- Email: [email protected]
Research on cotton fiber qualities evaluation based on optoelectronic techniques
Optik 124 (2013) 3876–3879
Contents lists available at ScienceDirect
Optik journal homepage: www.elsevier.de/ijleo
Research on cotton fiber qualities evaluation based on optoelectronic techniques Zhi-feng Zhang ∗ , Feng-xiao Zhai, Hong-jun Yang, Kun Yang Department of Physics, Zhengzhou University of Light Industry, Zhengzhou 450002, PR China
a r t i c l e
i n f o
Article history: Received 22 June 2012 Accepted 20 November 2012
Keywords: Maturity ratio Fineness Optoelectronic techniques Wavelet analysis
a b s t r a c t The fine and mature cotton fibers can make it possible to spin a finer yarn, and fineness and maturity of cotton fibers were essential qualitative characteristic, however, there was no direct or indirect measurement method that was both fast and reliable to estimate them. In this paper, a novel method was put forward to assess cotton fiber fineness and maturity based on optoelectronic measuring techniques. The experimental results were compared between the microscope measurement and system measurement and the linear fit results of two measuring methods of that linear fit were 0.98788, and standard deviation was 0.19081. Average cross-sectional widths of cotton samples measured by the microscope and the system had a fairly low correlation with the micronaire data. The linear fit results of the fiber maturity ratio of two measuring methods were 0.95587, and standard deviation was 0.33203. This method can be done in the lab and be used in the industry adherent to the present measurement instruments, for example AFIS, after improved. © 2012 Elsevier GmbH. All rights reserved.
1. Introduction Maturity and fineness of cotton fibers were essential qualitative characteristic and determined the quality of yarns. In spite of the importance of fineness and maturity for the textile industry, they were still viewed as a difficult technical problem. In the past 40 years research, two classified estimation methods to measure mature and immature cotton fibers in a given sample were developed, indirect methods and direct methods. Indirect methods included micronaire, dyeability, causticare, Shirley FMT, and near infrared methods. The direct measurement of the ribbon width of a fiber based on a microscope was regarded as a benchmark for all other tests. However, this direct technique suffered from significant experimental error due to the microscope measurements involved and the limited numbers of fibers that can be practically measured. These studies were tedious and time consuming without computers. Other direct techniques have failed to generate sufficient industry confidence because of the limitation of the measuring precision [1–6]. With the improvement of more versatile light sources, especially the laser, more detailed research on cotton fibers can be carried out. This paper presented a novel, rigorous, fast, and experimental approach to measure ribbon width of some varieties cotton fibers and to correlate these results with cotton properties, especially with fineness and maturity. Calibration of the measurement system was carried out using the normal fiber. The diffraction
∗ Corresponding author. E-mail address: [email protected] (Z.-f. Zhang). 0030-4026/$ – see front matter © 2012 Elsevier GmbH. All rights reserved. http://dx.doi.org/10.1016/j.ijleo.2012.11.037
optical signals were detected by a linear CCD and de-noised with wavelet analysis. Eight cotton varieties were measured by the optical system and compared to the measurement results of the microscope. The objective of the paper is to utilize the optoelectronic measuring technique to develop a non-contact measurement method capable of measuring the maturity and fineness of cotton fibers. The remainder of this paper is organized as follows: in Section 2, the proposed measuring principle, and measuring system are presented. Section 3 describes the experimental results and discussion and conclusions are drawn in Section 4. 2. The proposed system 2.1. Measuring principle It was well-known that many optical methods were used to measure the diameter of wires and fiber with high accuracy. Fraunhofer diffraction was a classic phenomenon in optical physics that arises from fairly simple a well-understood mechanism [7]. Fig. 1 showed the Fraunhofer diffraction schematic diagram. The system consisted of a light source emitting the monochromatic parallel light, and a lens, and linear CCD. The linear CCD was located behind a convex lens and on its focal plane. CCD detected and recorded the intensity distribution of diffraction fringe. If one cotton fiber replaced the slot, the ribbon width of cotton fiber can be obtained according Eq. (1): d=
2m f, Xm + X−m
m = 1, 2, 3, . . .
