Determination of fish gender using fractal analysis of ultrasoud images

TY - JOUR

T1 - Determination of fish gender using fractal analysis of ultrasoud images

AU - McEvoy, Fintan

AU - Tomkiewicz, Jonna

AU - Støttrup, Josianne

AU - Overton, Julie L.

AU - McEvoy, Conni

AU - Svalastoga, Eiliv Lars

PY - 2009

Y1 - 2009

N2 - The gender of cod Gadus morhua can be determined by considering the complexity in their gonadal ultrasonographic appearance. The fractal dimension (DB) can be used to describe this feature in images. B-mode gonadal ultrasound images in 32 cod, where gender was known, were collected. Fractal analysis was performed on these images and DB was determined using the box counting method. A receiver-operating curve (ROC) was drawn for DB as a test for male fish. Using a range of DB values, the maximum accuracy for this test was calculated and compared with the accuracy for identifying male fish by subjective analysis alone. The mean (and standard deviation) of the fractal dimension DB for male fish was 1.554 (0.073) while for female fish it was 1.468 (0.061); the difference was statistically significant (P=0.001). The area under the ROC curve was 0.84 indicating the value of fractal analysis in gender determination in cod. Maximum accuracy (0.84) for DB as a test for male fish was obtained using the threshold value DB=1.5058 compared with an accuracy of 0.78 for subjective image evaluation. The use of two thresholds, DB<1.4475 (females) and DB>1.5054 (males) gives an 80% certainty in the classification result. Fractal analysis is useful for gender determination in cod. This or a similar form of analysis may have wide application in veterinary imaging as a tool for quantification of complexity in images

AB - The gender of cod Gadus morhua can be determined by considering the complexity in their gonadal ultrasonographic appearance. The fractal dimension (DB) can be used to describe this feature in images. B-mode gonadal ultrasound images in 32 cod, where gender was known, were collected. Fractal analysis was performed on these images and DB was determined using the box counting method. A receiver-operating curve (ROC) was drawn for DB as a test for male fish. Using a range of DB values, the maximum accuracy for this test was calculated and compared with the accuracy for identifying male fish by subjective analysis alone. The mean (and standard deviation) of the fractal dimension DB for male fish was 1.554 (0.073) while for female fish it was 1.468 (0.061); the difference was statistically significant (P=0.001). The area under the ROC curve was 0.84 indicating the value of fractal analysis in gender determination in cod. Maximum accuracy (0.84) for DB as a test for male fish was obtained using the threshold value DB=1.5058 compared with an accuracy of 0.78 for subjective image evaluation. The use of two thresholds, DB<1.4475 (females) and DB>1.5054 (males) gives an 80% certainty in the classification result. Fractal analysis is useful for gender determination in cod. This or a similar form of analysis may have wide application in veterinary imaging as a tool for quantification of complexity in images

U2 - 10.1111/j.1740-8261.2009.01568.x

DO - 10.1111/j.1740-8261.2009.01568.x

M3 - Journal article

SN - 1058-8183

VL - 50

SP - 519

EP - 524

JO - Veterinary Radiology and Ultrasound

JF - Veterinary Radiology and Ultrasound

IS - 5

ER -