Zulfiqar Habib

COMSATS University Islamabad | CUI · Department of Computer Sciences

Inter-frame tampering in surveillance videos undermines the integrity of video evidence, potentially influencing law enforcement investigations and court decisions. This type of tampering is the most common tampering method, often imperceptible to the human eye. Until now, various algorithms have been proposed to identify such tampering, based on h...

Humans possess a natural ability to infer the three-dimensional (3D) structure of a scene by leveraging prior knowledge and visual understanding. Conversely, computers face significant challenges in 3D reconstruction, which has long been a subject of interest in computer graphics. However, recent advances in computer vision have introduced a range...

Anomaly detection has significant importance for the development of autonomous monitoring systems. Real-world anomalous events are complicated due to diverse human behaviors and class variations. Anomalous activities depend upon speed, length of activity, and motion features to comprehend suspicious behaviors. Fast activities are captured quickly w...

Predicting students’ academic performance is a critical research area, yet imbalanced educational datasets, characterized by unequal academic-level representation, present challenges for classifiers. While prior research has addressed the imbalance in binary-class datasets, this study focuses on multi-class datasets. A comparison of ten resampling...

Shoplifting poses a significant challenge for shop owners as well as other stakeholders, including law enforcement agencies. In recent years, the task of shoplifting detection has gained the interest of researchers due to video surveillance generating vast quantities of data that cannot be processed in real-time by human staff. In previous studies,...

Surveillance cameras are widely used to provide protection and security through online tracking or investigation of stored videos of an incident. Furthermore, footage of recorded videos may be used as strong evidence in the courts of law or insurance companies, but their authenticity cannot be taken for granted. Two common video inter-frame forgery...

Anomaly detection has significant importance for developing autonomous surveillance systems. Real-world anomalous events are far more complex and harder to capture due to diverse human behaviors and a wide range of anomaly types. A key factor in defining activity is the temporal length or duration of the activity. The time period required for an an...

Image forgery detection is important for sensitive domains such as courts of law. The main challenge is to develop a robust model that is sensitive to tampering traces. Existing techniques perform well on a limited dataset but do not generalize well across the datasets. Moreover, these techniques cannot reliably detect tampering that distorts the t...

Digital videos are now low-cost, easy to capture and easy to share on social media due to the common feature of video recording in smart phones and digital devices. However, with the advancement of video editing tools, videos can be tampered (forged) easily for propaganda or to gain illegal advantages—ultimately, the authenticity of videos shared o...

Human skin is the most exposed part of the human body that needs constant protection and care from heat, light, dust, and direct exposure to other harmful radiation, such as UV rays. Skin cancer is one of the dangerous diseases found in humans. Melanoma is a form of skin cancer that begins in the cells (melanocytes) that control the pigment in huma...

Video super-resolution (VSR) aims at generating high-resolution (HR) video frames with plausible and temporally consistent details using their low-resolution (LR) counterparts, and neighboring frames. The key challenge for VSR lies in the effective exploitation of intra-frame spatial relation and temporal dependency between consecutive frames. Many...

In recent years, learning-based approaches for 3D reconstruction have gained much popularity due to their encouraging results. However, unlike 2D images, 3D cannot be represented in its canonical form to make it computationally lean and memory-efficient. Moreover, the generation of a 3D model directly from a single 2D image is even more challenging...

In recent years, numerous techniques have been proposed for human activity recognition (HAR) from images and videos. These techniques can be divided into two major categories: handcrafted and deep learning. Deep Learning-based models have produced remarkable results for HAR. However, these models have several shortcomings, such as the requirement f...

Virtual characters are 3D geometric models of characters. They have a lot of applications in multimedia. In this paper, we propose a new physics-based deformation method and efficient character modelling framework for creation of detailed 3D virtual character models. Our proposed physics-based deformation method uses PDE surfaces. Here PDE is the a...

These days, videos can be easily recorded, altered and shared on social and electronic media for deception and false propaganda. However, due to sophisticated nature of the content alteration tools, alterations remain inconspicuous to the naked eye and it is a challenging task to differentiate between authentic and tampered videos. During the proce...

