xyz2double (Image Processing Toolbox User's Guide)

Image Processing Toolbox User's Guide

Convert color data from representation to double

Syntax

```
xyzd = xyz2double(XYZ)
```

Description

xyxd = xyz2double(XYZ) converts an M-by-3 or M-by-N-by-3 array of XYZ color values to double. xyzd has the same size as XYZ.

The Image Processing Toolbox follows the convention that double-precision XYZ arrays contain 1931 CIE XYZ values. XYZ arrays that are uint16 follow the convention in the ICC profile specification (ICC.1:2001-4, www.color.org) for representing XYZ values as unsigned 16-bit integers. There is no standard representation of XYZ values as unsigned 8-bit integers. The ICC encoding convention is illustrated by this table.

Value (X, Y, or Z)
uint16 Value

0.0
0

1.0
32768

1.0 + (32767/32768)
65535

Value (X, Y, or Z)	uint16 Value
`0.0`	`0`
`1.0`	`32768`
`1.0 + (32767/32768)`	`65535`

Class Support

xyz is a uint16 or double array that must be real and nonsparse. xyzd is of class double.

Example

Convert uint16-encoded XYZ values to double.

xyz2double(uint16([100 32768 65535]))
ans =

  3.0518e-003  1.0000e+000  2.0000e+000

For a full list of the toolbox color space conversion functions, see Color Space Conversions.

wiener2 xyz2uint16