sahi 0.3.1

A vision library for performing sliced inference on large images/small objects

SAHI: Slicing Aided Hyper Inference

A vision library for performing sliced inference on large images/small objects

Overview

Object detection and instance segmentation are by far the most important fields of applications in Computer Vision. However, detection of small objects and inference on large images are still major issues in practical usage. Here comes the SAHI to help developers overcome these real-world problems.

Getting started

Blogpost

Check the official SAHI blog post.

Installation

• Install sahi using conda:

conda install -c obss sahi

• Install sahi using pip:

pip install sahi

• Install your desired version of pytorch and torchvision:

pip install torch torchvision

• Install your desired detection framework (such as mmdet):

pip install mmdet

Usage

• Sliced inference:

result = get_sliced_prediction(
    image,
    detection_model,
    slice_height = 256,
    slice_width = 256,
    overlap_height_ratio = 0.2,
    overlap_width_ratio = 0.2
)

Refer to inference notebook for detailed usage.

• Slice an image:

from sahi.slicing import slice_image

slice_image_result, num_total_invalid_segmentation = slice_image(
    image=image_path,
    output_file_name=output_file_name,
    output_dir=output_dir,
    slice_height=256,
    slice_width=256,
    overlap_height_ratio=0.2,
    overlap_width_ratio=0.2,
)

• Slice a coco formatted dataset:

from sahi.slicing import slice_coco

coco_dict, coco_path = slice_coco(
    coco_annotation_file_path=coco_annotation_file_path,
    image_dir=image_dir,
    slice_height=256,
    slice_width=256,
    overlap_height_ratio=0.2,
    overlap_width_ratio=0.2,
)

Adding new detection framework support

sahi library currently only supports MMDetection models. However it is easy to add new frameworks.

All you need to do is, creating a new class in model.py that implements DetectionModel class. You can take the MMDetection wrapper as a reference.

Contributers

• Fatih Cagatay Akyon
• Cemil Cengiz
• Sinan Onur Altinuc