Setting up Iris Device Node

How to set up Iris device node in Devices window
In this article we will go through setting up Iris device node so that we will be able to receive the image obtained from Iris camera.
Create an Iris device node in the Devices window and select your physical Iris camera on the network from the dropdown menu.
Good to know: Physical camera needs to be powered up and connected to the network in order to be detected by LightAct and shown in the dropdown menu.
When the device node is connected to the physical camera, an image will appear in the device’s properties:
Iris camera device node has a number of settings so let’s go through them one by one.
  • Mode dropdown has 2 options: 3DCal and Projector calibration. Each of these 2 modes set Exposure time, Gain and Gamma camera settings to values that should be, by default, most useful for either calibrating the camera using 3DCal process, or calibrating all the projectors using Iris. If you change any of the camera values, their new value will get saved into either 3DCal or Projector calibration modes.
  • Exposure time [ms]: this determines the exposure time of the camera. The higher the value, the brighter the image.
  • Gain: also increases the brightness of the image, but in a different way. It makes the brighter parts of the image brighter while leaving the darker parts relatively untouched. That’s why increasing this parameter is usually quite useful for Projector calibration using Iris.
  • Gamma: this is another way to control the brightness of the image, but in most likelihood, you won’t need to adjust it. The lower the value, the brighter the image. If you put this value to its minimum which is 0.25, you will notice that it mainly works on the darker parts of the image by making them brighter. Please note, this is a post process operation, so you need to click Refresh texture before the effect of gamma will be visible.
  • Undistort: this checkbox governs whether the image will be undistorted using our undistort data. It should be checked at all times.

Iris Setup

Iris camera device node also offers a Setup window in which you can mask out areas from the incoming stream that will not be useful to the calibration process. This could be any area that is not part of your 3D Object. For example, if there is a glare appearing in your environment, the easiest way to eliminate it is to simply mask it out in the Setup window.
To open the Iris Setup window, click on Setup button of the Iris device node.
Here, you can add a polygon mask by clicking on the Add polygon button on the right-hand side of the window. Once the polygon appears, you can move it by clicking on and dragging its moving handle. You can also add points to it by double-clicking on the polygon lines, or remove points from it by right-clicking on them.
By default, the area which the polygon mask covers is red, indicating that this area has been masked out and will not be considered for Iris calibration.
You can also enable Inverse mask checkbox which will invert the effect of the mask. By selecting this checkbox, the areas that were previously masked will become visible, and vice versa.

Settings for 3DCal

If you remember, the first step after we are done with adjusting the settings of Iris device node will be to calibrate the Iris camera in the Viewport.
Good to know: calibration is a process of finding the location, rotation and lens properties (FOV, distortion and others) of camera or projector. It is a required step when using Iris.
For calibration, the camera needs to have a good view of the object without extensive under or over exposed areas. If there is no ambient light in the space, you can set the projectors to Edit color override so that they provide some general lighting.
After you are done, the image obtained from Iris camera should be similar to this:
As you can see, the projection object is not under nor over exposed, so that it will be possible to select the calibration points in the camera image.
The settings that we recommend (with a certain degree of certainty) are:
  • Exposure should be pretty high usually - for example around 30000,
  • Gain should be around 1,
  • Gamma should be around 1.
Good to know: Please make sure that the device’s mode is set to 3DCal when you adjust these values.

Settings for Projector Calibration

Settings for Projector calibration are different from the ones for 3DCal. When projector calibration is under way, every projector is projecting a series of black and white patterns and the camera needs to detect very clearly which area is white and which area is black.
Therefore, unlit areas need to be as dark as possible whereas the bright areas should be as white as possible.
The best approach to do this is to enable the Black and white override on a projector that’s projecting on the same part of the projection object that’s also in the camera’s view.
Good to know: when changing the camera's values for projector calibration, please make sure that the mode of Iris device node is set to Projector Calibration.
In the properties of Iris device node in the Devices window, you should make sure that the mode is set to Projector calibration. Then you can adjust the Exposure, Gain and Gamma values so that the image looks similar to the one below:
You can see that the lit areas are very white whereas the unlit areas are almost black.
Important: If you have a LightNet setup and are using Iris to calibrate a projector which is connected to a Secondary machine, please make sure that you have the right Machine selected in the projector's Properties.