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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
Details and Options Details and Options
Examples  
Basic Examples  
Scope  
Data  
Position  
Type  
Options  
Padding  
Applications  
Properties & Relations  
Possible Issues  
Interactive Examples  
See Also
Related Guides
History
Cite this Page

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

  • PixelValue is used to extract pixel values of a 2D or 3D image and is typically used for sampling the image.
  • 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
    {xmin;;xmax;;xstep,…}span of positions with steps
    {pos1,pos2,…}a list of position specifications
    markerimagea marker image
  • PixelValue assumes a pixel-aligned coordinate system that is shifted by 0.5 to the left and down with respect to the standard image coordinate system.
  • 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"] returns a pixel value in the range specified by "type". Possible settings for "type" include:
  • Automaticusing data type of image
    "Bit"integer 0 or 1
    "Byte"integer 0 through 255
    "Bit16"integer 0 through 65535
    "Real32"single-precision real (32 bit)
    "Real64"double-precision real (64 bit)
  • PixelValue can take a Padding option that is used when a specified position is beyond an image.

Examples

open all close all

Basic Examples  (2)

Value of the bottom-left corner pixel:

Wolfram Language code: PixelValue[[image], {100, 100}]

Pixel value in "Byte" type:

Wolfram Language code: PixelValue[[image], {100, 100}, "Byte"]

Scope  (11)

Data  (3)

A single pixel value of a grayscale image:

Wolfram Language code: PixelValue[Image[(⁠| | | | -- | -- | | 0 | .2 | | .4 | 1 |⁠)], {1, 1}]

A single pixel value of a color image:

Wolfram Language code: PixelValue[[image], {1, 1}]

A single pixel value of a 3D image:

Wolfram Language code: PixelValue[[image], {3, 1, 3}]

Position  (5)

A single pixel value of a grayscale image:

Wolfram Language code: PixelValue[[image], {10, 10}]

Specify a noninteger position:

Wolfram Language code: PixelValue[[image], {9.9, 10.4}]

Multiple pixel values:

Wolfram Language code: PixelValue[[image], {{10, 10}, {20, 20}, {30, 30}}]

Pixel values at a range of positions:

Wolfram Language code: PixelValue[[image], {10 ;; 20, 1 ;; 2}]

Use All to extract all pixels in one dimension:

Wolfram Language code: PixelValue[[image], {41, All}]

Pixel values at positions specified by a marker image:

Wolfram Language code: PixelValue[[image], [image]]

Type  (3)

By default, pixel values are returned in "Real" type:

Wolfram Language code: PixelValue[[image], {50, 50}]

Specify a different type:

Wolfram Language code: PixelValue[[image], {50, 50}, "Byte"]

Use Automatic to return values in the original image data type:

Wolfram Language code: PixelValue[[image], {50, 50}, Automatic]

Options  (1)

Padding  (1)

By default, pixels outside of an image are assumed to be zero:

Wolfram Language code: PixelValue[[image], Table[{i, 1}, {i, 6}]]

Specify a padding scheme:

Wolfram Language code: PixelValue[[image], Table[{i, 1}, {i, 6}], Padding -> "Periodic"]

Applications  (4)

Compute mean pixel value of a region of interest:

Wolfram Language code: PixelValue[[image], [image]]//Mean
Wolfram Language code: RGBColor@%

Pixel values on a path defined in a marker image:

Wolfram Language code: PixelValue[[image], [image]]

Plot the distribution of pixel values in a region of interest:

Wolfram Language code: Histogram[PixelValue[[image], [image]], {0, 1, 0.1}]

Extract image pixel values where corners are detected:

Wolfram Language code: i = [image];
Wolfram Language code: corners = ImageCorners[i, 4, 0.001, 3, MaxFeatureDisplacement -> 7]
Wolfram Language code: HighlightImage[i, {PointSize[Large], corners}]
Wolfram Language code: PixelValue[i, corners]

Properties & Relations  (2)

Use ImageData to extract pixel values. Value of the bottom-left pixel:

Wolfram Language code: PixelValue[[image], {1, 1}]
Wolfram Language code: ImageData[[image], DataReversed -> True][[1, 1]]

Bottom row of the image:

Wolfram Language code: PixelValue[[image], {All, 1}]
Wolfram Language code: ImageData[[image], DataReversed -> True][[1]]

Extract pixel values using ImageValue and special settings of Resampling and DataRange:

Wolfram Language code: PixelValue[[image], Table[{i, i}, {i, 3}]]
Wolfram Language code: ImageValue[[image], Table[{i, i}, {i, .75, 3, 1}], Resampling -> "Nearest", DataRange -> {{.5, 3.5}, {.5, 3.5}}]

Possible Issues  (2)

When coordinates lie on a boundary between pixels, the average of surrounding pixel values is returned:

Wolfram Language code: PixelValue[[image], {1.5, 1.5}]

When converting to "Bit" type, pixel values will get rounded:

Wolfram Language code: PixelValue[[image], {2, 2}]
Wolfram Language code: PixelValue[[image], {2, 2}, "Bit"]

Interactive Examples  (1)

Profile of a single image row:

Wolfram Language code: With[{img = [image]}, Manipulate[{ReplacePixelValue[img, {All, row} -> Red], ListLinePlot[PixelValue[img, {All, row}], PlotRange -> {0, 1}, ImageSize -> Small]}, {row, 1, 150, 1}]]
Wolfram Research (2010), PixelValue, Wolfram Language function, https://reference.wolfram.com/language/ref/PixelValue.html (updated 2014).

Text

Wolfram Research (2010), PixelValue, Wolfram Language function, https://reference.wolfram.com/language/ref/PixelValue.html (updated 2014).

CMS

Wolfram Language. 2010. "PixelValue." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2014. https://reference.wolfram.com/language/ref/PixelValue.html.

APA

Wolfram Language. (2010). PixelValue. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/PixelValue.html

BibTeX

@misc{reference.wolfram_2026_pixelvalue, author="Wolfram Research", title="{PixelValue}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/PixelValue.html}", note=[Accessed: 13-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_pixelvalue, organization={Wolfram Research}, title={PixelValue}, year={2014}, url={https://reference.wolfram.com/language/ref/PixelValue.html}, note=[Accessed: 13-June-2026]}