Scanning knowledge

Precision vs. Accuracy

Precision vs. Accuracy

If you’ve ever wondered about the difference between precision vs. accuracy when 3D scanning with a Revopoint 3D scanner, this quick guide is for you. Oh, and as sometimes, since people confuse the difference between accuracy and point distance, we’ve thrown that in as well.

What is Accuracy?

Accuracy is a 3D scanner’s ability to create a point cloud 3D model with dimensions close to the scanned object. In other words, high accuracy means the 3D model is very close to the actual object, while low accuracy means they’re significant deviations or errors.

What is Precision?

Precision is a 3D scanner’s ability, over repeated scans, to give measurements close to one another. In other words, high precision means that the scanner can measure and reproduce the shape and features of objects with a high degree of consistency. In contrast, low precision can result in data that varies significantly from one scan to another.

Precision vs. Accuracy

There are four targets with dots placed on them. The first target shows high accuracy and low precision with the dots in the middle of the target but not grouped too closely. The second target shows low accuracy, and low precision, with dots all over the target. The third target shows low accuracy and high precision with the dots grouped near the edge of the target. The last target shows high accuracy and precision, with the dots grouped tightly in the middle.

Point Distance/Resolution vs. Accuracy

Point distance and accuracy are two different aspects of 3D scanning that are related but have different meanings. 

In a nutshell, point distance is the distance between individual points in a 3D point cloud. A point cloud is a collection of millions of points in 3D space captured by a 3D scanner to represent the surface of an object. The smaller the point distance, the more points are captured, resulting in a higher-resolution point cloud with more detail. 

Accuracy, however, is how close the 3D model created by the scanner represents the scanned object’s actual shape, size, and features. A highly accurate 3D scanner will capture data points close to the object and generate a 3D model that matches the original object as closely as possible.

While point distance affects the level of detail in the 3D model, accuracy affects the overall quality and applicability of the model. A high point distance but low accuracy can result in a detailed but inaccurate 3D model. In comparison, a high accuracy but low point distance can result in a less-detailed but more accurate 3D model.

 

Reading next

Post-processing Your Point Cloud in Revo Scan
3D Scanning Tracking Aids

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