Dr. Surbhi Mathur | Gfsu (original) (raw)

Papers by Dr. Surbhi Mathur

International Journal of Electronic Security and Digital Forensics

Journal of Forensic Sciences & Criminal Investigation, 2018

Tremor is an unintentional, rhythmic muscle movement involving to and fro movements (oscillations... more Tremor is an unintentional, rhythmic muscle movement involving to and fro movements (oscillations) of one or more parts of the body. It is defined as unusual departure of line from its intended course resulting in disturbances in performance of fine motor skills. Such tremors and the consequent degradation of fine motor skills have significant implications for the field of forensic document examination. Document examiners frequently encounter the challenges of determining the authenticity of the documents containing tremors. There is broad range of possible causes of tremor in handwriting including the writers suffering from illiterate or having some health issues or due to illiteracy and many more. The main objective of this study is to highlight some specific characteristics differentiating the tremors seen in the handwriting of illiterate and fraud writers. A total of 80 handwriting samples were collected from the writers belonging to two different categories: illiterate and fraud. The samples so collected were examined for presence of tremors in each alphabet and numeral of all the 80 samples. The tremors were identified and recorded with respect to their occurrence at specific parts of the letters such as Upper, Middle and Lower part and also at the same time with respect to their occurrence in specific type of strokes such as Straight, Curved and Loops wherever applicable. The results were then evaluated and interpreted statistically.

2021 IEEE International Conference on Computation System and Information Technology for Sustainable Solutions (CSITSS), 2021

Closed-circuit television (CCTV) cameras are being extensively installed in the cities, apartment... more Closed-circuit television (CCTV) cameras are being extensively installed in the cities, apartments, homes, restaurants, educational institutions, shops and so on producing lots of data every second. Storing, processing and analyzing these video footages effectively is a challenging task. In the course of analysis of these video sequences, measurement of size of the objects in the scene is an interesting and a very challenging task. Though there are systems that can determine the height of a person, they are not computationally cost effective and very few of these works for CCTV footages.There are so many applications to find out the size of an object or a person with higher cost of maintenance and there is no application which finds the height of a person in video captured by CCTV. This project mainly focuses on the detection and calculation of height of a person in the CCTV footage using deep learning algorithm.The main objective is to build the system which determines the measurements of an object or a person in a pre-recorded video or CCTV footage or in image. The methodology adapted in the project is to find the bounding boxes around all the objects found in an input and is to determine the object class it belongs to. The python programming and machine learning techniques like YOLO algorithm, R-CNN is used for the object recognition.The posture of a person changes accordingly as his/her actions.The posture of a person effects the calculation of height as likely in a bending position of knees, the height may look less and determined accordingly. The input dataset is having various numbers of predefined classes in it, so that the detection of the various objects in the frames will be easier. The model detects the objects in images and objects in CCTV video footage with 81% accuracy. The custom dataset has been used to train and test the model.

International Journal of Research, 2018

Sequence of strokes is the study to determine the sequence in which writing strokes are made on t... more Sequence of strokes is the study to determine the sequence in which writing strokes are made on the paper. Determining sequence of strokes is an important part of forensic document examination. The choice of method depends on the accessibility and availability of the means at that time.

