Human Eye Simulators for the Whole Range of HMD Optical Measurements
Almalence announces a line of its Human Eye Simulators with a variety of camera designs to make an ideal fit for specific optical measurement requirements.
Almalence Human Eye Simulator is designed to be recognized as a real human eye by eye-tracking systems of near-eye displays. Not only it “looks like” an eye, but it also allows us to “see” like an eye, with a camera system sitting behind the eye pupil. To perfectly fit the specific requirements of the entire range of optical measurement tasks and the target display features, Almalence has developed a set of camera designs for its Eye Simulator.
There are three versions of the camera design, with different FOV and PPD. The narrowest FOV camera has the highest PPD of 87 pixels per degree and is designed to measure various pixel-level parameters (such as MTF or CA extent) of the highest-resolution displays, with the pixel density approaching or exceeding human vision resolution.
The intermediate FOV camera has a PPD of 44 and can be used to reliably measure various optical parameters of most of the mass-market head-mounted displays currently available. Providing a reasonable trade-off between the resolution and field of view, this is our most popular configuration.
The widest FOV camera with a PPD of 15 has a 95⁰ circular field of view and is designed to capture the full view of the projected scene in one shot. This is convenient to measure such parameters as geometric distortion or color non-uniformity. This camera, however, does not capture pixel-level information.
Any of the above camera designs can be also supplied with either Bayer-pattern RGB or monochrome sensor. Both versions can be used to measure the same set of parameters. The specific features of the two sensor options are:
- With the RGB sensor, all colors are captured in one shot. With the monochromatic sensor you can capture the same information by first illuminating just the R dots of the display, then G, then B. Therefore, three shots would be required with the monochromatic sensor to capture a full-color scene.
- At the same time, the monochromatic sensor provides a somewhat higher resolution, not obstructed by pixel interpolations during the de-mosaicing process of the RGB sensor.
- The monochromatic sensor, also, has no color moire issues. Beware though, that the monochromatic moire will still be present if camera resolution does not sufficiently exceed the resolution of the display.
- Using the RGB sensor causes some ambiguity in the inter-channel color mixture due to the difference in spectral characteristics of the color filters of the HMD display and the camera, thus the spectrum of a camera color channel can overlap the spectrum of another color channel in the display. This may affect the measurements of the color parameters of the display, such as color fidelity. Therefore, the mono sensor allows more precise measurements of the display color characteristics.
- For a color video recording, the RGB sensor is the only option.
Detailed Specifications
Camera Options
| HFOV | VFOV | PPD | Resolution | Pixel size | max FPS | Module WxH, mm |
|---|---|---|---|---|---|---|
| 30 | 20 | 87 | 3072 x 2048 | 2.4 µm | 60 | 30x30 |
| 70 | 45 | 44 | 3072 x 2048 | 2.4 µm | 60 | 30x30 |
| 95 | 95 | 15 | 2448 x 2048 | 3.45 µm | 75 | 36x36 |
Sensor Options
- Bayer-pattern RGB
- Monochromatic
Supported capture data types
- Y8; Y16; YUV8; YUV16; RGB; 12bit RAW
Camera interface
- USB-C
Focusing
- Manual
- Motorized, with auto-focus (adds an external motor which increases the size of the simulator)