pcshow

Plot 3-D point cloud

Syntax

pcshow(ptCloud)

pcshow(xyzPoints)

pcshow(xyzPoints,color)

pcshow(xyzPoints,colorMap)

pcshow(filename)

pcshow(___,Name,Value)

ax = pcshow(___)

Description

pcshow(ptCloud) displays points using the locations and colors stored in the point cloud object.

pcshow(xyzPoints) displays points specified by the xyzPoints matrix.

pcshow(xyzPoints,color) displays points contained in the xyzPoints matrix, with colors specified by color.

pcshow(xyzPoints,colorMap) displays points contained in the xyzPoints matrix, with colors specified by colorMap.

pcshow(filename) displays the point cloud stored in the file specified by filename.

pcshow(___,Name,Value) uses additional options specified by one or more Name,Value pair arguments, using any of the preceding syntaxes.

ax = pcshow(___) returns the plot axes.

Examples

Plot Spherical Point Cloud with Texture Mapping

Generate a sphere consisting of 600-by-600 faces.

numFaces = 600;
[x,y,z] = sphere(numFaces);

Plot the sphere using the default color map.

figure;
pcshow([x(:),y(:),z(:)]);
title('Sphere with Default Color Map');
xlabel('X');
ylabel('Y');
zlabel('Z');

Load and display an image for texture mapping.

I = im2double(imread('visionteam1.jpg'));
imshow(I);

Resize and flip the image for mapping the coordinates.

J = flipud(imresize(I,size(x)));

Plot the sphere with the color texture.

pcshow([x(:),y(:),z(:)],reshape(J,[],3));
title('Sphere with Color Texture');
xlabel('X');
ylabel('Y');
zlabel('Z');

Input Arguments

ptCloud — Point cloud

pointCloud object

Point cloud, specified as a pointCloud object. The object contains the locations, intensities, and RGB colors to render the point cloud.

Point Cloud Property	Color Rendering Result
Location only	Maps the z-value to a color value in the current color map.
Location and Intensity	Maps the intensity to a color value in the current color map.
Location and Color	Use provided color.
Location, Intensity, and Color	Use provided color.

filename — Point cloud filename

character vector | string scalar

Point cloud filename, specified as a character vector or a scalar string. The file must be supported by pcread. pcshow calls pcread to read the point cloud from the file, but does not store the data in the MATLAB^® workspace.

xyzPoints — Point cloud x, y, and z locations

M-by-3 matrix | M-by-N-by-3 matrix

Point cloud x, y, and z locations, specified as either an M-by-3 or an M-by-N-by-3 numeric matrix. The xyzPoints numeric matrix contains M or M-by-N [x,y,z] points. The z values in the matrix, which generally corresponds to depth or elevation, determine the color of each point. When you do not specify the C input color, the function maps the z value to a color in the current colormap.

color — Point cloud color

1-by-3 RGB Colorspec vector | M-by-3 matrix | M-by-N-by-3 matrix

Point cloud color of points, specified as one of:

• 1-by-3 RGB ColorSpec (Color Specification) vector,

• M-by-3 matrix

• M-by-N-by-3 matrix

You can specify the same color for all points or a different color for each point. When you set C to single or double, the RGB values range between [0, 1]. When you set C to uint8, the values range between [0, 255].

Points Input	Color Selection	Valid Values of C
xyzPoints	Same color for all points	ColorSpec (Color Specification) color character vector or a 1-by-3 RGB vector
	Different color for each point	M-by-3 matrix or M-by-N-by-3 matrix containing RGB values for each point.

colorMap — Point cloud color map

M-by-1 vector | M-by-N matrix

Point cloud color of points, specified as one of:

• M-by-1 vector

• M-by-N matrix

Points Input	Color Selection	Valid Values of C
xyzPoints	Different color for each point	Vector or M-by-N matrix. The matrix must contain values that are linearly mapped to a color in the current colormap.

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: 'VerticalAxisDir','Up' sets the vertical axis direction to up.

'MarkerSize' — Diameter of marker

6 (default) | positive scalar

Diameter of marker, specified as a positive scalar. The value specifies the approximate diameter of the point marker. MATLAB graphics define the unit as points. A marker size larger than six can reduce the rendering performance.

'VerticalAxis' — Vertical axis

'Z' (default) | 'X' | 'Y'

Vertical axis, specified as 'X', 'Y', or 'Z'. When you reload a saved figure, any action on the figure resets the vertical axis to the z-axis.

'VerticalAxisDir' — Vertical axis direction

'Up' (default) | 'Down'

Vertical axis direction, specified as 'Up' or 'Down'. When you reload a saved figure, any action on the figure resets the direction to the up direction.

'Parent' — Axes on which to display the visualization

axes graphics object

Axes on which to display the visualization, specified as an Axes object. To create an Axes object, use the axes function. To display the visualization in a new figure, leave 'Parent' unspecified.

Output Arguments

ax — Plot axes

axes graphics object

Plot axes, returned as an axes graphics object.

You can set the default center of rotation for the point cloud viewer to rotate around the axes center or around a point. Set the default behavior from the Computer Vision Toolbox Preferences.

Tips

• To improve performance, pcshow automatically downsamples the rendered point cloud when you rotate, pan, or zoom in or out by clicking the mouse. Downsampling is not applied for zoom in or out by using the mouse scroll mechanism. When using data tips, no downsampling is applied. The downsampling occurs only for rendering the point cloud and does not affect the saved points.

• To view point data or modify color display values, hover over the axes toolbar and select one of the following options.

  Feature	Description
  Datatip	Click Data Tips to view the data point values for any point in the point cloud figure. For a normal point cloud, the Data Tips displays the x,y,z values. Additional data properties for the depth image and lidar are: Point Cloud Data Data Value Properties Depth image (RGB-D sensor) Color, row, column Lidar Intensity, range, azimuth angle, elevation angle, row, column
  Background color	Click Rotate and then right-click in the figure for background options.
  Colormap value	Click Rotate and then right-click in the figure for colormap options. You can modify colornap values for the coordinate and range values available, depending on the type of point cloud displayed.
  View	Click Rotate to change the viewing angle of the point cloud figure to the XZ, ZX,YZ, ZY, XY, or the YX plane. Click Restore View to reset the viewing angle.

• pcplayer supports the 'opengl' option for the Renderer figure property only.