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A glossary for definitions used in our products and documentation.

The nomenclature of any new platform can be overwhelming at first. We have tried to conform to industry naming standards wherever possible in a bid to make the user experience both intuitive and welcoming to new users and experienced practitioners alike. However, computer vision and annotation tooling are relatively recent fields, and as such many terms may be used interchangeably in both the literature and industry.

Do not hesitate to contact for clarification on the features supported by Encord.


In the interests of brevity, we will refer to both image and video data as 'frames' in the definitions below.

Benchmark functionThe function used to review tasks with automated QA. The benchmark function works by comparing all labels in the annotator submission of the benchmark task against the gold standard label set in the source project’s task.
Benchmark taskAn annotation task in a project with automated QA, which has a corresponding task in the ‘source project’ that contains gold standard labels.
Bounding boxA rectangle used to annotate a feature by drawing the bounds of the feature
ClassificationA mutually-exclusive category applied to a frame
Crosshair navigationA way to navigate in 3d. Clicking on a location in one slice will change also the associated views
DatasetA collection of videos and/or images
Data UnitA package of data that constitutes a single annotation task. e.g. a video, a single image, an image group, or a DICOM series
FeatureAn object in a frame, or a classification applied to a frame. These can be used to identify something in a frame (object: 'this thing is an apple') or to classify the frame itself (classification: 'this frame has apples')
Frame classificationConsiders the frame/slice as a whole not the object(s) localisation
Hanging protocolAn arrangement of views e.g. Axial, sagittal and coronal
Hounsfield unitA linear transformation of the measured attenuaton coefficient e.g. air = -1000 HU, water = 0 HU
Image groupA collection of images presented as one data unit. Grouping images in the image group functionality allows Encord's platform to support enhanced performance on playback, and more automated labeling features. Also known as image sequences.
InstanceAlso known as an instance label in the platform, an instance is unique instantiation of an ontology entity, which depending on the data type, may contain many frame labels. For example, in 100 frame video tracking three cars on a road, there are three instances of 'car' and up to 100 frame labels for each car.
Key pointA dot used to annotate a feature by specifying its location
LabelSometimes denoted as a frame label in the platform, labels note relevant features in a frame and apply to a dataset used in model training. They are an annotation asserting which features in the desired ontology are true.
Label EditorThe UI for annotating data and managing labels
Maximum intensity projection (MIP)A method for 3d data that projects all voxels to a plane
Micro-modelA model specifically trained to label a dataset for training other models
ModelA program with a set of functions and parameters that allow it to recognise features in datasets. Different models have different strengths and weaknesses
Model trainingThe process of teaching a model an ontology. This is done by algorithmically changing model parameters until it can reliably recognise features that are labelled in a dataset
Model inferenceThe process of using a trained model to predict the presence of features in new data
ObjectSomething of interest in a frame. Defined by string together with an annotation. It can be used as part of an ontology to label entities of interest in a dataset used for model training
Object detectionThe ability of a model to reliably recognise when a frame contains an object of interest. An application of model inference
Object primitiveA unique object annotation type. Used to create templates of shapes (such as 3D cuboids and pose estimation skeletons) commonly used by your annotation team
Object trackingThe ability of a model to reliably detect and track objects in a sequence of frames over time. An application of model inference
OntologyA defined set of features and their relationships. This is what a model will be trained to apply to frames. Also known as a 'taxonomy'
PolygonA polygonal shape used to annotate a feature by drawing the bounds of a feature
PolylineA line composed of multiple segments
ProjectA self-contained, collaborative environment for managing all productivity tasks associated with labeling and modelling 1 or more datasets
QualityAn assessment of the accuracy of a set of labels
Semantic segmentationThe application of labels to each pixel in a frame in order to classify segments of the frame as part of the same entity
SliceAn single image of a dicom volume
TaskAn action required as part of the labeling workflow
Task ManagerThe UI for creating and managing tasks
ViewWindow displaying a specific viewing direction e.g. coronal
VolumeA set of images, also called slices or frames
WindowingChanging the appearance of the image to highlight particular structures