Evaluation Of Image Processing Algorithms Research Articles

Noise robustness evaluation of image processing algorithms for eye blinking detection

Robust algorithms for eye blinking detection are required due to the effects of noisy environments and varying light conditions on image-based detection methods. This paper compares five non-supervised image-based algorithms for eye blinking detection, evaluating their robustness to additive Gaussian noise. The algorithms were tested on a video dataset acquired using a smartphone and an ophthalmology chin rest. Through Monte Carlo simulation that introduces Gaussian noise at different intensities, we evaluate the algorithms’ precision, sensitivity, and F1-scores for frame classification, True Positive Rate (TPR), False Discovery Rate (FDR) and F1-score for the event detector. The results of experimental tests reveal significant variations in algorithms’ performance with increasing noise levels. Notably, the Image Correlation (IC) algorithm demonstrates superior eye blinking detection capabilities under various noise conditions, emerging as the most robust algorithm among those tested. This distinction highlights the potential of IC for reliable blink detection in noisy environments.

Enhancing Skin Cancer Classification on the PH2 Dataset Through Transfer Learning Technique

Skin, the largest organ of the human body, serves as a crucial barrier against external threats. Among the myriad skin diseases, melanoma, or skin cancer, stands out as one of the most perilous and lethal conditions. However, its prognosis dramatically improves when detected early. The advent of advanced diagnostic imaging methods has mitigated the risks associated with cancer treatment, facilitating precise diagnoses and enhancing treatment efficacy. The development and evaluation of image processing algorithms for medical image analysis heavily rely on the availability of medical images. In this study, we utilize dermoscopic images sourced from the PH2 database for analysis. Our results demonstrate that the Skin Cancer Classification (SCC) system, employing Convolutional Neural Networks (CNN), outperforms traditional methods in terms of accuracy (98.5%), specificity (100%), and sensitivity (97.5%) across both stages of evaluation. From the analysis, it is evident that the superiority of CNN-based SCC systems in accurately diagnosing skin cancer. This paper underscores the significance of leveraging advanced image processing techniques for medical image analysis, paving the way for reliable skin cancer classification systems with potential clinical applicability.

Performance evaluation of image processing algorithms for eye blinking detection

The eye is considered a rich source for gathering information on our daily lives. In addition, the necessity to classify the eye as open or closed and detect eye blinks is increasing in various fields. For instance, it has been proven that eye blinks can be related to different ophthalmological conditions.Nevertheless, accurate, and robust blink estimation poses significant challenges to the efficacy of real-time applications due to the variability of eye images and light conditions.In this paper eye blinking has been monitored using a chin rest and an iOS smartphone attached to a cartesian machinery. Five video-based eye blink algorithms to classify frames have been analyzed and compared in terms of performance. To evaluate the results, different widely used statistical metrics have been employed. The results show that the proposed techniques successfully detect eye blinks, whereas the frame classifier shows different scores depending on the algorithm used.

Magnetic Resonance Image Quality Assessment by Using Non-Maximum Suppression and Entropy Analysis.

An investigation of diseases using magnetic resonance (MR) imaging requires automatic image quality assessment methods able to exclude low-quality scans. Such methods can be also employed for an optimization of parameters of imaging systems or evaluation of image processing algorithms. Therefore, in this paper, a novel blind image quality assessment (BIQA) method for the evaluation of MR images is introduced. It is observed that the result of filtering using non-maximum suppression (NMS) strongly depends on the perceptual quality of an input image. Hence, in the method, the image is first processed by the NMS with various levels of acceptable local intensity difference. Then, the quality is efficiently expressed by the entropy of a sequence of extrema numbers obtained with the thresholded NMS. The proposed BIQA approach is compared with ten state-of-the-art techniques on a dataset containing MR images and subjective scores provided by 31 experienced radiologists. The Pearson, Spearman, Kendall correlation coefficients and root mean square error for the method assessing images in the dataset were 0.6741, 0.3540, 0.2428, and 0.5375, respectively. The extensive experimental evaluation of the BIQA methods reveals that the introduced measure outperforms related techniques by a large margin as it correlates better with human scores.

