WHITEPAPER – Machine Vision for Liquid Level Detection

September 29, 2016 - Embedded Machine Vision, Fixed Mount Machine Vision, Industry News, JADAK News, Machine Vision, Machine Vision, Machine Vision Services, Machine Vision Software, News, Product News


Advances in Embedded Medical Machine Vision for Liquid Level Detection

Improving Quality of Result and Time to Result in Clinical Diagnostic Testing

Machine Vision for Liquid Level PDF Icon-01By Robert Geiger, Senior Systems Engineer

Test TubeLiquid level detection is a process used in clinical diagnostics to verify reagents or sample containers in order to assist performance of various tests and ensure accurate results. There are several methods used today to measure liquid level and each come with a unique set of advantages and disadvantages. A primary challenge is how to perform these tests in a way that does not disturb the contents of the container. Foreign objects coming in to contact with a container, i.e. probes or other system equipment. Any contact with the container can lead to sample contamination, slower time to result and ultimately a less accurate analysis. Due to recent advances in embedded smart cameras and image processing technology, machine vision has become an effective technique regardless of container type, i.e. test tube, cuvettes, pipette tips or ampoules.

In this paper, we will outline the various techniques used today with a particular focus on the advantages of embedded machine vision and image analysis.


Plenty of clinical systems in the field today use capacitive, ultrasonic, pressure and even weight to determine the level or volume of a liquid. Many of these methods can be very effective, but each have limitations depending on the application needs and requirements.

Other methods require that the sensor have an open path to the top of the liquid.

Capacitive sensors are yet another technique used for liquid level detection, but are known to be less accurate than other methods.


SC-6LOf the potential methods mentioned above, embedded medical machine vision is emerging as a front-running technology for determining liquid level. As previously mentioned, no technique is without limitations, but machine vision is fast becoming recognized as a uniquely versatile, non-invasive and efficient approach.

Other advantages of a machine vision system include the ability to determine volume based on the liquid level of different types of containers.

In addition, image based systems afford users the ability to determine layers within the sample.

In some cases a biological sample would need to be agitated as part of the process. This can result in a liquid sample that contains a large amount of bubbles or foam on the top of the sample. Embedded machine vision systems can be engineered to distinguish these occurrences from the coherent liquid layer and, if required, report that back to the system for further analysis.


Undoubtedly, the most unique and advantageous aspect of a vision-based system is that it takes a picture of the sample being analyzed. Beyond basic liquid level and volume, machine vision and image analysis can provide lab technicians with even more details about a given sample in real-time, including:

  • Meniscus shape to give an indication of the characteristics of the sample
  • Color of the sample or individual layers
  • Illumination intensity to determine reaction process over time
  • Verification and tracking by 1D/2D barcodes
  • Container morphology and volume calculations
  • Images can be saved for archival purposes


To learn more about embedded medical machine vision and image analysis for your next project, contact JADAK to schedule a consultation.


Headquartered in Syracuse, NY, JADAK, LLC supports medical device manufacturers by delivering integrated camera based technologies and image analysis software for machine vision applications, RFID technologies for surgical tracking and reagent anti-counterfeiting measures, as well as Chart Recorders for EKG and Patient Monitors.

JADAKs line of micro-spectrometer products (SM Series) are ideal for embedded spectroscopy applications and are supported by JADAK’s industry leading engineering team providing integration and customer specific design services.

[1] https://www.jadaktech.com/products/magnetic-stripe-readers/smm-1400-spectrometer-module/

[2] http://chemwiki.ucdavis.edu/Core/Analytical_Chemistry/Analytical_Chemistry_2.0/10_Spectroscopic_Methods

[3] http://www.bravo-bruker.com/pdf/BRAVO_Brochure_EN.pdf, N.B. No trademark usage is indicated for the use of BRAVO, an acronym for Bruker Raman Verification Optics.


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