Fast Segment Anything Model (FastSAM)
The Fast Segment Anything Model (FastSAM) is a novel, real-time CNN-based solution for the Segment Anything task. This task is designed to segment any object within an image based on various possible user interaction prompts. FastSAM significantly reduces computational demands while maintaining competitive performance, making it a practical choice for a variety of vision tasks.
FastSAM is designed to address the limitations of the Segment Anything Model (SAM), a heavy Transformer model with substantial computational resource requirements. The FastSAM decouples the segment anything task into two sequential stages: all-instance segmentation and prompt-guided selection. The first stage uses YOLOv8-seg to produce the segmentation masks of all instances in the image. In the second stage, it outputs the region-of-interest corresponding to the prompt.
Real-time Solution: By leveraging the computational efficiency of CNNs, FastSAM provides a real-time solution for the segment anything task, making it valuable for industrial applications that require quick results.
Efficiency and Performance: FastSAM offers a significant reduction in computational and resource demands without compromising on performance quality. It achieves comparable performance to SAM but with drastically reduced computational resources, enabling real-time application.
Prompt-guided Segmentation: FastSAM can segment any object within an image guided by various possible user interaction prompts, providing flexibility and adaptability in different scenarios.
Based on YOLOv8-seg: FastSAM is based on YOLOv8-seg, an object detector equipped with an instance segmentation branch. This allows it to effectively produce the segmentation masks of all instances in an image.
Competitive Results on Benchmarks: On the object proposal task on MS COCO, FastSAM achieves high scores at a significantly faster speed than SAM on a single NVIDIA RTX 3090, demonstrating its efficiency and capability.
Practical Applications: The proposed approach provides a new, practical solution for a large number of vision tasks at a really high speed, tens or hundreds of times faster than current methods.
Model Compression Feasibility: FastSAM demonstrates the feasibility of a path that can significantly reduce the computational effort by introducing an artificial prior to the structure, thus opening new possibilities for large model architecture for general vision tasks.
The FastSAM models are easy to integrate into your Python applications. Ultralytics provides a user-friendly Python API to streamline the process.
To perform object detection on an image, use the
predict method as shown below:
from ultralytics import FastSAM from ultralytics.models.fastsam import FastSAMPrompt # Define an inference source source = 'path/to/bus.jpg' # Create a FastSAM model model = FastSAM('FastSAM-s.pt') # or FastSAM-x.pt # Run inference on an image everything_results = model(source, device='cpu', retina_masks=True, imgsz=1024, conf=0.4, iou=0.9) # Prepare a Prompt Process object prompt_process = FastSAMPrompt(source, everything_results, device='cpu') # Everything prompt ann = prompt_process.everything_prompt() # Bbox default shape [0,0,0,0] -> [x1,y1,x2,y2] ann = prompt_process.box_prompt(bbox=[200, 200, 300, 300]) # Text prompt ann = prompt_process.text_prompt(text='a photo of a dog') # Point prompt # points default [[0,0]] [[x1,y1],[x2,y2]] # point_label default  [1,0] 0:background, 1:foreground ann = prompt_process.point_prompt(points=[[200, 200]], pointlabel=) prompt_process.plot(annotations=ann, output='./')
This snippet demonstrates the simplicity of loading a pre-trained model and running a prediction on an image.
Validation of the model on a dataset can be done as follows:
Please note that FastSAM only supports detection and segmentation of a single class of object. This means it will recognize and segment all objects as the same class. Therefore, when preparing the dataset, you need to convert all object category IDs to 0.
FastSAM official Usage
FastSAM is also available directly from the https://github.com/CASIA-IVA-Lab/FastSAM repository. Here is a brief overview of the typical steps you might take to use FastSAM:
Clone the FastSAM repository:
Create and activate a Conda environment with Python 3.9:
Navigate to the cloned repository and install the required packages:
Install the CLIP model:
Download a model checkpoint.
Use FastSAM for inference. Example commands:
Segment everything in an image:
Segment specific objects using text prompt:
Segment objects within a bounding box (provide box coordinates in xywh format):
Segment objects near specific points:
Citations and Acknowledgements
We would like to acknowledge the FastSAM authors for their significant contributions in the field of real-time instance segmentation:
The original FastSAM paper can be found on arXiv. The authors have made their work publicly available, and the codebase can be accessed on GitHub. We appreciate their efforts in advancing the field and making their work accessible to the broader community.