Using the project‐based learning approach for incorporating an FPGA‐based integrated hardware/software tool for implementing and evaluating image processing algorithms into graduate level courses

AbstractVisual information plays an important role in almost all areas of our life. Today, much of this information is represented and processed digitally. Digital image processing is any form of signal processing for which the input is an image, such as a photograph or video frame; the output of image processing may be either an image or a set of characteristics or parameters related to the image. In this context, implementation and evaluation of image processing algorithms are complex tasks that require highly technical and multidisciplinary skills. Graduate students are required to develop both practical and theoretical exercises to understand how an algorithm works; however, they have to learn in an individual manner without adequate support. This article presents an innovative Project‐Based Learning approach to teach image processing algorithms using an FPGA‐based tool as the main support. Thus, instead of learning heavy programming tasks and mathematical functions, students are led step by step through five phases and then allowed to experiment with different algorithms. This article evaluates the proposed tool and shows results with diverse algorithms. © 2012 Wiley Periodicals, Inc. Comput Appl Eng Educ 21:E73–E88, 2013

Design and Performance Evaluation of Image Processing Algorithms on GPUs

In this paper, we construe key factors in design and evaluation of image processing algorithms on the massive parallel graphics processing units (GPUs) using the compute unified device architecture (CUDA) programming model. A set of metrics, customized for image processing, is proposed to quantitatively evaluate algorithm characteristics. In addition, we show that a range of image processing algorithms map readily to CUDA using multiview stereo matching, linear feature extraction, JPEG2000 image encoding, and nonphotorealistic rendering (NPR) as our example applications. The algorithms are carefully selected from major domains of image processing, so they inherently contain a variety of subalgorithms with diverse characteristics when implemented on the GPU. Performance is evaluated in terms of execution time and is compared to the fastest host-only version implemented using OpenMP. It is shown that the observed speedup varies extensively depending on the characteristics of each algorithm. Intensive analysis is conducted to show the appropriateness of the proposed metrics in predicting the effectiveness of an application for parallel implementation.

Performance evaluation of image processing algorithms on the GPU

The graphics processing unit (GPU), which originally was used exclusively for visualization purposes, has evolved into an extremely powerful co-processor. In the meanwhile, through the development of elaborate interfaces, the GPU can be used to process data and deal with computationally intensive applications. The speed-up factors attained compared to the central processing unit (CPU) are dependent on the particular application, as the GPU architecture gives the best performance for algorithms that exhibit high data parallelism and high arithmetic intensity. Here, we evaluate the performance of the GPU on a number of common algorithms used for three-dimensional image processing. The algorithms were developed on a new software platform called "CUDA", which allows a direct translation from C code to the GPU. The implemented algorithms include spatial transformations, real-space and Fourier operations, as well as pattern recognition procedures, reconstruction algorithms and classification procedures. In our implementation, the direct porting of C code in the GPU achieves typical acceleration values in the order of 10-20 times compared to a state-of-the-art conventional processor, but they vary depending on the type of the algorithm. The gained speed-up comes with no additional costs, since the software runs on the GPU of the graphics card of common workstations.

Design of Linear Equalizers Optimized for the Structural Similarity Index

We propose an algorithm for designing linear equalizers that maximize the structural similarity (SSIM) index between the reference and restored signals. The SSIM index has enjoyed considerable application in the evaluation of image processing algorithms. Algorithms, however, have not been designed yet to explicitly optimize for this measure. The design of such an algorithm is nontrivial due to the nonconvex nature of the distortion measure. In this paper, we reformulate the nonconvex problem as a quasi-convex optimization problem, which admits a tractable solution. We compute the optimal solution in near closed form, with complexity of the resulting algorithm comparable to complexity of the linear minimum mean squared error (MMSE) solution, independent of the number of filter taps. To demonstrate the usefulness of the proposed algorithm, it is applied to restore images that have been blurred and corrupted with additive white gaussian noise. As a special case, we consider blur-free image denoising. In each case, its performance is compared to a locally adaptive linear MSE-optimal filter. We show that the images denoised and restored using the SSIM-optimal filter have higher SSIM index, and superior perceptual quality than those restored using the MSE-optimal adaptive linear filter. Through these results, we demonstrate that a) designing image processing algorithms, and, in particular, denoising and restoration-type algorithms, can yield significant gains over existing (in particular, linear MMSE-based) algorithms by optimizing them for perceptual distortion measures, and b) these gains may be obtained without significant increase in the computational complexity of the algorithm.

