ColorHistogram Method

NI Vision for Visual Basic

ColorHistogram Method

Syntax

CWIMAQVision.ColorHistogram SourceImage, Plane1Histogram, Plane2Histogram, Plane3Histogram, ColorFormat [, NumberOfClasses = 256] [, Plane1Report] [, Plane2Report] [, Plane3Report] [, MaskImage]

Return Type

Long

On success, this method returns 0. On failure, this method returns a negative number.

Purpose

Obsolete—Use ColorHistogram3 instead. Calculates the histogram, or pixel distribution, of a color image.

Remarks

Use this method with image types RGB32 and HSL32. MaskImage must be a U8 image.

Parameters

SourceImage As CWIMAQImage

The color image used to compute the histogram.

Plane1Histogram As Variant

On return, the histogram report of the red (RGB), or the hue (HSL, HSV, HSI) plane.

Plane2Histogram As Variant

On return, the histogram report of the green (RGB), or the saturation (HSL, HSV, HSI) plane.

Plane3Histogram As Variant

On return, the histogram report of the blue (RGB), the luminance (HSL), the value (HSV), or the intensity (HSI) plane.

ColorFormat As CWIMAQColorFormats

The color space in which to perform the histogram.

NumberOfClasses As Variant

[Optional] The number of classes into which the method separates the pixels.

This parameter has a default value of 256.

Plane1Report As Variant

[Optional] On return, a CWIMAQHistogramReport object containing detailed statistics from the histogram calculated on the red or the hue plane, depending on the value of ColorFormat.

Plane2Report As Variant

[Optional] On return, a CWIMAQHistogramReport object containing detailed statistics from the histogram calculated on the green or the saturation plane, depending on the value of ColorFormat.

Plane3Report As Variant

[Optional] On return, a CWIMAQHistogramReport object containing detailed statistics from the histogram calculated on the blue, lightness, value, or intensity plane, depending on the value of ColorFormat.

MaskImage As Variant

[Optional] A CWIMAQImage object that indicates the region to use for computing the histogram. The method calculates the histogram using only those pixels in the image whose corresponding pixels in the mask are non-zero. Do not set this parameter if you want to perform a histogram on the entire image.

See Also

ColorHistogram3