What other measurement methods are there on the image measuring instrument for roundness?

What other measurement methods does the image measuring instrument have about roundness? Principle of systematic error: The same difference between the average value and the actual value of a large number of repeated measurements. Generally, errors in measurement results may be caused by incomplete measurement steps, some of which come from system errors, and some are from random errors. It is assumed that random errors come from unpredictable effects or random temporal and spatial variations of effects. If the system is derived from the identifiable influence on the measured influence quantity, some systematic errors can be eliminated, and some systematic errors can usually be reduced. System error source Instrument error: caused by the defect of the instrument itself or the instrument not being used according to the specified conditions. If the zero point of the instrument is not accurate, the instrument has not been adjusted, the influence of external ambient light, temperature, humidity, electromagnetic field, etc. on the measuring instrument, etc. Theoretical error method error: refers to the error caused by the measurement result approximate to the theoretical formula itself, or the experimental conditions cannot meet the requirements of the theoretical formula, or the error caused by the imperfect experimental method itself. For example, in the thermal experiment, when measuring the volt-ampere resistance, the heat loss caused by heat dissipation is not considered, and the influence of the resistance in the meter on the experimental results is not considered. Operation error: Refers to the error caused by the observer's personal feeling and the reaction or habit of the motor organs. It varies from person to person and is related to the mental state of the observer at the time. Reagent error refers to the deviation between the measurement result and the actual result due to the impurities contained in the distilled water used or the impurities used. Some system errors have been fixed. For example, the zero point of the instrument is not accurate, and some zero points are cumulative. If a heated and expanded steel rod is used for measurement, the reading is less than its true length. It should be noted that systematic errors always make the measurement results skewed, too large or too small. Therefore, averaging multiple measurements does not eliminate system errors.

During the data processing of the image measuring instrument, an error will occur in the computer. For example, when using the data type field, the result is not accurate due to the different digits processed, which is similar to the result calculated by rounding.