Temperature offset is a correction value that can be added to each pixel of an analysis object (image, point, line, or area). Offset value can be a constant or a calculated value defined by a script.

To set temperature offset right click on an analysis object (or empty space in the image to apply temperature offset to image). In the context menu select 'Temperature Offset'.

4 Temperature offset script 5 Temperature offset script

These script types are supported:

1.Table

2.Reference (correction by a black body)

Table script

Table script allows to read another analysis object value and adjust temperature offset depending on that value. Dependency between object value and offset value is defined by a table - several "object value to offset value" pairs.

Syntax:

table [linear] <measurement> <value_pair> <value_pair>...

 <measurement>: area|point|line <object_index> min|max|avg|val

 <value_pair>: <measurement_value> : <offset_value>

 

linear: When 'linear' is specified, calculated offset value will be linearly 

        interpolated using two closest entries from the table. When 'linear' is 

        not defined the offset value from the table is used unchanged as it is 

        defined for the corresponding range.

 

<measurement>: defines the analysis object (area, point or line) and its measurement 

               (min, max, avg or val) to be used as the control value. Please pay

               attention that points as well as lines and areas are indexed by 

               numbers (1,2,..), not by letters.

 

<value_pair>...: at least two "measurement:offset" pairs; values in each pair are 

                 separated by colon.

 

example: table point 2 val 40:5 50:0 60:-5

 

Point B value

Offset

Below 40

5

40 to 50

5

50 to 60

0

60 and above

-5

 

Reference script (correction by a black body)

Reference script can be used to correct camera reading drift if you have an object on the image with known temperature (usually a black body).

Syntax:

reference area|point|line <object_index> min|max|avg|val <reference_value>

 

Define analysis object (area, point or line) with index and its measurement (min, 

max, avg or val) to be used as the control value. Please pay attention that point 

objects are also indexed by numbers (1,2,..), not by letters.

 

<reference_value>: value that will be compared with the value measured by the camera

                   and used in the correction formula.

 

example: reference point 2 val 50

 

Meaning: point B measured value should be 50, if it is not, apply a correction to 

the measured signal so that point B value becomes 50.

In case of reference script, offset is applied to the measured camera signal, not to the temperature value. In simplified form, formula can be written as:

Offset = U(Treference) - Umeasured

Tcorrected = T(Umeasured + Offset)

where U is energy detected by camera sensor.

This provides proper compensation for objects with different emissivity factors.