MimDistance

Board	Supported
Host System	Yes
V4L2	Yes
Clarity UHD	Yes
Concord PoE	No
GenTL	Yes
GevIQ	Yes
GigE Vision	Yes
Indio	No
Iris GTX	Yes
Radient eV-CL	Yes
Rapixo CL	Yes
Rapixo CoF	Yes
Rapixo CXP	Yes
USB3 Vision	Yes

Perform a distance transformation.

Syntax

void MimDistance(
    AIL_ID    SrcImageBufId,     //in
    AIL_ID    DstImageBufId,     //out
    AIL_INT64 DistanceTransform  //in
)

Description

This function determines the shortest distance between each blob pixel and the blob's background, and assigns this distance to the pixel. It produces a type of contour mapping of a blob.

Parameters

SrcImageBufId (in, AIL_ID)

Specifies the identifier of the source of the operation. This parameter must be given an image buffer identifier.

DstImageBufId (out, AIL_ID)

Specifies the identifier of the destination of the resulting image. This parameter must be given an image buffer identifier.

DistanceTransform (in, AIL_INT64)

Specifies the way in which the minimum distance from blob pixel to background pixel is calculated. This parameter can be set to one of the following:

For specifying how to calculate the minimum distance

Value	Description
M_CHAMFER_3_4	Approximates the minimum distance using horizontal, vertical or diagonal pixel steps. Horizontal and vertical steps are counted as 3; diagonal steps are counted as 4. Then, the resulting distance is normalized by a factor of 3. This transform provides the best approximation to Euclidean distance.

This transform requires that the destination buffer be deep enough to hold a number at least three times the maximum distance from a blob pixel to its edge. For example, an 8-bit buffer (255 max) can be used for a maximum distance of 85 pixels and a 16-bit buffer (65535 max) for a maximum distance of 21845 pixels.

3x3 Distance Matrix:

[Image: Chamfer.png] | | M_CHESSBOARD | Approximates the minimum distance using horizontal, vertical, or diagonal pixel steps. All steps count as 1.

3x3 Distance Matrix:

[Image: Chessboard.png] | | M_CITY_BLOCK | Approximates the minimum distance using only horizontal or vertical pixel steps. Horizontal and vertical steps count as 1.

3x3 Distance Matrix:

[Image: Cityblock.png] | | M_EUCLIDEAN_DIST | Calculates the true minimum Euclidean distance using a straight-line path.

The Euclidean distance is calculated using the following formula, where:

|| || | | | [Image: Euclidean_distance.png] | - _x₁ _ and _y₁ _ represent the coordinates of the blob pixel.
- _x₂ _ and _y₂ _ represent the coordinates of the nearest background pixel. |

Note, the source buffer must be a 1-band, 8-bit image buffer of type M_UNSIGNED and the destination buffer must be a 1-band, 32-bit image buffer of type M_FLOAT. |

Remarks

In-place processing is supported, but the source and destination image buffers cannot partially overlap (a situation that can only occur when using child buffers).