Water status detection by thermal imaging, is a non-invasive and rapid assessment method, It provides great potential to improve irrigation planning. In this study the application of thermal imaging through mobile phones was used to assess crop water stress in tomato under three different irrigation treatments: soil moisture based irrigation using a TDR, crop water requirement based irrigation (CWR) and farmer practice (FP). Canopy temperature was determined by averaging several individual sample leaf temperatures from plant based thermal images. Relative differences between treated and non-treated leaves were used to calculate (CWSI) and stomatal conductance (sc). Crop water stress indices (CWSI) and canopy temperature varied diurnally with highest values captured during mid-day which corresponded to a higher soil moisture deficit. Stomatal conductance (sc) was high at low CWSI and reduced with increasing CWSI. Higher correlation was found between CWSI and stomatal conductance depend on diurnal and physiological stage of the crop R2 = 86 in TDR, R2 = 0.84 in CWR and R2 = 0.75 in farmer practice treatments at noon. In addition a high correlation between CWSI and yield indicate that the thermograph can predict yield. The measurement of canopy temperature in morning and noon were taken to study the effect of time on image acquisitions and it was found that at noon (1:00 pm up to 3:00pm) was the most appropriate time. The result could assist in designing precision irrigation scheduling for setting the threshold values.