Study Of Measurement Method For Yarn-dyed Fabric Solid Color Based On Hyper-spectral Imaging

Accurate measurement of fabric's color is a very important step in the textile industry,which is the basis for obtaining fabric's dyeing quality.Based on this,subsequent fabric production can be carried out.At present,spectrophotometric method is most commonly used to measure the color of solid-color fabrics.However,the spectrophotometric method can only be used to measure the fabric of single color.So it is not suitable for color measurement for multi-color fabrics or single yarn In order to meet the needs of the company's production and development,this thesis has conducted in-depth research on the precise measurement method of fabric color.In view of the shortcomings of the current technology,a hyperspectral imaging system is designed based on the analysis of spectral imaging technology.The hyper-spectral imaging technology is a combination of spectral technology and imaging technology,and can achieve the measurement of the spectral reflecting in a Region of Interesting(ROI)with more spectrum bands.So it can acquire more information of the color of textiles and achieve higher color measurement precision.The main contents of this thesis include the following four parts:(1)The basic theory of color measurement based on hyperspectral imaging was studied,and the color space and color difference calculation formula for fabric color difference calculation was determined.On this basis,a hyperspectral color measurement system was established to obtain spectral reflectances at different locations and different wavelengths of the fabric,and the color tristimulus values were calculated based on the spectral reflectance.Then1976L*a*b* color space and CMC(l:c)color difference calculation formula were used to calculate the fabric color difference.(2)The hyperspectral imaging system was used to measure the color of 15 pairs of solid-color yarn-dyed plain fabrics.The lightness difference,color chromatic difference,and color difference between the fabric samples were calculated.Comparing the color calculation results of the hyperspectral imaging system with the color measurement results of Datacolor 650,it can be concluded that the hyperspectral imaging system is superior to Datacolor 650 in the resolution of dark samples.(3)The stability of the solid-color yarn-dyed fabric measured by a hyperspectral imagingsystem was analyzed.The yarn-dyed fabric was repeatedly measured three times under the same experimental conditions,and the lightness difference,chromatic difference and color difference between each pair of yarn-dyed fabric samples was calculated.The comparison of the three measurement results shows that the hyperspectral color system has good measurement stability.(4)The theoretical model between the spectral reflectance of the yarn and the spectral reflectance of the solid-color yarn-dyed plain fabric was established.Moreover,the parameters in the yarn-fabric spectral reflectance model were determined by the Gauss Newton method optimization method.Based on this model parameter,the test experiments were carried out,the results of which shows that theoretical model can accurately predict the spectral reflectance of the fabric through the spectral reflectance of the yarn compared with the neural network model.Furthermore,five yarns instead of one yarn were used as experimental samples to improve the color prediction accuracy of the theoretical model.The above research shows that the color measurement system based on hyperspectral imaging can accurately measure the color of yarn-dyed fabrics,and the established theoretical model of yarn-fabric spectral reflectance can accurately predict the spectral reflectance of monochromatic yarn-dyed fabrics.