Table 2.

Layers of the pre-trained models utilized in the U-Net encoder part

VGG16	ResNet101	DenseNet121 (layer id)	InceptionV3 (layer id)	EfficientNetB5
block5_conv3	stage4_unit1_relu1	311	228	block6a_expand_activation
block4_conv3	stage3_unit1_relu1	139	86	block4a_expand_activation
block3_conv3	stage2_unit1_relu1	51	16	block3a_expand_activation
block2_conv2	relu0	4	9	block2a_expand_activation