Hey...I have some problem with conversion of thermal image from one temperature range to other range??

Hey... I hv a thermal image which pixels are mapped in range 17-42 degree celsius and i wanted it to map pixels of this image in range of 25-50 degree celcius ?? does anyone hav any idea how to do dis ???

thank u

[Walter Roberson]

What is the data representation? What value indicates 17 degrees? What value indicates 42? What value should indicate 25? What value should indicate 50? Is the relationship between data values and temperatures linear?