---
title: "Depth Point Cloud -- Lidar Point Cloud from Depth Image"
section: "Examples"
order: 76
description: "Depth Point Cloud -- Lidar Point Cloud from Depth Image — Vuer documentation"
---

import { Callout } from '@docs/components/Docs'

# Depth Point Cloud -- Lidar Point Cloud from Depth Image

We can save 3D pointclouds effciently using Jpeg compression, by representing it as RGBA or grayscale images. In this example, we use a grayscale PNG image for depth. Note that PNG encoding and decoding can be 20 $\times$ slower than the FFT operations in a jpeg, so for visualization purposes, you can use jpeg for both color and depth.

Generate point clouds directly from depth images using the `DepthPointCloud` component.

## Basic Example

```python
import asyncio

from vuer import Vuer, VuerSession
from vuer.schemas import DepthPointCloud

vuer = Vuer(workspace="./rgb_depth", killport=True)


@vuer.spawn(start=True)
async def main(sess: VuerSession):
  sess.upsert @ DepthPointCloud(
    key="depth-point-cloud",
    depth=vuer.localhost_prefix / "depth.png",
    cmap="viridis",
    colorMode=4,
  )
  await asyncio.sleep(0.001)

  await sess.forever()
```

<Callout>
  **Performance Tip**

  When rendering multiple `DepthPointCloud` instances, wrap them in a `DepthPointCloudProvider` for better performance. The provider enables frustum culling, level-of-detail rendering, and shared caching.
</Callout>

## With Provider (Recommended for Multiple Point Clouds)

```python
import asyncio

from vuer import Vuer, VuerSession
from vuer.schemas import DepthPointCloud, DepthPointCloudProvider

vuer = Vuer(workspace="./rgb_depth", killport=True)


@vuer.spawn(start=True)
async def main(sess: VuerSession):
  sess.upsert @ DepthPointCloudProvider(
    DepthPointCloud( key="pc-0", depth=vuer.localhost_prefix / "depth.png", position=[0, 0, 0] ),
    DepthPointCloud( key="pc-1", depth=vuer.localhost_prefix / "depth.png", position=[2, 0, 0] ),
    key="provider",
    frustumCulling=True,
  )

  await sess.forever()
```

## DepthPointCloud Parameters

| Parameter           | Type  | Default    | Description                                                             |
| ------------------- | ----- | ---------- | ----------------------------------------------------------------------- |
| `depth`             | str   | (required) | URL to 16-bit depth PNG image                                           |
| `rgb`               | str   | None       | URL to RGB image (uses depth grayscale if not provided)                 |
| `position`          | tuple | \[0, 0, 0] | Position in 3D space \[x, y, z]                                         |
| `rotation`          | tuple | \[0, 0, 0] | Rotation in Euler angles \[x, y, z]                                     |
| `scale`             | tuple | \[1, 1, 1] | Scale factors \[x, y, z]                                                |
| `fov`               | float | 58         | Vertical field of view in degrees (58 = RealSense D435)                 |
| `pointSize`         | float | 2.0        | Point size in pixels or world units                                     |
| `screenSpaceSizing` | bool  | True       | If true, points have constant pixel size                                |
| `cmap`              | str   | None       | Colormap: `"turbo"`, `"viridis"`, `"inferno"`, `"jet"`, or None for RGB |
| `colorMode`         | int   | 0          | Color mode (see table below)                                            |
| `depthMin`          | float | 0.1        | Minimum depth for visualization mapping                                 |
| `depthMax`          | float | 50         | Maximum depth for visualization mapping                                 |
| `heightMin`         | float | -2         | Minimum height for visualization mapping                                |
| `heightMax`         | float | 2          | Maximum height for visualization mapping                                |
| `minY`              | float | -Infinity  | Minimum world Y for filtering - points below are discarded              |
| `maxY`              | float | Infinity   | Maximum world Y for filtering - points above are discarded              |
| `cx`                | float | width/2    | Principal point X in pixels (optical center X)                          |
| `cy`                | float | height/2   | Principal point Y in pixels (optical center Y)                          |

### Color Modes

| Value | Mode    | Description                             |
| ----- | ------- | --------------------------------------- |
| 0     | depth   | Color by raw depth value                |
| 1     | camZ    | Color by camera Z distance              |
| 2     | camDist | Color by Euclidean distance from camera |
| 3     | localY  | Color by local Y coordinate             |
| 4     | worldY  | Color by world Y coordinate (height)    |

### Camera Intrinsics (cx/cy)

For cameras with off-center principal points (optical center), you can specify the `cx` and `cy` parameters to properly reconstruct the 3D point cloud. By default, they are centered at `width/2` and `height/2`.

```python
# Using camera intrinsics from calibration
sess.upsert @ DepthPointCloud(
    key="calibrated-pc",
    depth=vuer.localhost_prefix / "depth.png",
    rgb=vuer.localhost_prefix / "color.png",
    fov=58,           # Vertical FOV in degrees
    cx=320.5,         # Principal point X (pixels)
    cy=240.3,         # Principal point Y (pixels)
)
```

Common sources for camera intrinsics:

- **ROS camera\_info**: `K[2]` = cx, `K[5]` = cy
- **OpenCV calibration**: `cx`, `cy` from the camera matrix
- **RealSense SDK**: `ppx`, `ppy` from intrinsics

## DepthPointCloudProvider Parameters

| Parameter        | Type  | Default | Description                                              |
| ---------------- | ----- | ------- | -------------------------------------------------------- |
| `frustumCulling` | bool  | True    | Skip rendering point clouds outside camera view          |
| `cullingMargin`  | float | 2.0     | Margin multiplier for culling bounds                     |
| `lod`            | dict  | None    | Level-of-detail configuration with strides and distances |
| `bake`           | dict  | None    | Bake configuration for depth processing                  |
| `children`       | list  | \[]     | Child `DepthPointCloud` elements                         |