Multi-channel high-resolution imaging devices incorporating metalenses for color images
An apparatus includes, in some implementations, at least one image sensor, a plurality of metalenses, and readout and processing circuitry. The at least one image sensor includes pixel arrays, each of which is associated, respectively, with a different one of multiple optical channels configured for detection of incoming light rays of a respective color. The color for each optical channel differs from that of at least one of the other optical channels. Each of the metalenses is disposed, respectively, in a different one of the optical channels and is configured, respectively, to focus incoming light rays onto a different one of the pixel arrays. The readout and processing circuitry is operable to read out signals from the pixel arrays and to generate a respective lower-resolution image for each of the optical channels, and to process the lower-resolution images to obtain a higher-resolution multi-color image. Methods of operation are described as well.
1 . An apparatus comprising:
an image sensor including a plurality of pixel arrays, each of the pixel arrays being associated, respectively, with a different one of a plurality of optical channels configured for detection of incoming light rays of a respective color, wherein the color for each optical channel differs from that of at least one of the other optical channels;
a plurality of metalenses, each of which is disposed, respectively, in a different one of the plurality of optical channels and is configured, respectively, to focus incoming light rays onto a different one of the pixel arrays; and
readout and processing circuitry operable to read out signals from the plurality of pixel arrays and to generate a respective lower-resolution image for each of the optical channels, and to process the lower-resolution images to obtain a higher-resolution multi-color image,
wherein the image sensor and the plurality of metalenses are configured such that each of the pixel arrays is operable to acquire an image of a scene from a viewpoint that differs from the other pixel arrays to produce a sub-pixel shift in the image of the scene acquired by a first one of the pixel arrays relative to the image of the scene acquired by a second one of the pixel arrays.
2 . The apparatus of claim 1 wherein each of the plurality of metalenses is configured to focus incoming light rays of a different respective wavelength, or falling within a different respective range of wavelengths, onto a respective one of the pixel arrays.
3 . The apparatus of claim 2 wherein each particular one of the plurality of optical channels includes a respective optical filter configured to allow incoming light rays of the respective color associated with the particular channel to pass, and wherein each of the optical filters is disposed between the image sensor and a different respective one of the metalenses.
4 . The apparatus of claim 2 wherein each particular one of the plurality of optical channels includes a respective optical filter configured to allow incoming light rays of the respective color associated with the particular channel to pass, and wherein each of the optical filters is disposed over a different respective one of the metalenses.
5 . The apparatus of claim 2 wherein each of the pixel arrays is operable to acquire an image of a scene, and wherein there is a sub-pixel shift in the image acquired by a first one of the pixel arrays relative to the image acquired by a second one of the pixel arrays, the apparatus further including at least three optical channels associated, respectively, with wavelengths of red, green and blue light.
6 . The apparatus of claim 5 wherein the readout and processing circuitry is operable to process the lower-resolution images to obtain a higher-resolution multi-color image using a super-resolution protocol.
7 . The apparatus of claim 1 wherein each particular one of the plurality of optical channels includes a respective optical filter configured to allow incoming light rays of the respective color associated with the particular channel to pass.
8 . The apparatus of claim 7 wherein each of the optical filters is disposed between the image sensor and a different respective one of the metalenses.
9 . The apparatus of claim 7 wherein each of the optical filters is disposed over a different respective one of the metalenses.
10 . The apparatus of claim 1 including at least three optical channels associated, respectively, with wavelengths of red, green and blue light.
11 . The apparatus of claim 1 wherein the readout and processing circuitry is operable to process the lower-resolution images to obtain a higher-resolution multi-color image using a super-resolution protocol.
12 . A method comprising:
acquiring, by each of a plurality of pixel arrays associated with different respective optical channels of an imaging device, a respective lower-resolution image of a scene, where each of the lower-resolution images of the scene is based on light rays passing through a respective metalens of a plurality of metalenses in a respective one of the optical channels, and wherein each of the optical channels is configured, respectively, for light of a different color;
reading out, from the pixel arrays, signals representing the acquired lower-resolution images; and
using a super-resolution protocol to obtain a higher-resolution multi-color image of the scene based on the lower-resolution images,
wherein the plurality of pixel arrays and the plurality of metalenses are configured such that each of the pixel arrays is operable to acquire an image of a scene from a viewpoint that differs from the other pixel arrays to produce a sub-pixel shift in the lower-resolution image of the scene acquired by a first one of the pixel arrays relative to the lower-resolution image of the scene acquired by another one of the pixel arrays.
13 . The method of claim 12 including displaying the higher-resolution multi-color image on a display screen of a computing device.
14 . The method of claim 12 including displaying the higher-resolution multi-color image on a display screen of a smartphone.
15 . The method of claim 12 wherein each respective one of the plurality of metalenses focuses incoming light rays of a different respective wavelength, or falling within a different respective range of wavelengths, onto a respective one of the pixel arrays.
16 . The method of claim 15 wherein each metalens of the plurality of metalenses comprises meta-atoms arranged to resonate at a fixed frequency corresponding to the respective wavelength.