Thermography is a non-invasive technique that does not require physical contact with the substance, and it can be applied for the studies without causing physical damage or any contamination to the study object. This study aimed using non-invasive thermal imaging technique to assess fruit ripeness and convective & radiative heat transfer coefficients of human body during a physical exercise. For the fruit ripeness estimation, four uniform-sized, unripe, avocado, kiwi, and peach were chosen with the same skin texture, color, and firmness. Four batches of fruits with four fruits in a batch were included in the study. Thermal images of these fruits were captured using a thermal camera for three consecutive days at a specific time under the same environmental conditions. The thermal images show that the temperature of fruits increases along with their ripeness level during ripening which happens due to the respiration of the fruits. Thermography was also applied to measure the convective and radiative heat transfer coefficients and compared with the overall calculated radiative heat transfer coefficients and the ASHRAE handbook values. In this study, the human models were allowed to run on a treadmill with a range of speeds starting from 2 miles/hour to 10 miles/hour for stretch of thirty minutes. The recovery process included a fan-assisted cooling with an air velocity of 1.5 m/s for 30 minutes. Thermal images were taken for elbow, forehead, hands, and legs of the models and the convective heat transfer coefficient and radiative heat transfer coefficient were calculated. The human models included both male and female and belonged to two different age groups of less than 15 and above 40 with a total of 24 participants. This work demonstrates that thermal imaging technique is a preferable and non-invasive one that could be used for various applications.