supervision/docs/how_to/detect_small_objects.md

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---
# Detect Small Objects
This guide shows how to detect small objects
with the [Inference](https://github.com/roboflow/inference),
[Ultralytics](https://github.com/ultralytics/ultralytics) or
[Transformers](https://github.com/huggingface/transformers) packages using
[`InferenceSlicer`](/latest/detection/tools/inference_slicer/#supervision.detection.tools.inference_slicer.InferenceSlicer).
<video controls>
<source src="https://media.roboflow.com/supervision_detect_small_objects_example.mp4" type="video/mp4">
</video>
## Baseline Detection
Small object detection in high-resolution images presents challenges due to the objects'
size relative to the image resolution.
=== "Inference"
```python
import cv2
import supervision as sv
from inference import get_model
model = get_model(model_id="yolov8x-640")
image = cv2.imread(<SOURCE_IMAGE_PATH>)
results = model.infer(image)[0]
detections = sv.Detections.from_inference(results)
box_annotator = sv.BoxAnnotator()
label_annotator = sv.LabelAnnotator()
annotated_image = box_annotator.annotate(
scene=image, detections=detections)
annotated_image = label_annotator.annotate(
scene=annotated_image, detections=detections)
```
=== "Ultralytics"
```python
import cv2
import supervision as sv
from ultralytics import YOLO
model = YOLO("yolov8x.pt")
image = cv2.imread(<SOURCE_IMAGE_PATH>)
results = model(image)[0]
detections = sv.Detections.from_ultralytics(results)
box_annotator = sv.BoxAnnotator()
label_annotator = sv.LabelAnnotator()
annotated_image = box_annotator.annotate(
scene=image, detections=detections)
annotated_image = label_annotator.annotate(
scene=annotated_image, detections=detections)
```
=== "Transformers"
```python
import torch
import supervision as sv
from PIL import Image
from transformers import DetrImageProcessor, DetrForSegmentation
processor = DetrImageProcessor.from_pretrained("facebook/detr-resnet-50")
model = DetrForSegmentation.from_pretrained("facebook/detr-resnet-50")
image = Image.open(<SOURCE_IMAGE_PATH>)
inputs = processor(images=image, return_tensors="pt")
with torch.no_grad():
outputs = model(**inputs)
width, height = image_slice.size
target_size = torch.tensor([[width, height]])
results = processor.post_process_object_detection(
outputs=outputs, target_sizes=target_size)[0]
detections = sv.Detections.from_transformers(results)
box_annotator = sv.BoxAnnotator()
label_annotator = sv.LabelAnnotator()
labels = [
model.config.id2label[class_id]
for class_id
in detections.class_id
]
annotated_image = box_annotator.annotate(
scene=image, detections=detections)
annotated_image = label_annotator.annotate(
scene=annotated_image, detections=detections, labels=labels)
```
![basic-detection](https://media.roboflow.com/supervision_detect_small_objects_example_1.png)
## Input Resolution
Modifying the input resolution of images before detection can enhance small object
identification at the cost of processing speed and increased memory usage. This method
is less effective for ultra-high-resolution images (4K and above).
=== "Inference"
```{ .py hl_lines="5" }
import cv2
import supervision as sv
from inference import get_model
model = get_model(model_id="yolov8x-1280")
image = cv2.imread(<SOURCE_IMAGE_PATH>)
results = model.infer(image)[0]
detections = sv.Detections.from_inference(results)
box_annotator = sv.BoxAnnotator()
label_annotator = sv.LabelAnnotator()
annotated_image = box_annotator.annotate(
scene=image, detections=detections)
annotated_image = label_annotator.annotate(
scene=annotated_image, detections=detections)
```
=== "Ultralytics"
```{ .py hl_lines="7" }
import cv2
import supervision as sv
from ultralytics import YOLO
model = YOLO("yolov8x.pt")
image = cv2.imread(<SOURCE_IMAGE_PATH>)
results = model(image, imgsz=1280)[0]
detections = sv.Detections.from_ultralytics(results)
box_annotator = sv.BoxAnnotator()
label_annotator = sv.LabelAnnotator()
annotated_image = box_annotator.annotate(
scene=image, detections=detections)
annotated_image = label_annotator.annotate(
scene=annotated_image, detections=detections)
```
![detection-with-high-input-resolution](https://media.roboflow.com/supervision_detect_small_objects_example_2.png)
## Inference Slicer
[`InferenceSlicer`](/latest/detection/tools/inference_slicer/#supervision.detection.tools.inference_slicer.InferenceSlicer)
processes high-resolution images by dividing them into smaller segments, detecting
objects within each, and aggregating the results.
