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Stereo

NI Vision 2013 for LabVIEW Help

Edition Date: June 2013

Part Number: 370281U-01

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Owning Palette: Machine Vision
Requires: NI Vision Development Module

Use Stereo VIs to develop binocular stereo vision applications. A binocular stereo vision system uses two cameras that are separated by a short distance and are mounted almost parallel to one another.

Palette Object Description
IMAQ Create Binocular Stereo Session

Creates a binocular stereo vision session.

IMAQ Dispose Binocular Stereo Session

Destroys a binocular session and frees the space it occupied in memory. You must call this VI when the application no longer needs the session. This VI is required for each binocular stereo session created.

IMAQ Read Binocular Stereo File

Reads a binocular stereo session from the file specified by File Path.

IMAQ Write Binocular Stereo File

Writes a binocular stereo session to the file specified in File Path. This VI saves the exact state of the binocular stereo session.

IMAQ Learn Binocular Stereo Calibration

Learns binocular stereo information. This VI takes the calibrated template images from the left and right cameras as input, and computes the calibration information required for binocular stereo vision. The calibration process computes the rotation matrix and translation vector between the two cameras. It also computes the essential and fundamental matrices. During the learn process, this VI will also compute the lookup tables required to rectify the left and right images and identifies the regions in the left and right images that overlap.

This VI assumes that both the calibrated templates have been learned from the same set of grid images (or points). This VI will use the reference points stored in the two calibrated templates to learn the binocular stereo calibration information. It will use the points from the first set (the first grid image or points) to select the origin of the real world coordinate system.

IMAQ Get Binocular Stereo Calibration Info

Returns binocular stereo calibration information associated with an image.

IMAQ Stereo Correspondence (Block Matching)

Computes the disparity map for a pair of stereo images using a block matching method. This VI will implement the entire 3D reconstruction process internally until the disparity information is available. That is the VI will internally rectify the left and right images and then use the rectified images to compute the disparity information.

IMAQ Stereo Correspondence (SG Block Matching)

Computes the disparity map for a pair of stereo images using the semi-global block matching method. This VI will implement the entire 3D reconstruction process internally until the disparity information is available. That is the VI will internally rectify the left and right images and then use the rectified images to compute the disparity information.

IMAQ Get Rectified Image From Stereo

Returns the rectified image. The image returned can be from the left or right camera.

IMAQ Get Depth Image From Stereo

Returns the depth image associated with latest disparity image that was computed. Run this VI after running the IMAQ Stereo Correspondence (Block Matching) VI or IMAQ Stereo Correspondence (SG Block Matching) VI.

IMAQ Get Depth Planes From Stereo

Returns the X, Y and Z values (3D point coordinates) of all points in the input disparity image. The X, Y and Z coordinate values are returned as separate images.

IMAQ Convert Pixel To 3D Coordinates

Transforms pixel coordinates into real-world 3D coordinates according to the disparity value at the input pixel coordinates and the stereo calibration information present in the Binocular Stereo Session.

IMAQ Get Maximum Disparity 2

Returns the maximum disparity value expected for a point at a certain depth from a binocular stereo system. Use this VI to compute the number of disparities that the IMAQ Stereo Correspondence (Block Matching) VI or IMAQ Stereo Correspondence (SG Block Matching) should search over based on the minimum depth you expect the objects under inspection to be from the stereo system.

IMAQ Interpolate Disparity Image

Interpolates disparity values in a disparity image using polynomial interpolation. Interpolation sets pixels to approximate values in cases where the IMAQ Stereo Correspondence (Block Matching) VI or IMAQ Stereo Correspondence (SG Block Matching) VI cannot determine a disparity value, resulting in a smoother image.




 

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