Performance Evaluation in Image Processing

The scanning and computerized processing of images hadits birth in 1956 at the National Bureau of Standards (NBS,nowNationalInstituteofStandardsandTechnology(NIST))[1].Image enhancementalgorithms weresome of the first tobe developed [2]. Half a century later, literally thousands ofimage processing algorithms have been published. Some ofthese have been specific to certain applications such as theenhancement of latent fingerprints, whilst others have beenmore generic in nature, applicable to all, yet master of none.The scope of these algorithms is fairly expansive, rangingfrom automatically extracting and delineating regions of in-terest such as in the case of segmentation, to improving theperceived quality of an image, by means of image enhance-ment. Since the early years of image processing, as in manysubfields of software design, there has been a portion of thedesign process dedicated to algorithm testing. Testing is theprocessofdeterminingwhetherornotaparticularalgorithmhassatisfieditsspecificationsrelatingtocriteriasuchasaccu-racy and robustness. A major limitation in the design of im-ageprocessingalgorithmsliesinthedifficultyindemonstrat-ingthatalgorithmsworktoanacceptablemeasureofperfor-mance. The purpose of algorithm testing is two-fold. Firstlyit provides either a qualitative or a quantitative method ofevaluating an algorithm. Secondly, it provides a comparativemeasure of the algorithm against similar algorithms, assum-ing similar criteria are used. One of the greatest caveats indesigning algorithms incorporating image processing is howtoconceivethecriteriausedtoanalyzetheresults.Dowede-signacriterionwhichmeasuressensitivity,robustness,orac-curacy? Performance evaluation in the broadest sense refersto a measure of some required behavior of an algorithm,whether it is achievable accuracy, robustness, or adaptabil-ity. It allows the intrinsic characteristics of an algorithm tobe emphasized, as well as the evaluation of its benefits andlimitations.More often than not though, such testing has been lim-ited in its scope. Part of this is attributable to the actual lackof formal process used in performance evaluation of im-age processing algorithms, from the establishment of testingregimes, to the design of metrics. Selection of an appropri-ate evaluation methodology is dependent on the objectiveof the task. For example, in the context of image enhance-ment, requirements are essentially different for screen-basedenhancementandenhancementwhichisembeddedwithinasubalgorithm. Screen-based enhancement is usually assessedinasubjectivemanner,whereaswhenanalgorithmisencap-sulated within a larger system, subjective evaluation is notavailable,andthealgorithmitselfmustdeterminethequalityof a processed image. Very few approaches to the evaluationofimageprocessingalgorithmscanbefoundintheliterature,although the concept has been around for decades. A signif-icant difficulty which arises in the evaluation of algorithmsis finding suitable metrics which provide an objective mea-sure of performance. A performance metric is a meaningfuland computable measure used for quantitatively evaluatingthe performance of any algorithm. Consider the process ofassessing image quality. There is no single quantitative met-ric which correlates well with image quality as perceived bythe human visual system. The process of analyzing failure isintrinsically coupled with the process of performance evalu-ation.Inordertoascertainwhetheranalgorithmfailsornot,youhavetodefinethecharacteristicsofsuccess.Failureanal-ysisistheprocessofdeterminingwhyanalgorithmfailsdur-ing testing. The knowledge generated is then fed back to thedesign process in order to engender refinements in the algo-rithm.Thisisadifficultprocessinapplicationssuchasimageenhancement primarily because there is usually no referenceimagewhichcanbeusedasan“ideal”image.Theassessmentofimagequalityplaysanimportantroleinapplicationssuchas consumer electronics. Metrics could be used to monitororoptimizeimagequalityindigitalcameras,benchmarkandevaluate image enhancement algorithms. There is no singlemetric that correlates well with image quality as perceivedby the human visual system. Selection of an appropriate

Computer-generated noise images for the evaluation of image processing algorithms

Effective implementation of image processing algorithms for enhancement and restoration often assumes that the images are degraded by known statistical noise. Depending on the application, the type of noise present may vary. The noise distributions that are commonly encountered in image processing are the Gaussian, Rayleigh, negative exponential, and gamma. Typically, when computer-generated noise images are used for algorithm development they are spatially uncorrelated. It is the purpose of this paper to present various types of computer-generated two-dimensional correlated and uncorrelated noise images along with suggestions of several applications.