Video From Workspace

Import video from MATLAB workspace

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Libraries:
Computer Vision Toolbox / Sources

Description

The Video From Workspace block imports a video from the MATLAB^® workspace. The output of the block depends on the format of the video in the workspace.

• If the video is represented by an M-by-N-by-T array, the block outputs a grayscale video. M and N are the number of rows and columns in each video frame, and T is the number of frames in the video.

• If the video is represented by an M-by-N-by-C-by-T array, the block outputs a color video. M and N are the number of rows and columns in each video frame, C is the number of color channels, and T is the number of frames in the video.

Note

• If you generate code from a model that contains this block, it takes long to compile the code as the Simulink^® Coder™ puts all of the video data into the .c file. To shorten code generation time, convert your video data into a format supported by the From Multimedia File or Read Binary File block.

• The Video From Workspace block also supports fi objects. For more information on fi objects, see fi (Fixed-Point Designer).

Examples

Import Video from MATLAB Workspace

Import a video from MATLAB® to Simulink® workspace by using Video From Workspace block.

• Open Script

Ports

Output

Image — Output image or video

M-by-N-by-T array | M-by-N-by-C-by-T array

Output image or video, returned as an M-by-N-by-T array or M-by-N-by-C-by-T array. If the output is a 3-D array, the third dimension is the number of frames in the video. If the output is a 4-D array, the third dimension is the number of color channels, and the fourth dimension is the number of frames in the video.

Note

If an RGB image of size, M-by-N-by-3 array is imported from the MATLAB workspace, the block considers the third dimension to be the number of frames and processes the image as a grayscale video with 3 identical frames.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | Boolean | fixed point

R — Red color component of input video

3-D array

Red color component of the input video, returned as a 3-D array. The third dimension is the number of frames in the input video.

Note

The port label can be changed by using the Output port labels parameter.

Dependencies

To enable this port, set the Image signal parameter to Separate color signals.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | Boolean | fixed point

G — Green color component of input video

3-D array

Green color component of the input video, returned as a 3-D array. The third dimension is the number of frames in the input video.

Note

The port label can be changed by using the Output port labels parameter.

Dependencies

To enable this port, set the Image signal parameter to Separate color signals.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | Boolean | fixed point

B — Blue color component of input video

3-D array

Blue color component of the input video, returned as a 3-D array. The third dimension is the number of frames in the input video.

Note

The port label can be changed by using the Output port labels parameter.

Dependencies

To enable this port, set the Image signal parameter to Separate color signals.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | Boolean | fixed point

Parameters

Signal — Video to read

rand(32,32,3,5) (default) | M-by-N-by-T array | M-by-N-by-C-by-T array | MATLAB workspace variable

Specify the video to read from the workspace. The value for this parameter can be a 3-D numeric array, 4-D numeric array, or a MATLAB workspace variable.

To import an AVI file from the MATLAB workspace, use this process.

1. Read the file by using the VideoReader function.

   mov = VideoReader('filename.avi')
   

2. Specify the workspace variable, in this case mov as the value for the Signal parameter. If the AVI file has an associated colormap, it must satisfy these conditions.

   • The colormap must be empty or have 256 values.

   • The data must represent a grayscale image.

   • The data type of the pixel values must be uint8.

Sample time — Sample period of the output video

1 (default) | -1 | positive scalar

This parameter specifies the sample period of the output video as a positive scalar or -1. When set to -1, the block inherits the sample time from the simulink model.

Form output after final value by — Form of block output after final video frame

Setting to zero (default) | Holding final value | Cyclic repetition

Specify the block output for the duration of the simulation after the block generates the final video frame.

• Setting to zero — Generate zero-valued outputs.

• Holding final value — Repeat the final frame.

• Cyclic repetition — Repeat the video from the beginning.

Image signal — Output mode of video signal

One multidimensional signal (default) | Separate color signals

Specify the format in which the block returns a color video.

• One multidimensional signal — Return all color channels of the video in a single 4-D array. The third dimension is the number of color channels in the video.

• Separate color signals — Return each color channel of the video as a separate 3-D array. This setting enables a number of output ports on the block equal to the number of color channels in the video. Each port returns a single color channel.

Output port labels — Output port names

R|G|B (default) | text labels separated by vertical bars

Name the output ports. Use the vertical bar character, |, as a delimiter.

Example:: Red|Green|Blue

Dependencies

To enable this parameter, set the Image signal parameter to Separate color signals.

Block Characteristics

Data Types	Boolean | double | fixed point | integer | single
Multidimensional Signals	yes
Variable-Size Signals	no

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced before R2006a