US 3,971,065 · Granted 1976-07-20

The Bayer Filter Patent That Made Digital Color Photography Possible

Imagine a digital camera sensor made of millions of tiny light detectors, but they can't see color on their own. This patent arranges special colored filters over those detectors in a clever checkerboard pattern so the camera can figure out what color everything is. More detectors measure brightness (luminance), fewer measure color (chrominance), which tricks your brain into seeing full color even though most pixels are actually just tracking light intensity.

Curated and verified by the IsItPatented Editorial team

The plain-English version

What it protects

The claim covers a color imaging sensor where light-sensitive elements are arranged in a specific mosaic pattern: luminance-sensitive elements appear frequently (typically at every other position) in both horizontal and vertical directions, while chrominance-sensitive elements fill the remaining gaps. The pattern is created by layering selectively colored filters (like red, green, and blue) over a broad-spectrum solid-state sensor array. What's protected here is this particular spatial arrangement and the principle that you can build full-color images by sampling brightness at high frequency and color information at lower frequency.

Why it matters

This patent describes what became known as the Bayer filter array, one of the foundational techniques in digital imaging. By sampling brightness more densely than color, the design exploits how human vision works: our eyes are much more sensitive to brightness changes than color changes. This elegant trick allowed early digital cameras to produce convincing color images with fewer total pixels, making cameras smaller, cheaper, and more practical. The approach became an industry standard that persists in nearly every smartphone camera and digital camera sensor manufactured today.

Real-world use

Every photo you take on a smartphone or digital camera relies on this color filter pattern. The sensor in your phone camera has millions of red, green, and blue filtered pixels arranged in this Bayer mosaic, allowing it to capture full-color images with a single layer of detectors.

Original USPTO abstract

A sensing array for color imaging includes individual luminance- and chrominance-sensitive elements that are so intermixed that each type of element (i.e., according to sensitivity characteristics) occurs in a repeated pattern with luminance elements dominating the array. Preferably, luminance elements occur at every other element position to provide a relatively high frequency sampling pattern which is uniform in two perpendicular directions (e.g., horizontal and vertical). The chrominance patterns are interlaid therewith and fill the remaining element positions to provide relatively lower frequencies of sampling. In a presently preferred implementation, a mosaic of selectively transmissive filters is superposed in registration with a solid state imaging array having a broad range of light sensitivity, the distribution of filter types in the mosaic being in accordance with the above-described patterns.

Patent details

Publication number: US 3,971,065
Filing date: 1975-03-05
Grant date: 1976-07-20
Assignee: Eastman Kodak Company
Inventor(s): BAYER; BRYCE E.
CPC class: H04N23/12

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