US-20260129315-A1 - IMAGING DEVICE AND METHOD FOR OPERATING THE SAME

US20260129315A1US 20260129315 A1US20260129315 A1US 20260129315A1US-20260129315-A1

Abstract

Imaging devices and methods of operating the same are disclosed. In an embodiment, an imaging device includes an active pixel array, an optical black pixel array, and a memory. The active pixel array includes a plurality of active pixels, each of which generates a pixel signal in response to incident light. The optical black pixel array includes a plurality of optical black pixels configured to generate dark signals for correcting dark noises of the plurality of active pixels. The memory stores matching data indicating a plurality of black regions in the optical black pixel array respectively matched with the plurality of active pixels.

Inventors

Gon Ji LEE
Hyung Jun HAN

Assignees

SK Hynix Inc.

Dates

Publication Date: 20260507
Application Date: 20250514
Priority Date: 20241101

Claims (20)

1 . A method for operating an imaging device comprising: collecting a first pixel signal that is generated by a first active pixel included in an active pixel array in response to incident light; reading, from a memory, matching data indicating a first black region that corresponds to the first active pixel and is in an optical black pixel array that is designed to block incident light from entering pixels in the optical block pixel array; collecting first dark signals that are generated by a plurality of first optical black pixels included in the first black region of the optical black pixel array; and correcting the first pixel signal using the first dark signals.
2 . The method according to claim 1 , wherein the reading the matching data includes: determining positions of the plurality of first optical black pixels included in the first black region.
3 . The method according to claim 1 , wherein: the first pixel signal is generated by converting the first pixel signal into a first digital signal; and the first dark signals are generated by converting each of the first dark signals into a second digital signal.
4 . The method according to claim 3 , wherein the correcting the first pixel signal includes: calculating a first average by averaging the second digital signals.
5 . The method according to claim 4 , wherein the correcting the first pixel signal includes: subtracting the first average from the first digital signal.
6 . The method according to claim 1 , further comprising: collecting a second pixel signal that is generated by a second active pixel included in the active pixel array in response to the incident light; reading the matching data indicating a second black region in the optical black pixel array corresponding to the second active pixel; and collecting second dark signals that are generated by a plurality of second optical black pixels included in the second black region of the optical black pixel array.
7 . The method according to claim 6 , wherein the reading the matching data further includes: determining positions of the plurality of second optical black pixels included in the second black region.
8 . The method according to claim 6 , wherein: the second pixel signal is generated by converting the second pixel signal into a third digital signal; and the second dark signals are generated by converting each of the second dark signals into a fourth digital signal.
9 . The method according to claim 8 , further comprising: correcting the second pixel signal using the second dark signals wherein the correcting the second pixel signal includes: calculating a second average indicating an average of the fourth digital signals.
10 . The method according to claim 9 , wherein the correcting the second pixel signal further includes: subtracting the second average from the third digital signal.
11 . An imaging device comprising: an image sensor including: a pixel array configured to generate a plurality of pixel signals in response to incident light; and a memory configured to store matching data for correcting the pixel signals, wherein the pixel array includes: an active pixel array including a plurality of active pixels configured to receive incident light to generate the plurality of pixel signals; and an optical black pixel array including a plurality of optical black pixels configured to block incident light from being received by the optical black pixels to generate a plurality of dark signals indicating noise in the optical black pixels without being exposed to incident light for correcting the plurality of pixel signals, wherein the matching data indicates a plurality of black regions in the optical black pixel array respectively corresponding to the plurality of active pixels.
12 . The imaging device according to claim 11 , wherein the matching data indicates a position of each of optical black pixels included in a black region of the plurality of black regions.
13 . The imaging device according to claim 11 , wherein the matching data includes: information to match a plurality of active regions, obtained by dividing the active pixel array, with one of the black regions and match a plurality of active pixels included in each of the active regions with a same black region from among the black regions.
14 . The imaging device according to claim 13 , wherein: an average of dark noises of active pixels included in an active region is equal to an average of dark noises of optical black pixels included in a black region matched with the active region.
15 . The imaging device according to claim 11 , wherein the image sensor further includes: a readout circuit configured to convert each of the plurality of pixel signals and each of the plurality of dark signals into digital signals.
16 . The imaging device according to claim 15 , further comprising: an image signal processor configured to calculate an average of the digital signals converted from the plurality of dark signals generated by optical black pixels included in the black region, subtracts the calculated average from the digital signal converted from a pixel signal generated by an active pixel matched with the black region, and corrects the pixel signal based on a result of subtraction.
17 . The imaging device according to claim 16 , wherein: the plurality of active pixels includes a first active pixel configured to generate a first pixel signal, and a second active pixel configured to generate a second pixel signal; and the plurality of black regions includes a first black region matched with the first active pixel, and a second black region matched with the second active pixel.
18 . The imaging device according to claim 17 , wherein the plurality of active pixels further includes: a third active pixel configured to generate a third pixel signal, wherein the third active pixel is matched with the first black region.
19 . The imaging device according to claim 18 , wherein: a portion of the first black region is configured to overlap a portion of the second black region.
20 . The imaging device according to claim 18 , wherein: the first black region is spaced apart from the second black region.

