ONNX exports of Ultralytics YOLOv11-seg
(instance segmentation) in the configurations the occurra
object_detection_segmentation agent ships with. Companion to
occurra/object_detection —
same class set (person + bicycle + 4 vehicle subtypes), same naming
convention, same hardware-selection logic, with per-object pixel masks
on top of bounding boxes.
Nano size only (no small variant yet). Four precision variants. All
files are self-contained (no external-data sidecars).
FP16 weights, NMS embedded. Default for NVIDIA TensorRT EP.
fp8
FP8 quantized via TensorRT QDQ. Smallest VRAM footprint on Blackwell / Hopper.
int8
INT8 quantized with QDQ nodes embedded in the graph. No sidecar calibration cache needed.
640x640
Square input — same shape used by the upstream Ultralytics export.
The object_detection_segmentation agent reads the input shape directly
from the loaded ONNX (graph.input[0].type) — no sidecar config; the
file name is informational.
Which file to pick
Hardware
Recommended
Apple Silicon (CoreML / ANE)
yolo11n-seg_apple_640x640.onnx
NVIDIA RTX 4000+ / Blackwell
yolo11n-seg_fp8_640x640.onnx
NVIDIA older (no FP8)
yolo11n-seg_int8_640x640.onnx
CPU fallback
yolo11n-seg_fp16_640x640.onnx
The agent's _resolve_model_filename picks automatically based on
platform + GPU compute capability. Set
OBJECT_DETECTION_SEGMENTATION_MODEL=<filename> to force a specific
variant.
Outputs
Each ONNX has two outputs (Ultralytics-seg standard):
Output
Shape
Contents
output0
(batch, 4+80+32, N)
[cx, cy, w, h] + 80 class scores + 32 mask coefficients per anchor
output1
(batch, 32, proto_h, proto_w)
Prototype masks; coeffs @ protos reconstructs the per-detection mask.
The agent runs NMS in Python after filtering to the curated class set
(COCO 0/1/2/3/5/7 → person, bicycle, car, motorcycle, bus, truck) and
decodes masks in YoloSegOnnx. Bitplane bytes are passed to the C++
toolbox for denoising + RLE encoding.
Source
Ultralytics yolo11n-seg.pt checkpoints downloaded from Ultralytics'
release feed and re-exported via the occurra toolbox's
ai_agent_toolbox/agents/python/object_detection_segmentation/scripts/main.py
(NMS-free for Apple, with-NMS for NVIDIA; FP8/INT8 use TensorRT QDQ).
License
The model weights inherit Ultralytics YOLOv11's
AGPL-3.0
license. Commercial use requires a separate enterprise license from
Ultralytics — the ONNX export does not change that.