# PixelValue

PixelValue[image,ppos]

gives the pixel value of image at position pos.

PixelValue[image,ppos,"type"]

gives the pixel value converted to the specified type.

# Details and Options

• Pixel positions ppos can be in one of the following forms:
•  {x,y}or {x,y,z} single position in 2D or 3D {xmin;;xmax,…} span of positions {ppos1,ppos2,…} a list of position specifications markerimage a marker image
• In PixelValue[image,{xp,yp}], the pixel position {xp,yp}={x+1/2,y+1/2}, with {x,y} assumed to be in the standard image coordinate system, where the values of x range from 0 to width and y from 0 to height.
• In PixelValue, integer coordinates correspond to the centers of the pixels. In 2D, pixel position represents the center of the bottom-left pixel. In 3D, pixel position corresponds to the center of the bottom-left front pixel.
• PixelValue gives the value of the pixel nearest to {xp,yp}, except that when the position {xp,yp} lies on a boundary between pixels, the average of the pixels surrounding {xp,yp} is returned.
• Use ImageValue to extract interpolated values at {x,y} in the standard image coordinate system.
• With PixelValue[image,marker], nonzero pixels of the image marker are used as the list of positions.
• PixelValue[image,ppos] by default returns values between 0 and 1. Using PixelValue[image,ppos,"type"], pixel value is returned in the range specified by "type". See the reference page for Image for a list of all possible data types.
• PixelValue[image,ppos,Automatic] is equivalent to PixelValue[image,ppos,ImageType[image]].
• PixelValue can take a Padding option that is used when a specified position is beyond an image.

# Examples

open allclose all

## Basic Examples(3)

Value of the bottom-left corner pixel:

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Pixel value in "Byte" type:

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Value of a bottom-left front corner pixel in a 3D volume:

 In[1]:=
 Out[1]=