Algorithm for Estimating Length of Bent Objects

Abstract

A prototype algorithm was developed to measure the length of fish larvae, some of which were bent. The algorithm starts with the longest straight line spanning the object, then repeatedly segments the line as points are forced to lie along the center line of the object. There is less than 5% length improvement with the transition from four to eight line segments for objects with a general length/width ratio of about 10. Most improvements in length were of less than one pixel. Additional segmentation to 16 or more lines may be appropriate for objects with a greater ratio, but the number of segments should not exceed the length/width ratio. The algorithm logic can be transferred to other program languages and software packages for routine image analysis.