Table Of Contents

Color Histogram (G Dataflow)

Last Modified: June 25, 2019

Calculates the histograms extracted from the three planes of an image.

This node can function in one of six modes corresponding to the six color models: RGB, HSL, HSV, HSI, CIE L*a*b*, or CIE XYZ.

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image in

Reference to the source image.

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image mask

8-bit image specifying the region in the image to use for the calculation.

Only those pixels in the original image that correspond to an equivalent non-zero pixel in the mask image are used for the calculation. The entire image is used in the calculation if image mask is not connected.

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color mode

Image color format to use for the operation.

Name Value Description
RGB 0

Specifies the color format RGB (red, green, and blue)

HSL 1

Specifies the color format HSL (hue, saturation, and luminance)

HSV 2

Specifies the color format HSV (hue, saturation, and value)

HSI 3

Specifies the color format HSI (hue, saturation, and intensity)

Default: RGB

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number of classes

Number of classes used to classify the pixels.

Default: 256

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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.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error

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CIE L*a*b* white reference

Cluster that specifies the CIE X, Y, and Z values associated with white.

The default values of this control work with RGB values of (255, 255, 255) as white.

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image dup

Reference to the source image.

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red/hue/L*/X histogram report

Cluster that returns the detailed results from a histogram calculated on a red or hue plane, depending on the color mode.

This cluster is the same as the cluster used by the Histogram node.

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histogram

Histogram values in an array.

The elements found in this array are the number of pixels per class. The nth class contains all pixel values belonging to the interval [(Starting Value + (n - 1) × Interval Width), (Starting Value + n × (Interval Width - 1))].

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minimal value

Smallest pixel value used in calculating the histogram.

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maximal value

Largest pixel value used in calculating the histogram.

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starting value

Smallest pixel value from the first class calculated in the histogram and is always equal to 0.

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interval width

Length of each class.

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mean value

Mean value of the pixels used in calculating the histogram.

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standard variation

Standard deviation from the histogram.

A higher value corresponds to a better distribution of the values in the histogram and the image.

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area (pixels)

Number of pixels used in the histogram calculation.

This is influenced by the values specified in interval range and the contents of image mask.

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green/saturation/a*/Y histogram report

Cluster that returns the detailed results from a histogram calculated on the green or saturation plane, depending on the color mode.

This cluster is the same as the cluster used by the Histogram node.

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histogram

Histogram values in an array.

The elements found in this array are the number of pixels per class. The nth class contains all pixel values belonging to the interval [(Starting Value + (n - 1) × Interval Width), (Starting Value + n × (Interval Width - 1))].

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minimal value

Smallest pixel value used in calculating the histogram.

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maximal value

Largest pixel value used in calculating the histogram.

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starting value

Smallest pixel value from the first class calculated in the histogram and is always equal to 0.

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interval width

Length of each class.

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mean value

Mean value of the pixels used in calculating the histogram.

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standard variation

Standard deviation from the histogram.

A higher value corresponds to a better distribution of the values in the histogram and the image.

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area (pixels)

Number of pixels used in the histogram calculation.

This is influenced by the values specified in interval range and the contents of image mask.

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blue/luma/value/intensity/b*/Z histogram report

Cluster that returns the detailed results from a histogram calculated on the blue, luminance, value, or intensity planes, depending on the color mode.

This cluster is the same as the cluster used by the Histogram node.

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histogram

Histogram values in an array.

The elements found in this array are the number of pixels per class. The nth class contains all pixel values belonging to the interval [(Starting Value + (n - 1) × Interval Width), (Starting Value + n × (Interval Width - 1))].

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minimal value

Smallest pixel value used in calculating the histogram.

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maximal value

Largest pixel value used in calculating the histogram.

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starting value

Smallest pixel value from the first class calculated in the histogram and is always equal to 0.

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interval width

Length of each class.

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mean value

Mean value of the pixels used in calculating the histogram.

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standard variation

Standard deviation from the histogram.

A higher value corresponds to a better distribution of the values in the histogram and the image.

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area (pixels)

Number of pixels used in the histogram calculation.

This is influenced by the values specified in interval range and the contents of image mask.

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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.

error in does not contain an error error in contains an error
If no error occurred before the node runs, the node begins execution normally.

If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application


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