The purpose of this research is to evaluate and validate the performance of non-invasive imaging modalities for assessment of skin. A pressure cuff occlusion will be used to stimulate blood flow dynamic that these instruments are designed to sense. The researcher currently plan to assess only basic feasibility of the imaging instruments.

The primary reason for including pressure cuff occlusion in this protocol is to test the performance of Multi-Spectral Imaging and Laser Speckle Imaging can measure in the full range of vascular conditions ranging from ischemic (under-perfused or unsaturated) to hyperemic (over-perfused and over-saturated).

1. Modulated Imaging a non-contact optical imaging technology can detect the concentration of total hemoglobin, deoxygenated and oxygenated hemoglobin in absolute amounts in units of millimoles / unit volume of tissue measured.
2. Laser Speckle Imaging a non-contact optical imaging technology consists of a coherent light source, camera, and image acquisition system. This image device can measure and compare relative flow in vasculature at varied time points.

Inclusion Criteria:

• Male and female adult 18 years and older

Exclusion Criteria:

• Younger than 18 years of age
• Pregnant women

Study population will be selected from University of California Irvine, student and staff member.