Method and apparatus for capturing digital video

Patent No. US11490015 (titled "Method and apparatus for capturing digital video") on Mar 11, 2022. The application was issued on Nov 1, 2022.

'015 is related to the field of digital image processing, specifically addressing the problem of motion blur in captured video. Traditional methods for reducing blur often involve increasing sharpness or contrast, which can lead to data loss and altered image characteristics. The background context involves techniques for correcting image distortion caused by relative motion between the imaging device and the subject, or by optical distortion.

The underlying idea behind '015 is to selectively blur the background of a video while keeping the main subject in focus, creating a visually appealing effect. This is achieved by capturing a sequence of images and then processing them to identify a main subject and the background. The system then combines these images in a way that the subject remains sharp while the background is intentionally blurred.

The claims of '015 focus on a method and apparatus within an imaging device that captures digital video. The device displays a preview, captures a sequence of images, determines a main subject and background, generates modified images where the subject is sharp and the background is blurred, combines these into a final video, stores the video, and displays it to the user.

In practice, the invention captures multiple images in quick succession. The processor then analyzes these images to identify the main subject, potentially using techniques like pattern recognition or depth estimation. Based on the identified subject, the system then aligns and combines the images in a way that minimizes blur on the subject while introducing blur in the background. This might involve averaging pixel values for the subject and applying a blurring filter to the background.

This approach differs from prior art methods that attempt to remove blur uniformly across the entire image. Instead, '015 leverages the capture of multiple images to create a selective blur effect, enhancing the visual appeal of the video by drawing attention to the main subject while creating a shallow depth of field effect. The use of a processor to identify the subject and selectively apply blurring is a key differentiator, allowing for a more artistic and controlled final video. The focal length of the lens is also used to determine the subject and background.

How does this patent fit in bigger picture?

Technical Landscape

In the mid-2000s when ’015 was filed, digital image capture was typically implemented using CCD or CMOS sensors that recorded light continuously while a shutter remained open, making the process highly susceptible to motion-induced blur. At a time when systems commonly relied on mechanical lens stabilization or simple post-capture sharpening filters, correcting for relative motion between the camera and a subject was difficult because sharpening algorithms often resulted in significant data loss rather than true restoration. Furthermore, hardware and software constraints made the real-time calculation and inversion of two-dimensional transfer functions non-trivial, often forcing a trade-off between using fast shutter speeds, which limited light intake, or accepting motion blur in low-light conditions.

Prosecution Position

The examiner allowed the application because the prior art did not suggest the specific method of processing a sequence of images to distinguish a primary subject from its background. Specifically, the claims were approved for their unique ability to identify a designated subject within a video stream, generate a series of modified images where that specific subject is rendered without motion blur while the background remains blurred, and then assemble these processed frames into a final video.

Claims

This patent includes 30 claims, with independent claims 1, 11, and 21. The independent claims focus on a method and apparatuses for capturing digital video, processing images to identify a subject and background, and generating a final video where the subject is blur-free and the background is blurred. The dependent claims generally elaborate on the specifics of subject determination, user input, focal length considerations, background blurring, subject alignment, and generating a second video without background blur.

Key Claim Terms New

Definitions of key terms used in the patent claims.

Term (Source)	Support for Specification	Interpretation
Blur free (Claim 1, Claim 11, Claim 21)	The present invention processes image data in order to correct an image for distortion caused by imager movement or by movement of the subject being imaged. In another embodiment, the present invention can prevent image distortion due to motion of the imaging device or subject at relatively slow shutter speeds, resulting in a substantially undistorted image.	A state where the image of the designated subject does not exhibit distortion caused by relative motion between the imaging device and the subject or by optical distortion.
Designated subject (Claim 1, Claim 11, Claim 21)	As a way to align a designated subject, such as the car in this example, pattern recognition and segmentation algorithms may be used that are well known to those skilled in the art, and defined in current literature. Alternatively, a tracking signal that is transmitted from the subject can be used to convey its position. Alternatively, the user can indicate, such as by an indicator in a viewfinder, which object in the field of view is the designated subject to be kept blur-free.	A specific object or area within the captured images that is distinguished from the background and is intended to be rendered without blur in the final video.
Relative shift (Claim 21)	When increased accuracy is needed in obtaining h(n,m), those skilled in the art will recognize that, in some cases, the motion information from sensors can be used to calculate h(n,m), and an estimate of h(n,m) can also be calculated by blind estimation and the two transfer functions can be advantageously combined for more accurate results.	The displacement or movement between multiple captured images, used to determine the designated subject and background based on focal length.
Sequence of modified images (Claim 1, Claim 11, Claim 21)	background is blurred. As a way to align a designated subject, such as the car in this example, pattern recognition and segmentation algorithms may be used that are well known to those skilled in the art, and defined in current literature.	A series of images that have been processed such that the designated subject is blur-free while the background is blurred, intended for use in creating a final video.

Litigation Cases New

US Latest litigation cases involving this patent.

Case Number	Filing Date	Title
3:23-cv-00673	Apr 14, 2023	Clear Imaging Reasearch, LLC v. Apple Inc.

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US11490015

Application Number: US17693052A
Filing Date: Mar 11, 2022
Publication Date: Nov 1, 2022
External Links: Slate, USPTO, Google Patents

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