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Object Detection

Perform classification, object detection, transfer learning using convolutional neural networks (CNNs, or ConvNets), create customized detectors

Object detection is a computer vision technique for locating instances of objects in images or videos. Object detection algorithms typically leverage machine learning or deep learning to produce meaningful results. When looking at images or video, humans can recognize and locate objects of interest in a matter of moments. The goal of object detection is to replicate this intelligence using a computer. The best approach for object detection depends on your application and the problem you are trying to solve.

Deep learning techniques require a large number of labeled training images, so the use of a GPU is recommended to decrease the time needed to train a model. Deep learning-based approaches to object detection use convolutional neural networks (CNNs or ConvNets), such as R-CNN and YOLO, or use single-shot detection (SSD). You can train a custom object detector, or use a pretrained object detector by leveraging transfer learning, an approach that enables you to start with a pretrained network and then fine-tune it for your application. Convolutional neural networks require Deep Learning Toolbox™. Training and prediction are supported on a CUDA®-capable GPU. Use of a GPU is recommended and requires Parallel Computing Toolbox™. For more information, see Computer Vision Toolbox Preferences and Parallel Computing Support in MathWorks Products (Parallel Computing Toolbox).

Machine learning techniques for object detection include aggregate channel features (ACF), support vector machines (SVM) classification using histograms of oriented gradient (HOG) features, and the Viola-Jones algorithm for human face or upper-body detection. You can choose to start with a pretrained object detector or create a custom object detector to suit your application.

Labeled boats, neural network, and person detector


Image LabelerLabel images for computer vision applications
Video LabelerLabel video for computer vision applications


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Deep Learning Detectors

rcnnObjectDetectorDetect objects using R-CNN deep learning detector
fastRCNNObjectDetectorDetect objects using Fast R-CNN deep learning detector
fasterRCNNObjectDetectorDetect objects using Faster R-CNN deep learning detector
ssdObjectDetectorDetect objects using SSD deep learning detector (Since R2020a)
yolov2ObjectDetectorDetect objects using YOLO v2 object detector
yolov3ObjectDetectorDetect objects using YOLO v3 object detector (Since R2021a)
yolov4ObjectDetectorDetect objects using YOLO v4 object detector (Since R2022a)

Feature-based Detectors

readAprilTagDetect and estimate pose for AprilTag in image (Since R2020b)
readArucoMarkerDetect and estimate pose for ArUco marker in image (Since R2024a)
generateArucoMarkerGenerate ArUco marker images (Since R2024a)
readBarcodeDetect and decode 1-D or 2-D barcode in image (Since R2020a)
acfObjectDetectorDetect objects using aggregate channel features
peopleDetectorACFDetect people using aggregate channel features
vision.CascadeObjectDetectorDetect objects using the Viola-Jones algorithm
vision.ForegroundDetectorForeground detection using Gaussian mixture models
vision.PeopleDetector(To be removed) Detect upright people using HOG features
vision.BlobAnalysisProperties of connected regions

Detect Objects Using Point Features

detectBRISKFeaturesDetect BRISK features
detectFASTFeaturesDetect corners using FAST algorithm
detectHarrisFeaturesDetect corners using Harris–Stephens algorithm
detectKAZEFeaturesDetect KAZE features
detectMinEigenFeaturesDetect corners using minimum eigenvalue algorithm
detectMSERFeaturesDetect MSER features
detectORBFeaturesDetect ORB keypoints
detectSIFTFeaturesDetect scale invariant feature transform (SIFT) features (Since R2021b)
detectSURFFeaturesDetect SURF features
extractFeaturesExtract interest point descriptors
matchFeaturesFind matching features

Select Detected Objects

selectStrongestBboxSelect strongest bounding boxes from overlapping clusters using nonmaximal suppression (NMS)
selectStrongestBboxMulticlassSelect strongest multiclass bounding boxes from overlapping clusters using nonmaximal suppression (NMS)

Load Training Data

boxLabelDatastoreDatastore for bounding box label data (Since R2019b)
groundTruthGround truth label data
imageDatastoreDatastore for image data
objectDetectorTrainingDataCreate training data for an object detector
combineCombine data from multiple datastores

Train Feature-Based Object Detectors

trainACFObjectDetectorTrain ACF object detector
trainCascadeObjectDetectorTrain cascade object detector model
trainImageCategoryClassifierTrain an image category classifier

