darknet19

(Not recommended) DarkNet-19 convolutional neural network

• 

darknet19 is not recommended. Use the imagePretrainedNetwork function instead and specify the "darknet19" model. For more information, see Version History.

Syntax

net = darknet19

net = darknet19('Weights','imagenet')

layers = darknet19('Weights','none')

Description

DarkNet-19 is a convolutional neural network that is 19 layers deep. You can load a pretrained version of the network trained on more than a million images from the ImageNet database [1]. The pretrained network can classify images into 1000 object categories, such as keyboard, mouse, pencil, and many animals. As a result, the network has learned rich feature representations for a wide range of images. The network has an image input size of 256-by-256. For more pretrained networks in MATLAB^®, see Pretrained Deep Neural Networks.

DarkNet-19 is often used as the foundation for object detection problems and YOLO workflows [2]. For an example of how to train a you only look once (YOLO) v2 object detector, see Object Detection Using YOLO v2 Deep Learning. This example uses ResNet-50 for feature extraction. You can also use other pretrained networks such as DarkNet-19, DarkNet-53, MobileNet-v2, or ResNet-18 depending on application requirements.

net = darknet19 returns a DarkNet-19 network trained on the ImageNet data set.

This function requires the Deep Learning Toolbox™ Model for DarkNet-19 Network support package. If this support package is not installed, then the function provides a download link.

net = darknet19('Weights','imagenet') returns a DarkNet-19 network trained on the ImageNet data set. This syntax is equivalent to net = darknet19.

layers = darknet19('Weights','none') returns the untrained DarkNet-19 network architecture. The untrained model does not require the support package.

Examples

Download DarkNet-19 Support Package

Download and install the Deep Learning Toolbox Model for DarkNet-19 Network support package.

Type darknet19 at the command line.

darknet19

If the Deep Learning Toolbox Model for DarkNet-19 Network support package is not installed, then the function provides a link to the required support package in the Add-On Explorer. To install the support package, click the link, and then click Install. Check that the installation is successful by typing darknet19 at the command line. If the required support package is installed, then the function returns a SeriesNetwork object.

darknet19

ans = 

  SeriesNetwork with properties:

         Layers: [64×1 nnet.cnn.layer.Layer]
     InputNames: {'input'}
    OutputNames: {'output'}

Visualize the network using Deep Network Designer.

deepNetworkDesigner(darknet19)

Explore other pretrained neural networks in Deep Network Designer by clicking New.

If you need to download a neural network, pause on the desired neural network and click Install to open the Add-On Explorer.

Output Arguments

net — Pretrained DarkNet-19 convolutional network

SeriesNetwork

Pretrained DarkNet-19 convolutional neural network, returned as a SeriesNetwork object.

layers — Untrained DarkNet-19 convolutional neural network architecture

Layer array

Untrained DarkNet-19 convolutional neural network architecture, returned as a Layer array.

References

[1] ImageNet. http://www.image-net.org.

[2] Redmon, Joseph. “Darknet: Open Source Neural Networks in C.” https://pjreddie.com/darknet.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

For code generation, you can load the network by using the syntax net = darknet19 or by passing the darknet19 function to coder.loadDeepLearningNetwork (MATLAB Coder). For example: net = coder.loadDeepLearningNetwork('darknet19').

The syntax darknet19('Weights','none') is not supported for code generation.

GPU Code Generation

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

Usage notes and limitations:

• For code generation, you can load the network by using the syntax net = darknet19 or by passing the darknet19 function to coder.loadDeepLearningNetwork (GPU Coder). For example: net = coder.loadDeepLearningNetwork('darknet19').

  For more information, see Load Pretrained Networks for Code Generation (GPU Coder).

• The syntax darknet19('Weights','none') is not supported for GPU code generation.

Version History

Introduced in R2020a

R2024a: Not Recommended

darknet19 is not recommended. Use the imagePretrainedNetwork function instead and specify "darknet19" as the model.

There are no plans to remove support for the darknet19 function. However, the imagePretrainedNetwork function has additional functionality that helps with transfer learning workflows. For example, you can specify the number of classes in your data using the numClasses option, and the function returns a network that is ready for retraining without the need for modification.

The imagePretrainedNetwork function returns the network as a dlnetwork object, which does not store the class names, To get the class names of the pretrained network, use the second output argument of the imagePretrainedNetwork function.

This table shows some typical usages of the darknet19 function and how to update your code to use the imagePretrainedNetwork function instead.

Not Recommended	Recommended
net = darknet19;	[net,classNames] = imagePretrainedNetwork("darknet19");
net = darknet19(Weights="none");	net = imagePretrainedNetwork("darknet19",Weights="none");

The imagePretrainedNetwork returns a dlnetwork object, which also has these advantages:

• dlnetwork objects are a unified data type that supports network building, prediction, built-in training, visualization, compression, verification, and custom training loops.

• dlnetwork objects support a wider range of network architectures that you can create or import from external platforms.

• The trainnet function supports dlnetwork objects, which enables you to easily specify loss functions. You can select from built-in loss functions or specify a custom loss function.

• Training and prediction with dlnetwork objects is typically faster than LayerGraph and trainNetwork workflows.

To train a neural network specified as a dlnetwork object, use the trainnet function.