A digital image is a rich medium of information. The development of user-friendly image editing tools has given rise to the need for image forensics. The existing methods for the investigation of the authenticity of an image perform well on a limited set of images or certain datasets but do not generalize well across different datasets. The challen...

Now-a-days, videos can be easily recorded and forged with user-friendly editing tools. These videos can be shared on social networks to make false propaganda. During the process of spatial forgery, the texture and micro-patterns of the frames become inconsistent, which can be observed in the difference of two consecutive frames. Based on this obser...

With the advent of mobile robots in commercial applications, the problem of path-planning has acquired significant attention from the research community. An optimal path for a mobile robot is measured by various factors such as path length, collision-free space, execution time, and the total number of turns. MEA* is an efficient variation of A* for...

This paper presents an action verification system for rehabilitation of patients with limited mobility. In this regard, a kinect sensor is used to capture the image-sequences of patients for identification of different actions in real time during rehabilitation exercisers at home. Then, a set of most discriminating features is extracted from a huma...

Reliable brain tumor radiology is one of the serious mortality issues of medical hospitals and on priority of healthcare departments. In this research, the presence of brain tumor and its type (if exists) is automatically diagnosed from magnetic resonance imaging (MRI). The first step is most important where suitable parameters from Gabor texture a...

The drive of this study is to develop a robust system. A method to classify brain magnetic resonance imaging (MRI) image into brain‐related disease groups and tumor types has been proposed. The proposed method employed Gabor texture, statistical features, and support vector machine. Brain MRI images have been classified into normal, cerebrovascular...

Diabetic Retinopathy (DR) is a major cause of blindness in diabetic patients. The increasing population of diabetic patients and difficulty to diagnose it at an early stage are limiting the screening capabilities of manual diagnosis by ophthalmologists. Color fundus images are widely used to detect DR lesions due to their comfortable, cost-effectiv...

Non-holonomic mobile robots are used in various disciplines such as mining, cleaning, medical surgery, autonomous cars, security and surveillance applications. Path planning algorithms, such as A*, D*, PRM, RRT* and RRT*-AB generate rectilinear (linear piece-wise) path for non-holonomic robots. Path following or trajectory tracking algorithms are u...

An energy efficient online approach for performing coverage task in an unknown environment proposed in this paper. Although, energy consumption is an important optimality criteria, the current state of the art backtracking path planning approaches do not consider energy consumption required by robot to follow the path. This paper presents an energy...

Spiral curves are free from singularities and curvature extrema. These are used in path smoothing applications to overcome the abrupt change in curvature and super-elevation of moving object that occurs between tangent and circular curve. Line to circle spiral transition is made of straight line segment and curvature continuous spiral curve. It is...

In computational and clinical environments, autoclassification of brain magnetic resonance image (MRI) slices as normal and abnormal is challenging. The purpose of this study is to investigate the computer vision and machine learning methods for classification of brain magnetic resonance (MR) slices. In routine health-care units, MR scanners are be...

Rapidly exploring Random Tree Star (RRT*) has gained popularity due to its support for complex and high-dimensional problems. Its numerous applications in path planning have made it an active area of research. Although it ensures probabilistic completeness and asymptotic optimality, its slow convergence rate and large dense sampling space are prove...

This paper presents an efficient online approach for complete coverage path planning of mobile robots in an unknown workspace based on online boustrophedon motion and an optimized backtracking mechanism. The presented approach first performs a single continuous boustrophedon motion until a critical point is reached. In order to completely cover the...

Human activity recognition (HAR) is an important research area in the fields of human perception and computer vision due to its wide range of applications. These applications include: intelligent video surveillance, ambient assisted living, human computer interaction, human-robot interaction, entertainment, and intelligent driving. Recently, with t...

Human activity recognition (HAR) is an important research area in computer vision due to its vast range of applications. Specifically, the past decade has witnessed enormous growth in its applications, such as Human Computer Interaction, intelligent video surveillance, ambient assisted living, entertainment, human-robot interaction, and intelligent...

