e57FileReader

R2026b

Read point cloud data from E57 file

Since R2023a

Description

The e57FileReader object reads point cloud data from an E57 file.

Creation

Syntax

e57Reader = e57FileReader(fileName)

Description

e57Reader = e57FileReader(fileName) creates an e57FileReader object that reads point cloud data from an E57 file. The fileName argument, which specifies the absolute or relative path to the E57 file, sets the FileName object property. You specify fileName as character vector or string scalar.

Properties

FileName — Name of E57 file

Read-only: character vector

This property is read-only.

Name of the E57 file, stored as a character vector.

FormatName — Format name in E57 file header

Read-only: character vector

This property is read-only.

Format name in the E57 file header, stored as a character vector.

GUID — Globally unique identifier in E57 file header

Read-only: character vector

This property is read-only.

Globally unique identifier in the E57 file header, stored as a character vector.

Version — E57 file version

Read-only: character vector

This property is read-only.

E57 file version, stored as a character vector.

LibraryVersion — Library version used to save E57 file

Read-only: character vector

This property is read-only.

Library version used to save the E57 file, stored as a character vector.

FileCreationTime — File creation date and time

Read-only: datetime object

This property is read-only.

File creation date and time, stored as a datetime object.

NumPointClouds — Number of point clouds

Read-only: nonnegative integer

This property is read-only.

Number of point clouds in the E57 file, stored as a nonnegative integer.

PointCloudIndex — Index of next point cloud to read

positive integer

Since R2026b

Index of the next point cloud to read, specified as a positive integer. If you do not specify an index to the readPointCloud object function, it reads the point cloud at this index and increments this property value by one after completing the read operation. The value of this index cannot not exceed the number of point clouds in the E57 file when a read operation begins.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Object Functions

readPointCloud	Read point cloud data from E57 file
readCRS	Read coordinate reference system data from E57 file
hasPointCloud	Determine if another point cloud is available in E57 file
reset	Reset e57FileReader object to first frame

Examples

Read and Visualize Point Cloud Data from E57 File

Download a ZIP file containing an E57 file, and then unzip the file.

zipFile = matlab.internal.examples.downloadSupportFile("lidar","data/e57ParkingLot.zip");
saveFolder = fileparts(zipFile);
e57FileName = [saveFolder filesep 'parkingLot.e57'];
if ~exist(e57FileName,"file")
    unzip(zipFile,saveFolder)
end

Create an e57FileReader object using the downloaded E57 file.

e57Reader = e57FileReader(e57FileName);

Define a variable for storing point clouds, ptCloudArr and their corresponding poses, tformArr.

ptCloudArr = [];
tformArr = []; 

Read the point clouds sequentially. Use the hasPointCloud object function to check whether the next point cloud is available.

while hasPointCloud(e57Reader)
   [ptCloud,pcMetadata] = readPointCloud(e57Reader);
    for j = 1:numel(ptCloud) % To read multiple returns
        ptCloudArr = [ptCloudArr ptCloud(j)];
        tformArr = [tformArr pcMetadata.RelativePose];
    end
end

Align the point clouds from the file to create a map.

pcMap = pcalign(ptCloudArr,tformArr); 

Display the map.

figure
pcshow(pcMap)

More About

E57 File Format

The E57 file format, specified by the American Society for Testing and Materials (ASTM), is an open standard for storing point cloud and image data along with associated sensor metadata. Each E57 file has a hierarchical tree structure based on the XML format. An E57 file has a header, a binary section, and an XML section.

• Header — Contains information such as the file version number and the location of the XML section.

• Binary section — Contains the actual data of the point clouds and images.

• XML section — Contains a hierarchical tree that references the data stored in the binary section.

  This figure shows the typical structure of the XML section.

  

  The E57Root element is the root node of the XML hierarchy. It stores point clouds and images in a common file coordinate system. The structure also contains additional file information, such as file creation date and time.

  Data3D element stores each point cloud as an individual structure. Each structure stores the pose information and individual point attributes of the point cloud.

  Images2D element stores images as individual structures, similar to the Data3D element.

  For more information on the E57 file format, see the standard specification on the ASTM INTERNATIONAL website.

Version History

Introduced in R2023a

R2026b: Object stores index of next point cloud in PointCloudIndex property

The object now includes a PointCloudIndex property that specifies the index of the next point cloud for the readPointCloud object function to read if you do not specify an index to the function.

R2026b: New object functions to determine next point cloud availability and reset object to first frame

The object has these new object functions:

• hasPointCloud — Determine if another point cloud is available in E57 file

• reset — Reset e57FileReader object to the first frame

R2026a: hasCRSData object function has been removed

hasCRSData object function of the e57FileReader object has been removed. To check for CRS data in an E57 file, use ~isempty(readCRS(e57FileReader)) instead of hasCRSData(e57FileReader).

R2025a: hasCRSData object function will be removed in future release

The hasCRSData object function of the e57FileReader object will be removed in a future release.