Optical CMM Gauge Capability Evaluation for Sub Millimeter Molded Features
Optical CMM capability on sub-millimeter molded features requires material-specific bias correction and telecentric backlighting to maintain GR&R under 20%.
Spatial Resolution
Meaning
Information capacity describes the ability of an imaging system to distinguish between two closely spaced points as separate entities. Defining the spatial resolution determines the level of detail that a camera or sensor can capture from a workpiece.
Optical Limit
Diffraction and lens quality set the maximum detail possible for a given focal length and aperture. High spatial resolution allows for the measurement of tiny features and the detection of small surface cracks. This property is determined by the size of the pixels on the sensor and the magnification of the optics.
Detail Discrimination
Ability to see sharp edges and fine textures depends on having enough data points across the feature of interest. If the spatial resolution is too low, the edges of a part will appear blurry and the measurement software will lose accuracy. Metrology engineers select cameras with high pixel counts to ensure that the smallest features are properly sampled.
Digital Sampling
Mathematical rules require that a feature be covered by multiple pixels to be accurately measured. Increasing the spatial resolution improves the precision of automated gauging but also increases the amount of data the system must process. A balanced system provides enough detail for the measurement without slowing down the production line throughput.