Camera-based calibration

This function requires the Wings VIOSO License. See Licenses and functions.

Calibration requires a suitable camera. See Suitable cameras for calibration and Using an uEye camera.

Hook up camera and data projector and start them. The control monitor should be the primary monitor using ID 1 to avoid problems in display allocation. This can be verified via the graphics card driver software. During calibration, this configuration must not be changed any more. If Windows has chosen some other allocation...

Create your multidisplay project and, next to Multidisplay configuration, click and select All displays on the master starting with monitor 2 and select VIOSO calibration. If you want to activate VIOSO calibration for a project at a later time...

In the main menu click Multidisplay and select VIOSO calibration...
Under Create calibration select the corresponding Screen and calibration mode:
Simple mode ...should be appropriate for most applications and takes about 1 minute per projector.
Detailed mode ...allows separate adjustment of brightness and calibration grid. This option is only useful if your video projectors have different brightnesses or if simple mode does not achieve the required result. Due to the manual settings this mode takes distinctly longer.
Recalibration ...performs a recalibration with the same settings as the startup calibration without any further query. This function can also be performed via a trigger. See Automatic calibration of a permanent installation.

Click Start calibration and a dialog box will appear. Under Select display(s) to calibrate the displays used for projection are highlighted.
For Setup method choose the type of projection surface:
Flat screen / fast scanning ...is used for geometrically defined flat surfaces, i.e. inclined flat surfaces.
Curved screen / fast scanning (experimental) ... for geometrically definable, uniform surfaces, i.e. cylindrical, conical or spherical sections.
Any surface / detailed scanning ...for geometrically undefined surfaces, such as rock walls, three-dimensional sculptures, etc. Note: For flat surfaces this mode causes single-pixel artefacts.
Manual setup without using the camera ...allows manual adjustment if no camera is available.
Calculate blending based on a previous calibration.....does not require a complete calibration but calculates only blending (soft edge masks) across all selected and previously calibrated displays.

Under Camera for autosetup select the camera you want to use for the calibration and click Next.

Notes:

For Camera disable automatic white balance and automatic exposure, as well as autofocus, so that you have to make all the settings manually and are able to check them.
The Projectors should show the same settings with regard to brightness, picture mode and color temperature, i.e. they should produce as identical pictures as possible.
If the expected video projector is not available, a dialog for video projector selection will appear automatically.

For Display arrangement you select the arrangement of your projectors or projected images. If you select Horizontal or Vertical strip you make sure that the soft edge masks are aligned. For any other setup, e.g. a dome where more than two projector images overlap at one point, select Grid/Arbitrary arrangement.
With Save as you can enter a different name for the calibration file. After changing the name you need to click OK.

Options...

Click Next, following which a checkerboard pattern will be projected and an additional window showing the video image be opened up. Start by choosing the required camera recording mode (resolution, frame rate, etc.) below the video image and sharpen the image manually. Align the video projectors so that they fill the projection area and sufficiently large overlap areas are created. The projector image should extend slightly beyond the projection area; later on, the image can only be adjusted in size to fill the screen.

Align the camera so that it captures the entire projection image. You can verify this in the video window on the right. For certain applications, such as a dome projection, for example, Overlay crosshairs and Overlay grid are useful tools that offer guide lines.

Now you need to mask the projection area in the preview via the calibration wizard such that only the check pattern is visible and no irritating reflections or light sources are visible. There are two options for masking:
For rectangular projection areas choose tool draw lines and click outside each of the corner points of the projection surface. Close the frame by double-clicking near the starting point while holding the Alt key down.
For irregular projection areas choose tool draw freehand, hold down the left mouse key and draw a frame around the projection area.
In order to mask unwanted border regions, click fill and the border area. Following this some red masking will appear leaving only the projection area free.
If masking did not turn out as expected you can delete it. Select defill and click on the masking. Alternatively, hold the Ctrl key while right-clicking the masking. Following this you can create some new masking.