(1)
Z.-f. Zhang et al. / Optik 124 (2013) 3876–3879
1
3877
3
2
X
θ
d
f
Monochromatic parallel light
Fig. 1. Schematic diagram of the simple diffraction: 1, slot; 2, convex lens; and 3, linear CCD plane.
where d was the cotton ribbon width; m was the diffraction fringe order; Xm is the minimum diffraction fringes to the center; X−m is the same order minimum to the center on the other side; and f is the focal length of the convex lens. The standard fineness (Hs ) of the cotton fiber was given by the following Eq. (2): Hs =
0.577 2 P 4
(2)
where was the cell–wall density in g/cm3 ( = 1.52 g/cm3 ) and P was the outside perimeter of the cotton fiber. Typical fiber cross sections were converted to a circular type having the same perimeter and wall thickness [8]. The perimeter was related to an effective circular diameter or ribbon width (RW). The ribbon width of the fiber can be expressed as a function of the fiber standard fineness as follows:
RW = 1.11
Hs
(3)
Therefore, the mean ribbon width (RWmean ) of cotton variety can be estimated by direct measurement for the fiber fineness. Cotton’s fineness had not direct relation to fiber’s maturity. However, mature cotton variety generally had more change and wider cross-section width. So maturity ratio (MR) of the variety cotton fiber can be obtained from Eq. (4): MR = RWSD × RWmean
(4) 2
2
2
where RWSD = ((RW1 −RWmean ) +(RW2 − RWmean ) + · · · + (RWn − RWmean ) )/n, and RWmean = (RW1 + RW2 + · · · + RWn )/n. 2.2. Measuring system’s composition The experimental setup to measure the cotton fiber was shown in Fig. 2. It was composed of a 0.8 mW polarized and stabilized He–Ne laser (EDMUND J61-374) with wavelength 632.8 nm, and the diameter of the radiated beam (1/e2 ) 0.48 mm, and an iris (EDMUND J56-276) to avoid the scattering light to He–Ne laser 10 mm, and a polaroid (DHC GCL-05) used to avoid the scattering light and reduce the incident beam power to avoid the saturation to the linear CCD to the iris 100 mm, and a fiber holder fixed on the linear stage (DHC GCMH-1284) with 1 m resolution to the polaroid 200 mm, and convex lens (DHC GCL-010615) with focal length 100 mm to the holder 15 mm, and the central block before the center part of the CCD to avoid the saturation with 4 mm, and the linear CCD (MIGHTEX TCN-1304-U) with 3648 pixels, of size 8 m located on the convex lens focal point. The length from the holder to lens could limit the diffraction fringe detected by CCD for the lens diameter limitation. The distance from the holder to the lens should be less 55 mm when the fifth-order dark fringe was
Fig. 2. Experimental setup for measuring the cotton fiber: 1, He–Ne laser; 2, iris; 3, polaroid; 4, cotton fiber; 5, fiber holder; 6, convex lens; 7, central block; and 8, linear CCD.
detected by CCD to the normal fiber (13.5 m) in our optical system. The quality of the diffraction pattern in the large-angle field became bad. The whole detection range of CCD cannot be used, so the fiber should be closest possible to the lens for detecting most minima and maxima. The distance, 17 mm, in our measurement system can meet the measuring requirement. The wavelet transform is prior to the traditional method in removing the noise from the signal [9–11]. Fig. 3 showed the principle of wavelet analysis. An original signal was decomposed to a high- and low-frequency component at several decomposition levels: fj,t =
M
hm Sj−1, ((2j−m)mod N/2j−1 )+1
(5)
m=1
Fj,t =
M
lm Sj−1, ((2j−m)mod N/2j−1 )+1
(6)
m=1
where h and l were high-pass and low-pass filters, respectively. fj,t and Fj,t were detail and approximation coefficients at level j, respectively. Reconstruction to the original signal can be performed by the detail coefficient and approximate coefficient as shown in Eq. (7), and repeating this process finally gave an original signal as S0,t : Sj,t =
M
hm f 0
j+1,((t+m−2)mod N/2j )+1
m=1
+
M
lm F 0
j+1,((t+m−2)mod N/2j )+1
m=1
(7)
Original Signal Level 1 Level 2 Level 3 Level N Fig. 3. Scheme of fast discrete wavelet transform. The symbol aj indicates the approximation coefficient from a low-pass filter and dj is a detail coefficient from the high-pass filter at level j (j = 1, 2, 3, . . ., N).
3878
Z.-f. Zhang et al. / Optik 124 (2013) 3876–3879
Avearge Ribbon Width - System (um)
18.5 START
READ-IN CCD SIGNAL
LEFT SIGNAL
18.0 17.5
COTTON VARIETY R = 0.98788 SD = 0.19081 N=8
Sample 3 Sample 4 Sample 5
17.0
Sample 2 Sample 1
16.5
Sample 8
16.0
Sample 7
15.5 15.0 14.5
RIGHT SIGNAL
Sample 6 14.0 14.5
15.0
15.5
16.0
16.5
17.0
17.5
Average Ribbon Width - Microcope (um)
WAVELET DE-NOISE (SYM8, 6)
Fig. 5. Average ribbon widths of eight cotton varieties with system and microscope measurement.
