Assessment of apple bruise resistance under transient collisions through X-ray computed tomography and image processing

To evaluate the resistance of apples to bruising under transient impact loads, a pendulum device was initially employed to gather collision data. Subsequently, an image acquisition and processing system was utilised to compute the apple surface bruise area, and X-ray computed tomography technology was utilised to precisely calculate the bruise volume. Based on the CT image and bruise area image analysis, the difference between bruised area and normal tissue on the apple after collision, and effects of impact energy on apple bruising volume and bruise area has been elaborated in detail. Results analysis revealed a general increase in both bruise volume and bruise area with escalating impact energy, and there is a strong correspondence between bruise volume and bruise area across different storage days and impact energies. The relationship between bruise volume and bruise area under different storage duration were also established. On the base of bruise resistance index (BRI) model utilising impact energy and bruise volume as variables, those analysis led to the establishment of a new bruise resistance index (BRI*) model employing impact energy and bruise area as independent variables. The effectiveness of BRI* model in assessing apple bruise resistance was demonstrated by comparing the corresponding relative error for bruise thresholds of BRI and BRI* under the same condition. The relative error ≤3.3% underscores the accuracy of the new model and proves the proposed BRI* model to be an efficient and rapid tool for assessing the degree of apple bruising.