Introduction
Using methods of obtaining information by a non-invasive method in the aquatic environment is in demand and is constantly used in all sectors of aquaculture. In biology, we often estimate the state of the object by its color. The classical spectrophotometric methods have a disadvantage of the point measurement , where only small area of the fish skin could be evaluated . Such method is invasive , since there is a direct contact. The correctly set camera could give a valuable color characteristic
across the whole fish body, if image processing methods are applied . Proper light and camera calibration are two related , but separated tasks . To improve the measurement acquisition , we developed a simple device, a box or chamber , with standardized light conditions , automatic camera calibration , environmental sensors , weighting scale , and software applications for color analysis and evaluation.
Materials and Methods
The existing methods for the white balance were mostly developed for the corrections of the image taken with the incorrect settings. However, they are general enough to work directly on camera setting. Since the amount of light from the LEDs illumination is suffcient, two simplest methods of white balance algorithms could be used, the Retinex method, and GrayWorld method.
The captured images could be easily analysed with the software application for the segmentation (fish to background), color transformations and characteristics (sRGB , cRGB , LAB, HSV), image and set characteristics. The segmentation and color analysis is tuning automatically the parameters and thresholds.
Results and Discusion
The camera is calibrated automatically, using described methods. The standard color checker chart was used for the comparison of white balance calibration.
The device is standardizing the condition for the color measurements , automatically setup the camera parameters as white balance, brightness , and contrast to allows accurate color analysis from the captured images . The devise is easy to use, without advance user operation . It is connected with the analysing software for the segmentation , color transformation , and statistic . The device should help with the data aquisition as well as the analysis , comparison , and color evaluation.
Acknowledgment
The study was _supported by the Ministry of Education , Youth and Sports of the Czech Republic - project CENAKVA (LM 2018099), the CENAKVA Centre Development (No:CZ:1:05/2:1:00/19: 0380) and project Biodiversity CZ:02:1:01:/0:0/0: 0/16/025/0007370), as well as TACR GAMA (TG 03010027 PoC02_ 23) and by the GAJU 017/2016/Z. This project also received funding from the European Union’ s Horizon 2020 research and innovation programme under grant agreement N° 871108 (AQUAEXCEL3.0). This output reflects only the author’s view and the European Union cannot be held responsible for any use that may be made of the information contained therein
References
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