Table 2.

Summary of CNN-based data analysis approach in imaging-based plant phenotyping.

Phenotyping category	Phenotyping task	Main processing approach	Particular improvement strategy	References
Plant stress	Stress detection and classification	Image classification	NA	[43, 44, 47–53]
			Sliding window	[45, 57]
			Explainable visualization	[55, 56]
			Advanced imaging	[58]
			Synthetic data augmentation	[54]
		Object detection	NA	[46]
Plant development	Plant lodging	Image classification	NA	[68]
	Canopy morphology measurement	Object detection	NA	[61, 65]
		Semantic segmentation	NA	[59, 63, 64]
	Leaf morphology measurement	Instance segmentation	NA	[60, 62]
	Characterization of plant growth pattern	Combination of CNN and other DL methods	NA	[66, 67]
Plant development	Counting plant/plant organs in still images	Regression	NA	[69, 70, 72, 79]
			Synthetic data augmentation	[71, 73]
			Multiscale and multimodal data fusion	[74, 75]
			Nonsupervised learning mode	[76, 78, 80]
			Explainable visualization	[77]
		Image classification	NA	[82, 83]
		Object detection	NA	[84–91, 93, 94]
			Sliding window	[92, 95]
			Synthetic data augmentation	[95]
		Semantic segmentation	NA	[96–101]
			Sliding window	[101]
		Instance segmentation	NA	[102–106]
			Synthetic data augmentation	[102, 103, 105, 106]
Plant development	Counting plant/plant organs in image sequences and videos	Object detection	2D orthoimage reconstruction	[111–113]
			3D structure reconstruction	[107, 115–119]
			Video tracking	[108–110]
		Semantic segmentation	Movement encoding	[114]
Plant development	Counting root tips	Regression	NA	[120]
	Root system architecture segmentation	Semantic segmentation	NA	[120–124]
			Inpainting for oversegmentation correction	[125, 127]
			Advanced imaging	[126, 128]
			Synthetic data augmentation	[125, 126]
Postharvest quality	Fruit chemical composition measurement	Regression	NA	[138]
	Fruit defect detection	Image classification	NA	[131, 132, 135, 136, 140]
			Advanced imaging	[134]
			Sliding window	[129, 137]
	Fruit defect quantification	Semantic segmentation	NA	[141]
			Advanced imaging	[139]