<video controls>
<source src="https://media.roboflow.com/supervision_detect_small_objects_example_2.mp4" type="video/mp4">
</video>
=== "Inference"
```{ .py hl_lines="9-14" }
import cv2
import numpy as np
import supervision as sv
from inference import get_model
model = get_model(model_id="yolov8x-640")
image = cv2.imread(<SOURCE_IMAGE_PATH>)
def callback(image_slice: np.ndarray) -> sv.Detections:
results = model.infer(image_slice)[0]
return sv.Detections.from_inference(results)
slicer = sv.InferenceSlicer(callback = callback)
detections = slicer(image)
box_annotator = sv.BoxAnnotator()
label_annotator = sv.LabelAnnotator()
annotated_image = box_annotator.annotate(
scene=image, detections=detections)
annotated_image = label_annotator.annotate(
scene=annotated_image, detections=detections)
```
=== "Ultralytics"
```{ .py hl_lines="9-14" }
import cv2
import numpy as np
import supervision as sv
from ultralytics import YOLO
model = YOLO("yolov8x.pt")
image = cv2.imread(<SOURCE_IMAGE_PATH>)
def callback(image_slice: np.ndarray) -> sv.Detections:
result = model(image_slice)[0]
return sv.Detections.from_ultralytics(result)
slicer = sv.InferenceSlicer(callback = callback)
detections = slicer(image)
box_annotator = sv.BoxAnnotator()
label_annotator = sv.LabelAnnotator()
annotated_image = box_annotator.annotate(
scene=image, detections=detections)
annotated_image = label_annotator.annotate(
scene=annotated_image, detections=detections)
```
=== "Transformers"
```{ .py hl_lines="13-28" }
import cv2
import torch
import numpy as np
import supervision as sv
from PIL import Image
from transformers import DetrImageProcessor, DetrForObjectDetection
processor = DetrImageProcessor.from_pretrained("facebook/detr-resnet-50")
model = DetrForObjectDetection.from_pretrained("facebook/detr-resnet-50")
image = cv2.imread(<SOURCE_IMAGE_PATH>)
def callback(image_slice: np.ndarray) -> sv.Detections:
image_slice = cv2.cvtColor(image_slice, cv2.COLOR_BGR2RGB)
image_slice = Image.fromarray(image_slice)
inputs = processor(images=image_slice, return_tensors="pt")
with torch.no_grad():
outputs = model(**inputs)
width, height = image_slice.size
target_size = torch.tensor([[width, height]])
results = processor.post_process_object_detection(
outputs=outputs, target_sizes=target_size)[0]
return sv.Detections.from_transformers(results)
slicer = sv.InferenceSlicer(callback = callback)
detections = slicer(image)
box_annotator = sv.BoxAnnotator()
label_annotator = sv.LabelAnnotator()
labels = [
model.config.id2label[class_id]
for class_id
in detections.class_id
]
annotated_image = box_annotator.annotate(
scene=image, detections=detections)
annotated_image = label_annotator.annotate(
scene=annotated_image, detections=detections, labels=labels)
```
![detection-with-inference-slicer](https://media.roboflow.com/supervision_detect_small_objects_example_3.png)
## Small Object Segmentation
[`InferenceSlicer`](/latest/detection/tools/inference_slicer/#supervision.detection.tools.inference_slicer.InferenceSlicer) can perform segmentation tasks too.
=== "Inference"
```{ .py hl_lines="6 16 19-20" }
import cv2
import numpy as np
import supervision as sv
from inference import get_model
model = get_model(model_id="yolov8x-seg-640")
image = cv2.imread(<SOURCE_IMAGE_PATH>)
def callback(image_slice: np.ndarray) -> sv.Detections:
results = model.infer(image_slice)[0]
return sv.Detections.from_inference(results)
slicer = sv.InferenceSlicer(callback = callback)
detections = slicer(image)
mask_annotator = sv.MaskAnnotator()
label_annotator = sv.LabelAnnotator()
annotated_image = mask_annotator.annotate(
scene=image, detections=detections)
annotated_image = label_annotator.annotate(
scene=annotated_image, detections=detections)
```
=== "Ultralytics"
```{ .py hl_lines="6 16 19-20" }
import cv2
import numpy as np
import supervision as sv
from ultralytics import YOLO
model = YOLO("yolov8x-seg.pt")
image = cv2.imread(<SOURCE_IMAGE_PATH>)
def callback(image_slice: np.ndarray) -> sv.Detections:
result = model(image_slice)[0]
return sv.Detections.from_ultralytics(result)
slicer = sv.InferenceSlicer(callback = callback)
detections = slicer(image)
mask_annotator = sv.MaskAnnotator()
label_annotator = sv.LabelAnnotator()
annotated_image = mask_annotator.annotate(
scene=image, detections=detections)
annotated_image = label_annotator.annotate(
scene=annotated_image, detections=detections)
```
![detection-with-inference-slicer](https://media.roboflow.com/supervision-docs/inference-slicer-segmentation-example.png)