Method and apparatus for correcting multi-exposure motion image

1. A method for correcting a multi-exposure motion image, comprising:

mapping a luminance of an extended frame using a luminance mapping relationship between a reference frame and multiple extended frames to obtain a virtual frame;

calculating a global motion vector between the virtual frame and the reference frame;

correcting a pixel of the extended frame in a pointer offset manner to obtain a first extended frame after correction when the global motion vector comprises a translational motion vector;

correcting the pixel of the extended frame in an interpolation manner to obtain the first extended frame after correction when the global motion vector comprises the translational motion vector and a rotational motion vector;

detecting a pixel of the first extended frame according to the reference frame to obtain a local error pixel of the first extended frame; and

correcting a luminance of the local error pixel of the first extended frame to obtain a second extended frame after correction.

2. A method for correcting a multi-exposure motion image, comprising:

mapping a luminance of an extended frame using a function, indicating relationship between a reference frame and multiple extended frames to obtain a virtual frame;

calculating a global motion vector between the virtual frame and the reference frame;

correcting a pixel of the extended frame according to the global motion vector to obtain a first extended frame after correction;

detecting a pixel of the first extended frame according to the reference frame to obtain a local error pixel of the first extended frame;

calculating a luminance value range of the first extended frame; and

modifying a luminance value of the first extended frame to obtain a second extended frame after modification when the luminance value of the first extended frame is not within the luminance value range.

3. The method according to claim 2 , wherein correcting the luminance of the local error pixel of the first extended frame to obtain the second extended frame after luminance correction further comprises skipping modifying the luminance value of the first extended frame when the luminance value of the first extended frame is within the luminance value range.

4. The method according to claim 2 , wherein calculating the luminance value range of the first extended frame comprises:

obtaining a luminance value x of a pixel location of the first extended frame by using an inverse function of the luminance mapping function;

mapping the luminance value x to obtain an expected value fx; and

determining that the luminance value range of the first extended frame is [fx−ix, fx+ax] according to the luminance value x, the expected value fx, and an exposure relationship between the extended frame and the reference frame, wherein ix and ax are fixed limit constants.

5. The method according to claim 4 , wherein modifying the luminance value of the first extended frame to obtain the second extended frame after modification comprises modifying the luminance value of the first extended frame as the expected value fx.

6. The method according to claim 4 , wherein modifying the luminance value of the first extended frame to obtain the second extended frame after modification comprises modifying the luminance value of the first extended frame as a minimum value of absolute difference values between all values within the range [fx−ix,fx+ax] and the luminance value x.

7. The method according to claim 4 , wherein modifying the luminance value of the first extended frame to obtain the second extended frame after modification comprises modifying the luminance value of the first extended frame according to the following formula:

x

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=

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+

(

1

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x

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=

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(

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wherein the a is a weighting coefficient obtained by means of calculation, Thr is a closest expected value, β is a smooth control coefficient, x is a luminance value, and fx is an expected value, and ix and ax are fixed limit constants.

8. An apparatus for correcting a multi-exposure motion image, comprising:

a memory configured to store an instruction; and

a processor configured to execute the instruction stored in the memory so as to:

map a luminance of an extended frame using a function, indicating relationship between a reference frame and multiple extended frames to obtain a virtual frame;

calculate a global motion vector between the virtual frame and the reference frame;

correct a pixel of the extended frame according to the global motion vector to obtain a first extended frame after correction;

detect a pixel of the first extended frame according to the reference frame to obtain a local error pixel of the first extended frame;

calculate a luminance value range of the first extended frame; and

modify a luminance value of the first extended frame to obtain a second extended frame after modification when the luminance value of the first extended frame is not with the luminance value range.

9. The apparatus according to claim 8 , wherein the processor is further configured to execute the instruction stored in the memory so as to:

obtain a luminance value x of a pixel location of the first extended frame by using an inverse function of the luminance mapping function;

map the luminance value x to obtain an expected value fx; and

determine that the luminance value range of the first extended frame is [fx−ix, fx+ax] according to the luminance value x, the expected value fx, and an exposure relationship between the extended frame and the reference frame, wherein ix and ax are fixed limit constants.

10. The apparatus according to claim 9 , wherein the processor is further configured to execute the instruction stored in the memory so as to modify the luminance value of the first extended frame as the expected value fx.

11. The apparatus according to claim 9 , wherein the processor is further configured to execute the instruction stored in the memory so as to modify the luminance value of the first extended frame as a minimum value of absolute difference values between all values within the range [fx−ix, fx+ax] and the luminance value x.

12. The apparatus according to claim 9 , wherein the processor is further configured to execute the instruction in the memory so as to modify the luminance value of the first extended frame according to a formula, wherein the formula is:

x

′

=

a

*

Thr

+

(

1

-

a

)

*

x

a

=

min

⁡

(

1

,



Thr

-

x



/

β

)

Thr

=

{

fx

-

ix

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when

⁢

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x

<

fx

-

ix

fx

+

ax

⁢

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when

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x

>

fx

+

ax

,

wherein the a is a weighting coefficient obtained by means of calculation, Thr is a closest expected value, β is a smooth control coefficient, the x is a luminance value, fx is an expected value, and ix and ax are fixed limit constants.

13. The method according to claim 1 , further comprising calculating a luminance value range of the first extended frame.

14. The method according to claim 1 , further comprising modifying a luminance value of the first extended frame to obtain a second extended frame when the luminance value of the first extended frame is not within a luminance value range of the first extended frame.

15. The method according to claim 14 , further comprising skipping modifying the luminance value of the first extended frame to obtain the second extended frame when the luminance value of the first extended frame is within the luminance value range.

16. The method according to claim 1 , further comprising obtaining a luminance value x of a pixel location of the first extended frame using an inverse function of the luminance mapping function.

17. The method according to claim 16 , further comprising mapping the luminance value x to obtain an expected value fx.

18. The method according to claim 17 , determining that a luminance value range of the first extended frame is [fx−ix, fx+ax] according to the luminance value x, the expected value fx, and an exposure relationship between the extended frame and the reference frame, wherein ix and ax are fixed limit constants.

19. The method according to claim 17 , further comprising modifying the luminance value of the first extended frame as the expected value fx.

20. An apparatus for correcting a multi-exposure motion image, comprising:

a memory configured to store an instruction; and

a processor configured to execute the instruction stored in the memory so as to:

map a luminance of an extended frame by using a luminance mapping relationship between a reference frame and multiple extended frames to obtain a virtual frame;

calculate a global motion vector between the virtual frame and the reference frame;

correct a pixel of the extended frame in a pointer offset manner to obtain a first extended frame after correction when the global motion vector comprises a translational motion vector;

correct the pixel of the extended frame in an interpolation manner to obtain the first extended frame after correction when the global motion vector comprises the translational motion vector and a rotational motion vector;

detect a pixel of the first extended frame according to the reference frame to obtain a local error pixel of the first extended frame; and

correct a luminance of the local error pixel of the first extended frame to obtain a second extended frame after correction.