ImageStatistics node
This documentation is for version 1.0 of ImageStatistics (net.sf.openfx.ImageStatistics).
Description
Compute image statistics over the whole image or over a rectangle. The statistics can be computed either on RGBA components, in the HSVL colorspace (which is the HSV colorspace with an additional L component from HSL), or the position and value of the pixels with the maximum and minimum luminance values can be computed.
The color values of the minimum and maximum luma pixels for an image sequence can be used as black and white point in a Grade node to remove flicker from the same sequence.
Inputs
Input 
Description 
Optional 

Source 
No 
Controls
Parameter / script name 
Type 
Default 
Function 

Restrict to Rectangle / 
Boolean 
On 
Restrict statistics computation to a rectangle. 
Bottom Left / 
Double 
x: 0 y: 0 
Coordinates of the bottom left corner of the rectangle 
Size / 
Double 
w: 1 h: 1 
Width and height of the rectangle 
HiDPI / 
Boolean 
Off 
Should be checked when the display area is HighDPI (a.k.a Retina). Draws OpenGL overlays twice larger. 
Auto Update / 
Boolean 
On 
Automatically update values when input or rectangle changes if an analysis was performed at current frame. If not checked, values are only updated if the plugin parameters change. 
Interactive Update / 
Boolean 
Off 
If checked, update the parameter values during interaction with the image viewer, else update the values when pen is released. 
Min. / 
Color 
r: 0 g: 0 b: 0 a: 0 
Minimum value. 
Max. / 
Color 
r: 0 g: 0 b: 0 a: 0 
Maximum value. 
Mean / 
Color 
r: 0 g: 0 b: 0 a: 0 
The mean is the average. Add up the values, and divide by the number of values. 
S.Dev. / 
Color 
r: 0 g: 0 b: 0 a: 0 
The standard deviation (S.Dev.) quantifies variability or scatter, and it is expressed in the same units as your data. 
Skewness / 
Color 
r: 0 g: 0 b: 0 a: 0 
Skewness quantifies how symmetrical the distribution is.
• A symmetrical distribution has a skewness of zero.
• An asymmetrical distribution with a long tail to the right (higher values) has a positive skew.
• An asymmetrical distribution with a long tail to the left (lower values) has a negative skew.
• The skewness is unitless.
• Any threshold or rule of thumb is arbitrary, but here is one: If the skewness is greater than 1.0 (or less than 1.0), the skewness is substantial and the distribution is far from symmetrical.

Kurtosis / 
Color 
r: 0 g: 0 b: 0 a: 0 
Kurtosis quantifies whether the shape of the data distribution matches the Gaussian distribution.
•A Gaussian distribution has a kurtosis of 0.
•A flatter distribution has a negative kurtosis,
•A distribution more peaked than a Gaussian distribution has a positive kurtosis.
•Kurtosis has no units.
•The value that this plugin reports is sometimes called the excess kurtosis since the expected kurtosis for a Gaussian distribution is 0.0.
•An alternative definition of kurtosis is computed by adding 3 to the value reported by this plugin. With this definition, a Gaussian distribution is expected to have a kurtosis of 3.0.

Analyze Frame / 
Button 
Analyze current frame and set values. 

Analyze Sequence / 
Button 
Analyze all frames from the sequence and set values. 

Clear Frame / 
Button 
Clear analysis for current frame. 

Clear Sequence / 
Button 
Clear analysis for all frames from the sequence. 

HSVL Min. / 
Color 
h: 0 s: 0 v: 0 l: 0 
Minimum value. 
HSVL Max. / 
Color 
h: 0 s: 0 v: 0 l: 0 
Maximum value. 
HSVL Mean / 
Color 
h: 0 s: 0 v: 0 l: 0 
The mean is the average. Add up the values, and divide by the number of values. 
HSVL S.Dev. / 
Color 
h: 0 s: 0 v: 0 l: 0 
The standard deviation (S.Dev.) quantifies variability or scatter, and it is expressed in the same units as your data. 
HSVL Skewness / 
Color 
h: 0 s: 0 v: 0 l: 0 
Skewness quantifies how symmetrical the distribution is.
• A symmetrical distribution has a skewness of zero.
• An asymmetrical distribution with a long tail to the right (higher values) has a positive skew.
• An asymmetrical distribution with a long tail to the left (lower values) has a negative skew.
• The skewness is unitless.
• Any threshold or rule of thumb is arbitrary, but here is one: If the skewness is greater than 1.0 (or less than 1.0), the skewness is substantial and the distribution is far from symmetrical.

HSVL Kurtosis / 
Color 
h: 0 s: 0 v: 0 l: 0 
Kurtosis quantifies whether the shape of the data distribution matches the Gaussian distribution.
•A Gaussian distribution has a kurtosis of 0.
•A flatter distribution has a negative kurtosis,
•A distribution more peaked than a Gaussian distribution has a positive kurtosis.
•Kurtosis has no units.
•The value that this plugin reports is sometimes called the excess kurtosis since the expected kurtosis for a Gaussian distribution is 0.0.
•An alternative definition of kurtosis is computed by adding 3 to the value reported by this plugin. With this definition, a Gaussian distribution is expected to have a kurtosis of 3.0.

Analyze Frame / 
Button 
Analyze current frame as HSVL and set values. 

Analyze Sequence / 
Button 
Analyze all frames from the sequence as HSVL and set values. 

Clear Frame / 
Button 
Clear HSVL analysis for current frame. 

Clear Sequence / 
Button 
Clear HSVL analysis for all frames from the sequence. 

Luminance Math / 
Choice 
Rec. 709 
Formula used to compute luminance from RGB values.
Rec. 709 (rec709): Use Rec. 709 (0.2126r + 0.7152g + 0.0722b).
Rec. 2020 (rec2020): Use Rec. 2020 (0.2627r + 0.6780g + 0.0593b).
ACES AP0 (acesap0): Use ACES AP0 (0.3439664498r + 0.7281660966g + 0.0721325464b).
ACES AP1 (acesap1): Use ACES AP1 (0.2722287168r + 0.6740817658g + 0.0536895174b).
CCIR 601 (ccir601): Use CCIR 601 (0.2989r + 0.5866g + 0.1145b).
Average (average): Use average of r, g, b.
Max (max): Use max or r, g, b.

Max Luma Pixel / 
Double 
x: 0 y: 0 
Position of the pixel with the maximum luma value. 
Max Luma Pixel Value / 
Color 
r: 0 g: 0 b: 0 a: 0 
RGB value for the pixel with the maximum luma value. 
Min Luma Pixel / 
Double 
x: 0 y: 0 
Position of the pixel with the minimum luma value. 
Min Luma Pixel Value / 
Color 
r: 0 g: 0 b: 0 a: 0 
RGB value for the pixel with the minimum luma value. 
Analyze Frame / 
Button 
Analyze current frame and set min/max luma values. 

Analyze Sequence / 
Button 
Analyze all frames from the sequence aand set min/max luma values. 

Clear Frame / 
Button 
Clear luma analysis for current frame. 

Clear Sequence / 
Button 
Clear luma analysis for all frames from the sequence. 