Description

CROSS-REFERENCE TO RELATED APPLICATION This patent document claims the priority and benefits of Korean patent application No. 10-2024-0153644, filed on Nov. 1, 2024, the disclosure of which is incorporated herein by reference in its entirety as part of the disclosure of this patent document. TECHNICAL FIELD The technology and embodiments disclosed in this patent document generally relate to an imaging device, and more particularly to an imaging device including an image sensing device. BACKGROUND An imaging device can output a final image by performing correction processes in an image processing device on a raw image generated by an image sensor embedded in the imaging device. An image sensor is a device that captures optical raw images by converting light into electrical signals using a photosensitive semiconductor material that reacts to light. With advancements in industries such as automotive, medical, computer and communication industries, the demand for high-performance image sensors is increasing in various fields such as smartphones, digital cameras, game machines, IoT (Internet of Things), robots, security cameras and medical micro cameras. The image sensor may be roughly divided into charge coupled device (CCD) image sensors and complementary metal oxide semiconductor (CMOS) image sensors. CCD image sensors offer a better image quality compared to the CMOS image sensors, but they tend to consume more power and are larger in size. CMOS image sensors are smaller in size and consume less power than CCD image sensors. Furthermore, CMOS image sensors are fabricated using the CMOS fabrication technology, and thus photosensitive elements and other signal processing circuitry can be integrated into a single chip, enabling the production of miniaturized image sensors at a lower cost. For these reasons, CMOS image sensors are being developed for many applications including mobile devices. The image processing device is embedded in the imaging device, and may perform necessary corrections on the raw image to generate the final image. SUMMARY Various embodiments of the disclosed technology relate to improving the quality of the final image output by the imaging device by correcting noise such as a dark current that is produced by an active pixel array included in an image sensor when no incident light is present or received by the active pixel array, and more particularly to technology for reducing a deviation that may occur between an average value of noise generated from the entire optical black pixel array which is an optical pixel array that is designed to block incident light so that the pixel signals are generated by the pixels in the optical black pixel array are caused by the dark current and an average value of noise generated from the entire active pixel array, thereby. In an embodiment of the disclosed technology, a method for operating an imaging device may include: collecting a first pixel signal that is generated by a first active pixel included in an active pixel array in response to incident light; reading, from a memory, matching data indicating a first black region in an optical black pixel array corresponding to the first active pixel; collecting first dark signals that are generated by a plurality of first optical black pixels included in the first black region of the optical black pixel array; and correcting the first pixel signal using the first dark signals. In some implementations, the reading the matching data may include: determining positions of the plurality of first optical black pixels included in the first black region. In some implementations, the first pixel signal is generated by converting the first pixel signal into a first digital signal; and the first dark signals are generated by converting each of the first dark signals into a second digital signal. In some implementations, the correcting the first pixel signal may include: calculating a first average by averaging the second digital signals. In some implementations, the correcting the first pixel signal may include: subtracting the first average from the first digital signal. In some implementations, the method may further comprise: collecting a second pixel signal that is generated by a second active pixel included in the active pixel array in response to the incident light; reading the matching data indicating a second black region in the optical black pixel array corresponding to the second active pixel; and collecting second dark signals that are generated by a plurality of second optical black pixels included in the second black region of the optical black pixel array. In some implementations, the reading the matching data may further include: determining positions of the plurality of second optical black pixels included in the second black region. In some implementations, the second pixel signal is generated by converting the second pixel signal into a third digital signal. The second dark signals are generated by