Submitted to: Transactions of the ASAE
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/13/2004
Publication Date: 2/23/2005
Citation: Peng, Y., Lu, R. 2005. Modeling multispectral scattering profiles for predction of apple fruit firmness. Transactions of the ASAE. Volume 48(1): 235-242. Interpretive Summary: Firmness is a key quality attribute in determining consumer acceptance and satisfaction with apple fruit. Nondestructive sensing technology would provide the fruit industry with a means to deliver superior, consistent fruit to the marketplace. This research was to develop a mathematical model to describe light scattering profiles acquired from apple fruit by using our newly developed multispectral imaging system and relate model parameters to fruit firmness. Results demonstrated that the proposed mathematical model accurately described light scattering profiles from apple fruit and could be used to predict fruit firmness. Relatively good firmness predictions were obtained with the correlation coefficient (r) of 0.82 and the standard error (SE) of 6.2 N for apples from one test and r=0.76 and SE=6.0 N for the other test. The model will be incorporated into our prototype fruit internal quality sensing system for real time grading of apples and other tree fruits. U.S. apple industry produces more than 10 billion pounds of apples annually with the farm gate value of more than $1.5 billion. The technology under development in this research will enable the fruit industry to deliver premium quality fruit to the consumer and thus improve industry competitiveness and profitability.
Technical Abstract: Nondestructive measurement of fruit firmness would allow the fruit industry to deliver superior fruit to the marketplace and assure consumer acceptance and satisfaction. The objective of this research was to develop mathematical models to describe the relationship between fruit firmness and multispectral scattering in apples. Scattering images were acquired from Red Delicious apples using two different multispectral imaging systems at wavelengths 680 nm, 880 nm, 905 nm and 940 nm. Radial scattering profiles were accurately described by the Lorentzian distribution function with three independent profile parameters. Firmness prediction models were constructed using multi-linear regression against twelve Lorentzian parameters for four wavelengths and were verified with separate sets of apple fruit. The prediction models were able to give good firmness predictions with the correlation coefficient (r) of 0.82 and the standard error for validation (SEV) of 6.39 N for one set of apple samples, and r = 0.76 and SEV = 6.01 N for another set.