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ImageValue[image,pos]

gives the interpolated value of image at position pos.

ImageValue[image,pos,"type"]

gives the value converted to the specified type.

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

ImageValue

ImageValue[image,pos]

gives the interpolated value of image at position pos.

ImageValue[image,pos,"type"]

gives the value converted to the specified type.

Details and Options

  • ImageValue is used to extract interpolated values of a 2D or 3D image and is typically used for sampling the image.
  • Pixel positions pos 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
  • ImageValue assumes the standard image coordinate system.
  • Use PixelValue to use integer indices for extracting exact pixel values of the image.
  • ImageValue[image,pos] by default returns values between 0 and 1.
  • ImageValue[image,pos,"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)
  • The following options can be given:
  • DataRange Fullrange of image coordinates
    Padding 0padding method to use
    Resampling "Linear"interpolation method to use
  • Possible settings for DataRange include:
  • Automatic{{0,1},{0,h/w}} in 2D, {{0,1},{0,d/w},{0,h/w}} in 3D
    Full{{0,w},{0,h}} in 2D, {{0,1},{0,d},{0,h}} in 3D (default)
    {{left,right},{bottom,top}}explicit coordinate ranges in 2D
    {{left,right},{front,back},{bottom,top}}explicit coordinate ranges in 3D
  • With Resampling->"Nearest", when the position pos lies on a boundary between pixels, the average of the pixels surrounding pos is returned. »

Examples

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Basic Examples  (2)

Image value in a color image:

Wolfram Language code: ImageValue[[image], {177.1, 47.7}]

Image value in "Byte" type:

Wolfram Language code: ImageValue[[image], {177.1, 47.7}, "Byte"]

Scope  (12)

Data  (4)

A single value of a grayscale image:

Wolfram Language code: ImageValue[Image[(⁠| | | | -- | -- | | 0 | .2 | | .4 | 1 |⁠)], {0.5, 0.5}]

ImageValue typically returns interpolated values:

Wolfram Language code: ImageValue[Image[(⁠| | | | -- | -- | | 0 | .2 | | .4 | 1 |⁠)], {1.0, 0.5}]

A single value of a color image:

Wolfram Language code: ImageValue[[image], {0.5, 0.5}]

A single value of a 3D image:

Wolfram Language code: ImageValue[[image], {2.5, 0.5, 2.5}]

Position  (5)

A single value of an image:

Wolfram Language code: ImageValue[[image], {50.3, 33.5}]

Multiple values:

Wolfram Language code: ImageValue[[image], {{86.5, 53.3}, {11.8, 1.9}, {59.6, 52.1}}]

Image values at a range of positions:

Wolfram Language code: ImageValue[[image], {33.3 ;; 38.6, 50. ;; 55.5}]

Use All to extract all values in one dimension:

Wolfram Language code: ImageValue[[image], {40.5, All}]

Image values at positions specified by a marker image:

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

Type  (3)

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

Wolfram Language code: ImageValue[[image], {50.3, 33.5}]

Specify a different type:

Wolfram Language code: ImageValue[[image], {50.3, 33.5}, "Byte"]

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

Wolfram Language code: ImageValue[[image], {50.3, 33.5}, Automatic]

Options  (3)

DataRange  (1)

By default, image value assumes a data range of {{0,width},{0,height}}:

Wolfram Language code: i = [image];
Wolfram Language code: ImageValue[i, ImageDimensions[i] / 2]

Pixel value at the center of an image using a normalized data range:

Wolfram Language code: ImageValue[i, {1 / 2, 1 / 2}, DataRange -> {{0, 1}, {0, 1}}]

Padding  (1)

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

Wolfram Language code: ImageValue[[image], Table[{i, 0.5}, {i, 0.5, 6, 1}]]

Specify a padding scheme:

Wolfram Language code: ImageValue[[image], Table[{i, 0.5}, {i, 0.5, 6, 1}], Padding -> "Periodic"]

Resampling  (1)

By default, the linear resampling is used:

Wolfram Language code: ImageValue[Image[{{0, .1}, {.2, .3}}], {.9, .9}]
Wolfram Language code: ImageValue[Image[{{0, .1}, {.2, .3}}], {1.5, 1.5}]

Specify a different resampling:

Wolfram Language code: ImageValue[Image[{{0, .1}, {.2, .3}}], {.9, .9}, Resampling -> "Cubic"]

Use the nearest value to avoid resampling:

Wolfram Language code: ImageValue[Image[{{0, .1}, {.2, .3}}], {.9, .9}, Resampling -> "Nearest"]

Applications  (4)

Compute mean image value of a region of interest:

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

Image values along a path defined in a marker image:

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

Intensity profile of the path:

Wolfram Language code: ListLinePlot[%]

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

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

Extract image 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: ImageValue[i, corners]

Possible Issues  (3)

With Resampling->"Nearest" and integer coordinates, the average of the pixels surrounding the specified coordinate is returned:

Wolfram Language code: ImageValue[[image], {1, 1}, Resampling -> "Nearest"]

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

Wolfram Language code: ImageValue[[image], {1.5, 1.5}]
Wolfram Language code: ImageValue[[image], {1.5, 1.5}, "Bit"]

Extracting value at multiple positions is much faster if done at once rather than extracting one at a time:

Wolfram Language code: img = [image]; coordinates = ImageValuePositions[img, Green, 0.6];
Wolfram Language code: AbsoluteTiming[r1 = ImageValue[img, coordinates];]
Wolfram Language code: AbsoluteTiming[r2 = Table[ImageValue[img, point], {point, coordinates}];]
Wolfram Language code: r1 === r2

Interactive Examples  (1)

Profile of a single image row:

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

Text

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

CMS

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

APA

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

BibTeX

@misc{reference.wolfram_2026_imagevalue, author="Wolfram Research", title="{ImageValue}", year="2014", howpublished="\url{https://reference.wolfram.com/language/ref/ImageValue.html}", note=[Accessed: 13-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_imagevalue, organization={Wolfram Research}, title={ImageValue}, year={2014}, url={https://reference.wolfram.com/language/ref/ImageValue.html}, note=[Accessed: 13-June-2026]}