# Modes

Check out our video on how to adjust the visible range for the O3R cameras:
:::{youtube} LhtemnOsJp4
:::


## Overview
|Variable name|Short description|Available values|  
|--|--|--|
|`mode` (for the 3D imager) |This parameter designates the measurement range: 2 or 4 meters.|standard_range2m, standard_range4m, cyclic_4m_2m_4m_2m|

## Description

The O3R has the specificity to provide several measurement ranges. A distance measurement is computed only for a subspace of the scene. Elements *fully* outside of the range are not taken into account and have no impact on the measurement (for instance by causing artifacts like [stray-light](./ProcessingParams/strayLight.md) or Multi-Path Interference).

>Note: Objects *very* close to the beginning or end of the measurement range can still have an impact on the measurement.

By default, the O3R provides two measurement ranges: two and four meters. These ranges use different frequencies to perform the Time-of-Flight (ToF) measurement and therefore show different characteristics, especially in how they are affected by artifacts. The four-meter mode shows higher noise levels than the two-meter mode (around twice as much).

## Example

Let’s look at a simple scene: three boxes are placed in front of the camera, one, two, and three meters away (see image below).
![RGB view of the scene](resources/modes_scene.png)

The table below shows the computed distance measurement in the distance image view and the point cloud view with the two modes available by default:

| Mode| Distance Image| Point Cloud|
|--|--|--|
| 2 m| ![Distance image for the two meter mode](resources/2m_mode_distance.png)| ![Point cloud for the two meter mode](resources/2m_mode_cloud.png)|
| 4 m| ![Distance image for the four meter mode](resources/4m_mode_distance.png)| ![Point cloud for the four meter mode](resources/4m_mode_cloud.png)|

The third box, which is three meters away from the camera, is outside of the measurement range when using the two-meter mode; however it is visible when using the four-meter mode.

> Note: Using the [offset](./AcquisitionParams/index_acquisition_params.md#offset) parameter in combination with the mode is interesting and allows for a lot of flexibility in using the coded modulation ToF technology. We encourage you to investigate strategies using multiple modes in combination with offsets.