ScanCONTROL 2800 laser triangulation technology

Laser triangulation sensors for measuring the straight-line distance from the sensor to the target have been used for more than a decade, and the method has evolved as digital electronics and high-powered digital signal processors (DSPs) have made lasers less sensitive to target color, texture, and surroundings, as well as ambient light and temperature variations.

At about the same time, vision cameras have been on the market for detecting label orientation, detecting surface defects, and more recently for measuring specific features of parts, such as apertures, groove gaps, or channels on machined (formed) parts. Many vision camera manufacturers and system support companies have tried to extend the vision camera detection principle to the field of metrology. However, other features such as step height, extrusion profile shape, and volume of the processed product, as well as robot positioning and guidance, remain a difficult task to measure with vision cameras.

Step Height Measurement

Laser triangulation provides good resolution for step height measurement, determining extrusion product profile shape, and robot positioning and control. However, even this measurement method has its limitations because the laser sensor's very small spot size means that multiple sensors are required, making the solution complex and expensive.

Combining a laser triangulation sensor with a controller can obtain two-dimensional data from a line. However, the triangulation sensor should produce a line, not a point, and the controller should output the distance across the line. The limitations of these systems are that they are large and have moving parts in the sensor head, which are easily damaged by vibration and shock. The

ScanCONTROL 2800 sensor developed by Micro-Epsilon overcomes these limitations. The system is equipped with a solid-state laser line projection device, has no moving parts, and has been shock and vibration tested according to ISO standards to withstand 15g shock and 2g vibration respectively.

scanCONTROL 2800 / 2810

Because the sensor is based on laser triangulation, it can be used to perform metrology tasks according to the absolute measurement principle. The sensor data output is along the FireWire interface, which is based on the vision camera FireWire protocol, so users will find it very simple to interface with it.

No vision problems

Because the technology is not based on the vision camera principle, there are no traditional problems encountered when using a vision camera package. Its features are as follows:

(1) Lighting - ScanCONTROL-2800 functions like a Micro-Epsilon laser triangulation sensor, and the light intensity can be adjusted for each measurement without averaging or filtering. No external lighting source or uniform lighting source is required. The sensor can operate outdoors on a vehicle or in a factory without protection from ambient light.

(2) Distance from camera lens to target - The ScanCONTROL2800 has a depth of field of up to 250mm (Z coordinate) and a straight line length of 150mm (Y coordinate). As long as it is within this measurement window, the target can be accurately measured. Vision cameras require the target to be repeatedly placed in front of the reading lens.

(3) Measurement speed - Conventional camera systems and some other triangulation systems can generally only run at a speed of 50 frames per second. ScanCONTROL2800 is equipped with a high-speed CMOS matrix element and a very powerful DSP, which can increase the speed to 4000 faces/s. Such a high measurement rate enables it to be used in a variety of applications, such as high-speed robot positioning and control, real-time measurement of extrusion contours, glue beads, weld contours, etc., and volume calculation.

(4) System accuracy - ScanCONTROL 2800 is a device based on the absolute measurement principle. The accuracy expressed is calculated in microns, not in pixels or sub-pixel resolution. For most target surfaces, the resolution can be as low as 10um. The resolution on the X-axis can be selected from 64, 128, 256, 512 and 1024 points. By combining the resolution on the X-axis with the specially customized straight line length, the resolution required by the user can be obtained. (end)