Measurement of volume of macaw palm fruit using traditional and the digital Moiré techniques

ABSTRACT The macaw palm crop has been studied because of its bioenergy potential due to the high oil yield, which is linked to fruit maturity stage. Digital images have been adopted as a contactless way to obtain information about fruit surface area and volume, acting as a sensor for quality control and the classification of fruits, based on physical aspects during the maturation stage. The aim of this study was to estimate the volume of macaw palm fruits from digital models obtained by the Moiré technique using only one camera, associated with digital image-processing tools to unwarp the images, allowing the comparison with conventional methods. The volumes obtained by the Moiré technique were compared with those obtained by water displacement method (WDM) and millet-seed displacement method (SDM). The results show that the volumes measured by the Moiré technique exhibited a mean error of 13.54% compared with the SDM, and 11.09% when compared to WDM, which indicates that the digital Moiré technique is a robust, low-cost tool to measure the volume of macaw palm fruits.

Moiré Techniques Based on Memory Function of Laser Scanning Microscope for Deformation Measurement at Micron/Submicron Scales

This paper presents two up-to-date moiré techniques for deformation measurement based on the memory function of a laser scanning microscope (LSM). The two techniques are the LSM overlapping moiré method and the LSM secondary moiré method. The formation principles and the measurement principles of these two methods are presented and compared to those of the traditional scanning moiré method for the first time. The applicable conditions and characteristics of these three moiré techniques are analyzed. Some typical moiré fringes on a strain gauge, carbon fiber reinforced plastics, a polyimide film, and a silicon wafer are illustrated. Our proposed LSM overlapping moiré method and LSM secondary moiré method are able to expand the application range of the LSM in deformation measurement to the micron and the submicron scales.