US 9,854,188 B2Granted

Calibration of defective image sensor elements

AssigneeGoogle Inc.

InventorsMarc Stewart Levoy, Roman Lewkow

Life of this patent

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Abstract

The present disclosure relates to methods and systems that may reduce pixel noise due to defective sensor elements in optical imaging systems. Namely, a camera may capture a burst of images with an image sensor while adjusting a focus distance setting of an optical element. For example, the image burst may be captured during an autofocus process. The plurality of images may be averaged or otherwise merged to provide a single, aggregate image frame. Such an aggregate image frame may appear blurry. In such a scenario, “hot” pixels, “dead” pixels, or otherwise defective pixels may be more easily recognized and/or corrected. As an example, a defective pixel may be removed from a target image or otherwise corrected by replacing a value of the defective pixel with an average value of neighboring pixels.

Claims20

Dependent claims

An optical imaging system comprising:

an image sensor comprising a plurality of sensor elements, the sensor elements configured to represent respective pixels in captured images;
an optical element coupled to the image sensor and configured to define a focus distance setting of the captured images;
and
a controller comprising a memory and at least one processor, wherein the processor is configured to execute instructions stored in the memory so as to carry out operations, the operations comprising:
causing the image sensor to capture a plurality of images, the images captured with different respective focus distance settings defined by the optical element;
combining the plurality of images into an aggregate image;
based on the aggregate image, determining a condition of a particular sensor element of the plurality of sensor elements;
causing the image sensor to capture a payload image;
and
adjusting, in the payload image, a value of a particular pixel that is associated with the particular sensor element.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/972,075Filed 16 Dec 2015
Published: US 2017/0180659 A122 Jun 2017
Granted: 26 Dec 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

G06T 3/4038
Scaling of whole images or parts thereof, e.g. expanding or contracting: image mosaicing, e.g. composing plane images from plane sub-images
H04N 17/002
Diagnosis, testing or measuring for television systems or their details: for television cameras
H04N 23/676
Focus control based on electronic image sensor signals: bracketing for image capture at varying focusing conditions
H04N 23/743
Circuitry for compensating brightness variation in the scene: bracketing, i.e. taking a series of images with varying exposure conditions