Optimal path for robot in collision free space is influenced by a number of factors such as path length, total number of turns, and execution time. A* is a well-known grid based path planning approach used for path planning of robots. In this paper, an efficient variation of A*, named Memory Efficient A* (MEA*), is proposed to find optimal path bet...

The Complete Coverage Path Planning (CCPP) algorithm finds a collision free path while covering every accessible region within an environment. CCPP is fundamental to many real world robotic applications such as mine sweeping, cleaning, painting, surveillance, and agriculture field operations. The current state of the art coverage algorithms usually...

Optimal path planning refers to find the collision free, shortest, and smooth route between start and goal positions. This task is essential in many robotic applications such as autonomous car, surveillance operations, agricultural robots, planetary and space exploration missions. Rapidly-exploring Random Tree Star (RRT*) is a renowned sampling bas...

This paper presents a novel feature descriptor for multiview human action recognition. This descriptor employs the region-based features extracted from the human silhouette. To achieve this, the human silhouette is divided into regions in a radial fashion with the interval of a certain degree, and then region-based geometrical and Hu-moments featur...

Image enhancement is one of the most important and visually appealing areas of digital image processing and computer vision. It is considered as a very important part of pre-processing for the development of industrial, security, forensic, medical, and many other applications. Although significant efforts were devoted in the past, a completely auto...

Digital image acquisition is now a simple task and information in the form of digital images is drastically increasing on social media, which has both positive and negative impacts on a society in many different ways. Advanced user-friendly tools have made it easy to manipulate image content in order to gain illegal advantage or to make false propa...

In this paper we derive admissible curvature continuous areas for monotonically increasing curvature continuous smooth curve by using a single Pythagorean hodograph (PH) quintic polynomial of contact matching Hermite end conditions. Curves with monotonically increasing or decreasing curvatures are considered highly smooth (fair) and are very useful...

Diabetic retinopathy (DR) is a complication where the retina of a diabetic patient is damaged due to fluid leakage from the blood vessels into the retina and the patient may suffer from complete blindness if untreated. Hemorrhages and Microaneurysms (HMAs) are the early signs that appear in retina at the initial stage of DR. Early diagnosis of HMAs...

This paper describes a method to smooth an arc spline. Arc splines are G1 continuous segments made of circular arcs and straight lines. We have proposed a smooth version of the arc spline by replacing its parts with C-, S-, and J-shaped spiral transitions, stitched with G2 continuity, by using a single segment of Pythagorean hodograph quintic funct...

This paper considers how to smooth three kinds of G biarc models, the C-, S-, and J-shaped transitions, by replacing their parts with spiral segments using a single cubic Bézier curve. Arc spline is smoothed to G continuity. Use of a single curve rather than two has the benefit because designers and implementers have fewer entities to be concerned....

This paper explores the possibilities of very simple analysis on derivation of spiral regions for a single segment of a cubic function matching positional, tangential, and curvature end conditions. Spirals are curves of monotone curvature with constant sign and have the potential advantage that the minimum and the maximum curvature exist at their e...

This paper finds reachable regions for a single segment of parametric rational cubic Bézier spiral matching G2 Hermite data. First we derive spiral conditions for rational cubics and then we use a free parameter to find the admissible region for a spiral segment with respect to the curvatures at its endpoints under the fixed positional and tangenti...

This paper finds a spiral segment matching G2 Hermite conditions for a single Pythagorean hodograph quintic polynomial. We have significantly simplified the existing methods with computationally stable spiral conditions and discovers more spiral regions for the existence of unsolved problems in the past. A spiral is free of local curvature extrema,...

Arc splines are planar, tangent continuous, piecewise curves made of circular arcs and straight line segments. They are important in manufacturing industries because of their use in the cutting paths for numerically controlled cutting machinery, highway route and robot paths. This paper considers how to smooth three kinds of G¹ biarc mod...

This paper describes a method for joining two circles with a C-shaped and an S-shaped transition curve, composed of a cubic Bézier segment. As an extension of our previous work; we show that a single cubic curve can be used for blending or for a transition curve preserving G 2 continuity regardless of the distance of their centers and magnitudes of...

