Patent FR-3002355-A1 (FR)
Title: Monitoring culture photosynthetic microalgae in photobioreactor, comprises capturing digital color image of culture of microorganisms, calculating color component of regions of image, and determining spatial distribution of color component
Inventor: SIALVE BRUNO
IPC: C12M1/34
Filed: 2013-02-18
Abstract: The method comprises capturing a digital color image (58) of culture of microorganisms using an image capturing device (2), calculating a color component of regions (8, 9) of the digital image, determining a spatial distribution of the color component in time and/or space area of the digital image, and analyzing the spatial distribution of the color component for detecting abnormality of the development of microorganism culture. The image capturing device is a digital camera or a digital still camera. The color component comprises luminance and chrominance. The method comprises capturing a digital color image (58) of culture of microorganisms using an image capturing device (2), calculating a color component of regions (8, 9) of the digital image, determining a spatial distribution of the color component in time and/or space area of the digital image, and analyzing the spatial distribution of the color component for detecting abnormality of the development of microorganism culture. The image capturing device is a digital camera or a digital still camera. The color component comprises luminance and chrominance. The calculating step comprises converting the information of the color area of the digital image to a luminance and chrominance color model. The calculating step comprises calculating a color component realized within the space of region of the digital image. The distribution determining step comprises recording a temporal evolution of the color component associated with a temporal indication of measurement in a memory. The distribution analyzing step comprises comparing the temporal evolution of the color component with temporal evolution of reference of the distribution of the color component, and calculating a derivative of the temporal evolution of the color component to detect an abnormality of culture development in response to a change of sign of the derivative with respect to time. The spatial distribution comprises a set of color component values corresponding to portions different from the region of the digital image. The analyzing step further comprises determining a standard deviation or a variance of the color component values, comparing the spatial distribution of the color component to the spatial distribution of reference, determining an average gradient of the spatial distribution of the color component, and comparing the mean gradient to a maximum allowable average gradient. The method further comprises determining cell density of the culture of microorganisms according to a luminance component of the image region, determining concentration of a pigment of the microorganism culture according to a chrominance component of the image region, detecting a settling or sedimentation of the culture in response to the result of the analysis of the spatial distribution of the component color, detecting formation of a biofilm or flocculation in the culture in response to the result of the analysis of the spatial distribution of the color component, and calibrating the color information. The calibrating step comprises selecting information of a color pattern in a reference area of the digital image, comparing the color pattern information with the color reference information, and changing the color depending on the result of the comparison. An independent claim is included for a device for monitoring of a culture of photosynthetic micro-organisms.