For 3D sensors, field of view and X-axis resolution are important and related parameters. X resolution is critical to detect features on parts and is based on the number of camera pixels divided across the field of view. As the field of view expands, the X resolution decreases due to less pixels to cover the larger area. Since the sensor field of view is trapezoidal in shape, X-axis resolution is best when the target is at the near end of the sensor measurement range and worse at the far end.
While high resolution over a wide field of view can be achieved by mounting two or more sensors side by side and calibrating them to a common coordinate system, it is more cost effective and simpler to implement wider fields of view using a single sensor based on a higher resolution camera.
The Need for High X-Axis Resolution
For all 3D sensors, X-axis resolution (also known as the profile data interval) is limited by the camera chip inside. For example, a sensor with a 2-megapixel camera offering 2048 pixel columns will provide better resolution than a 1-megapixel camera offering 1024 pixel columns for the same field of view. The X resolution determines if features appearing along the projected laser line will be detected or not. If features are smaller than the profile data interval, then they will go undetected. Ensuring your sensor has an X resolution smaller than the smallest feature you need to measure is critical. In addition, ensuring the sensor has a field of view that captures the overall part is desirable, otherwise, two or more sensors will be necessary.
Megapixel Cameras Lead To Higher Data Processing
Large megapixel cameras are now appearing in sensors such as the MikroCAD series that leverages a 2Mp camera to offer both wider fields of view and very high X resolution. Use of high resolution cameras inside the sensor result in much higher data density requiring higher throughput pixel processing to generate 3D profile data. In this regard, all-in-one smart 3D sensors utilize powerful embedded processors to handle the data load. As a result, a side benefit is faster scanning speeds and increased resolution in the direction of travel.
Megapixel Sensors Simplify Inspection
The ability to provide high resolution and large field of view at the same time allows the user to detect and measure micro-features while capturing the entirety of a scanned part. Large megapixel sensors simplify inspection system design by replacing two or more sensors with a single sensor while delivering exceptional X resolution.