Table Of Contents
Estimate Flat Field Model (G Dataflow)
Returns a flat field image by fitting a mathematical model on the supplied image.
ROI descriptor
Region of interest (ROI) within which the flat field operation is computed.
global rectangle
Coordinates of the bounding rectangle.
contours
Individual shapes that define an ROI.
ID
Object specifying if contour is the external or internal edge of an ROI.
Type
Shape type of the contour.
Coordinates
Relative position of the contour.
image src
Reference to the source image.
image dst
Reference to destination flat field image.
mask image
Reference to the mask image.
The mask image represents the background region on image src.
surface fit options
Cluster of options used to determine the surface fit to construct the flat field image.
model
Input that specifies the surface fitting model.
| Name | Description |
|---|---|
| Polynomial | Uses a 2D polynomial mathematical model to determine the image. |
sampling grid size
Cluster specifying the size of the grid the node uses when fitting the model.
The larger the grid size, the more accurate the fit will be. The time to estimate the flat field image will increase with a larger grid size.
sizeX
Size of the window in the x-dimension.
sizeY
Size of the window in the y-dimension.
polynomial degree
Input that specifies the polynomial degree the algorithm uses to estimate the background of the image.
The time to estimate the flat field image increases with a higher degree.
error in
Error conditions that occur before this node runs.
The node responds to this input according to standard error behavior.
Standard Error Behavior
Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.
Default: No error
background estimation options
Cluster of options used to estimate the background region of image src.
estimate background?
Input that enables background estimation algorithm when set to TRUE.
method
Input that selects the method the algorithm uses to estimate the background of the model image.
| Name | Value | Description |
|---|---|---|
| polynomial | 0 |
Uses a polynomial algorithm with a specified polynomial degree to estimate the background. |
| background correction | 1 |
Performs background correction to eliminate non-uniform lighting effects and then performs thresholding using the interclass variance thresholding algorithm. |
| NiBlack | 2 |
Computes thresholds for each pixel based on its local statistics using the NiBlack local thresholding algorithm. |
polynomial degree
Input that specifies the polynomial degree the algorithm uses to estimate the background of the image.
The time to estimate the flat field image increases with a higher degree.
window size (32x32)
Cluster specifying the size of the window the node uses when calculating a local threshold.
sizeX
Size of the window in the x-dimension.
sizeY
Size of the window in the y-dimension.
Niblack deviation factor in
Input that specifies the k constant used in the Niblack local thresholding algorithm, which determines the weight applied to the variance calculation.
Valid k constants range from 0 to 1. The lower the deviation factor, the closer the pixel value must be to the mean value selected as part of a particle. Setting the Niblack deviation factor in to 0 increases the performance of the node, as the pixel variance is not calculated.
flat field image out
Estimated flat field image.
error out
Error information.
The node produces this output according to standard error behavior.
Standard Error Behavior
Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.
Where This Node Can Run:
Desktop OS: Windows
FPGA: Not supported
Web Server: Not supported in VIs that run in a web application