Methods of producing laser speckle contrast images

1. A method comprising:

obtaining a raw speckle image of a sample;

converting the raw speckle image to a laser speckle contrast image using a laser speckle contrast algorithm; and

converting the laser speckle contrast image to a relative correlation time image using a relative correlation time algorithm;

wherein the laser speckle contrast algorithm is a direct algorithm that uses the following formula:

k

=

s

I

〈

I

〉

=

∑

i

=

1

N

⁢

(

I

i

-

〈

I

〉

)

2

N

-

1

〈

I

〉

where speckle contrast k is equal to the standard deviation of time-integrated intensity s I divided by the mean time-integrated intensity (I) and where N is a positive integer.

2. A method comprising:

obtaining a raw speckle image of a sample;

converting the raw speckle image to a laser speckle contrast image using a laser speckle contrast algorithm; and

converting the laser speckle contrast image to a relative correlation time image using a relative correlation time algorithm;

wherein the laser speckle contrast algorithm is a sums algorithm that uses the following formula:

k

=

s

I

〈

I

〉

=

N

⁢

∑

i

=

1

N

⁢

I

i

2

-

(

∑

i

=

1

N

⁢

I

i

)

2

N

⁡

(

N

-

1

)

∑

i

=

1

N

⁢

I

i

N

where speckle contrast k is seen to be equal to the standard deviation of time-integrated intensity s I divided by the mean time-integrated intensity (I) and where N is a positive integer.

3. A method comprising:

obtaining a raw speckle image of a sample;

converting the raw speckle image to a laser speckle contrast image using a laser speckle contrast algorithm; and

converting the laser speckle contrast image to a relative correlation time image using a relative correlation time algorithm;

wherein the laser speckle contrast algorithm is a fast Fourier transform-based convolution algorithm that uses the following formula:

k

=

s

I

〈

I

〉

=

∑

i

=

1

N

⁢

(

I

i

-

〈

I

〉

)

2

N

-

1

〈

I

〉

where speckle contrast k is seen to be equal to the standard deviation of time-integrated intensity s I divided by the mean time-integrated intensity (I) and where N is a positive integer.

4. A method comprising:

obtaining a raw speckle image of a sample;

converting the raw speckle image to a laser speckle contrast image using a laser speckle contrast algorithm; and

converting the laser speckle contrast image to a relative correlation time image using a relative correlation time algorithm;

wherein the laser speckle contrast algorithm is a roll algorithm that uses the following formula:

k

=

s

I

〈

I

〉

=

N

⁢

∑

i

=

1

N

⁢

I

i

2

-

(

∑

i

=

1

N

⁢

I

i

)

2

N

⁡

(

N

-

1

)

∑

i

=

1

N

⁢

I

i

N

where speckle contrast k is seen to be equal to the standard deviation of time-integrated intensity s I divided by the mean time-integrated intensity (I) and where N is a positive integer.

5. A method comprising:

obtaining a raw speckle image of a sample;

converting the raw speckle image to a laser speckle contrast image using a roll algorithm that uses the following formula:

k

=

s

I

〈

I

〉

=

N

⁢

∑

i

=

1

N

⁢

I

i

2

-

(

∑

i

=

1

N

⁢

I

i

)

2

N

⁡

(

N

-

1

)

∑

i

=

1

N

⁢

I

i

N

where speckle contrast k is seen to be equal to the standard deviation of time-integrated intensity s I divided by the mean time-integrated intensity (I) and where N is a positive integer; and

converting the laser speckle contrast image to a relative correlation time image using a relative correlation time algorithm.

6. The method of claim 5 wherein the relative correlation time algorithm is a Newton method algorithm, a table method algorithm, a hybrid method algorithm, or an asymptote method algorithm.

7. The method of claim 5 wherein converting the raw speckle image to a laser speckle contrast image occurs at a rate greater than or equal to 100 images per second.

8. The method of claim 5 wherein converting the laser speckle contrast image to the relative correlation time image occurs at a rate greater than or equal to 200 images per second.