Measure Grayscale Statistics; Measure Color Statistics - National Instruments IMAQ Vision for Measurement Studio User Manual

Measure Grayscale Statistics

Measure Color Statistics

© National Instruments Corporation
When you need to make intensity measurements on particles in an image,
you can use a mask to define the particles. First, threshold your image to
make a new binary image. For more information on binary images, see
Chapter 4, Blob Analysis. You can input the binary image or a labeled
version of the binary image as a mask image to the intensity measurement
function. If you want to make color comparisons, convert the binary image
into an ROI descriptor using
You can measure grayscale statistics in images using light meters or
quantitative analysis functions. You can obtain the center of energy for an
image with the centroid function.
Use
imaqLightMeterPoint()
the image. Use
imaqLightMeterLine()
along a line in the image, such as mean intensity, standard deviation,
minimum intensity, and maximum intensity. Use
imaqLightMeterRect()
rectangular region in an image.
Use
imaqQuantify()
image or individual regions in the image: mean intensity, standard
deviation, minimum intensity, maximum intensity, area, and the percentage
of the image that you analyzed. You can specify regions in the image with
a labeled image mask. A labeled image mask is a binary image that has
been processed so that each region in the image mask has a unique intensity
value. Use
imaqLabel()
Use
imaqCentroid()
region within an image.
Most image processing and analysis functions apply to 8-bit images.
However, you can analyze and process individual components of a color
image.
Using
imaqExtractColorPlanes()
into various sets of primary components, such as RGB (Red, Green, and
Blue), HSI (Hue, Saturation, and Intensity), HSL (Hue, Saturation, and
Luminance), or HSV (Hue, Saturation, and Value). Each component
becomes an 8-bit image that you can process like any other grayscale
Chapter 3
imaqMaskToROI()
to measure the light intensity at a point in
to get pixel value statistics
to get the pixel value statistics within a
to obtain the following statistics about the entire
to label your image mask.
to compute the energy center of the image, or of a
, you can break down a color image
3-7 IMAQ Vision for LabWindows/CVI User Manual
Grayscale and Color Measurements
.