Standard test image

About: Standard test image is a research topic. Over the lifetime, 5217 publications have been published within this topic receiving 98486 citations.

Biometric Image Authentication using Watermarking

Abstract: In this paper, we propose an invertible authentication watermarking algorithm which can detect block-wise malicious manipulations in biometric images. Our method uses an invertible watermark that can also detect manipulated area simultaneously. Virtually all watermarking schemes introduce a small amount of irrecoverable distortion in original biometric images. But our new method is invertible in the sense that, if the data is deemed authentic, distortion due to authentication can be removed if it becomes necessary to obtain the original biometric image. In our method two watermarks are embedded into biometric image. The first one is based on the conventional method which can completely remove the distortion due to authentication if the data is deemed authentic. The second one can detect the block-wise malicious manipulation using the Cyclic Redundancy Check (CRC) concept in the image block. Our proposed method can classify a test image into two types; authentic, and manipulated. Also, this technique provides cryptographic strength when verifying image integrity because the probability of making an undetectable modification to the image can be directly related to a secure cryptographic element, such as a hash function.

Automatic visual inspection of printed circuit board for defect detection and classification

Abstract: Inspection of printed circuit board (PCB) has been a crucial process in the electronic manufacturing industry to guarantee product quality & reliability, cut manufacturing cost and to increase production. The PCB inspection involves detection of defects in the PCB and classification of those defects in order to identify the roots of defects. In this paper, all 14 types of defects are detected and are classified in all possible classes using referential inspection approach. The proposed algorithm is mainly divided into five stages: Image registration, Pre-processing, Image segmentation, Defect detection and Defect classification. The algorithm is able to perform inspection even when captured test image is rotated, scaled and translated with respect to template image which makes the algorithm rotation, scale and translation in-variant. The novelty of the algorithm lies in its robustness to analyze a defect in its different possible appearance and severity. In addition to this, algorithm takes only 2.528 s to inspect a PCB image. The efficacy of the proposed algorithm is verified by conducting experiments on the different PCB images and it shows that the proposed afgorithm is suitable for automatic visual inspection of PCBs.

Method and apparatus for enhancing and thresholding images

Abstract: An image processing method and system for generating enhanced binary image data from greyscale input image data. The method includes the steps of (a) receiving first image data, the first image data being greyscale image data defining an input image, (b) performing a high frequency boost operation on the first image data to produce second image data, (c) performing a linear interpolation operation on the second image data to produce third image data, the third image data having a resolution higher than the resolution of the second image data, (d) performing a contrast enhancement operation on the third image data to produce fourth image data, and (e) thresholding the fourth image data to produce fifth image data, the fifth image data being binary image data defining an output image. The techniques find application, for example, in over-the-desk scanning of documents, and in video-conferencing.

Composite Fourier-plane nonlinear filter for distortion-invariant pattern recognition

Abstract: We investigate composite Fourier-plane nonlinear filters for distortion-invariant pattern recognition. Different types of noise such as spatially nonoverlapping color background noise, other nontarget objects, real scene noise, and additive white noise are used to investigate the performance of the filter. Computer simulation results are presented to show the performance enhancement using Fourier-plane nonlinearities in the composite filter designs. The training image sets and the test image sets are generated by in-plane and out-plane rotation of different aircraft.

A hybrid block based watermarking algorithm using DWT-DCT-SVD techniques for color images

Abstract: In this paper, we propose a robust watermarking technique which combines features of Discrete wavelet transformation (DWT), discrete cosine transformation and singular value decomposition. In this technique DWT is used to decompose the color images into various frequency and time scale. Block DCT is applied on DWT coefficients of various frequency to provide high level of robustness. DCT transformed blocks of size 4x4 are further decomposed using dual SVD technique to get singular values in which watermark is to be hidden. Algorithm is tested using Lena test image in RGB and YIQ color model. As per the results combining feature of DWT-DCT with SVD technique provides robustness against image processing and geometric attacks in YIQ color model than RGB color model.