The Experiment: Utilizing the versatile DronePoints stencil system, we applied identical patterns on a uniform faded asphalt surface using four distinct spray paint colors: black, orange, blue, and red, under uniform lighting to maintain fairness in our experiment.
For the aerial imaging, we chose a DJI Inspire 2 drone, specifically equipped with a Zenmuse X4S 20 MP camera. Notably, the Zenmuse X4S, while highly capable, represents an older sensor technology in our testing arsenal. This choice was strategic, aimed at lowering the image quality to test the visibility of the markings under testing conditions with a higher Ground Sample Distance (GSD) of approximately 1 inch.
Results: The analysis of aerial imagery revealed striking differences in visibility among the tested paint colors. Black and red paints emerged as the leaders for their exceptional visibility and contrast from aerial perspectives. This result was particularly enlightening given our test parameters, which included a higher GSD due to the older sensor technology of the Zenmuse X4S camera. Here's a breakdown of each color's performance:
Black and Red: Demonstrated high contrast, especially effective on lighter surfaces, ensuring its markings were conspicuously visible from our 300 feet AGL flight level.
Orange and Blue: While adequate under certain conditions, these colors lacked the stark contrast achieved by black and red, particularly in the context of our higher GSD imaging scenario.
Discussion: The superior performance of black and red spray paints in our aerial imagery is attributed to their stark contrast against a wide variety of background colors found in natural and urban environments. The choice to use an older sensor technology for this experiment underscores the importance of color visibility even as image resolution varies – a critical consideration for mapping professionals who may encounter varied imaging scenarios in the field.
Conclusion: Selecting the right spray paint color for ground markers plays a critical role in the success of aerial surveying and mapping projects. Our experiment highlights the necessity of choosing high-contrast colors, like black and red, to ensure visibility in aerial imagery, a factor that becomes even more crucial under less-than-ideal imaging conditions. For professionals in aerial mapping and surveying, these findings offer a clear guide to enhancing the accuracy and efficiency of their work, regardless of camera sensor advancements.