We survey recent developments in the design of large-capacity content-addressable memory (CAM). A CAM is a memory that implements the lookup-table function in a single clock cycle using dedicated comparison circuitry. CAMs are especially popular in network routers for packet forwarding and packet classification, but they are also beneficial in a variety of other applications that require high-speed table lookup. The main CAM-design challenge is to reduce power consumption associated with the large amount of parallel active circuitry, without sacrificing speed or memory density. In this paper, we review CAM-design techniques at the circuit level and at the architectural level. At the circuit level, we review low-power matchline sensing techniques and searchline driving approaches. At the architectural level we review three methods for reducing power consumption.

https://www.pagiamtzis.com/pubs/pagiamtzis-jssc2006.pdf

Content-addressable memory (CAM) circuits and architectures: a tutorial and survey

An interactive display table has a display surface for displaying images and upon or adjacent to which various objects, including a user's hand(s) and finger(s) can be detected. A video camera within the interactive display table responds to infrared (IR) light reflected from the objects to detect any connected components. Connected component correspond to portions of the object(s) that are either in contact, or proximate the display surface. Using these connected components, the interactive display table senses and infers natural hand or finger positions, or movement of an object, to detect gestures. Specific gestures are used to execute applications, carryout functions in an application, create a virtual object, or do other interactions, each of which is associated with a different gesture. A gesture can be a static pose, or a more complex configuration, and/or movement made with one or both hands or other objects.

Recognizing gestures and using gestures for interacting with software applications

https://romisatriawahono.net/lecture/rm/survey/computer%20vision/Mukhopadhyay%20-%20Hough%20Transform%20-%202014.pdf

A survey of Hough Transform

An electronic device with a display and a fingerprint sensor may authenticate a user for a respective function. While a respective function of the device is in a locked state, the device displays a graphical element on the display, the graphical element indicating a first direction of finger movement that enables unlocking of the respective function. While displaying the graphical element, the device detects an input that includes movement of a finger in the first direction over the fingerprint sensor and determines whether the input meets unlock criteria based at least in part on fingerprint information of the finger detected by the fingerprint sensor during the input. In accordance with a determination that the input meets the unlock criteria, the device unlocks the respective function; and in accordance with a determination that the input does not meet the unlock criteria, the device maintains the respective function in the locked state.

Embedded authentication systems in an electronic device

A system and method for conducting electronic commerce are disclosed. In various embodiments, the electronic transaction is a purchase transaction. A user is provided with an intelligent token, such as a smartcard containing a digital certificate. The intelligent token suitably authenticates with a server on a network that conducts all or portions of the transaction on behalf of the user. In various embodiments a wallet server interacts with a security server to provide enhanced reliability and confidence in the transaction. In various embodiments, the wallet server includes a toolbar. In various embodiments, the digital wallet pre-fills forms. Forms may be pre-filled using an auto-remember component.

Methods and Apparatus for Conducting Electronic Transactions

An authentication token includes a personal collation unit and communication unit. The personal collation unit includes a sensor, storage unit, and collation unit. The sensor detects biometrical information of a user and outputs the detection result as sensing data. The storage unit stores in advance registered data to be collated with the biometrical information of the user. The collation unit collates the registered data with the sensing data and outputs the collation result as authentication data. The communication unit transmits the authentication data from the personal collation unit to the use device as communication data. The personal collation unit and communication unit are integrated.

Authentication token and authentication system

A parallel algorithm, in order to extract parametric curves from a two-dimensional (2-D) image space, is proposed. It is based on the Hough transform (HT) and uses the content addressable memory (CAM) as the main processor. A set of simulated results for circular shape extraction are presented in order to demonstrate its merit. Hence, voting, thresholding, and three-dimensional (3-D) peak extraction are efficiently performed within the CAM. In addition, and in order to reduce the quantization errors, a weighted AT algorithm (WHT), which uses a weighted voting is proposed. Experimental results indicate that a real-time shape extraction for an image 256/spl times/256 can be achieved within a small amount of hardware. Therefore, CAM-based HT can be considered as a promising attraction for next generation pattern recognition platforms.

On using the CAM concept for parametric curve extraction

An image processing apparatus for extracting lines from an image using the Hough transform. A processor element is assigned to each quantization point in a Hough space. Each processor element calculates, for each scanning line of the image, intersections of the scanning line and the line corresponding to this processor element once per scanning line. A black pixel (a Hough transform object point) on the scanning line is also obtained sequentially. The coordinate values of the intersection are compared with those of the Hough transform object point, and when they agree, voting to a ballot box memory of the processor element is performed. The voting results become Hough transform data. This makes it possible to implement a high speed Hough transform, and to reduce the size of the apparatus.

Image processing method and apparatus for extracting lines from an image by using the Hough transform

This paper describes a new capacitive-sensing circuit technique that improves the quality of images captured with capacitive fingerprint sensor LSIs. The quality of the captured image depends on the surface condition of the finger. When the finger is dry, the electrical resistance of the finger surface is high. The finger surface resistance induces a voltage drop in the electrical potential of the finger surface (which should be grounded), which leads to poor image quality. To capture clear images even when the finger is dry, the circuit technique improves the image quality using the series resistance caused at the finger surface. The potential of the finger surface is controlled by an enhancement plate and a voltage control circuit. A test chip implementing this technique was fabricated on a 0.5 ?m CMOS process and a sensor process. The chip captures a clear fingerprint image of a dry finger, confirming the effectiveness of the circuit technique for capturing clear fingerprint images independent of the finger surface condition with the capacitive fingerprint sensor LSIs.

Capacitive-Sensing Circuit Technique for Image Quality Improvement on Fingerprint Sensor LSIs

A biological image correlation device includes: an image quality priority decision section (40) for evaluating image quality for each of a plurality of first image data consisting of biological images relating to the same object, according to a particular index which is in relation of a monotone function with verification accuracy of biological verification, assigning priority to each of the first image data according to the evaluation result, and outputting them; first image storage sections (6, 81) for storing the first image data to which the priority is assigned and output from the image priority decision section (40); second image storage sections (8, 61) for storing second image data used for comparison and correlation with the first image data; an image correlation section (7) for comparing and correlating the reference image data stored in the second image storage section with the first image data stored in the first image storage sections (6, 81) and outputting the comparison/correlation result; and a control section (9) for controlling the aforementioned components. The control section (9) makes the image correlation section (7) compare/correlate the second image data stored in the second image storage sections (8, 61) with the first image data stored in the first image storage sections (6, 81) according to the aforementioned priority and output the correlation result from the image correlation section (7).

Mamoru Nakanishi

Papers

Authentication token and authentication system

On using the CAM concept for parametric curve extraction

Image processing method and apparatus for extracting lines from an image by using the Hough transform

Capacitive-Sensing Circuit Technique for Image Quality Improvement on Fingerprint Sensor LSIs

Biological image correlation device and correlation method thereof