This paper describes a method for joining two circles with an S-shaped or with a broken back C-shaped transition curve, composed of at most two spiral segments. In highway and railway route design or car-like robot path planning, it is often desirable to have such a transition. It is shown that a single cubic curve can be used for blending or for a...

Spiral curves of one-sided, monotone increasing or decreasing curvature have the advantage that the minimum and maximum curvature is at their endpoints and they contain no inflection points or local curvature extrema. This paper derives a spiral condition for a rational cubic spline on the endpoint curvatures under the fixed positional and tangenti...

Spirals are curves of monotone curvature with constant sign and therefore such curves are free from singularities (loops, cusps), inflection points, and local curvature extrema. These properties make the study of spiral segments an interesting problem both in practical and aesthetic applications. An important issue in this paper is to design spiral...

The paper describes a method to join two circles with a C-shaped and an S-shaped transition curve, composed of a Pythagorean hodograph quintic segment, preserving G^2 continuity. It is considered desirable to have such a curve in satellite path planning, highway or railway route designing, or non-holonomic robot path planning. As an extension of ou...

In the highway and rail route designs, or a car-like robot path planning it is often desirable to have a method of joining a circle to a circle with an S-shaped or a broken back C-shaped spiral transition. This paper describes a transition between two such circles. It is shown that a single Pythagorean hodograph quintic curve can be used for blendi...

The paper derives a spiral condition, for a single Pythagorean hodograph quintic transition curve of G2 contact, between two circles with one circle inside the other. A spiral is free of local curvature extrema, making spiral designs an interesting mathematical problem with importance for both physical and aesthetic applications. In the constructio...

This paper derives a spiral condition for a single Bézier cubic transition curve of G2 contact, between two circles with one circle inside the other. In high way, railway route, or satellite path design it is often desirable to have a transition curve from circle to circle. A spiral is free of local curvature extrema, making spiral design an intere...

We consider the shape of two point Hermite interpolation on the sphere. A three-parameter family of spherical rational quartic curves has been derived. We derive the singularity conditions theoretically and discuss the shape of the solutions, which is characterized by the presence of loops and cusps on restricted as well as whole segment. Our resul...

A rational cubic spline, with shape control parameters, has been discussed here with the view to its application in computer graphics. It incorporates both conic sections and parametric cubic curves as special cases. An efficient scheme is presented which constructs a curve interpolating a set of given data points and allows subsequent interactive...

IntroductionG2 Cubic TransitionG2 PH Quintic TransitionNumerical Examples and Critical AnalysisSummaryReferences

We present the composition of G² curves by joining circular arcs and/or straight line segments with cubic Bezier and Pythagorean hodograph quintic spiral transitions. Recent work demonstrates some applications in geometric modelling and a constrained G² continuous spiral transition curve that falls within a closed boundary.

A method for the family of the G 2 Pythagorean hodograph (PH) quintic spiral transition from straight line to circle is discussed. This method is then extended to a pair of spirals between two straight lines or two circles. We derive a family of quintic transition spiral curves joining them. Due to flexibility and wide range of shape control parame...

We obtain a G² fair curve by adding a spiral segment to one end of an existing curve. The added segments are cubic and Pythagorean hodograph quintic spirals. We derive the more explicit reachable regions for the end points of the added spirals. Spiral segments are useful in the design of fair curves. The advantage of our technique is its...

A rational cubic spline, with shape parameters, has been discussed with the view to its application in Computer Graphics. It incorporates both conic sections and parametric cubic curves as special cases. The parameters (weights), in the description of the spline curve can be used to modify the shape of the curve, locally and globally. The rational...

A method for drawing a guided $G^{2}$ continuous cubic spiral spline curve that falls within a closed boundary is presented. The boundary is composed of straight line segments and circular arcs. Spiral segments consist of transitions from straight line to straight line or circle. Guided curve can easily be controlled by shape control parameter. Our...

A smooth curve interpolation scheme for convex data has been developed. This scheme uses piecewise rational cubic spline functions with both unit and chord-length parametrization test. The necessary and sufficient conditions on inflection points and singularities for a convex data have been presented. Shape preserving parameters are automatically g...

