DVS Viewer

Version: 1.5.0 — this guide is based on this release.

Stream from a DELTA camera, record event data, and review your recordings in one application. Screenshots show the Windows version.

Connect a camera

01Select a cameraChoose the connected device.
02Apply a settingUse a file for your camera model.
03Start streamingView events and begin recording.

1. Select the data source

Connect the camera by USB and launch DVS Viewer. In Devices found, select the camera and click Display. You can select up to two devices. The list shows the model, serial number when available, and connected USB speed.

Devices found dialog with DELTA-10 and DELTA-01, device checkboxes, Open File Instead, and Display — Select your camera, then click **Display**. Use **Open File Instead** to review a recording without a camera.

If the camera is missing from the list, follow the driver and connection steps in Installation.

2. Select and apply a camera setting

Move the pointer over the image to reveal the camera toolbar. 1. Device selects the camera. 2. Setting selects a .txt file and starts applying it to that camera. 3. The folder button opens a setting file from another location and applies the selected file in the same way. Selecting a file configures the camera; it does not start normal streaming.

Camera toolbar with Device selector, Setting file menu, file-open button, and Start button; sensor controls are waiting for a setting — 1 Select the device2 Choose its setting file3 Open another setting file

After selecting a setting file:

Wait for the Camera setting applied notification at the bottom right. This confirms that setting application has completed.
The triangular Start button in the camera toolbar becomes available. Click Start to begin live streaming.

The image below shows the completed state: 1 is the confirmation, followed by 2, the Start control used for the next step.

DELTA-10 2200 FPS setting applied, Start button enabled, and Camera setting applied notification at the bottom right — 1 Setting application completed2 Click Start to begin streaming

Standard setting files and automatic application

Camera	Standard full-sensor setting	Target frame rate
DELTA-01	`Delta_01_1000FPS.txt`	1,000 FPS
DELTA-10	`Delta_10_2200FPS.txt`	2,200 FPS

The DELTA-10 2,200 FPS setting is included with the Viewer. For higher frame rates at smaller resolutions, download an additional high-speed preset, place it in the Viewer's settings folder, and select it here. Match the setting to the camera model; stereo settings are for the corresponding stereo configuration.

Under Options, Auto-apply recommended setting on camera select applies the recommended file automatically when you select a camera. With this option off, select the required file yourself.

3. Start and stop live streaming

Click Start in the camera toolbar. Events appear in the image area, and the bottom status bar reports the incoming frame rate, resolution, and USB data rate. Hover over the image to reveal the toolbar again; its Stop control pauses camera acquisition.

While streaming, camera-setting and sensor controls are disabled. Stop streaming and finish recording before changing the setting file, sensor settings, or USB parameters, then start again.

Live DELTA-10 event image, sensor controls disabled during capture, and live FPS and data rate in the bottom status bar — The sensor setting shows the selected target FPS. The bottom status bar shows the incoming rate during operation.

Display settings

Choose how events form an image

Display Settings → Frame Generation controls how incoming events are grouped into images. In File Player, the same controls appear under Player Settings.

Choose the mode and interval before starting live streaming. Pause file playback before changing them.

Mode	One image contains
Time	Events within the selected interval of sensor time, in milliseconds.
Event	Events accumulated up to the selected event count. The image rate follows scene activity.
Frame	Events accumulated across the selected number of sensor frames.

For an approximately 60-image/s preview, the Viewer suggests 17 ms in Time mode, or 37 frames at 2,200 sensor FPS and 16 frames at 1,000 sensor FPS in Frame mode. Actual screen updates also depend on scene activity, playback speed, and rendering performance.

Frame Generation card: Time, Event, Frame, and Show 1 image per 37 frames — Change the grouping interval with **Show 1 image per…**.

Advanced USB settings

Open Options → Advanced USB Settings… while stopped. Keep the camera-selected defaults for normal use. Defaults are restored each time you select a camera.

Advanced USB Settings: USB Timeout 5000 ms, Buffer Count 64, and USB Transfer Size 256 KiB

Control	Purpose
USB Timeout (ms)	Time allowed for a USB transfer to complete. The standard value is 5,000 ms.
Buffer Count	Number of USB receive buffers. The standard value is 64.
USB Transfer Size	Amount requested in each USB transfer. The DELTA-10 default shown above is 256 KiB; DELTA-01 uses its own camera default.

These are host transfer settings. Use Sensor Settings → Frame rate to change the sensor's capture rate.

Record data

Start live streaming, then open Display Settings → Save Option. Choose the format and check Save location and the available disk space. Change… selects a different recording folder.

Format	Available during	Saved content	Folder under the save location
Raw .dvs	Live streaming	Camera data before image generation. Recommended for high-speed capture and later playback.	`RawDataSave`
Image .bmp	Live streaming or file playback	Images produced by Frame Generation.	`MatSave`
Video .avi	Live streaming or file playback	A video made from generated images.	`MatSave`

Save Option card with Raw .dvs selected, save location, free space, Start Saving, and Open Save Folder — Select **Raw .dvs**, then click **Start Saving**.

Save Duration dialog set to 10 seconds with the instruction Set to 0 for unlimited recording — Enter seconds and click **Start Saving**. Set 0 to continue until you stop recording.

Recording in progress with red REC timer, saved data size, and Stop Saving button — **REC** shows elapsed time and **Saved data** shows written data. Use **Stop Saving** to finish early.

