ImageFileScan

ImageFileScan[f,inputfile]

applies the function f to the list of channel values for each pixel of the image stored in inputfile.

Details and Options

  • ImageFileScan can be used to read and process successive pixel data from a very large image file whose size could exceed available memory.
  • The channel values supplied to f are normally in the range 0 to 1, regardless of the underlying type used in the Image object.
  • ImageFileScan[f,…] discards the results of applying f to the pixels. Unlike ImageFileApply, ImageFileScan does not create a new file and returns Null.
  • ImageFileScan is useful in carrying out an operation on individual pixels where the operation has a "side effect", such as making an assignment.
  • ImageFileScan works with TIFF, JPEG, and PNG files.
  • ImageFileScan works on images with any number of channels.
  • The image file inputfile can be given as a string or a File object.
  • ImageFileScan traverses the image in a row-wise order from left to right.
  • You can use Throw to exit from ImageFileScan. »
  • The following options can be given:
  • InterleavingTruewhether to supply f lists of channel values
    MethodAutomaticmethod to use
  • The following suboptions can be given to Method:
  • "ImageList"Allframes to process from a file with multiple images
    "MaxBlockSize"8000000maximal size of image blocks in pixels loaded into the memory
  • The value of the option "MaxBlockSize" may be exceeded if it is smaller than the smallest block supported for the input file.

Examples

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Basic Examples  (3)

Compute the total intensity of an out-of-core image:

Out-of-core image histogram:

Compare with in-memory level computation:

Compute the minimum and maximum values for each channel:

Generalizations & Extensions  (1)

Throw works inside ImageFileScan:

Wolfram Research (2012), ImageFileScan, Wolfram Language function, https://reference.wolfram.com/language/ref/ImageFileScan.html (updated 2016).

Text

Wolfram Research (2012), ImageFileScan, Wolfram Language function, https://reference.wolfram.com/language/ref/ImageFileScan.html (updated 2016).

CMS

Wolfram Language. 2012. "ImageFileScan." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2016. https://reference.wolfram.com/language/ref/ImageFileScan.html.

APA

Wolfram Language. (2012). ImageFileScan. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ImageFileScan.html

BibTeX

@misc{reference.wolfram_2025_imagefilescan, author="Wolfram Research", title="{ImageFileScan}", year="2016", howpublished="\url{https://reference.wolfram.com/language/ref/ImageFileScan.html}", note=[Accessed: 29-May-2025 ]}

BibLaTeX

@online{reference.wolfram_2025_imagefilescan, organization={Wolfram Research}, title={ImageFileScan}, year={2016}, url={https://reference.wolfram.com/language/ref/ImageFileScan.html}, note=[Accessed: 29-May-2025 ]}