Abstract:The body dimension parameters of livestock play a crucial role in various fields such as animal selection breeding, health monitoring, and genetic studies of performance. The automatic measurement of these parameters represents an important research direction in digital agriculture. Relied on a dual-depth camera measurement system to collect point cloud data of live pigs and aimed to develop an algorithm capable of automatically identifying and extracting pig feature points, feature surfaces, and body dimension parameters. Given that pig point cloud data often contain significant noise issues, a filtering algorithm with multiple filters stacked was innovatively proposed, in contrast to traditional single-filter methods. To achieve automatic detection of pig feature points and surfaces, an algorithm for automatically extracting feature points was proposed based on the convexity and concavity of side and top-view contour lines, and an algorithm for automatically extracting feature surfaces based on the trend of trunk cross-sectional area changes, differing from approaches that calculated feature points from a single perspective. Addressing the limitations of existing body dimension parameters in terms of variety and fitting accuracy, totally 17 body dimension parameters and 12 common shape factors from pig point cloud data were successfully automatically extracted. To validate the effectiveness of the algorithm, a detailed analysis of 200 sets of point cloud data from 20 live pigs was conducted. Experimental results showed that the average total filtering error was 3.84%, and under the condition that the original point cloud accuracy reached 0.036mm, the average measurement error of pig body dimension parameters was only 2.46%. Additionally, a principal component-based weight analysis on the 17 geometric parameters and 12 shape factors of pigs was conducted, discussing the weights of different body dimension parameters and shape factors in pig geometric morphology analysis. In summary, the research result can provide an effective method for high-throughput measurement of animal three-dimensional phenotypic parameters, not only improving measurement accuracy and efficiency but also providing strong support for in-depth research in fields such as animal selection breeding and health monitoring.