Tracking Preferences
The Tracking Preferences tab allows you to configure settings for tracking detected people.
- For Mode: Specifies which operator mode is affected by the current settings on this page. See here for information about the different modes.
- Maximum change to continue tracking
- Face position: The maximum face position change to continue tracking, specified in percentage relative to the original face image size.
- Person position: The maximum person position change to continue tracking, specified in percentage relative to the original person image size.
- Size: The maximum size change to continue tracking, specified in percentage relative to the object size.
- Stop tracking a face after it has lingered for: Specifies how many additional frames SAFR will continue to keep a tracked face around after SAFR has failed to detect the face in the most recent frame.
- Minimum recognitions to lock on to identity: Minimum number of consecutive recognition attempts that must produce the same identity before SAFR locks onto the identity.
- Minimum recognitions to learn identity: Minimum number of consecutive face recognitions required to register a face into the Identity Database. This setting also affects the quality of the reference face signature recorded for an identity.
Increasing this value increases the minimum quality of the face signature stored for a newly registered identity, but it decreases how quickly SAFR registers new identities.
- Initial recognition attempts: Number of initial recognition attempts to make on an unrecognized face as quickly as possible.
- Failed recognition back-off interval: After making the initial recognition attempts as quickly as possible, back up the amount specified by this setting for each subsequent recognition. This continues until the retry interval is reached.
- Retry failed recognition after every: The interval in which to run recognition requests if the face has not been recognized.
- Reconfirm identity after every: Specifies how often a face's identity is reconfirmed, in milliseconds. If you set this value to zero, SAFR continues to re-confirm a face's identity at its normal rate. Increasing this value increases the confirmation rate and improves SAFR tracking subjects in crowded settings at the cost of increased CPU and network usage.
- Update identity every: Updates the identity when the currently saved identity is older than the updated identity.
- High precision tracking: Decreases event fragmentation and increases the stickiness of SAFR's tracking algorithm at the cost of computer processing power. This setting should be enabled if you are experiencing duplicate or missing Direction of Travel events. See Camera Preferences for information about the Direction of Travel feature.
- Update identity with better image: Updates the identity when the currently saved identity is of lower quality (in all aspects) than the new image.
- Enable correlation of faces by size: Enables face correlation of tracked faces, which compares detected faces looking for a change in area.
In most situations this setting should be enabled, but disabling it may help performance when there is only a single face to track and head movements are very fast.
- Enable motion prediction: Enables face motion prediction, which predicts which direction the face is moving in order to maintain tracking.
In most situations this setting should be enabled, but disabling it may improve performance when tracked faces are moving in highly irregular motion patterns.
- Stop tracking on failed re-recognition: Enabling this option causes identity tracking to stop when SAFR doubts a confirmation of face tracking failures. SAFR is then forced to obtain a new identity lock. Enabling it may produce more discontinuity in recognition events and provide additional protection against mistaken tracking.
This setting rarely needs to be enabled.
- Minimum failed recognitions to stop tracking identity: When a face is being tracked recognitions are continually confirming the identity. The identity is also being verified if it is transferred from a person object. In these cases, if the recognition or verification consecutively fails this number of times then the identity will be reset and no longer associated with the face because we are no longer sure it is the same identity.
- Reconfirm identity in video after each Key Frame: When a key frame is encountered in a video file all the faces that are being tracked are marked as unconfirmed so that their identities are reconfirmed to make sure they are the same person. This setting only applies to video files; it can't be used with live video. If a video file does not represent recorded live video then this can typically be set to true for better tracking during scene changes.