Gamma correction of digital video data by calculating linearly interpolated gamma correction values
AssigneeSony Corporation
InventorMichael A. Kutner
Life of this patent
Estimating the term…
Abstract
An apparatus, including a lookup table memory, for gamma correcting a digital video signal based on the assumption that for small gamma, gamma correction is a linear function so that for a digital video input signal value x a gamma correction value d to be added to x can be calculated as a function of an opertor selected variable a according to the formulae: d=10.multidot.0.multidot.(x-x.sup.1.10) or d=10.multidot.9.multidot.(x-x.sup..90 ).
Claims4
Apparatus for gamma correcting an input digital video signal comprising:
- means for calculating linearly interpolated gamma correction values (d) according to one of the formulae:
- d=10.multidot.a.multidot.(x-x.sup.1.10)
- or
- d=10.multidot.a.multidot.(x-x.sup.0.90),
- where a is an operator selected variable;
- and
- lookup table means, loaded with said linearly interpolated gamma correction values, for receiving input digital video signals and outputting a corresponding digital video signal as corrected by adding to the input signal corresponding linearly interpolated gamma correction values.
Apparatus for gamma correcting an input digital video signal comprising:
- lookup table means, including a digital memory, for storing gamma corrected, digital video signal values, receiving input digital video signals and outputting gamma corrected digital video signals corresponding to said input digital video signals;
- and
- means for calculating linearly interpolated gamma correction lookup table values according to one of the formulae:
- d=10.multidot.a.multidot.(x-x.sup.1.10)
- or
- d=10.multidot.a.multidot.(x-x.sup.0.90),
- where d is the value to be added to an input digital video signal having a value x and a is an operator selected variable and loading said lookup table values into said digital memory.
A method of gamma correcting an input digital video signal comprising the steps of:
- calculating linearly interpolated gamma correction values (d) according to either of the formulae:
- d=10.multidot.a.multidot.(x-x.sup.1.10)
- or
- d=10.multidot.a.multidot.(x-x.sup.0.90),
- where a is an operator selected variable;
- loading said linearly interpolated gamma correction values into a digital lookup table;
- and
- receiving input digital video signals at the digital lookup table and outputting a corresponding digital video signal as corrected by adding to the input signal corresponding linearly interpolated gamma correction values stored in the lookup table.
Dependencies are inferred from the claim text.