Train Deep Learning Based Object Detectors

trainRCNNObjectDetectorTrain R-CNN deep learning object detector
trainFastRCNNObjectDetectorTrain Fast R-CNN deep learning object detector
trainFasterRCNNObjectDetectorTrain Faster R-CNN deep learning object detector
trainSSDObjectDetectorTrain an SSD deep learning object detector (Since R2020a)
trainYOLOv2ObjectDetectorTrain YOLO v2 object detector
trainYOLOv3ObjectDetectorTrain YOLO v3 object detector (Since R2024a)
trainYOLOv4ObjectDetectorTrain YOLO v4 object detector (Since R2022a)

Augment and Preprocess Training Data for Deep Learning

balanceBoxLabelsBalance bounding box labels for object detection (Since R2020a)
bboxcropCrop bounding boxes (Since R2019b)
bboxeraseRemove bounding boxes (Since R2021a)
bboxresizeResize bounding boxes (Since R2019b)
bboxwarpApply geometric transformation to bounding boxes (Since R2019b)
bbox2pointsConvert rectangle to corner points list
imwarpApply geometric transformation to image
imcropCrop image
imresizeResize image
randomAffine2dCreate randomized 2-D affine transformation (Since R2019b)
centerCropWindow2dCreate rectangular center cropping window (Since R2019b)
randomWindow2dRandomly select rectangular region in image (Since R2021a)
integralImageCalculate 2-D integral image

R-CNN (Regions With Convolutional Neural Networks)

rcnnBoxRegressionLayerBox regression layer for Fast and Faster R-CNN
fasterRCNNLayersCreate a faster R-CNN object detection network (Since R2019b)
rpnSoftmaxLayerSoftmax layer for region proposal network (RPN)
rpnClassificationLayerClassification layer for region proposal networks (RPNs)
regionProposalLayerRegion proposal layer for Faster R-CNN
roiAlignLayerNon-quantized ROI pooling layer for Mask-CNN (Since R2020b)
roiInputLayerROI input layer for Fast R-CNN
roiMaxPooling2dLayerNeural network layer used to output fixed-size feature maps for rectangular ROIs
roialignNon-quantized ROI pooling of dlarray data (Since R2021b)

YOLO v2 (You Only Look Once version 2)

yolov2LayersCreate YOLO v2 object detection network
yolov2TransformLayerCreate transform layer for YOLO v2 object detection network
yolov2OutputLayerCreate output layer for YOLO v2 object detection network
spaceToDepthLayerSpace to depth layer (Since R2020b)

Focal Loss

focalCrossEntropyCompute focal cross-entropy loss (Since R2020b)

SSD (Single Shot Detector)

ssdMergeLayerCreate SSD merge layer for object detection (Since R2020a)

Anchor Boxes

estimateAnchorBoxesEstimate anchor boxes for deep learning object detectors (Since R2019b)
cuboid2imgProject cuboids from 3-D world coordinates to 2-D image coordinates (Since R2022b)
insertObjectAnnotationAnnotate truecolor or grayscale image or video
insertObjectMask Insert masks in image or video stream (Since R2020b)
insertShapeInsert shapes in image or video
showShapeDisplay shapes on image, video, or point cloud (Since R2020b)
evaluateObjectDetectionEvaluate object detection data set against ground truth (Since R2023b)
objectDetectionMetricsObject detection quality metrics (Since R2023b)
mAPObjectDetectionMetricMean average precision (mAP) metric for object detection (Since R2024a)
bboxOverlapRatioCompute bounding box overlap ratio
bboxPrecisionRecallCompute bounding box precision and recall against ground truth


Deep Learning Object DetectorDetect objects using trained deep learning object detector (Since R2021b)


Get Started

Training Data for Object Detection and Instance Segmentation

Get Started With Deep Learning

  • Deep Learning in MATLAB (Deep Learning Toolbox)
    Discover deep learning capabilities in MATLAB® using convolutional neural networks for classification and regression, including pretrained networks and transfer learning, and training on GPUs, CPUs, clusters, and clouds.
  • Pretrained Deep Neural Networks (Deep Learning Toolbox)
    Learn how to download and use pretrained convolutional neural networks for classification, transfer learning and feature extraction.