Morphological Analysis of Pressure Injury Images

Abstract

This paper details the morphological analysis of pressure injuries when using a novel methodology developed to process medical images, intended to de-compose the contained information in different contrast levels. This technique was developed using parametric surface equations based on a toroidal geometry, which decompose the image vertically and horizontally by using synthetic frequencies calculated directly from the image. In conjunction with Otsu's threshold algorithm, this technique allows for development of a methodology that is similar to level set, where the objective is to calculate the curve that describes the contours from objects within an image without the need to solve a differential equation. After the decomposition and image binarization, morphological operations are used to obtain the entire domain of the desired object within an image. A data set with 37 images of pressure injuries, provided by the Centre IGURCO, were synthetized using the proposed methodology. In order to evaluate the performance, digital image correlation was used as a measure, where the segments obtained are compared with manual segmentation made by professionals. The results present percentage errors below the 9% for the used parameters with an average image correlation of 0.92 ± 0.036. The proposed methodology is therefore considered a good estimation using a consistent non-invasive technique for the assessment of the healing process of the wound.