Definition
An automatic colony counter is an instrument used to automatically identify and count the number of colonies in a Petri dish. It realizes efficient counting of colonies through image acquisition and processing technology, replacing the traditional manual visual counting method, and is widely used in food, environment, agriculture and industrial microbial detection.
How it works:
The instrument works on the basis of digital image processing technology. First, high-resolution images of Petri dishes were obtained through the built-in illumination system and camera. Then, algorithms such as edge detection and threshold segmentation were used to distinguish colonies from background. Finally, the number of eligible colonies was automatically identified and counted through morphological analysis and feature extraction. Some instruments can filter colony size or color according to preset rules.
Measurement method
The standard measurement process includes the following steps: place the Petri dish on the instrument stage and initiate image acquisition; The system automatically focuses and acquires the image; image enhancement and segmentation by software algorithm; Users can adjust counting parameters as needed, such as setting the minimum or maximum colony diameter range; The instrument outputs the colony number and distribution report. The measurement process usually refers to the microbial counting guidelines in international standards such as ISO 7218 and relevant industry standards.
Influencing factors
Counting accuracy is influenced by a variety of factors. The transparency and scratches of the Petri dish may interfere with the image quality; Overlapping colonies or blurred edges can lead to recognition errors; Lighting uniformity affects image contrast; The degree of difference between the color of the medium and the color of the colony can also affect the segmentation effect. In addition, parameter settings such as threshold selection and size filtering range need to be adjusted according to the actual sample characteristics.
Applications:
The instrument is suitable for scenarios that require quantitative analysis of microorganisms. In the field of food processing, it is used to monitor the hygiene indicators of raw materials and finished products; In environmental monitoring, for the determination of the total number of colonies in water or air samples; In agricultural research, microbial load can be assessed on soil or crop surfaces; Industrial fields such as cosmetics or chemical products are also often used for microbiological quality control.
Selection considerations
When choosing an instrument, a number of parameters should be considered comprehensively. Image resolution affects the ability to recognize small colonies. The type of illumination system, such as ring light or diffused light, needs to match the characteristics of the sample; Software functions should support flexible parameter adjustment and data export formats. The throughput requirements determine the choice of manual single-dish processing or automatic multi-dish continuous scanning models; In addition, instrument calibration methods and compliance standard systems are also important references.