Showing papers by "Nalini K. Ratha published in 1999"

System and method for liveness authentication using an augmented challenge/response scheme

Abstract: An integrated signal sensor with processing power to augment a challenge from server and compute the response is proposed to guarantee that the sensed signal is live and not stored. The sensor-processor computes the response to the augmented challenge based on the signal charactersitics of the sensed signal and then transmits both the signal and the response. The host or the server can verify the response to authenticate liveness of the input image/signal and reject it if the response is different. Areas of application include automated biometrics and remote medical imaging.

Computer vision algorithms on reconfigurable logic arrays

Abstract: Computer vision algorithms are natural candidates for high performance computing systems. Algorithms in computer vision are characterized by complex and repetitive operations on large amounts of data involving a variety of data interactions (e.g., point operations, neighborhood operations, global operations). In this paper, we describe the use of the custom computing approach to meet the computation and communication needs of computer vision algorithms. By customizing hardware architecture at the instruction level for every application, the optimal grain size needed for the problem at hand and the instruction granularity can be matched. A custom computing approach can also reuse the same hardware by reconfiguring at the software level for different levels of the computer vision application. We demonstrate the advantages of our approach using Splash 2-a Xilinx 4010-based custom computer.

System and method for data hiding in compressed fingerprint images

Abstract: A method to hide small messages in a wavelet compressed fingerprint image is presented. The method is characterized by random placement of the message bits in the compressed and quantized indices. The compressed image can be decompressed by any certified decompressor without any visible difference. However, the decoder aware of the decompression can only retrieve the hidden message in the image and additionally decompress the image without any error in pixel values.

System and method for generating a rolled surface representation from a set of partial images

Abstract: The invention is a system and method for constructing a rolled surface image from a set of partial surface images. A sequence of individual partial surface images is acquired as an object is progressively rolled across the surface of an imaging device. The imaging device is configured so that only that part of the object's surface which is in close proximity is imaged. To produce a complete rolled surface image, i.e. a composite image, the value of each pixel of the composite image is derived by performing a suitable pixel operation on the set of corresponding pixels in the input partial surface images. This is possible because each partial image is represented as a fixed size and each pixel in each of the partial images has a unique position in the partial image. The system can also directly produce a list of salient surface features. Localized features are extracted from each individual partial image whereas other specific attributes of each image are ignored. The features from different partial surface images are then matched up to generate clusters of observations associated with each unique surface feature. These clusters are analyzed to produce more accurate positional information as well as a confidence measure for each observed feature in the complete set covering the rolled surface of the object.

System and method for securing acceptance degree of biometric image

Abstract: PROBLEM TO BE SOLVED: To obtain a fingerprint acquisition system which is accurate and highly reliable by accepting a biometric image only when one or more components are in respectively assigned ranges. SOLUTION: A force detecting device 665 senses a force or torque applied to the fingerprint image acquisition system. The force or torque that an image forming device 660 receives is transferred to a force sensor 665 to be measured. The force sensor 665 generates a stream of force data and a computer 610 reads a stream of force or torque of data. A sensor 665 measures the force that an object applies when the contacting of a fingerprint of the object is sensed. The force and torque that the object applies are monitored intermittently by the computer 610 and a biometric image is optionally selected and displayed. When the image is acquired, the force and torque are analyzed by the computer 610 and when the pressure is extremely high or low, or when the shearing torque is high, the image is excluded.