Medico-legal Update, 2022

Journal of Punjab Academy of Forensic Medicine & Toxicology, 2020

Journal of Forensic Science & Criminology, 2016

Although the rapid development of forensic speaker recognition technology has been conducted, the... more Although the rapid development of forensic speaker recognition technology has been conducted, there are still many problems to be solved. The biggest problem arises when the cases involving disguised voice samples come across for the purpose of examination and identification. Such type of voice samples of anonymous callers are frequently encountered in crimes involving kidnapping, blackmailing, hoax extortion and many more, where the speaker makes a deliberate effort to manipulate their natural voice in order to conceal their identity due to the fear of being caught. Voice disguise causes serious damage to the natural vocal parameters of the speakers and thus complicates the process of identification. The sole objective of this doctoral project is to find out the possibility of rendering definite opinions in cases involving disguised speech by experimentally determining the effects of different disguise forms on personal identification and percentage rate of speaker recognition for various voice disguise techniques such as raised pitch, lower pitch, increased nasality, covering the mouth, constricting tract, obstacle in mouth etc by analyzing and comparing the amount of phonetic and acoustic variation in of artificial (disguised) and natural sample of an individual, by auditory as well as spectrographic analysis. With the advancement of crime, the criminals are now capable of imparting deliberate change in their voice characteristics to prevent recognition and for misleading the investigation [21,22]. For example: "A criminal make use of a simple handkerchief over The science of crime investigation relies on one basic principle known as the "Principle of exchange". According to this principle when two objects come in contact with one another, there will be transfer of substance between the two [1-4]. Similarly for the crime site it is believed that no matter where a criminal goes or what a criminal does, by coming into contact with things, a criminal can leave all sorts of evidence, including DNA, fingerprints, footprints, hair, skin cells, blood, bodily fluids, pieces of clothing, fibers and more. At the same time, they will also take something away from the scene with them. The scenario reverses in the situation where there is no immediate crime scene like cases involving blackmailing, kidnapping, extortion, threatening, anonymous calls, ransom calls, hoax calls, obscene calls, harassment calls, match fixing etc, where the criminals resort to the aid of telephones and mobiles in order to maintain their anonymity for fear of detection [5-7]. In these circumstances, the voice of an individual is an important clue for identification. Forensic speaker identification is the application of science to solve the problems related to identification of the unknown speaker in criminal investigation. Voice is the unique sound produced by vocal organs of living organism [8]. Although DNA is considered as the most important evidence for criminal investigation, but the truth is that DNA can't talk [9,10]. The voice of a person can be successfully used as a biometric feature as it is well accepted by the users and can be easily recorded using microphones and hardware of low costs [5,11,12]. It can provide an unconventional and more secure means of permitting entry without any need of remembering a password, lock combination etc or the use of keys, magnetic card or any other fallible device which can be easily stolen [7,13,14]. In the present era, widely available facilities of telephones, mobiles and tape recorders results in the misuse of the device and thus, making them an efficient tool in commission of criminal offences, where the criminals frequently misuse these modes of communication, believing that they will remain incognito, and nobody would recognize them. It is fortunately no longer true [15-17]. The voice of an individual can successfully recognize him and pin the crime on him [18-20].

Journal of Forensic Research, 2016

Although the rapid development of speaker recognition technology is happening, there are still ma... more Although the rapid development of speaker recognition technology is happening, there are still many problems to be solved. The biggest problem arises when the cases of disguised voice samples are come across for the purpose of identification. The samples of disguise are frequently encountered in the forensic scenario like in case of anonymous calls, ransom calls and threatening calls where the speaker makes a deliberate effort to change their voice in order to hide their identity due to the fear of being caught. Voice disguise complicates the process of speaker identification by causing damage to the normal vocal parameters of the speakers; especially fundamental frequency (F0) which is the basic frequency with which the vocal cords of individuals vibrates. The aim of this paper is to study the amount of variation occurring in F0 of disguise and normal speech samples of speakers. This will also aid in determining the validity and reliability of F0 parameter of voice under different disguise conditions.

Journal of Punjab Academy of Forensic Medicine & Toxicology

Speaker recognition comprises all those activities which attempt to link a speech sample to its s... more Speaker recognition comprises all those activities which attempt to link a speech sample to its speaker through its acoustic or perceptual properties [1]. Speech signal is a multidimensional acoustic wave (Figure 1), which provides information regarding speaker characteristics, spoken phrase, speaker emotions, additional noise, channel transformations etc [2,3]. The human voice is unique personal trait. For indistinguishable voice, the two individuals should have the identical vocal mechanism and identical coordination of their articulators, which is least probable. However, the some amount variations also occur in the speech exemplars obtained from the same speaker. This is due to the fact that a speaker cannot exactly imitate the same utterance again and again. Even, the signature of an individual also shows variation from trails to trials.

Many techniques have been developed to determine the sequence of strokes depending on the nature ... more Many techniques have been developed to determine the sequence of strokes depending on the nature of writing instrument, type of ink or type of material. Determining the sequence of stroke is still very challengeable job for forensic document experts. With the popularity in different types of writing instruments and ink, the determination of sequence of stroke can be problematic. The application of allied sciences and analytical techniques of forensic science to questions concerning documents is termed forensic document examination. Determining sequence of strokes is an integral part of forensic document examination. The need for the investigation of sequence of strokes of writing emerges when it is alleged that a statement is written after the signature was done on the document or this examination can be performed to learn which of the handwriting was last written. The examination of sequence determination is very important job to fix the accountability of the person who had forged ...