Method of differentiating microbial colonies in an image
A method of identifying microbial colonies in a culture device is provided. The method comprises using an imaging device to produce a first image of a thin film culture device while providing illumination to a front side of the device and to produce a second image of the thin film culture device while providing illumination to a back side of the device. The method further comprises analyzing the first and second images to identify microorganism colonies in each image, analyzing the first and second images values of a size parameter for a colony at a particular location in the culture device, and comparing the values. The method can be used to differentiate and count at least two colony types.
1. A non-transitory computer readable medium comprising computer readable instructions that, when executed by a processor, cause a culture plate scanning system comprising the processor to:
obtain a first image of a thin film culture device, wherein the first image is produced while illuminating the device with a first ratio of front-side illumination to back-side illumination;
obtain a second image of the thin film culture device, wherein the second image is produced while illuminating the device with a second ratio of front-side illumination to back-side illumination that is lower than the first ratio;
analyze the first and second images to identify microorganism colonies in each image;
analyze the first image to calculate a first value of a size parameter for a colony at a particular location in the culture device;
analyze the second image to calculate a second value of the size parameter at the particular location in the culture device; and
compare the first value to the second value.
2. The non-transitory computer readable medium of claim 1 further comprising computer readable instructions that, when executed in the processor cause the system to use the first or second image to count a number of microorganism colonies in the culture device.
3. The non-transitory computer readable medium of claim 1 further comprising computer readable instructions that, when executed in the processor, cause the system to classify the colony at the particular location as a colony belonging to a microorganism group.
4. The non-transitory computer readable medium of claim 3 further comprising computer readable instructions that, when executed in the processor, cause the system to count a number of colonies belonging to the microorganism group.
5. The non-transitory computer readable medium of claim 4 further comprising computer readable instructions that, when executed in the processor, cause the system to use the first and second image to count a number of colonies that belong to a first group and count a number of colonies that belong to a second group.