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US 8,570,386 B2Granted
Method of merging images and relative method of generating an output image of enhanced quality
AssigneeSTMicroelectronics S.r.l.
InventorsAlfio Castorina, Giuseppe Spampinato, Alessandro Capra, Arcangelo Ranieri Bruna
Life of this patent
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Abstract
A method of processing and device configure to process digital images to enhance image quality and correct motion blur. A number N of images of a scene are captured with an exposure time T. An order of sharpness of the images is determined and the sharpest image is used as a reference image for generating an output image.
Claims20
A method, comprising:
- merging a number of two or more images N of a same scene into an output image in an image processing system, by,
- determining an order of sharpness among the N images, the determining including identifying a sharpest image in the N images;
- determining vertical and horizontal offsets with respect to the sharpest image in the N images for other images in the N images and generating corresponding offset-free images;
- generating pixels of an intermediate image by combining corresponding pixels of the sharpest image and the offset-free images, the generating pixels of the intermediate image including calculating a weight of a pixel of an offset-free image based on a calculated standard deviation of noise and an absolute value of a difference between an intensity of the pixel and of a respective pixel of the sharpest image;
- and
- filtering noise from the intermediate image to generate the output image, the determining, generating and filtering being performed by one or more configured devices of the image processing system.
3 more elements
A method, comprising:
- generating an output image having a level of illumination corresponding to an exposure time T, by,
- taking a plurality of N images of a same scene over an exposure time T/N;
- amplifying a luminance of each of the images up to the level of illumination;
- determining an order of sharpness among the N images, the determining including identifying a sharpest image in the N images;
- determining vertical and horizontal offsets with respect to the sharpest image in the N images for other images in the N images and generating corresponding offset-free images;
- generating pixels of an intermediate image by combining corresponding pixels of the sharpest image and the offset-free images, the generating pixels of the intermediate image including calculating a weight of a pixel of an offset-free image based on a calculated standard deviation of noise and an absolute value of a difference between an intensity of the pixel and of a respective pixel of the sharpest image;
- and
- filtering noise from the intermediate image to generate the output image, the determining, the generating and the filtering being performed by a configured image processing system.
5 more elements
A device to process a set of two or more images of a scene, comprising:
- a sensor configured to generate the set of images of the scene;
- a memory configured to store the set of images and respective characteristic curves;
- a raster processing block configured to generate respective signals representing a noise rms value and a sharpness parameter for each image in the set;
- an ordering block configured to assign an order to each image in the set based on the sharpness parameters, the ordering indicating a sharpest image in the set of images;
- a stabilization block configured to generate signals representing horizontal and vertical offsets for images with respect to the sharpest image in the set based on characteristic curves;
- and
- an image processing pipeline having a noise reduction block configured to generate an output image filtered from noise, and an image generation block configured to generate an RGB image corresponding to the set of images, wherein the image processing pipeline is configured to assign a pixel weight based on a noise rms value and on an absolute value of a difference between an intensity of the pixel and of a respective pixel of the sharpest image.
4 more elements
A system to process a set of two or more digital images, comprising:
- a sharpness block configured to determine a sharpest image in the set of images;
- an image stabilization block configured to compensate for motion in the set of images using the sharpest image in the set of images as a reference by determining vertical and horizontal offsets with respect to the sharpest image for other images in the set of images and generating corresponding offset-free images;
- and
- an image processing block configured to:
- generate pixels of an intermediate image by combining corresponding pixels of the sharpest image and the offset-free images, the generating pixels of the intermediate image including calculating a weight of a pixel of an offset-free image based on a calculated standard deviation of noise and on an absolute value of a difference between an intensity of the pixel and of a respective pixel of the sharpest image;
- and
- reduce noise in an output image generated from the set of images.
4 more elements
A non-transitory computer readable memory medium comprising contents that cause a computing device to implement a method of merging a plurality of N images into a single output image, the method including:
- determining an order of sharpness among the N images, the determining identifying a sharpest image among the N images;
- determining vertical and horizontal offsets with respect to the sharpest image in the N images for other images in the N images and generating corresponding offset-free images;
- generating pixels of an intermediate image by combining corresponding pixels of the sharpest image and the offset-free images, the generating pixels of the intermediate image including calculating a weight of a pixel of an offset-free image based on a calculated standard deviation of noise and on an absolute value of a difference between an intensity of the pixel and of a respective pixel of the sharpest image;
- and
- filtering noise from the intermediate image to generate the output image.
2 more elements
Dependencies are inferred from the claim text.