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Using the Sequencer Feature with Blackfly S
KB Number: 11019
Technical Application Note TAN2016003: Using the Sequencer
Application Note Description
This document provides an overview of the Sequencer function in the Blackfly S camera.
The sequencer allows you to control the acquisition parameters of an image sequence. This includes defining the camera feature settings as well as when the camera transitions from one sequence to the next.
One application of the sequencer is in the creation of high dynamic range images where your image source has dramatically different light and shadow in the same scene. Another application might be to examine multiple pieces of a larger image as separate entities with different exposures. An astronomy application could increase the camera's dynamic range by capturing multiple images with different settings, then adding and averaging them. A scientific application could use a filter wheel in front of the lens and adjust the camera's settings every time the wheel rotates.
With sequencer, each image can have its own defined feature set. Blackfly S allows up to 8 sequencer sets.
A key advantage to the Sequencer is that it does not sacrifice time to change feature properties and the camera can maintain a high frame rate while imaging.
These are the steps to setup and run sequencer. The following sections provide more detail.
The feature settings used in a sequencer set are a combination of the features specifically configured for the set and what was active when the set was saved. Because many of the camera features are dependently linked to each other, settings may be saved to a set that are outside of the sequencer configuration.
Sequencer features can be classified as follows:
Direct—direct features are those you define as being part of the set with specified values which may vary from one set to another and are independently recorded for each set. Examples include: exposure time, gain, resolution, and offset.
Implied—implied features are those that are dependent on the direct features. Their settings are recorded for each set. While you do not define their values as part of the set, they are included so that their values are valid. They can be modified during the configuration of a set, but are locked during sequencer operation.
Fixed—fixed features are those that are the preconditions to implied or direct features. These settings are recorded to guarantee the sequenced features are valid. Fixed features have a single value for the entire sequence. This is locked during sequencer configuration and operation. Examples of features that are locked include: chunk data, trigger mode, pixel format and binning, and color transformation.
Forced—forced features are those whose settings are predefined. These are automatic features that if enabled would control other features and invalidate the settings. They are forced into the Off (manual) mode during sequencer operation. During sequencer configuration, they are modifiable, to allow you to achieve the desired conditions which can then be recorded for later operation. All auto algorithm features are turned off when using sequencer, even for those features that are not directly configured (for example, auto white balance).
Non-sequenced—non-sequenced are features that are not controlled or affected by the sequencer.
Direct features that are defined as part of sequencer set configuration must be enabled prior to entering configuration mode. By default, the sequencer is set to have all features enabled.
To enable a sequencer feature
As some of the features used in the sequencer are not directly defined in the sequencer sets, they should be defined outside of sequencer configuration. As their definition might have an impact on the validity of the sequencer set, they should be defined prior to entering the configuration mode.
Features that are fixed, include:
As auto algorithms are turned off during sequencing, manual values for some features, such as white balance, may be needed.
Once direct features have been enabled, and fixed features defined, you can enter the Sequencer Configuration Mode to define the sequencer sets. In order to enter Sequencer Configuration Mode, the Sequencer Mode must be Off. By default, both the Sequencer Mode and the Sequencer Configuration Mode are set to Off.
To enter configuration mode
When you enter the configuration mode, the camera determines which features are implied and fixed and locks them from being modified. If you find you need to adjust a fixed feature, exit the configuration mode by turning it to Off. Make any modifications and enter the configuration mode again.
The Configuration Mode allows you to define the features to be used for each sequencer set, as well as the transitions between them. Blackfly S supports up to 8 sequencer set definitions. You must define a minimum of 2.
To configure a sequencer set
Once a sequencer set has been defined and is valid, it can be loaded as the active set. This is similar to user set loading except that if affects a much smaller range of features. Loading a sequencer set is useful when you want to configure multiple sets with very similar features.
To copy from an existing sequencer set
Once you have defined and saved your sequencer sets you must exit the configuration mode to enable the sequencer to run. Exiting configuration mode performs a final validation on the sequencer configuration settings.
To exit configuration mode
Once you have a valid configuration you can execute the sequencer. The camera cannot be streaming when you execute a sequencer session.
To execute sequencer
Programming the Sequencer
The Spinnaker SDK provides a Sequencer example to assist in programming the sequencer for your application. The example is available for C++, C#, and C source code.
The Spinnaker SDK is available from the Point Grey Downloads site.
Source code examples are in:
C:\Program Files\Point Grey Research\Spinnaker\src