Click Next to start calibration. Depending on the number of video projectors this will take a few minutes. In Detailed Mode further dialogs will be displayed...

At the end of calibration you will see a test image which can still be corrected to precisely fill the projection area. For rectangular projection areas select the Vioso tools deform and linear and drag the corner points towards the projection surface corners. If the projection surface is warped or shows a barrel- or pillow shaped distortion caused by camera lens distortions select Bicubic. Following this Bezier handles will appear after marking the corner points which allow distortions to be eliminated.

Note: Before a point can be adjusted it needs to be highlighted by clicking it. The highlighted point can then be grabbed and dragged.

If the camera cannot be set up perpendicular to the screen the center of the image will not be right in the center of the projection surface. Add a vertical grid line by clicking . Highlight the central intersection point and move the image center until it is right in the middle of the projection surface.

The tool functions are explained below. All tool buttons showing a small triangle at the bottom right corner have two functions and can be changed over by clicking them.

Undo last edit ...to undo the last editing steps; various steps are available

Scale mode ...drag the round corner points or intersection points to change the size proportionally. Drag the square handles to shift all the grid points of the corresponding border or grid line. Dragging the picture off the intersection points moves the image as a whole.

Deform mode ...by dragging the round corner or intersection points only the area down to the next grid line is changed. Dragging one of the square handles moves the corresponding line in parallel. Dragging the picture off the intersection points moves the image as a whole.

Holding the Ctrl key while clicking the intersection points allows you to highlight several of them one after the other. These intersection points can then be moved together although this would only make sense for the round intersection points.
Increase or reduce the view in size by turning the mouse wheel while holding the Alt key. This allows for more accurate and easier editing. The visible section can be shifted with the mouse while holding the Alt key.
Right-click the grid to select further functions such as Zoom or Pan. Reset View resumes the default view.

Toggle borders ...displays the rectangular handles for adjusting the border lines.

Toggle tangents ...displays the Bezier handles of highlighted, round grid intersection points.

Coarse shift ... of a highlighted intersection point by pressing the cursor key.

Fine shift ...of a highlighted intersection point by pressing a cursor key.

Double columns ...increases the number of grid columns to double the amount (vertical lines).

Reduce columns ...reduces the number of grid columns to half the amount (vertical lines).

Double grid lines ...increases the grid lines to double the amount (horizontal lines).

Reduce grid lines ...reduces the number of grid lines to half the amount (horizontal lines).

Linear interpolation ...the grid lines remain straight during shifting.

Bicubic interpolation ...results in shifting bent grid lines, e.g. in a distortion of the image. If a round handle is highlighted, they are provided with additional Bezier handles which allow direction and degree of warping to be changed. This allows barrel or pillow shaped distortions caused by camera lens distortions to be eliminated.

Save warp snapshot ...saves the current warp grid.

Load snapshot ...opens a list of available snapshots that can be activated by highlighting them.

Use coordinates ...applies manually entered coordinates (in the fields below) to the highlighted intersection point.

Once the image has been accurately aligned with the projection area, click Next and a message will appear announcing the end of calibrating. Close the dialog by clicking Next again.

You still need to save this calibration. If you want this calibration to be loaded automatically upon starting Wings VIOSO click Save as startup calibration. If you want to save this calibration under a particular name click Save calibration and you will be able to load it manually at a later time.
Click Close to terminate this process.

An existing calibration can also be corrected manually, e.g. geometry or softedge mask. For this purpose you can select a test image in the calibrator window or load any images. See Manual calibration adjustment.
When a project with Vioso calibration is opened the startup calibration is loaded automatically.
You can load any calibration that has been saved manually by clicking Load calibration and selecting the desired file. If you highlight several calibration files they are loaded cumulatively.
For cumulative loading of a startup calibration turn to the Stumpfl support team for further information.
The VIOSO Calibrator can also be started in stand-alone mode via the main menu Programs.