# Automated Cart with VIS/NIR Hyperspectral Reflectance and Fluorescence Imaging Capabilities
## 4 Conclusions  
The primary impetus for developing this laser-induced VIS/NIR fluorescence imaging system was to allow the acquisition of high resolution hyperspectral fluorescence images in fields, irrespective of solar lighting conditions. The validation of the system described herein represents the successful transition of high resolution laser-induced fluorescence imaging for use in fields. The system is unique and allows examination of problems such as the spread of fecal materials in produce fields over time. A particular advantage of the system is the ability to progress in small, precise, steps and to acquire sets of images with different acquisition parameters at each step. This ability allows the system to be used to model the operating characteristics of different optical systems and to contrast detection efficacy using identical, real world, targets. In particular, this ability could be used to address potential cost and detection sensitivity tradeoffs among different camera systems. For commercial interests, this would allow the selection of the least expensive camera and optics that would likely detect the level of contamination of concern. Another use of the ability to acquire sets of images would be to examine fluorescence decay characteristics by acquiring fluorescence response data at appropriate delay times and intervals.  
For food safety, detection of fecal materials in fields is a recognized concern and validation results demonstrate the ability to detect fecal materials outside during daylight hours and to differentiate fecal responses from the responses of intact plant leaves. For a commercial system to be used to detect fecal materials in fields, validation results suggest that detection could be accomplished using a single wavelength by taking advantage of the faster fluorescence decay of intact plant materials compared to the slower fluorescence decay of fecal materials. While issues related to food safety were the driving factors for development of this system, the system is a powerful research tool that has the potential to address a wide variety of research concerns.  
Figure 13: Fluorescence image at 673 nm using a gate delay of 20 ns and a gate width of 10 ns. The graph shows the representative spectra for spinach leaves and dairy manure.  
**Acknowledgments:** This work was funded by the United States Department of Agriculture (USDA). Partial support for [PERSON] was provided by the Department of Mechanical Engineering, University of Maryland, Baltimore County, Baltimore, MD, USA. The USDA is an equal opportunity employer.  
**Author Contributions:** [PERSON] conceived of this project and wrote the manuscript. [PERSON] designed and built the cart and optical mount while a Master of Science (MS) graduate student and after graduation ran tests of the system. [PERSON] was the university graduate advisor of [PERSON] and helped with the technical aspects of equipment designs. [PERSON] provided background information concerning the design of the optical sub-system.  
**Conflicts of Interest:** The authors declare no conflict of interest.