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ImageFileFilter[f,inputfile,r,outputfile]

applies the function f to the range r neighborhood of each pixel in each channel of the image stored in inputfile and stores the result in outputfile.

Details and Options
Details and Options Details and Options
Examples  
Basic Examples  
Options  
Interleaving  
Method  
Applications  
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ImageFileFilter

ImageFileFilter[f,inputfile,r,outputfile]

applies the function f to the range r neighborhood of each pixel in each channel of the image stored in inputfile and stores the result in outputfile.

Details and Options

  • ImageFileFilter can be used to read, process, and write successive blocks of data from a very large image file whose size could exceed available memory.
  • ImageFileFilter[f,inputfile,r] stores the result under the "Image" directory in $WolframDocumentsDirectory.
  • ImageFileFilter works with TIFF, JPEG, and PNG files. The created outputfile always has the same file format, data type, and dimensions as the inputfile.
  • ImageFileFilter works on images with any number of channels.
  • The image files inputfile and outputfile can be given as a string or a File object.
  • ImageFileFilter[f,inputfile,r] replaces the value of each pixel by the result of applying the function f to the × array of values around that pixel.
  • ImageFileFilter[f,"inputfile",{rrow,rcol}] uses range rrow in the row direction, and rcol in the column direction.
  • The function f should always return a number or a list of any length.
  • The channel values supplied to f are normally in the range 0 to 1, regardless of the underlying type used in the Image object. The function f is assumed to return channel values that are normally in the range 0 to 1.
  • ImageFileFilter operates separately on each channel in an image.
  • The following options can be given:
  • Interleaving Truewhether to supply f lists of channel values
    Padding"Fixed"what values to assume beyond the image
    Method Automaticmethod to use
  • The following suboptions can be given to Method:
  • "ImageList"Allframes to process from a multi-frame file
    "MaxBlockSize"8000000maximal size of image blocks in pixels loaded into the memory
  • With the default setting Interleaving->False, the elements in the arrays to which f is applied are individual channel values for the pixels.
  • For the most efficient file processing, stripes or tiles of the image may be accessed in a specific order.
  • The value of the option "MaxBlockSize" may be exceeded if it is smaller than the smallest block supported for the input file.
  • With "ImageList"->{l1,l2,…}, the output image only contains the processed frames.
  • Padding->None is not supported by ImageFileFilter.

Examples

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Basic Examples  (2)

Out-of-core processing of an image:

Thumbnail of the resulting image:

Specify the output file name:

Options  (2)

Interleaving  (1)

Compute the average over all channels using Interleaving->True:

Thumbnail of the resulting image:

Method  (1)

Apply the function only to one frame of a multi-image file using "ImageList":

Apply the function to a list of frames:

Applications  (1)

Out-of-core correlation with a Gaussian kernel:

Thumbnail the resulting image: