How to configure a hardware-triggered acquisition from a GigE Vision camera?

Prashant Kumar answered . 2024-12-21 15:05:43

• MATLAB R2016a or later, Image Acquisition Toolbox, and GigE Vision hardware support package
• GigE Vision compliant camera with hardware triggering capability; this example uses a Basler acA1300.
• Gigabit Ethernet adapter, which provides a direct camera network connection, configured as described in the "GigE Vision Quick Start Configuration Guide"
• External triggering setup, which can provide a triggering signal to  the camera trigger line input. For example, a DAQ device with digital output, an Arduino board, or a function generator instrument can be used to output a custom triggering signal. Refer to the camera usermanual for triggering signal voltage level / current requirements and for correct signal connections to the camera input lines.

v = videoinput('gige', 1, 'Mono8');
s = v.Source;

% Determine optimum streaming parameters as described in the 
% "GigE Vision Quick Start Configuration Guide"
% s.PacketSize = 
% s.PacketDelay =

Immediate acquisition By default, an immediate acquisition takes place when videoinput start function is executed, if a hardware triggering configuration is not explicitly specified.

For simplicity, this example performs an acquisition of a finite number of frames, and stores them in MATLAB base workspace.

% Set exposure time and mode
s.ExposureMode = 'Timed';
s.ExposureTimeAbs = 4000;

% The default videoinput trigger type is 'immediate', which is explicitly
% configured here for clarity.
triggerconfig(v, 'immediate');

% Specify number of frames to acquire
v.FramesPerTrigger = 30;
v.TriggerRepeat = 0;

% Start continuous buffered acquisition and wait for acquisition to complete
start(v);
wait(v, 10);

% Transfer acquired frames and timestamps from acquisition input buffer 
% into workspace
[data, ts] = getdata(v, v.FramesAvailable);

Display acquired frames and plot acquisition timestamps.

figure;
imaqmontage(data)

figure;
plot(ts, '.')
xlabel('Frame index');
ylabel('Timestamp (s)');

% Specify total number of frames to be acquired
% One frame is acquired for each external signal pulse.
numFrames = 30;
v.FramesPerTrigger = 1;
v.TriggerRepeat = numFrames - 1;

% Specify 'hardware' videoinput trigger type 
triggerconfig(v, 'hardware', 'DeviceSpecific', 'DeviceSpecific');

Configure camera for FrameStart trigger mode and specify external triggering signal input line and desired trigger condition.

% This requires setting the TriggerSelector first; once a TriggerSelector 
% value is selected, setting a trigger property (for example, 
% TriggerMode to 'on') applies only to the specified trigger mode (FrameStart).
s.TriggerSelector = 'FrameStart';
s.TriggerSource = 'Line1';
s.TriggerActivation = 'RisingEdge';
s.TriggerMode = 'on';

% Specify a constant exposure time for each frame
s.ExposureMode = 'Timed';
s.ExposureTimeAbs = 4000;

% Start hardware-triggered buffered continuous acquisition, and wait for 
% acquisition to complete
start(v)
wait(v, 10)

% Transfer acquired frames and timestamps from acquisition input buffer 
% into workspace
[data2, ts2] = getdata(v, v.FramesAvailable);

Display acquired frames and timestamps

figure;
imaqmontage(data2)

figure;
plot(ts2, '.')
xlabel('Frame index');
ylabel('Timestamp (s)');

% Specify total number of frames to be acquired
% One frame is acquired for each external signal pulse.
numFrames = 30;
v.FramesPerTrigger = 1;
v.TriggerRepeat = numFrames - 1;

% Specify 'hardware' videoinput trigger type 
triggerconfig(v, 'hardware', 'DeviceSpecific', 'DeviceSpecific');

Configure camera for FrameStart trigger mode and specify external triggering signal input line and desired trigger condition.

% This requires setting the TriggerSelector first; once a TriggerSelector 
% value is selected, setting a trigger property (for example, 
% TriggerMode to 'on') applies only to the specified trigger mode (FrameStart).
s.TriggerSelector = 'FrameStart';
s.TriggerSource = 'Line1';
s.TriggerActivation = 'RisingEdge';
s.TriggerMode = 'on';

% For exposure time control configure a TriggerWidth exposure mode
s.ExposureMode = 'TriggerWidth';
% Specify camera ExposureOverlapTimeMaxAbs in microseconds
s.ExposureOverlapTimeMaxAbs = 5000;

% Start hardware-triggered buffered continuous acquisition, and wait for 
% acquisition to complete
start(v)
wait(v, 10)

% Transfer acquired frames and timestamps from acquisition input buffer 
% into workspace
[data3, ts3] = getdata(v, v.FramesAvailable);

Display acquired frames and timestamps

figure;
imaqmontage(data3)

figure;
plot(ts3, '.')
xlabel('Frame index');
ylabel('Timestamp (s)');

figure;
plot(diff(ts3), '-x');
xlabel('Frame index');
ylabel('diff(Timestamp) (s)');

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