The distribution of image and object sizes for the MS COCO ‘ship’ category.

A red triangle in the plot indicates the size of an image. A blue circle indicates the size of a ship.</p

The MariBoatsSubclass dataset.

(a) The histogram of the number of images and labelled ships in individual categories in MariBoatsSubclass. (b) Delineations of representative images of each category in MariBoatsSubclass.</p

Test results of SOLOv2 in the three instance segmentation datasets.

Test results of SOLOv2 in the three instance segmentation datasets.</p

Overview of several existing open-source datasets of marine ships.

Overview of several existing open-source datasets of marine ships.</p

A representative example of incomplete segmentation by Mask R-CNN, SOLO and SOLOv2.

The red circles represent the parts of ships that should be detected but are not detected. Insets: amplified images of the objects with the red circles.</p

Illustration of the difference between 2D spatial pooling and 1D strip pooling in instance segmentation.

(a) The original image. (b) 2-D spatial pooling. (c)1D strip pooling. (d) The segmentation result using the GALA mechanism.</p

Test results of Mask-RCNN in three instance segmentation datasets.

Test results of Mask-RCNN in three instance segmentation datasets.</p

Schematic diagram of the enhanced feature pyramid structure.

EFPN represents our enhanced improvement of the feature pyramid. GALA represents our proposed global and local attention mechanism. C1-C4 represent the feature maps of different sizes extracted from the backbone network, respectively, and P1-P4 represent the predicted objects of different scales, respectively. The original structure of the feature pyramid network is shown in the lower right.</p

The scheme depicts the GALA mechanism.

C represents the number of channels, that is, the number of feature maps.H and W represents the height and width of the feature maps, respectively.</p

Test results of SOLO in the three instance segmentation datasets.

Test results of SOLO in the three instance segmentation datasets.</p