ReviewVisual quality detection of aquatic products using machine vision
Introduction
Nowadays, aquatic products have received great popularity because of their high nutritive value and delicious taste. When consumed, their quality would determine their value, price and “best-used-before” date (Sun, 2011). The quality may be presented as appearance, odor, flavor and texture. Appearance attributes, such as size, shape and color, are assigned to visual quality (Alasalvar et al., 2011). These attributes directly influence the products’ acceptance and thus affect most consumers’ purchase trends consciously or subconsciously. Therefore, detecting these attributes is of great significance for better purchase decision and higher economic value.
Traditionally, visual quality detection is predominantly done by trained inspectors, which is labor-costing, time consuming, and difficult to quantify (Balaban et al., 2008). Manual processing and grading is inevitably influenced by human factors such as mistakes, occasional omission in processing as well as fatigue (Mathiassen et al., 2006). Alternatively, machine vision can provide fast, objective and robust measurement (Brosnan and Sun, 2002). Machine vision has been widely applied for quality assurance purposes in different industries (Gümüş et al., 2011). While, the aquaculture industry is a low technology industry for most activities started out in the natural way (Balchen, 1986). Machine vision still has not achieved a common utilization in aquaculture (Zion, 2012). This review described applications of this technology in visual quality detection of some aquatic products, including fishes, shrimp, oyster and scallop. These aquatic products have been studied by many researchers through measuring size, shape, and color parameters using various machine vision systems and methods. The objective of this review is to highlight development in detection methods, machine vision systems, image analysis and processing approaches, and analyzes its characteristics, so as to unlock the potential application of machine vision in aquaculture.
Section snippets
Machine vision system
Machine vision is a novel technology for recognizing objects, extracting and analyzing quantitative information from digital images. A typical machine vision system (MVS) often consists of an image acquisition system, image processing and statistical analysis procedures as shown in Fig. 1. Essential elements of an image acquisition system include: a camera, an illumination device, a frame-grabber, and a computer. Images are processed via pre-treatment, segmentation, and feature extraction (
Visual quality detection based on size and shape measurement
Visual quality detection, for the seek of sorting, grading, counting and species classification of aquatic products, was mainly based on measurement of size (i.e. length, area, volume, width, height and so on) and shape. In this section, methods and systems for size and shape measurement were reviewed for several application fields including fishes, shrimp, scallop and oyster.
Visual quality detection based on color analysis
Color is an important visual quality criteria of many products. It contains the basic information corresponding to human vision (Dowlati et al., 2012) and is closely related to consumer perception. Consumers usually tend to associate color with freshness, high quality and better flavor (Gormley, 1992). Color can be measured subjectively by sensory panels, which, however, is difficult to convert to reproducible numerical values (Balaban, 2008). Color can also be determined by instrumental
Discussion and conclusions
This paper reviewed the applications of machine vision and associated technologies in visual quality detection of aquatic products. After years of development, machine vision technology has been improved along with progress of cameras, illumination systems, design of the light box, and also image analysis methods. Parameters used for size measurement ranged from length to area, perimeter, width and heights on the purpose of sorting and grading, and species classification. For color measurement,
Acknowledgements
We thank the National Key Technologies R&D Program of China (2012BAD29B04) for funding of this project. The research was supported by the Program for Zhejiang Leading Team of S&T Innovation (2011R50029).
References (79)
- et al.
Development and application of The Two Image method for accurate object recognition and color analysis
J. Food Eng.
(2012) - et al.
Inspection and grading of agricultural and food products by computer vision systems – a review
Comput. Electron. Agric.
(2002) - et al.
Improving quality inspection of food products by computer vision –– a review
J. Food Eng.
(2004) - et al.
Extracting fish size using dual underwater cameras
Aquacult. Eng.
(2006) - et al.
A dual camera system for counting and sizing Northern Bluefin Tuna (Thunnus thynnus; Linnaeus, 1758) stock, during transfer to aquaculture cages, with a semi automatic Artificial Neural Network tool
Aquaculture
(2009) - et al.
Application of machine-vision techniques to fish-quality assessment
TrAC Trends Anal. Chem.
(2012) - et al.
Freshness assessment of gilthead sea bream (Sparus aurata) by machine vision based on gill and eye color changes
J. Food Eng.
(2013) - et al.
The accuracy and precision of underwater measurements of length and maximum body depth of southern bluefin tuna (Thunnus maccoyii) with a stereo-video camera system
Fish Res.
(2003) - et al.
Application of computer vision technique for on-line monitoring of shrimp color changes during drying
J. Food Eng.
(2013) - et al.
Automatic grading and packing of prawns
Comput. Electron. Agric.
(1993)