1. A device comprising: a housing having a surface for coupling to a biological tissue; an array of emitters, the array including at least a first emitter and a second emitter, the array coupled to the surface; a first detector and a second detector coupled to the surface, the first detector having a first output and the second detector having a second output, the array coupled to a processor and wherein the processor is configured to select the first emitter and the second emitter from the array of emitters, wherein the first emitter and the second detector are separated by a first dimension and the second emitter and the first detector are separated by approximately the first dimension, the first dimension selected to correspond with a region of interest in a first layer of the biological tissue, the first emitter and the first detector are separated by a second dimension and the second emitter and the second detector are separated by approximately the second dimension, the second dimension selected to correspond with an exclusion region in a second layer of the biological tissue, the first layer having a first depth below the surface and the second layer having a second depth below the surface, the first depth greater than the second depth, and wherein the first emitter and the second emitter are configured to be sequentially powered and unpowered, and wherein the first dimension and the second dimension correspond to the selected emitters; and a port coupled to the housing and configured to communicate at least one of the first output or the second output to a module.