Main Content

readEncodedTile

Read data from specified tile

collapse all in page

Syntax

tileData = readEncodedTile(t,tileNumber)
[Y,Cb,Cr] = readEncodedTile(t,tileNumber)

Description

tileData = readEncodedTile(t,tileNumber) returns image data contained in the tile specified by tileNumber from the TIFF file represented by the Tiff object t.

The readEncodedTile function trims the area in a tile that is outside of the ImageLength and ImageWidth boundaries. Therefore, image data from tiles that occur on the right edge or the bottom edge of the image can have different dimensions.

example

[Y,Cb,Cr] = readEncodedTile(t,tileNumber) returns the YCbCr components of the image data contained in the tile specified by tileNumber from the TIFF file represented by the Tiff object t. Use this syntax only with images that have a YCbCr photometric interpretation.

Depending upon the values of the YCbCrSubSampling tag, the size of the Cb component can differ from the Y component.

example

Examples

collapse all

Open Live Script

Read a tile of image data from a TIFF file that contains an image with a tiled layout.

t = Tiff('peppers_RGB_tiled.tif','r');

Determine the number of tiles and the tile size in the image.

nTiles = numberOfTiles(t)
nTiles = 
36

tileSize = [getTag(t,'TileLength') getTag(t,'TileWidth')]
tileSize = 1×2

    32    48

Read and display the 19th tile of the image. The readEncodedTile function trims the area in a tile that is outside of the ImageLength and ImageWidth boundaries. Therefore, image data from tiles that occur on the right edge or the bottom edge of the image can have different dimensions.

tile = readEncodedTile(t,19);
imshow(tile,'InitialMagnification','fit'); % Magnify for display
title('19^{th} Tile of Peppers Image (RGB)');

Figure contains an axes object. The hidden axes object with title 19 toThePowerOf th baseline blank Tile blank of blank Peppers blank Image blank (RGB) contains an object of type image.

Close the Tiff object. 

close(t);
Open Live Script

Read a tile of image data from a YCbCr TIFF file that contains an image with a tiled layout.

t = Tiff('peppers_YCbCr_tiled.tif','r');

Determine the number of tiles and the tile size in the image.

nTiles = numberOfTiles(t)
nTiles = 
36

tileSize = [getTag(t,'TileLength') getTag(t,'TileWidth')]
tileSize = 1×2

    32    48

Read and display the Y component of the 19th tile of the image. The readEncodedTile function trims the area in a tile that is outside of the ImageLength and ImageWidth boundaries. Therefore, image data from tiles that occur on the right edge or the bottom edge of the image can have different dimensions.

[Y,Cb,Cr] =  readEncodedTile(t,19);
imshow(Y,'InitialMagnification','fit') % Magnify for display
title('19^{th} Tile of Peppers Image (YCbCr)')

Figure contains an axes object. The hidden axes object with title 19 toThePowerOf th baseline blank Tile blank of blank Peppers blank Image blank (YCbCr) contains an object of type image.

Close the Tiff object. 

close(t);

Input Arguments

collapse all

Tiff object representing a TIFF file. Use the Tiff function to create the object.

Tile number, specified as a positive integer. Tile numbers are one-based numbers.

Example: 15

Data Types: double

Output Arguments

collapse all

Tile data, returned as a numeric array.

Luma component of the tile data, returned as a two-dimensional numeric array.

Blue-difference chroma component of the tile data, returned as a two-dimensional numeric array.

Red-difference chroma component of the tile data, returned as a two-dimensional numeric array.

Limitations

  • readEncodedTile returns image data from SVS files as RGB data only, even for SVS files with YCbCr photometric interpretation.

Algorithms

collapse all

References

This function corresponds to the TIFFReadEncodedTile function in the LibTIFF C API. To use this function, you must be familiar with the TIFF specification and technical notes. View this documentation at LibTIFF - TIFF Library and Utilities.

Version History

Introduced in R2009b

See Also

| |

Topics