Core Concepts#

Acquisition Lifecycle#

Camera → Transport → Buffer Queue → Application
                         ↑
                   RetrieveResult()

Mental Model#

Camera runs asynchronously.
Python retrieves synchronously.
Buffers decouple both domains.

Blocking Behavior#

Slow processing may lead to backlog and dropped frames. You can specify a suitable timeout value for RetrieveResult() to avoid waiting indefinitely for a grab result.

RetrieveResult() → Waits until frame or timeout

GenICam Nodes#

What is a GenICam Node?#

A GenICam node represents a single configurable feature or property of a camera. Nodes are defined in the GenICam standard, which provides a uniform way for accessing camera functionality independent of the hardware vendor.

Each node behaves like a strongly-typed parameter and exposes various information:

Name (e.g., ExposureTime)
Data type (e.g., Float, Integer, Enumeration, etc.)
Access rights (read-only or read/write)
Valid value ranges or options

In pypylon, nodes are accessed as attributes of the camera object and provide methods like the following:

exposure_time = camera.ExposureTime   # Read exposure time in microseconds.
camera.ExposureTime.Value = 3000  # Value is in microseconds. Check Increment and ValueRange for valid values.

Common Node Types#

参数	示例	描述
Float	`ExposureTime`	Continuous values that map to discrete hardware settings
Integer	`Width`	Discrete values
Enumeration	`TriggerMode`	Predefined string values
Boolean	`AcquisitionFrameRateEnable`	True/False
命令	`ExecuteSoftwareTrigger`	Executes an action

Understanding nodes is essential because all camera configuration in pypylon is performed through them.

pylon Parameters#

pylon parameters wrap GenICam nodes and provide an extended consistent interface for reading and writing values. They also handle type conversion, range checking, and access mode handling.

If a node is not found, the pylon.PlaceholderParameter is returned, which allows your code to handle missing nodes gracefully. This is often a scenario in setups where different camera models or firmware versions may have different available features.

var = camera.NotThere.GetValueOrDefault(1)
camera.NotThere.TrySetValue(3000)

Setting Parameters

To change certain parameters, acquisition must be stopped first:

camera.StopGrabbing()
camera.Width.Value = 640
camera.StartGrabbing()