. By allowing software to reliably find and read watermarks on images that had been resized or tilted by users, it enabled automated tracking of copyrighted material across the internet. It solved a major technical hurdle for companies trying to enforce intellectual property rights in a digital environment.
Filed
April 27, 2000
Granted
May 20, 2003
Market context
Who's building on this
Companies in this space
Digimarc Corporation remains a primary player in this space, continuing to develop advanced digital watermarking and identification technologies. Major media companies and content protection firms utilize similar principles to track digital assets across global networks.
Market impact
This patent helped establish the technical feasibility of robust digital watermarking, which became a standard tool for media companies to track unauthorized distribution. It moved the industry away from relying on visible, easily removable labels toward invisible, persistent digital signatures.
Claim 1 — Plain English
What this patent covers
This patent describes a way to embed invisible 'orientation markers' into a digital image. These markers are essentially a specific pattern of energy peaks that appear when the image is analyzed using a mathematical process called a Fourier transform. Because these peaks follow a predictable geometric pattern, a computer can compare the distorted version of an image against the known original pattern to calculate exactly how much it has been rotated or scaled. This allows software to automatically 'undo' these distortions to recover hidden data, such as a copyright watermark, without needing the original, unedited file.
The clever bit
The innovation lies in embedding the orientation markers in the spatial frequency domain as a pattern of energy peaks, which remain mathematically discoverable even after the image has been transformed or degraded.
What it does not cover
- Does not cover visible watermarks like logos or text overlays.
- Does not cover methods that require the original, unedited image to calculate distortion.
- Does not cover distortion types other than rotation and scaling, such as perspective warping or cropping.
- Does not cover non-digital image formats or physical analog prints.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
PatentBrief Score
Impact Score
Strong
Citation count
40/40
Highly cited
Claim breadth
20/20
Very broad protection
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$144K – $461K
Midpoint $288K · expired or expiring · industry ×1.6
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
The original legal language
Original claims
31 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Rhoads, G. B. (2003). How Digital Images Hide Invisible Markers to Track Rotation and Scaling (U.S. Patent No. 6,567,533). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/6567533/playstation-2-emotion-engine
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
Embed
Add this patent to your site
Drop this plain-English patent card into any blog post or article — free, no signup. It always links back to the full breakdown here.
<div data-patentlens-widget data-patent-number="US6567533"></div> <script src="https://patentbrief.org/embed.js" async></script>
Stay in the loop
Get a weekly digest of new patents.
One email per week. No spam. Unsubscribe anytime.
Keep exploring
Related patents you should know
US 4683195 · 1987
How to Make Billions of Copies of a DNA Segment
This patent describes the Polymerase Chain Reaction (PCR), a method to rapidly create many copies of a specific piece of DNA or RNA, enabling its detection and analysis.
Cetus Corp
US 8697359 · 2014
How to Edit Genes in Human Cells Using an Engineered CRISPR System
This patent describes an engineered CRISPR-Cas9 system for precisely cutting DNA in eukaryotic cells to change how genes work, opening the door for gene editing in complex organisms.
Massachusetts Institute of Technology
US 7657849 · 2010
How the iPhone's Slide-to-Unlock Gesture Works
Apple's 2010 patent describes unlocking a device by dragging a specific graphical image across the touchscreen along a predefined path, a gesture that became iconic with the original iPhone.
Apple Inc
US 4733665 · 1988
How Doctors Implant a Permanent Stent Using a Balloon
This patent describes the method for placing a permanent, expandable wire mesh tube inside a blood vessel or other body tube using a balloon-tipped catheter to widen it and keep it open.
Expandable Grafts Partnership
US 4965188 · 1990
How to Make Many Copies of a DNA Piece with Heat
This patent describes the Polymerase Chain Reaction (PCR) method, a technique to make millions of copies of a specific DNA segment using a heat-resistant enzyme and repeated temperature changes.
Cetus Corp
US 4235871 · 1980
How to Encapsulate Active Materials in Lipid Bubbles Efficiently
This patent describes a method for trapping biologically active substances inside tiny, multi-layered fat bubbles called liposomes, using a specific water-in-oil emulsion and gel-forming process to improve how much material gets captured.
Individual
More to explore
More in Software & Internet
US 4405829 · 1983 · Massachusetts Institute of Technology
How RSA Public-Key Encryption Keeps Digital Messages Secret
US 6285999 · 2001 · Leland Stanford Junior University
How Websites Get Ranked by Importance
US 5960411 · 1999 · Amazon com Inc
How Amazon's One-Click Ordering Works for Online Purchases
US 7669123 · 2010 · Facebook Inc
Displaying Friends' Activities in a Social Network Feed
New to patents?
Common Questions
Frequently Asked Questions
What does How Digital Images Hide Invisible Markers to Track Rotation and Scaling cover?
A method for hiding invisible patterns in digital images that allow computers to detect if an image has been rotated or resized, even if the original version is missing.
Who owns patent US 6567533?
Digimarc Corp owns this patent, granted in 2003.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 6567533 cited by?
This patent has been cited by 136 later patents that build on its ideas.
What problem does this patent solve?
This technology was foundational for digital rights management and content protection in the early 2000s. By allowing software to reliably find and read watermarks on images that had been resized or tilted by users, it enabled automated tracking of copyrighted material across the internet. It solved a major technical hurdle for companies trying to enforce intellectual property rights in a digital environment.
What does this patent NOT cover?
Does not cover visible watermarks like logos or text overlays.
Patent monitoring