Abstract
This paper presents a single-bit CMOS image sensor (CIS) that uses a data processing technique with an edge detection block for simple iris segmentation. In order to recognize the iris image, the image sensor conventionally captures high-resolution image data in digital code, extracts the iris data, and then compares it with a reference image through a recognition algorithm. However, in this case, the frame rate decreases by the time required for digital signal conversion of multi-bit digital data through the analog-to-digital converter (ADC) in the CIS. In order to reduce the overall processing time as well as the power consumption, we propose a data processing technique with an exclusive OR (XOR) logic gate to obtain single-bit and edge detection image data instead of multi-bit image data through the ADC. In addition, we propose a logarithmic counter to efficiently measure single-bit image data that can be applied to the iris recognition algorithm. The effective area of the proposed single-bit image sensor (174 × 144 pixel) is 2.84 mm2 with a 0.18 μm 1-poly 4-metal CMOS image sensor process. The power consumption of the proposed single-bit CIS is 2.8 mW with a 3.3 V of supply voltage and 520 frame/s of the maximum frame rates. The error rate of the ADC is 0.24 least significant bit (LSB) on an 8-bit ADC basis at a 50 MHz sampling frequency.
Highlights
In recent years, the development of various information technologies has increased the importance of security systems for mobile devices
The digital code with the iris image data is compared to the reference image using algorithms in the application processor (AP) [5,6]
CMOS image sensor (CIS), we propose a single-bit that can function using a basic structure of existing CIS, we propose a single-bit CIS that candisplay displayan aniris iris segmentation pattern with an edge detection block to obtain a single-bit output instead of multi-bit segmentation pattern with an edge detection block to obtain a single-bit output instead of multi-bit output
Summary
The development of various information technologies has increased the importance of security systems for mobile devices. A CMOS image sensor (CIS) plays an important role in capturing the iris images to be analyzed and converted. When the comparison image and the measurement environment important to recognize a unique pattern. In the measurement pixels in the CIS at the same point may have different conventional iris recognition method, the provides only high-resolution image data, re-analyzes values. In the conventional iris recognition method, the CIS provides only high-resolution the image converts the data data, into iris pattern data, it with image [9]. ADC conversion time are unavoidable, than 8–10 bit) after the analog-to-digital conversion, high image resolution and slow ADC conversion leading to a decreasedleading frame rate time are unavoidable, to a [10,11].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