We derive a value to determine the shape of a cubic curve segment. It can be easily calculated from the Hermite data at two points.

Walton & Meek (1996) obtained a fair G² cubic transition spiral curve joining a straight line and a circle. We derive a family of cubic transition spiral curves joining them. We not only simplify and extend their analysis but also provide more degrees of freedom with less restrictive shape control parameters. The idea of straight line to...

Meek and Walton [2] have examined the shapes of G2 planar single cubic transition S- and C-shaped curves connecting two circles. We show that use of another parameter makes their analysis more complete and easier to read. We presented a very short algorithm with less restrictive ratio of the larger to the smaller radii of the given circular arcs. I...

We show that two point G 1 -Hermite quadratic and T-cubic spline interpolations to a smooth spiral are spirals if the interpolation points are taken close enough. The use of spirals gives the designer an excellent and speedy control over the shape of curve that is produced because there are no internal curvature maxima, curvature minima, inflection...

We derive a value to determine the shape of a parametric cubic curve segment without use of trans- formation. It can be easily calculated from the Hermite data at two points. The number and location of curvature extrema are determined without its practical computation.

We show that two-point G2 Hermite cubic spline interpolation to a smooth spiral is a spiral. Its unit tangent matches given unit tangents and its signed curvature matches given signed curvatures at end points of the given spiral. Spiral segments are useful in the design of fair curves and have the advantages that there are no unplanned curvature ma...

We consider the problem of G^2 two-point Hermite interpolation by a rational cubic. Given two points with tangent vectors and curvatures, the necessary and sufficient conditions are placed on the weights of the rational cubic curve which ensures that (i) if the data suggest a C -shaped curve, the rational cubic interpolates a C -shaped curve withou...

We derive regions for T-cubic and arc/T-cubic spirals to two-point Hermite interpo- lation in terms of unit tangent vectors with help of Mathematica. The use of spirals gives the designer an excellent and speedy control over the shape of curve that is produced be- cause there are no internal curvature maxima, curvature minima, inflection points, lo...

We consider a uniformly parameterized planar rational cubic interpolation. The necessary and sufficient conditions on inflection points and singularities for a convex data have been presented. This paper uses the remaining two degrees of freedom. Shape preserving parameters are automatically generated and the degree of smoothness attained is G 2 ....

This paper discusses the distribution of inflection points and singularities on a piecewise parametric rational cubic spline. Necessary and sufficient conditions for a convex data have been presented. A high degree of smoothness is obtained with automatic estimation of two families of shape preserving parameters for local convexity

A rational cubic spline, with one family of shape parameters, has been discussed with the view to its application in Computer Graphics. It incorporates both conic sections and parametric cubic curves as special cases. The parameters (weights), in the description of the spline curve can be used to modify the shape of the curve, locally and globally,...

A rational cubic spline with a family of shape parameters is discussed from the viewpoint of its application in computer graphics. It incorporates both conic sections and parametric cubic curves as special cases. The parameters (weights), in the description of the spline curve can be used to modify the shape of the curve, locally and globally, at t...

A piecewise rational cubic spline curve has been described. The designed curve possesses parameters (weights) in each interval which can be used to control the shape of the curve. A very simple distance-based approximated derivative scheme is presented to calculate the control points. Also, for any interval, it is possible to calculate control poin...

A scheme for generating plane curves which interpolates given data is described. A curve is obtained by patching together rational cubics and straight-line segments which, in general, is C¹ continuous. It is a local scheme which controls the shape of the curve and preserves the shape of the data by being local convexity-preserving. A par...

Walton & Meek [13] obtained fair G 2 Pythagorean hodograph (PH) quintic transition S-and C-shaped curves connecting two circles. It was shown that an S-shaped curve has no curvature extremum and a C-shaped curve has a single curvature extremum. We simplified and completed their analysis. A family of fair PH quintic transition curves between two cir...

We present an efficient geometric algorithm for web-based visualization of two point geometric Hermite conic and arc/conic spiral segments. We compare our results with Tschirnhausen cubic spirals and find our conic spiral segments more flexible and suitable for demonstration as a graphics tool where the user interface is provided via a web browser....