iVn Video Capture Interface
The iVn iCon module connects to high-resolution USB3 cameras to record video frames synchronized with all behavioral, electrophysiology, fiber photometry, and other research data. Record video from one camera with an iV1, or up to two cameras simultaneously per iV2 module. The iV2 module also includes real-time subject tracking.
- Records video from one or two USB cameras
- Synchronizes video frames with all other recorded behavioral and neurophysiological data
- Displays selected camera output on unit for easy camera setup and subject monitoring
Frame data is sent through the iCon interface back to the PC, shown on the Synapse window, and saved with the rest of your data as an MP4 file. You can review the video files along with your data in OpenScope.
See the Hardware Manual for information on iVn technical specifications.
iVn Options
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| iV2 Interface |
Shutter Control
Gating allows you to turn frame capture on / off dynamically, if you only want to capture frames around particular events. See Capture Control below.
Exposure
Compression
Image Framing
Tracking
The Store to CSV option saves a CSV file with the same prefix as the mp4 video file. The format of each row of the csv file is the frame number followed by information on each of the tracked points:
{FRAME_NUMBER},{TRACKED_POINT_1},{TRACKED_POINT_2},...,{TRACKED_POINT_N}
where {TRACKED_POINT_N} is:
{POINT_ID_N},{IS_VALID_N},{CONFIDENCE_N},{REGION_N},{X_N},{Y_N}
Load Management
At Idle time, the Load meter dynamically updates the processing load on the iVn. This calculation is based on the type of module (iV1 vs iV2), the number of cameras, the requested frame rate and resolution, the encoding for each camera, and the complexity of the tracking algorithm (iV2 only). This gives you an idea of the load on the system. Always double-check for lost frames in the Synapse iCon tab at run-time.
Image dynamics and how well it can compress the images. A rapidly changing image will consume more iVn processing power and be lower quality to meet the compression bandwidth setting limits. The iVn has an onboard 10 second frame buffer that allows it to catch up after periods of rapidly changing images. A small progress bar indicator on the LCD screen shows the state of this buffer. If it fills up, you will see Frame Errors in the Synapse run-time tab, indicating lost frames. The frame buffer is shared by both cameras.
Capture Control
The Capture Control options appear when Gating is enabled.
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| iV2 Gating Options |
Triggered Capture Interval enables frame capture for a specified amount of time when triggered. This can be triggered manually through a button on the run-time iCon tab interface, from another gizmo (Hal Input Port), or through the SynapseAPI.
Synapse API Control
If using Triggered Capture Interval, you just need to trigger frame acquisition with one call:
import tdt
syn = tdt.SynapseAPI()
syn.setParameterValue('iCon(1)', 'V1_OutEnab_1', 1)
Otherwise you can toggle capture on/off with this:
import time
import tdt
syn = tdt.SynapseAPI()
syn.setParameterValue('iCon(1)', 'V1_OutEnab_1', 1)
time.sleep(1)
syn.setParameterValue('iCon(1)', 'V1_OutEnab_1', 0)
If Gating is disabled, or if Gating is enabled and Hal Input Port is True, you can use FrameEnab
to selectively override frame capture:
import time
import tdt
syn = tdt.SynapseAPI()
syn.setParameterValue('iCon(1)','V1_FrameEnab',1)
time.sleep(1)
syn.setParameterValue('iCon(1)','V1_FrameEnab',0)
Getting Started
Start by clicking the "Cam1" button to enable the first camera (and "Cam2" if you have a second camera) and Commit.
Reference Video
The first thing to do is create a reference video. This gives you a frame in Synapse to set up area of interest for recording. It also retrieves the camera properties which includes the available resolutions.
To create a reference video:
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Click "Preview" in Synapse.
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Position the camera to capture the area of interest. Use the front panel of the iVn module or the iCon tab in Synapse run-time window to view the camera image.
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On the iCon tab in Synapse run-time window, click the small brightness/contrast icon to open the camera hardware settings to adjust brightness, contrast, etc.
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Click the "Make Ref. Video for Cropping" button.
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Wait ~10 seconds and verify that the image is updating and you see Cam epocs. There will be a gap in the epoc events as it switches to Reference Mode, as shown in the example below:
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Click the Synapse "Idle" button to return to the iVn configuration. Synapse saved a short video at 5 fps containing the full sensor image, and retrieved the available camera resolution settings.
Note
The reference videos are saved in
C:\TDT\Synapse\CamRefswith the prefixFrameRef -
In Idle mode, click the "Setup" button.
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This opens the "Configure Video Transform" dialog. This is where you set the desired camera resolution, and set rotation and digital zoom / cropping on the image.
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Click "OK" to exit the dialog, and click "Commit" in Synapse to save your experiment changes.
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If you have a second camera, repeat Steps 7-9 for "Cam2".
Real-Time Tracking
The iV2 module offers two methods for computing real-time positional information of the subject. R-Track is a rodent tracking method of searching for the body and head of a rodent. D-Track is a dot tracking method that searches for the location of a certain color within the frame.
Contact TDT Support support@tdt.com for help setting up real-time subject tracking.