KR-20260064115-A - APPARATUS FOR DETECTING PUPIL AREA BASED ON CMOS IMAGE SENSOR

KR20260064115AKR 20260064115 AKR20260064115 AKR 20260064115AKR-20260064115-A

Abstract

A pupil area measurement device based on a CMOS image sensor according to one embodiment of the present invention comprises: a pixel array having a plurality of interconnected pixels arranged in a matrix form and capturing a user's eye to obtain a plurality of pixel values; and a pupil area processing unit that determines the pupil area by performing an area reduction operation, which is provided for each pixel and binarizes the obtained pixel values into black and white, and performs an area expansion operation, which is performed to obtain a remaining high-density core area by progressively whitening a pixel area with low black density multiple times, and a white pixel area adjacent to the core area by progressively blackening a pixel area multiple times. By doing so, the pupil area can be effectively measured with a simpler configuration.

Inventors

유상동
송재훈
최진한

Assignees

아이칩 주식회사

Dates

Publication Date: 20260507
Application Date: 20241031

Claims (7)

In a CMOS image sensor-based pupil area measurement device, A pixel array having a pixel region arranged in a matrix form and having a plurality of interconnected pixels, and acquiring a plurality of pixel values by capturing the user's eye; and A pupil area measuring device comprising a pupil area processing unit that determines the pupil area of the eye by performing an area reduction operation to obtain a remaining high-density core area by binarizing the pixel values obtained for each pixel into black and white and whitening a pixel area with low black density multiple times in stages, and an area expansion operation to expand the core area by blackening a white pixel area adjacent to the core area multiple times in stages.
In paragraph 1, The pupil region processing unit above is a pupil region measuring device that binarizes a plurality of pixel values for each of the above pixels.
In paragraph 1 or 2, The pupil region processing unit above is a pupil region measuring device that performs the region expansion operation by changing the pixel value to black when, for each pixel, at least one of two or more surrounding pixels has a pixel value of black.
In paragraph 1 or 2, The pupil area processing unit above is a pupil area measuring device that performs the area reduction operation by changing the pixel value to white when, for each pixel, at least one of two or more surrounding pixels has a pixel value of white.
In paragraph 1, A pupil area measuring device that determines the core area as the center of the pupil area when the number of pixel columns or rows of the core area remaining after the above area reduction operation is less than or equal to a predetermined value.
In paragraph 5, A pupil area measuring device that determines the size of the pupil area based on the size of the center of the pupil area and the number of pixel columns or rows corresponding to the number of times the area reduction operation or the area expansion operation is performed.
In paragraph 1, A pupil area measuring device that determines the size of the pupil area based on the number of pixel columns or rows of a pixel group having black pixel values among the pixels of the determined pupil area.

Description

Apparatus for detecting pupil area based on CMOS image sensor The present invention relates to a pupil area measuring device, and more specifically, to a CMOS image sensor-based pupil area measuring device that determines the pupil area of the eye through pixel-level data processing using a CMOS image sensor. Changes in the size of a person's pupil are useful for estimating emotions, such as psychological state, and can also serve as an indicator of cognitive responses, such as thinking ability or concentration. Therefore, technology for measuring pupil area, including pupil size, is being utilized in various fields. In measuring the pupil area, an image of the user's eye is captured by an image sensor such as a camera, and the pupil area is identified from the acquired image. In this process, processor-based software algorithm technology is used. However, processors executing these algorithms consume a significant amount of power, and depending on the algorithm's performance, accurately measuring the pupil area can take a considerable amount of time. Furthermore, implementing the function to measure pupil size increases component size, which hinders product miniaturization and leads to higher manufacturing costs. FIG. 1 is a block diagram illustrating the configuration of a pupil area measuring device according to one embodiment of the present invention. FIG. 2 illustrates the configuration of a processing unit of a pixel and pupil area measuring device according to one embodiment of the present invention. FIGS. 3 and FIGS. 4 are drawings illustrating examples in which a region reduction operation and a region expansion operation are performed according to an embodiment of the present invention. FIG. 5 is a flowchart of the operation for determining the pupil area in a pupil area measuring device according to one embodiment of the present invention. FIG. 6 is a diagram illustrating an example of determining the pupil area in an eye image according to one embodiment of the present invention. FIG. 7 is a diagram relating to a region reduction operation and the determination of the end point of the region reduction operation according to one embodiment of the present invention. FIG. 8 is a diagram relating to a region expansion operation and the determination of a pupil region according to a region expansion operation according to an embodiment of the present invention. FIG. 9 is a diagram illustrating a configuration for determining the size of a pupil area according to one embodiment of the present invention. FIG. 10 is a diagram relating to the acquisition of location information of a pupil area according to one embodiment of the present invention. FIG. 11 is a drawing regarding the determination of the size of the pupil area according to one embodiment of the present invention. Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. FIG. 1 is a block diagram illustrating the configuration of a pupil area measuring device according to one embodiment of the present invention. The pupil area measuring device (1) is mounted on an electronic device, such as, for example, a user terminal or a head-mounted display apparatus (HMD), and provides information on the pupil area. According to one embodiment, the pupil area measuring device (1) is implemented as a device based on a single-chip CMOS (complementary metal oxide silicon) image sensor (CIS: CMOS image sensor). The CMOS image sensor is an image sensor manufactured using CMOS manufacturing technology, and since the circuit for image signal processing can be integrated into a single chip, it is easier to miniaturize the module through a System On Chip (SoC). In addition, the CMOS image sensor enables effective measurement of the pupil area with a simpler configuration and enables pixel-level image processing by the pixel array (100) described later. According to one embodiment of the present invention, the pupil area measuring device (1) can perform two functions. First, the pupil area measuring device (1) performs the function of providing information on the pupil area based on image data, that is, an eye image, that captures the user's eye. Second, the pupil area measuring device (1) performs the function of outputting the captured image data through an image output unit (150). In one embodiment, the image output unit (150) includes a Correlated Double Sampling (CDS) circuit and an A/D converter (ADC) to convert the captured image data into a digital signal and output it. The pupil area measuring device (1) includes a pixel array (100). Referring to FIG. 1, the pixel array (100) has a plurality of pixels having pixel areas arranged in a matrix form, and captures the user's eye to obtain a plurality of pixel values. According to one embodiment, the pixel array (100) is configured in the form of a matrix having an M×N matri