Recording complete, with the Saved notification and Open folder link — Wait for the **Saved** notice. Use its **Open folder** link or **Open Save Folder** to find the result.

After capture stops, the Viewer may still be finishing disk writes. Wait for the completion notice before disconnecting a recording drive or closing the application. If the Viewer reports a save failure or incomplete recording, check that message before using the result.

Save images or video

Select Image .bmp to save each generated image as a separate bitmap. Select Video .avi to combine generated images into a video. Both use the current Frame Generation mode and display colors, so choose those settings before saving.

The results are stored under MatSave in your selected save location: an image sequence has its own folder, while a video is saved as an .avi file. Use Open Save Folder to find them.

Saved bitmap images in a folder on the left and an AVI video playing on the right — **Left:** individual generated images. **Right:** the generated images saved as a video.

File playback

Open a recording

Choose Open File Instead on the initial device screen, or select File Player in the camera's Device menu. No connected camera is required to replay a DVS recording.

Device menu showing File Player above connected DELTA cameras — Select **File Player** to change this view from a camera to a recording.

Click Open File in the image area, or drag a .dvs file onto it. The file dialog starts in the current recording folder. The player also accepts supported .cisraw camera recordings; the event display controls below describe DVS .dvs files.

Open Camera Raw File dialog in NRV Delta RawDataSave, showing a recorded .dvs file — Choose a recording and click **Open**. Check the loaded filename in the playback toolbar.

Play, pause, and move through the file

Move the pointer over the image to reveal the playback toolbar near the bottom. The toolbar shows the filename, elapsed and total time, and playback controls.

Button	What it does
1. Previous — left arrow with a bar	Move backward by the number in Frame Skip → Skip per click. The Left arrow key performs the same action.
2. Play / Pause — triangle / two bars	The triangle starts or resumes playback. It changes to two bars while playing; click again to pause at the current position.
3. Next — right arrow with a bar	Move forward by Skip per click frames. The Right arrow key performs the same action.
4. Timeline — slider between the two time labels	Drag the handle to move to another point in the recording. The labels show the elapsed and total time.
5. Close File — square at the far right	Close and unload the current recording, returning to file selection. Use Play / Pause to keep the current file open while paused.

Full File Player window

File Player window with the playback toolbar over the image and Player Settings on the right — The toolbar appears when the pointer is over the image. **Player Settings** on the right controls image generation, speed, repeat, and colors.

Player setting	Action
Play Speed	Choose ×1, ×0.5, ×0.25, ×0.125, or ×0.0625.
Playback Mode	Choose Play once or Repeat.
Frame Skip → Skip per click	Set the number of frames moved by each Previous / Next click or left / right arrow key press.

The bottom status bar shows the resolution and frame, event, and raw-data counts as the file is processed. Pause playback to change Frame Generation, then resume to inspect the recording with the new image grouping.

Gray and RGB display

Choose Color Format under Player Settings. These controls change how the recorded ON and OFF events are drawn.

The same scene in Gray on the left and RGB on the right

Gray format: ON white, OFF black, None gray — **Gray**
ON: white · OFF: black · no event: gray.
The Gray colors are fixed.

RGB format: ON red, OFF blue, None white — **RGB**
Default ON: red · OFF: blue · no event: white.
Click a color swatch to customize it.

Sensor settings

Apply a camera setting and stop streaming to use Sensor Settings. These controls change the camera's output. The Sensor Controls guide explains individual features, and Camera Interfaces shows the ports and cable connections for external equipment.

Control	What you can change
Sensitivity	Select Very low through Very high. Higher sensitivity detects smaller brightness changes and generally produces more events.
Frame rate	Select a target in 50 FPS steps: DELTA-01 100–1,000 FPS; DELTA-10 100–2,200 FPS with its standard full-sensor profile.
Global settings	Global Reset synchronizes the pixels' brightness reference. Global Hold fixes the end of the brightness-change measurement interval across pixels. See Global Reset and Global Hold for the measurement principle.
External trigger	Choose free-running capture or one of the three trigger modes. See External Trigger.
Output signals / Clock source	Use DELTA-10's output signals or external reference clock.
Sensor flip	Flip the camera output horizontally, vertically, or both. See Sensor Flip.
Event output	Select both polarities, OFF only, ON only, or All as ON. See Event Output.
Sensor region (ROI)	Move or resize the region, enter coordinates, or select SD / Full sensor. See Sensor Region.

For external trigger operation, keep the reset settings applied by the selected trigger mode. Follow the trigger guide when setting up an external signal.

Keep and reuse a sensor configuration

The BASIC row provides a Preset list and three file actions:

Import opens a portable .json sensor preset. Apply presets to the matching camera model while stopped.
Export saves the current sensor configuration as a portable .json preset.
Setfile generates a .txt camera setting file for reuse from the Setting menu.

The FLIP card marked Display only mirrors the current view. Use Sensor flip when you want the change to be made by the sensor and included in the camera's output.

More Viewer tools

Menu	Use it for
Options	Recommended-setting auto-apply, Advanced USB Settings, and choosing cameras again.
Stereo	Arrange the selected camera views and use the stereo recording controls for paired capture.
Debug → Packet analyzer	Inspect a recorded raw file or a live capture in the analyzer.
Export	Convert a `.dvs` recording to an HDF5 `.h5` file. Select the source and output location, then export.
Calibration	Open the integrated calibration workflow. See Using the DVS Calibration App.
Rectify	Apply calibration results to the displayed images. See Use Rectify in Viewer.