<p>TOF cameras suffer from many systematic errors from both sensor and illumination unit which result in inhomogeneus lighting for example. </p>

<p>I did a detailed study on this topic that can be find at this address:
<a href="https://arxiv.org/pdf/1505.05459.pdf" rel="nofollow noreferrer">https://arxiv.org/pdf/1505.05459.pdf</a></p>

<p>The error gets a lot worth on the border of your frame, as the active illumination has never:</p>

<ol>
<li>same fov as camera</li>
<li>same power on center and border of the frame</li>
</ol>

<p>For your case I think the problem is happening at the border where the measured distance gets extremely unlinear for the border pixels. Check figure 5 and 15 in the paper.</p>

<p>Possible solutions:</p>

<ol>
<li>Try to remain between 1 and 3 meter distance.</li>
<li>Concentrate more on the central 2/3 of the frame.</li>
</ol>
Why does a object parallel to my ToF sensor doesn't look parallel in the point cloud?
<p>I was comparing Kinect V2 with my own ToF sensor and I found a different place.</p>

<p>Below is a point cloud with RGB information produced by Kinect V2, which is placed in front of a object, and the object is placed between two walls. This means the two walls are parallel to Kinect V2's view line.</p>

<p><img src="https://i.stack.imgur.com/0qOcR.png" alt="Front View"></p>

<p>If I drag the point cloud, you can see the point cloud of two walls in the .ply file are parallel with each other and parallel with the Kinect' view line.</p>

<p>Look from top of the point cloud
<img src="https://i.stack.imgur.com/qOQns.png" alt="The Left Wall">
<img src="https://i.stack.imgur.com/eiU8L.png" alt="The Right Wall"></p>

<p>However, if I use my own ToF sensor to catch the point cloud under same environment and same view(please ignore the difference of the object in the middle, it has been changed), the point cloud looks like this(color camera hasn't been implemented)
<img src="https://i.stack.imgur.com/KMgoT.png" alt="My ToF Sensor"></p>

<p>The left wall(red circle area) somehow distorted like a "/"(The right wall cannot visualize due to my sensor's FOV)</p>

<p>I was confused by this phenomenon, I pretty sure Kinect V2 did some processes to fix this issue, but I cannot figure it out.</p>

<p>Can someone give me some clues about the scene I saw?</p>

<p>If there is any further information need to be provided, feel free to ask. </p>