A project from A to Z

Step 1. Before Starting a Project > 1. Designing the Image Acquisition Plan - PIX4Dmapper


This article points out three important factors to take into consideration when designing an image acquisition plan.

In order to have high-accuracy results in the most efficient way, a high overlap between the images is required. Therefore, the image acquisition plan has to be carefully designed in order to ensure enough overlap. The image acquisition plan depends on the required GSD by the project specifications and the terrain type/object to be reconstructed. A bad image acquisition plan will lead to inaccurate results or processing failure and will require acquiring images again.

When designing the image acquisition plan the following factors need to be taken into consideration:

  • Image acquisition plan type: The image acquisition plan type depends on the type of terrain/object to be reconstructed.
  • Ground Sampling Distance (GSD): The required GSD by the project specifications will define the distance (flight height) at which the images have to be taken. For more information: Ground sampling distance (GSD) in photogrammetry
  • Overlap: The overlap depends on the type of terrain that is mapped and will determine the rate at which the images have to be taken.

Nowadays, technologically advanced UAVs come with very good software that can design the image acquisition plan given some parameters (area of interest, the percentage of overlap between the images, the desired GSD, etc). In this case, the images are taken automatically by the UAV according to the selected image acquisition plan without any user intervention.

Important: PIX4Dmapper allows the user to process using a Processing Template. The templates with the label Rapid/Low Res produce fast results at a low resolution that can be used on the field as an indicator of how good the dataset is.

If the Rapid/Low Res processing does not yield good results, the dataset is highly likely not adequate and it is necessary to acquire images again. However, in some cases, the Rapid/Low Res option fails while the Full processing successfully reconstructs the model.

For more information about the difference between Rapid/Low Res and Full processing: Full Processing vs Rapid / Low Resolution.

The design of the image acquisition plan consists of 3 steps:

a. Selecting the Image Acquisition Plan Type
b. Computing the Flight Height for a given GSD
c. Computing the Image Rate for a given Frontal Overlap