# A Novel Breast-Volume Self-Measurement Method with Improved Convenient and Accuracy
## 4 Discussion  
The primary finding of this study is that the proposed self-measurement method for breast volume achieved a relative error of only 3.8%, demonstrating superior accuracy compared to traditional methods, including 3D scanning (4.8%) and conventional volume equations (86.3%). This high accuracy indicates that the method provides reliable breast  
Figure 11: Calculation result of volume. Figure 10: Schematic diagram of partial elliptical cones in the right and left regions. volume data, making it a practical solution for applications in bra sizing, personal health monitoring, and body image assessments. This study introduces an innovative approach for self-measuring breast volume, utilizing a new volume calculation formula based on a geometric approximation model that combines irregular ellipsoids and elliptical cones. Accurate breast measurements are essential for proper bra sizing, as they form a foundational basis for lingerie design and production. To optimize the model's accuracy, five key measurement parameters were selected, including upper-cup vertical distance, lower-cup vertical distance, front-cup arc distance, side-cup arc distance, and breast height. The proposed method thus stands out in terms of accuracy, ease of use, and applicability. The analysis shows that the specimen drainage method, considered the \"gold standard\" for breast-volume measurement, involves immersing breast specimens in a water-filled container and calculating the displaced water volume to determine breast volume. Due to its fixed sample nature, this method offers high repeatability, but is impractical for daily measurements, making it somewhat limited [34]. Additionally, breast morphology changes are equally important for breast shape analysis, not just absolute volume data [35]. In this study, the defined breast-shape characteristics primarily assess both breast volume (size) and breast shape features (length, width, height, position, and other shape parameters). The combined measurement of breast volume and shape features is also a key indicator for assessing bilateral breast asymmetry [36; 37], allowing for a complete evaluation of the overall breast shape. These findings align with previous studies that evaluated breast volume, shape, and surface area [38]. Although 3D scanning provides accurate measurements, it is expensive and cannot directly capture breast volume, with limitations in detecting finer details [39]. Furthermore, most scanning devices used for human measurement rely on laser technology, which may pose potential risks if used improperly [40], and each scan can be costly [41]. These factors restrict the use of 3D scanning in routine human measurements. Unlike the complex and expensive 3D scanning technology, this new method simplifies breast-volume measurement, reducing the need for specialized equipment and enhancing the feasibility of self-assessment. This study developed a novel breast shape-measurement tool based on the newly proposed breast-volume measurement method, which has been granted a Chinese patent (Patent No. : ZL 2022 1 0831873.1). The tool is wearable, and its measurement parameters are derived from the method proposed in this research, focusing on key breast dimensions such as circumference (underbust), length (upper-bust vertical distance, lower-bust arc distance), width (anterior-bust arc distance, lateral-bust arc distance), and height (breast height). These parameters are used to calculate breast volume and assess bilateral breast asymmetry. To ensure the accuracy of self-measurement, the tool includes a standard operating procedure. Additionally, a WeChat mini-program (v. 8.0.53) has been developed to enable efficient data recording, conversion, and analysis when using the new breast shape-measurement tool. This study also highlights the relationship between breast volume and women's psychological health and body image. Previous research has shown that body measurements and body shape perception significantly impact women's self-awareness and psychological well-being [42].