Awesome

Pretrained DeepLabv3+ Network for Semantic Segmentation

This repository provides a pretrained DeepLabv3+[1] semantic segmentation model for MATLAB®.

Requirements

• MATLAB® R2020a or later.
• Deep Learning Toolbox™.
• Computer Vision Toolbox™.

Overview

Semantic segmentation is a computer vision technique for segmenting different classes of objects in images or videos. This pretrained network is trained using PASCAL VOC dataset[2] which have 20 different classes including airplane, bus, car, train, person, horse etc.

For more information about semantic segmentation, see Getting Started with Semantic Segmentation Using Deep Learning.

Getting Started

Download or clone this repository to your machine and open it in MATLAB®.

Download the pretrained network

Use the below helper to download the pretrained network.

model = helper.downloadPretrainedDeepLabv3Plus;
net = model.net;

Semantic Segmentation Using Pretrained DeepLabv3+

% Read test image from images folder
image = imread('visionteam.jpg');

% Resize the image to the size used to train the network. 
% The image is resized such that smallest dimension is 513.
sz = size(image);
[~,k] = min(sz(1:2));
scale = 513/sz(k);
img  = imresize(image, scale, "bilinear");

% Use semanticseg function to generate segmentation map.
result = semanticseg(img, net);

% Generate the overlaid result using generated map.
overlay = labeloverlay(img , result, 'Transparency', 0.4);

% Visualize the input and the result.
overlay = imresize(overlay, sz(1:2), 'bilinear');
montage({image, overlay});

Left-side image is the input and right-side image is the corresponding segmentation output.

Train Custom DeepLabv3+ Using Transfer Learning

Transfer learning enables you to adapt a pretrained DeepLabv3+ network to your dataset. Create a custom DeepLabv3+ network for transfer learning with a new set of classes using the configureDeepLabv3PlusTransferLearn.m script. For more information about training a DeepLabv3+ network, see Semantic Segmentation Using Deep Learning

Code Generation for DeepLabV3+

Code generation enables you to generate code and deploy DeepLabv3+ on multiple embedded platforms.

Run codegenDeepLabv3Plus.m. This script calls the deepLabv3Plus_predict.m entry point function and generate CUDA code for it. It will run the generated MEX and gives output.

• Performance (in FPS) is measured on a TITAN-RTX GPU using 513x513 image.

For more information about codegen, see Deep Learning with GPU Coder

Accuracy

Metrics are mIoU, global accuracy and mean accuracy computed over 2012 PASCAL VOC val data.

• During computation of these metrics, val images are first resized such that the smaller dimension of the images are scaled to 513 because that matches the training preprocessing and then a center crop of size 513x513 is used for evaluation.

References

[1] Chen, Liang-Chieh, et al. "Encoder-decoder with atrous separable convolution for semantic image segmentation." Proceedings of the European conference on computer vision (ECCV). 2018.

[2] The PASCAL Visual Object Classes Challenge: A Retrospective Everingham, M., Eslami, S. M. A., Van Gool, L., Williams, C. K. I., Winn, J. and Zisserman, A. International Journal of Computer Vision, 111(1), 98-136, 2015.

Copyright 2021 The MathWorks, Inc.