Introduction

Postmortem injury assessment and interpretation can be considered a very important part of forensic science and an important element in the clarification of cause and manner of death. The quantitative methods of image analysis can offer objective data concerning the structure of the injury, its edge architecture, geometrical properties (such as length, width, area, perimeter, and solidity), and gray-level textures [1]. Forensic professionals have used visual inspection, gross pathology, and their own expertise to assess injuries such as abrasions, contusions, cuts, ligature marks, and gunshot wounds [2]. While traditional forensic examination has been the bedrock of forensics, visual assessment by nature is subjective and can differ between examiners based on experience, surroundings, and image quality [3]. This subjectivity can affect forensic documentation and interpretations, especially when there is subtlety or overlap among injury characteristics [4].

The recent developments in digital imaging and computational image analysis techniques have created new possibilities for quantitative evaluation in forensic sciences [5]. Digital image analysis provides the ability to extract quantifiable information about morphology and texture from photographs and thereby minimize reliance on subjective analysis [6]. In forensic applications, the use of quantifiable measurements through imaging can help document injuries and make scientific observations [7].

The existing software tools for image analysis include NIH ImageJ, a popular image processing software developed by the National Institutes of Health (Bethesda, MD, USA). The software is capable of quantitatively analyzing the morphological parameters such as length, width, area, perimeter, and shape of a body structure [8,9]. These features can help to understand additional aspects related to the geometrical, surface, and structural properties of an injury [10].

Morphometrics is a useful method in evaluating images from a quantitative perspective. Parameters such as area and perimeter provide information about the size and shape of injuries; meanwhile, solidity indicates the regularity and tightness of the injury margins [11]. Lesions with irregular or discontinuous margins tend to have smaller solidity compared with injuries having smooth boundaries [12]. These parameters might assist forensic evaluators in quantifying observations when discrimination proves challenging visually [13].

Moreover, along with morphometric analysis, gray-level texture analysis has become significant in evaluating images digitally [14]. Gray-level features can be extracted based on variations in intensity values of pixels in a chosen ROI and might indicate tissue heterogeneity and texture properties of the image [15]. Features such as minimum gray level, maximum gray level, median gray level, and standard deviation (SD) can demonstrate variations in tissue structure and image intensity [16]. Some previous research has indicated that variations in texture could help detect minor differences in tissue structures and injuries [17].

Forensic photographic standards are yet another vital prerequisite for a meaningful image-based study [18]. Camera perspective, lighting conditions, exposure, and scaling can play an important role in influencing any morphometric or texture measure [19]. Thus, the implementation of forensic scales such as the ABFO No. 2 scale (American Board of Forensic Odontology; Florida, USA) in combination with standardized imaging conditions has been suggested as one means of reducing measurement errors [20].

Although there has been increasing research activity in forensic image analysis, existing literature is relatively sparse and uncoordinated. Previous research has been centered around discrete measurements, specific injuries, and imaging methods used for experiments rather than a comprehensive quantification [21]. Moreover, few papers have been published by resource-limited forensic centers, wherein computational methodologies are in development [22]. Moreover, issues related to reproducibility, observer bias, multicollinearity between morphological measures, and the absence of external validation remain barriers to forensic applications [23].

In the current study, parameters such as size, shape (length, width, area, perimeter, and solidity), and grayscale properties (minimum gray level, maximum gray level, median gray level, and SD) of the injuries were measured by standardized quantitative morphometric and texture analyses on digitized images.

The current study should be seen more as an exploratory study to generate hypotheses rather than as a conclusive study to validate any diagnosis. The results obtained could form the basis of further studies that would involve standardized imaging procedures, automatic image analysis algorithms, and external validation sets.

The aim of the current study was to evaluate the potential of quantitative morphometric and gray-level texture analysis of post-mortem injuries utilizing the ImageJ software and to determine whether these parameters may serve as objective additional information in forensic documentation of injuries.