Purpose
This document will explain how to ensure that the Smart Eye Pro (SEP) software is setup to "know" the location of the LED flashes. Since the SEP software doesn't have a direct connection to the LED flashes (like it does to the cameras), it cannot communicate directly with them. The exponator controls the flashes independently of the SEP SW (i.e., PC). Regardless, the following process is important to ensure that the various SEP algorithms can perform their calculations correctly by understanding where the LED flashes are located.
Process
1. Open the SEP application.
2. Navigate (via the toolbar) to "Settings > Hardware..." or press Alt+F6 keys to open the "Hardware Settings".
Figure 1 - Opening the Hardware Settings dialog
3. On the resulting Hardware Settings dialog select the "Flash Setup" tab.
Figure 2 - The Hardware Settings Dialog and Tabs
The Flash Setup tab is used to define where the LED flashes are located in the environment. This area is used to make the SEP software "aware" of where the LED Flashes are located in the test environment. Typically the LED flashes are mounted to a camera via a beam, but they can also be placed independently/freely in the environment using a dedicated mount.
3.a. When the LED flash is connected to a beam that is attached to one of the cameras, the process is quite simple. The beams that are supplied by Smart Eye with the SEP system are 10cm (0.100m) in length and are aligned to the X-axis of the cameras.
Note: Each camera has its own X,Y,Z coordinate system. The positive Y direction goes "up" (away from the earth plane), the positive Z direction extends towards the subject (at you when looking at the camera), and the positive X direction goes to the right (when looking at the camera).
Note: The cameras can only be rotated by 180 degrees as the image is rectangular, therefore the LED flash will always be located either to the left or right of the camera.
Under the "Coordinate System" column, select the camera that the LED flash position is relative to. Next, define the X, Y, and Z coordinate offsets from that camera.
- If the LED flash is located to the right of the camera (when looking at it), put an X-value of "0.100".
- If the LED flash is located to the left of the camera (when looking at it), put an X-value of "-0.100".
Regardless of the side of the camera, the distance from the camera to the LED flash is the same (i.e., 10 cm noted as 0.100 m) and the difference is the sign indicating the side of the camera on which the flash is located (left: negative, right: positive). As there are no Y-axis or Z-axis offsets, these values are set to zero.
Figure 3 - LED Flash is on a Beam Connected to Camera 1 and Located to the Left of the Camera
3.b. When the LED flash is placed independently in the environment (i.e., not connected to a camera via a beam), the process is slightly more involved. Some means of determining the LED flash location - relative to the system's World Coordinate System (WCS) origin - must be performed. The simplest solution is to use the Laser Chessboard Tool (LCT) to measure the LED flash's position, but it is also possible to use other measuring tools. The caveat is that the LCT will provide a very accurate location for the LED flash whereas using another method is sure to introduce some error.
Under the "Coordinate System" column, select the World Coordinate System (i.e., "WCS") as the basis for the flash's offset. Once you've collected the X, Y and Z offset values from the LCT, input those into the associated columns. All of the X, Y and Z values for this type of LED flash definition are sure to be unique, non-zero values.
4. After a LED flash has been added to the Flash Setup or after editing the location of an existing LED flash, the updated location and orientation can be viewed in the "3D World View" window. If this view is not already open, navigate (via the toolbar) to "Window > New 3D World View" and then look at the 3D World View window.
Figure 4 - Opening the 3D World View Window
The 3D World View window displays the cameras, flashes, and World Model Objects (used for gaze intersection/tracking). The LED flashes are represented using a yellow dot and the number associated with each LED flash (in order from top to bottom in the Hardware Settings dialog's Flash Setup tab). The camera(s) are represented using a three-dimensional axis labeled with the respective camera number. Each camera is displayed using its own origin and axes shown in Red (X), Green (Y) and Blue (Z).
Figure 5 - 3D World View Window
Figure 5 shows a 3D World View window containing three cameras, two LED flashes, and one world model object labeled as "SEScreen". The first LED flash (the yellow dot labeled '1') is physically connected to camera one (the 3D axis labeled as '1') via a 10cm beam and is found at the bottom-left of Figure 5. The second LED flash (the yellow dot labeled '2') is physically connected to camera three (the 3D axis labeled as '3') via a 10cm beam and is found at the bottom-right of Figure 5. Camera two (the 3d axis labeled as '2') does not have a LED flash connected to it.
LED flash 1 has been defined in the Hardware Settings > Flash Setup tab as follows:
Coordinate System: "Camera 1" (LED flash location is being based on Camera 1's 3D coordinate system)
X: "0.100" (indicating a positive 10cm offset along Camera 1's X-axis)
Y: "0.000" (indicating there is no Y-axis offset from Camera 1)
Z: "0.000" (indicating there is no Z-axis offset from Camera 1)
LED flash 2 has been defined in the Hardware Settings > Flash Setup tab as follows:
- Coordinate System: "Camera 3" (LED flash location is being based on Camera 3's 3D coordinate system)
- X: "-0.100" (indicating a negative 10cm offset along Camera 3's X-axis)
- Y: "0.000" (indicating there is no Y-axis offset from Camera 3)
- Z: "0.000" (indicating there is no Z-axis offset from Camera 3)
If you need further assistance with this topic or any other technical topic, please feel free to contact Smart Eye Support (support@smarteye.se) and we will be more than happy to assist you.
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