Biological tissues are a combination of cellular and acellular components. The extracellular matrix (ECM), or the acellular component of tissues, is often overlooked. Tracking changes in the ECM grants insight into how aging, diseases and treatments might affect tissue structures and cellular responses. Using gray-level texture analysis, we analyzed the architecture of fibrillar collagen, a major component of the ECM. Several gray-level textural features were extracted from second harmonic generation (SHG) images and used to characterize collagen network arrangements. This work provides a basis for a classification model aimed to track changes in the cellular microenvironment. This information is vital if we wish to continue exploration of how diseases develop in different tissues, and develop novel and effective treatments for different types of chronic diseases.