Why is AP so low?（No changes were made. ）

[Eli-yu-first]

Hello blogger, may I ask which framework (/yhenon/pytorch-retinanet) on github I am running directly. No changes were made. Why is Average Precision (AP) so low?
"""
Average Precision (AP) @[ IoU=0.50 | area= all | maxDets=100 ] = 0.467
Average Precision (AP) @[ IoU=0.75 | area= all | maxDets=100 ] = 0.321
Average Precision (AP) @[ IoU=0.50:0.95 | area= small | maxDets=100 ] = 0.121
Average Precision (AP) @[ IoU=0.50:0.95 | area=medium | maxDets=100 ] = 0.327
Average Precision (AP) @[ IoU=0.50:0.95 | area= large | maxDets=100 ] = 0.445
Average Recall (AR) @[ IoU=0.50:0.95 | area= all | maxDets= 1 ] = 0.273
Average Recall (AR) @[ IoU=0.50:0.95 | area= all | maxDets= 10 ] = 0.419
Average Recall (AR) @[ IoU=0.50:0.95 | area= all | maxDets=100 ] = 0.447
Average Recall (AR) @[ IoU=0.50:0.95 | area= small | maxDets=100 ] = 0.229
Average Recall (AR) @[ IoU=0.50:0.95 | area=medium | maxDets=100 ] = 0.488
Average Recall (AR) @[ IoU=0.50:0.95 | area= large | maxDets=100 ] = 0.613
"""