GEOCAL

GEOCAL is a geometric camera calibration device that uses a beam expanded laser in combination with a diffractive optical element (DOE). This device introduces a new dimension in geometric camera calibration.

Geometric camera calibration is essential for systems from certain industries, particularly those relying on the detection of objects in a moving scene (e.g., automotive, ADAS, security). After geometric calibration, the camera system will be able to more concretely measure distances and detect objects in a scene. A calibrated system will also be better equipped to compensate for high distortion levels (especially for wide field-of-view cameras) and to accurately align stereo camera pairs.

GEOCAL 是一種幾何照相機校准裝置，它使用擴束激光器與衍射光學元件 (DOE) 相結合。該設備為幾何相機校准引入了一個新的維度。

幾何相機校准對於某些行業的系統至關重要，尤其是那些依賴於在移動場景中檢測物體的系統（如汽車、ADAS、安防）。經過幾何校准後，攝像系統將能更具體地測量距離和檢測場景中的物體。經過校准的系統還能更好地補償高失真度（尤其是寬視場相機），並準確對齊立體相機對。

分類: 測試設備

描述
下載文件

What are the main characteristics of GEOCAL?

Ability to generate a regular grid of light spots originating from infinity
Measure geometric distortion, focal length, and principal point
The camera position is translation invariant (to a certain extent)
Easily manage the angle of camera rotation
No relay lens required
A very compact design
Calibrate large field-of-view cameras
Stereo camera alignments and adjustments
Remove lens distortion using GEOCAL and OpenCV

Why the GEOCAL?

The methods currently utilized for geometric camera calibration rely on test charts with regular patterns, but these patterns need to be scaled depending on the field of view and the intended object distance. Another problem facing the modern methods is the dependence on a relay lens when using a compact device or wanting to calibrate from infinity. GEOCAL avoids the use of test charts and a relay lens while, at the same time, improving the overall accuracy of the calibration. Finally, GEOCAL is suitable for measuring geometric distortion without the use of a test chart.

Test feature	Checkerboard	GEOCAL
A compact solution that saves floor space	x	✔︎
Test multiple FoVs without reconfiguration	x	✔︎
Calibrate multiple cameras at the same time*	x	✔︎
Does not require external lighting	x	✔︎
Does not require large test charts for wide FoVs or long focus distances	x	✔︎
Measures INTRINSIC and EXTRINSIC paramters	x	✔︎
No relay lens required	x	✔︎
Able to align stereo pairs	x	✔︎

*Assuming that the lenses all fit inside the DOE port diameter

GEOCAL XL

In addition to the standard GEOCAL, we also offer the GEOCAL XL. This version has a significantly larger output window with a useable aperture of Ø 155 mm as opposed to the standard Ø 77 mm. The GEOCAL XL is ideal for geometric calibration of cameras with large front lenses and in instances where the distance between the camera and GEOCAL needs to be large (e.g., calibrating through a windshield).

GEOCAL IR

The GEOCAL IR version expands the laser diode wavelength range to 935 nm, allowing you to perform geometric camera calibrations in the NIR (near-infrared region.

GEOCAL evaluation software

The GEOCAL has a standalone software with a GUI interface for evaluating test results. An API is also available for our customers to apply the GEOCAL functionality into to their custom software, production line solutions, or device testing applications. Both the software and API are compatible with the GEOCAL XL. Please contact our sales team for more information on the API.

For further questions please see our FAQ section available for download at the bottom of this page.

A technical background on geometric camera calibration is also available for download at the bottom of this page.

GEOCAL
Principle	DOE-based geometric calibration of digital cameras
Light source	Frequency-stabilized diode laser
Wavelength	632,8 nm
Diffractive optical element (DOE)	Generates a very evenly distributed point grid, virtually originating from infinity
Output window	Usable aperture: Ø 77 mm (camera lens needs to have an equal or smaller diameter) Usable aperture XL: Ø 155 mm (camera lens needs to have an equal or smaller diameter)
Usable FoV	Approx. 30 – 120° (more extreme values still need to be tested)
Output power	5 mW
Dimensions (W x H x D)	ca. 550 mm x 144 mm x 162 mm XL ca. 850 mm x 244 mm x 270 mm
Weight	Approx. 4.5 kg Approx. 10 kg