ImageData

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`ImageData`

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ImageData[image]

gives the array of pixel values in an Image or Image3D object image.

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ImageData[image,"type"]

gives the array of pixel values converted to the specified type.

Details and Options

ImageData[image] by default gives a 2D or 3D array whose elements are lists of values for each channel. For a single-channel image, only a value and not a list of values is returned.
In 2D, the array generated by ImageData[image] is arranged in the same way that the image is displayed, with the first row corresponding to the top row of pixels in the image.
In 3D, the array generated by ImageData[image] is arranged such that the first part corresponds to the top slice, with rows running from back to front, and columns running from left to right.
For binary images, ImageData[image] returns integer values 0 or 1. For images of type "Byte" or "Bit16", ImageData[image] always normalizes values to lie between 0 and 1. For images of a real type, ImageData[image] returns whatever real values are used in the image.
Possible types specified by ImageData[image,"type"] are:

	"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)

ImageData[image,Automatic] is equivalent to ImageData[image,ImageType[image]].
ImageData has the option Interleaving.
With the default setting Interleaving->True, ImageData returns a 2D or 3D array of lists of channel values.
With Interleaving->False, ImageData returns a list of 2D or 3D arrays of values for each channel.
Interleaving->Automatic returns in the native form used to store the image.
ImageData accepts a DataReversed option. With DataReversed->True, the order of the rows is reversed.

Examples

open allclose all

Basic Examples (3)Summary of the most common use cases

Channel data for the first five pixels of the first row:

In[1]:=1

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https://wolfram.com/xid/0bdpj8f2q-6hvtuj

Out[1]=1

Construct a byte-valued image:

In[1]:=1

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https://wolfram.com/xid/0bdpj8f2q-7lclkw

Out[1]=1

Extract normalized raster data:

In[2]:=2

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https://wolfram.com/xid/0bdpj8f2q-53sjcj

Out[2]=2

Extract raw bytes:

In[3]:=3

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https://wolfram.com/xid/0bdpj8f2q-5iovbf

Out[3]=3

Extract data from a 3D image:

In[1]:=1

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https://wolfram.com/xid/0bdpj8f2q-e65o1r

Options (3)Common values & functionality for each option

DataReversed (1)

By default, data is returned from the top to the bottom:

In[1]:=1

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https://wolfram.com/xid/0bdpj8f2q-csu948

Out[1]=1

Reverse the order of rows:

In[2]:=2

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https://wolfram.com/xid/0bdpj8f2q-mqdon1

Out[2]=2

Interleaving (2)

Data of multichannel images is by default returned in interleaved form:

In[1]:=1

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https://wolfram.com/xid/0bdpj8f2q-pzhm0t

Out[1]=1

This gives the pixel data in planar form:

In[2]:=2

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https://wolfram.com/xid/0bdpj8f2q-x31mx8

Out[2]=2

Retrieve the image data in interleaved form:

In[1]:=1

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https://wolfram.com/xid/0bdpj8f2q-iimsnf

Out[1]=1

In[2]:=2

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https://wolfram.com/xid/0bdpj8f2q-fjl93k

Retrieve the image data in planar form:

In[3]:=3

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https://wolfram.com/xid/0bdpj8f2q-d50nn5

Out[3]=3

Properties & Relations (2)Properties of the function, and connections to other functions

ImageData and Raster assume a different ordering of the rows:

In[1]:=1

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https://wolfram.com/xid/0bdpj8f2q-gh5xx

Out[1]=1

To visualize image data using Raster, the rows need to be reversed:

In[1]:=1

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https://wolfram.com/xid/0bdpj8f2q-qcs6t8

Out[1]=1

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