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Camera on Vessel: A Camera-Based System to Measure Change in Water Volume in a Drinking Glass
Idowu Ayoola1, Wei Chen2, Loe Feijs3
1Designed Intelligence, Department of Industrial Design, Technische Universiteit Eindhoven, The Netherlands. i.b.i.ayoola@tue.nl.
Insights
This study developed a smart device to monitor patient fluid intake, crucial for managing chronic conditions like heart failure. The system accurately estimates water levels in a conical glass using image processing, aiding patient compliance with fluid restrictions.
Area of Science:
- Biomedical Engineering
- Medical Device Technology
- Image Processing
Background:
- Patient non-compliance with lifestyle changes and medical advice is a major challenge in chronic disease management.
- Heart failure and hemodialysis patients require strict fluid restrictions due to hemodynamic instability.
- Effective management of fluid imbalance necessitates monitoring intake, retention, and excretion for early intervention.
Purpose of the Study:
- To develop a smart device for monitoring patient drinking activities.
- To accurately infer real-time water levels and volume in a conical glass.
- To support adherence to fluid restrictions in patients with chronic health conditions.
Main Methods:
- An empirical approach using a low-resolution camera and Arduino microcontroller.
- Image processing in MATLAB, including Sobel filtering for level gradient extraction.
- Ellipsoidal fitting to estimate cup size and least-squares criterion for measurement fitting.
Main Results:
- Accurate estimation of water level and volume in a conical glass.
- Low covariance between estimated measurements and the mean.
- A low variation of 3% from the ground truth in estimated results.
Conclusions:
- The developed smart device can effectively monitor fluid intake.
- The image processing method provides accurate water level and volume estimations.
- This technology can aid in managing fluid balance for patients with chronic diseases, improving compliance.
Abstract:
A major problem related to chronic health is patients' "compliance" with new lifestyle changes, medical prescriptions, recommendations, or restrictions. Heart-failure and hemodialysis patients are usually placed on fluid restrictions due to their hemodynamic status. A holistic approach to managing fluid imbalance will incorporate the monitoring of salt-water intake, body-fluid retention, and fluid excretion in order to provide effective intervention at an early stage. Such an approach creates a need to develop a smart device that can monitor the drinking activities of the patient. This paper employs an empirical approach to infer the real water level in a conically shapped glass and the volume difference due to changes in water level. The method uses a low-resolution miniaturized camera to obtain images using an Arduino microcontroller. The images are processed in MATLAB. Conventional segmentation techniques (such as a Sobel filter to obtain a binary image) are applied to extract the level gradient, and an ellipsoidal fitting helps to estimate the size of the cup. The fitting (using least-squares criterion) between derived measurements in pixel and the real measurements shows a low covariance between the estimated measurement and the mean. The correlation between the estimated results to ground truth produced a variation of 3% from the mean.
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