WAVELET DE-NOISE (SYM8, 6)
20
20
MICROSCOPE R = 0.68234 SD = 0.63274 N=8
FIND THE POSITION (FIRST BRIGHT AND SECOND DARK)
ERROR LESS THAN 10% (DIAMETER OF BRIGHT AND DARK)
19
18
18
17
17
16
16
System R = 0.68121 SD = 0.89162 N=8
15
14 2
YES
3
4
15
System Measurement (um)
NO
Microscope Measurement (um)
19 FIND THE POSITIONS (FIRST BRIGHT AND SECOND DARK)
14
5
6
Micronaire Value
Fig. 6. Relation between micronaire and ribbon width of different cotton varieties.
SAVE
COTTON VARIETIES R = 0.95587 SD = 0.33203 N=8
5.0
Fig. 4. Program flowchart based on wavelet analysis.
Fig. 4 showed the program flowchart measuring the cotton fiber diameter based on wavelet transform denoising. The wavelet was sym8 and the level was 6. Firstly, the program was started and the data CCD detected were read in. Next, the signal was divided into two parts from the center. Then, the two parts were de-noised with wavelet analysis respectively and the maxima and minima were found. Finally, the cotton fiber diameter and fineness and maturity can be calculated according to Eqs. (1), (3) and (4). The measuring results were saved in the computer.
System Maturity Ratio
4.5
Sample 3 Sample 4 Sample 1
4.0
Sample 2 3.5
Sample 5 Sample 8
3.0
Sample 7
2.5 2.0
Sample 6
1.5 1.5
2.0
2.5
3.0
3.5
4.0
Microscope Maturity Ratio
3. Results and discussion Fig. 7. Maturity ratio between microscope measurement and system measurement.
Cotton samples were selected randomly from eight varieties. The ribbon width of cotton samples were measured with the measuring system and the microscope respectively. Table 1 showed the average ribbon widths and micronaire values of eight cotton samples varieties. Fig. 5 showed the linear fit results of two measuring methods that linear fit was 0.98788, and standard Table 1 Average ribbon widths and micronaires of eight cotton varieties. Variety
System (m)
Microscope (m)
Micronaire
Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8
16.8 17.0 18.1 17.8 16.8 14.5 16.3 15.9
16.0 16.4 17.1 16.9 16.2 14.6 16.0 15.4
3.1 3.3 3.9 5.47 4.1 2.6 3.5 3.7
deviation was 0.19081. Fig. 6 showed the relation of ribbon widths measured by the microscope and diffraction methods respectively and micronaire value. RWmean measured by the microscope and the diffraction had a fairly low correlation with the micronaire data; this was because a micronaire value was a combined measurement of both fineness and maturity. Fig. 7 showed the maturity ratios of eight cotton fiber varieties had the relation between the optoelectronic technique measurement and the microscope measurement. The linear fit result of two measuring methods was 0.95587, and standard deviation was 0.33203. The optoelectronic system can estimate the cotton fiber qualities. 4. Conclusion The fine and mature cotton fibers can make it possible to spin a finer yarn, and fineness and maturity of cotton fibers were essential qualitative characteristic, however, there was no direct or indirect
Z.-f. Zhang et al. / Optik 124 (2013) 3876–3879
measurement method that was both fast and reliable to estimate them. In this paper, a novel method was put forward to assess cotton fiber fineness and maturity based on the optical diffraction. At present, this method can be done in the lab and be used in the industry adherent to the present measurement instruments, for example AFIS, after improved. The experimental results were compared between the microscope measurement and diffraction measurement and the linear fit results of two measuring methods of that linear fit was 0.98788, and standard deviation was 0.19081. RWmean measured by the microscope and the diffraction had a fairly low correlation with the micronaire data; this was because a micronaire value was a combined measurement of both fineness and maturity. The linear fit result of the fiber maturity ratio of two measuring methods was 0.95587, and standard deviation was 0.33203. Acknowledgments This research work is supported by Doctoral Foundation of Zhengzhou University of Light Industry, and Science and Technology Department of Henan Province of China (No. 122102210436), Foundation of Henan Educational Commission (No. 2011B510019), and Key Members of the Outstanding Young Teacher of Zhengzhou University of Light Industry (No. 2011XGGJS).
