Intelligent micro flight sensing system for detecting the internal and external quality of apples on the tree

•The quality of apples on the tree was detected by flying method at close range.•A miniature low-cost multispectral sensor was optimized.•An RGB-D camera was used to recognize the position and size of apples.•Compared and analyzed the static and dynamic acquisition results of the spectrum.•The flying detector can be used in smart agriculture and unmanned farms.