The DL1 basically serves as a laser ruler superimposed on the surface being looked at. Two quality laser beam projectors are mounted in parallel, such that the distance between the centers of their projected dots remains constant no matter how far away from them. The dual dots are clearly displayed on the image being looked at, which may be either on a TV monitor, on a computer screen, or on a paper printout of the video image. Since the distance between the dots is known, an accurate measurement may be interpolated for any feature in the image.

The DL1 is factory adjusted for laser beam parallelism and distance. Its user's manual includes a procedure on how to easily perform these calibrations in the field. The distance between the beams and their projected dots is factory preset at 1.0 inch, but may be field-adjusted to between 1 inch/25mm and
2 inches/50mm.

The DL1 also incorporates a high-presicion pan and tilt base that can be adjusted by hand, through the use of finger knobs, so that the dual laser spots appear at a convenient location inside the image being viewed. This adjustment is made by the user whenever the distance between the DL1 and the surface being looked at changes significantly.

The laser projectors are powerful enough for their spots to be visible in sunlight at more than 200 feet. Furthermore, the DL1 is supplied with a red light filter that may be screwed onto the VT1 and VT1M television camera, to filter out all light except red, thus making the dual dots more visible on sunlit surfaces.

Characteristics:

- Heavy duty anodized aluminum construction.

- Two red lasers category llla, 4.9 mW at 635 nm, 2.2mm diameter circular beams, divergence 0.4 mrad.

- On-Off switch and LED indicator on rear panel directly facing the operator.

- Power 8-18 Vdc 200 mA.

- Internal adjustment for distance between lasers, from 1"/25mm to 2"/50mm, factory adjusted to 1.0".

- X and Y internal adjustments for beam parallelism.

- Single spring bolt on base for easy adjustment of beam direction.

- RoboProbe proprietary universal dovetail mount (VT1 and VT1M only) allows easy installation and removal.

- Light filter for screwing onto VT1 and VT1M camera: high saturation Dichroic glass with 600 nm cutoff.