ASTM E3125-17

4.1 This standard provides a test method for obtaining the point-to-point distance measurement errors for medium-range 3D imaging systems. The results from this test method may be used to evaluate or to verify the point-to-point distance measurement performance of medium-range 3D imaging systems. The results from this test method may also be used to compare performance among different instruments.

4.2 The purpose of this document is to provide test procedures that are sensitive to instrument error sources. The point-to-point distance measurement performance of the IUT obtained by the application of this test method may be different from the point-to-point distance measurement performance of the IUT under some real-world conditions. For example, object geometry, texture, surface reflectance factor, and temperature, as well as particulate matter, thermal gradients, atmospheric pressure, humidity, ambient lighting in the environment, mechanical vibrations, and wind induced test setup instability will affect the point-to-point distance measurement performance (see Appendix X10 for a discussion on thermal effects). A derived-point such as the center of a suitable sphere or plate target that meets the requirements described in Section 7 provides a reliable point in space that is minimally impacted by target-related properties such as geometry, surface texture, color, and reflectivity. Additional tests not described in this standard may be required to assess the contribution of these influence factors on point-to-point distance measurements.

4.3 The test may be carried out for instrument acceptance, warranty or contractual purposes by mutual agreement between the manufacturer and the user. The IUT is tested in accordance with manufacturer-supplied specifications, rated conditions, and technical documentation.

4.4 For the purposes of understanding the behavior of the IUT and without warranty implications, this test may be modified as necessary to evaluate the point-to-point distance measurement performance of the IUT outside the manufacturer’s rated conditions, but within the manufacturer’s limiting conditions.

4.5 The manufacturer may provide different performance specification values for different sets of rated conditions, for example, better point-to-point distance measurement performance might be specified under a set of more restrictive environmental conditions. The user is advised that the IUT’s performance may differ significantly in other modes of operation, with other instrument settings, or outside the rated conditions, and should consult the manufacturer for performance specifications of the operating mode and instrument settings that best represent the planned usage.

4.6 This standard is intended to expand and complement the ranging tests described in Test Method E2938. While Test Method E2938 specifically describes the evaluation of the ranging capability of any medium-range 3D imaging system, this standard provides test procedures to evaluate the point-to-point distance error due to the combined effect from angular and ranging errors of a particular type of these systems, that is, spherical coordinate 3D imaging systems.

1.1 This test method covers the performance evaluation of laser-based, scanning, time-of-flight, single-detector 3D imaging systems in the medium-range and provides a basis for comparisons among such systems. This standard best applies to spherical coordinate 3D imaging systems that are capable of producing a point cloud representation of an object of interest. In particular, this standard establishes requirements and test procedures for evaluating the derived-point to derived-point distance measurement performance throughout the work volume of these systems. Although the tests described in this standard may be used for non-spherical coordinate 3D imaging systems, the test method may not necessarily be sensitive to the error sources within those instruments.

1.2 System performance is evaluated by comparing measured distance errors between pairs of derived-points to the manufacturer-specified, maximum permissible errors (MPEs). In this standard, a derived-point is a point computed using multiple measured points on the target surface (such as the center of a sphere). In the remainder of this standard, the term point-to-point distance refers to the distance between two derived-points.

1.3 The term “medium-range” refers to systems that are capable of operating within at least a portion of the ranges from 2 m to 150 m. The term “time-of-flight systems” includes phase-based, pulsed, and chirped systems. The word “standard” in this document refers to a documentary standard in accordance with Terminology E284.

1.4 This test method may be used once to evaluate the Instrument Under Test (IUT) for a given set of conditions or it may be used multiple times to assess the performance of the IUT for various conditions (for example, surface reflectance factors, environmental conditions).

1.5 SI units are used for all calculations and results in this standard.

1.6 This test method is not intended to replace more in-depth methods used for instrument calibration or compensation, and specific measurement applications may require other tests and analyses.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.