squeezesegv2Layers

(Not recommended) Create SqueezeSegV2 segmentation network for organized lidar point cloud

Since R2020b

squeezesegv2Layers is not recommended. Use the squeezesegv2Network function (since R2024a) instead. For more information, see Version History.

Syntax

lgraph = squeezesegv2Layers(inputSize,numClasses)

lgraph = squeezesegv2Layers(___,Name,Value)

Description

lgraph = squeezesegv2Layers(inputSize,numClasses) returns a SqueezeSegV2 layer graph lgraph for organized point clouds of size inputSize and the number of classes numClasses.

SqueezeSegV2 is a convolutional neural network that predicts pointwise labels for an organized lidar point cloud.

Use the squeezesegv2Layers function to create the network architecture for SqueezeSegV2. This function requires Deep Learning Toolbox™.

lgraph = squeezesegv2Layers(___,Name,Value) specifies options using one or more name-value pair arguments in addition to the input arguments in the previous syntax. For example, 'NumEncoderModules',4 sets the number of encoders used to create the network to four.

Examples

Create Standard SqueezeSegV2 Network

Set the network input parameters.

inputSize = [64 512 5];
numClasses = 4;

Create a SqueezeSegV2 layer graph.

lgraph = squeezesegv2Layers(inputSize,numClasses)

lgraph = 
  LayerGraph with properties:

     InputNames: {'input'}
    OutputNames: {'focalloss'}
         Layers: [168x1 nnet.cnn.layer.Layer]
    Connections: [186x2 table]

Display the network.

analyzeNetwork(lgraph)

Create Custom SqueezeSegV2 Network

Set the network input parameters.

inputSize = [64 512 6];
numClasses = 2;

Create a custom SqueezeSegV2 layer graph.

lgraph = squeezesegv2Layers(inputSize,numClasses, ...
'NumEncoderModules',4,'NumContextAggregationModules',2)

lgraph = 
  LayerGraph with properties:

     InputNames: {'input'}
    OutputNames: {'focalloss'}
         Layers: [232x1 nnet.cnn.layer.Layer]
    Connections: [257x2 table]

Display the network.

analyzeNetwork(lgraph)

Input Arguments

inputSize — Size of network input

two-element row vector | three-element row vector

Size of the network input, specified as one of these options:

• Two-element vector of the form [height width].

• Three-element vector of the form [height width channels], where channels specifies the number of input channels. Set channels to 3 for RGB images, to 1 for grayscale images, or to the number of channels for multispectral and hyperspectral images.

numClasses — Number of classes

integer greater than 1

Number of semantic segmentation classes, specified as an integer greater than 1.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: 'NumEncoderModules',4 sets the number of encoders used to create the network to four.

NumEncoderModules — Number of encoder modules

2 (default) | nonnegative integer

Number of encoder modules used to create the network, specified as the comma-separated pair consisting of 'NumEncoderModules' and a nonnegative integer. Each encoder module consists of two fire modules and one max-pooling layer connected sequentially. If you specify 0, then the function returns a network with a default encoder that consists of convolution and max-pooling layers with no fire modules. Use this name-value pair to customize the number of fire modules in the network.

NumContextAggregationModules — Number of context aggregation modules

3 (default) | integer in the range [0,3]

Number of context aggregation modules (CAMs), specified as the comma-separated pair consisting of 'NumContextAggregationModules' and an integer in the range [0,3]. If you specify 0, then the function creates a network without a CAM.

Output Arguments

lgraph — Layers

LayerGraph object

Layers that represent the SqueezeSegV2 network architecture, returned as a layerGraph (Deep Learning Toolbox) object.

More About

SqueezeSegV2 Network

• A SqueezeSegV2 network consists of encoder modules, CAMs, intermediate fixed fire modules [1] for feature extraction, and decoder modules. The function automatically configures the number of decoder modules based on the specified number of encoder modules.

• The function uses narrow-normal weight initialization method to initialize the weights of each convolution layer within encoder and decoder subnetworks.

• The function initializes all bias terms to zero.

• The function adds the padding for all convolution and max-pooling layers such that the output has the same size as the input (if the stride equals 1).

• The height of the input tensor is significantly lower than the width in organized lidar point cloud data. To address this, the network downsamples the width dimension of the input data in convolution and max-pooling layers. The width of the input data must be a multiple of 2^{(D + 2)}, where D is the number of encoder modules used to create the network.

• This function does not provide a recurrent conditional random field (CRF) layer.

References

[1] Wu, Bichen, Xuanyu Zhou, Sicheng Zhao, Xiangyu Yue, and Kurt Keutzer. “SqueezeSegV2: Improved Model Structure and Unsupervised Domain Adaptation for Road-Object Segmentation from a LiDAR Point Cloud.” In 2019 International Conference on Robotics and Automation (ICRA), 4376–82. Montreal, QC, Canada: IEEE, 2019.https://doi.org/10.1109/ICRA.2019.8793495.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.

GPU Code Generation
Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.

Version History

Introduced in R2020b

R2024a: Not recommended

Starting in R2024a, the squeezesegv2Layers function is not recommended. Use the squeezesegv2Network function instead.

There are no plans to remove support for the squeezesegv2Layers function. However, the squeezesegv2Network function is recommended. The squeezesegv2Network function returns a dlnetwork (Deep Learning Toolbox) object, which support a wider range of network architectures that you can create or import from external platforms.

This table shows a typical usage of the squeezesegv2Layers function and how to update your code to use the squeezesegv2Network function instead.

Not Recommended	Recommended
lgraph = squeezesegv2Layers(inputSize,numClasses)	net = squeezesegv2Network(numPoints,numClasses)