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Read and write blocks of blocked image data as image files

Since R2021a


The GenericImageBlocks object is an adapter that reads and writes 2-D blocked image data as image files.

When writing to disk, the object creates an individual image file for each block and saves the image files in a folder. For multiresolution images, the object creates one subfolder for each resolution level. The object also creates and saves a MAT file with information about the blocked image, including the image size, block size, and data type.

By default, the object writes images as PNG files. To use a different file format, create the object and then change the file format using the BlockFormat property. For example, to write images as JPG files, use this code.

adapter = images.blocked.GenericImageBlocks;
adapter.BlockFormat = "jpg";

The table lists the support that the GenericImageBlocks object has for various blockedImage capabilities.

Data types

This object supports 2-D images only:

  • Binary images of size m-by-n with data type logical

  • Grayscale images of size m-by-n with data type uint8

  • Truecolor (RGB) images of size m-by-n-by-3 with data type uint8

Multiple resolution levelsYes
Process blocks in parallel using the apply functionYes
Resume block processing using the apply functionYes




adapter = images.blocked.GenericImageBlocks creates a GenericImageBlocks object that reads and writes blocked image data as image files, with one image file per block.


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Image file format for each block of data, specified as a string that identifies one of the formats supported by imwrite.

Example: "tif"

Data Types: string


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Create blocked image.

bim = blockedImage('tumor_091R.tif');

Write image data to files. Specify the images.blocked.GenericImageBlocks adapter.

wa = images.blocked.GenericImageBlocks();
wa.BlockFormat = "tif";
write(bim, "dirOfTIFFs", "Adapter", wa);

Create a blocked image from the folder of images. The blockedImage object automatically picks the appropriate adapter.

bt = blockedImage("dirOfTIFFs");
  GenericImageBlocks with properties:

    BlockFormat: "tif"

Version History

Introduced in R2021a