3879
References [1] E.F. Hequet, B. Wyatt, N. Abidi, Creation of a set of reference material for cotton fiber maturity measurements, Textile Res J 76 (2006) 576–586. [2] B. Xu, Y. Huang, Image analysis for cotton fibers. Part II: cross-sectional measurements, Textile Res J 74 (2004) 409–416. [3] B. Xu, B. Pourdeyhimi, J. Sobus, Fiber cross-sectional shape analysis using imaging techniques, Textile Res J 63 (12) (1993) 717–730. [4] D.P. Thibodeaux, J.P. Evans, Cotton fiber maturity by image analysis, Textile Res J 56 (1996) 130–139. [5] R. Matic-Leigh, D.A. Cauthen, Determining cotton fiber maturity by image analysis. Part I: direct measurement of cotton fiber characteristics, Textile Res J 64 (1994) 534–544. [6] E.K. Boylston (Southern Regional Research Cent), D.P. Thibodeaux, J.P. Evans, Applying microscopy to the development of a reference method for cotton fiber maturity, Textile Res J 63 (2) (1993) 80–87. [7] M. Born, E. Wolf, Principles of Optics, Pergamon, Oxford, 1980. [8] B. Xu, Y.L. Ting, Fiber-image analysis. Part II: measurement of general geometric properties of fibers, J Textile Inst 87 (2) (1996) 284–295. [9] Z. Zhifeng, S. Zhan, S. Yuling, G. Zhan, Denoising of sensor signals for the flange thickness measurement based on wavelet analysis, Optik 122 (2011) 681–686. [10] Q. Zhang, R. Aliaga-Rossel, P. Choi, Denoising of gamma-ray signals by interval-dependent thresholds of wavelet analysis, Meas Sci Technol 17 (2006) 731–735. [11] Zhifeng Zhang, Chao Lu, Fangzhen Zhang, Yufen Ren, Kun Yang, Su. Zhan, A novel method for non-contact measuring diameter parameters of wheelset based on wavelet analysis, Optik 123 (2012) 433–438.
Contents lists available at ScienceDirect
Optik journal homepage: www.elsevier.de/ijleo
Research on cotton fiber qualities evaluation based on optoelectronic techniques Zhi-feng Zhang ∗ , Feng-xiao Zhai, Hong-jun Yang, Kun Yang Department of Physics, Zhengzhou University of Light Industry, Zhengzhou 450002, PR China
a r t i c l e
i n f o
Article history: Received 22 June 2012 Accepted 20 November 2012
Keywords: Maturity ratio Fineness Optoelectronic techniques Wavelet analysis
a b s t r a c t The fine and mature cotton fibers can make it possible to spin a finer yarn, and fineness and maturity of cotton fibers were essential qualitative characteristic, however, there was no direct or indirect measurement method that was both fast and reliable to estimate them. In this paper, a novel method was put forward to assess cotton fiber fineness and maturity based on optoelectronic measuring techniques. The experimental results were compared between the microscope measurement and system measurement and the linear fit results of two measuring methods of that linear fit were 0.98788, and standard deviation was 0.19081. Average cross-sectional widths of cotton samples measured by the microscope and the system had a fairly low correlation with the micronaire data. The linear fit results of the fiber maturity ratio of two measuring methods were 0.95587, and standard deviation was 0.33203. This method can be done in the lab and be used in the industry adherent to the present measurement instruments, for example AFIS, after improved. © 2012 Elsevier GmbH. All rights reserved.
1. Introduction Maturity and fineness of cotton fibers were essential qualitative characteristic and determined the quality of yarns. In spite of the importance of fineness and maturity for the textile industry, they were still viewed as a difficult technical problem. In the past 40 years research, two classified estimation methods to measure mature and immature cotton fibers in a given sample were developed, indirect methods and direct methods. Indirect methods included micronaire, dyeability, causticare, Shirley FMT, and near infrared methods. The direct measurement of the ribbon width of a fiber based on a microscope was regarded as a benchmark for all other tests. However, this direct technique suffered from significant experimental error due to the microscope measurements involved and the limited numbers of fibers that can be practically measured. These studies were tedious and time consuming without computers. Other direct techniques have failed to generate sufficient industry confidence because of the limitation of the measuring precision [1–6]. With the improvement of more versatile light sources, especially the laser, more detailed research on cotton fibers can be carried out. This paper presented a novel, rigorous, fast, and experimental approach to measure ribbon width of some varieties cotton fibers and to correlate these results with cotton properties, especially with fineness and maturity. Calibration of the measurement system was carried out using the normal fiber. The diffraction
∗ Corresponding author. E-mail address: [email protected] (Z.-f. Zhang). 0030-4026/$ – see front matter © 2012 Elsevier GmbH. All rights reserved. http://dx.doi.org/10.1016/j.ijleo.2012.11.037
optical signals were detected by a linear CCD and de-noised with wavelet analysis. Eight cotton varieties were measured by the optical system and compared to the measurement results of the microscope. The objective of the paper is to utilize the optoelectronic measuring technique to develop a non-contact measurement method capable of measuring the maturity and fineness of cotton fibers. The remainder of this paper is organized as follows: in Section 2, the proposed measuring principle, and measuring system are presented. Section 3 describes the experimental results and discussion and conclusions are drawn in Section 4. 2. The proposed system 2.1. Measuring principle It was well-known that many optical methods were used to measure the diameter of wires and fiber with high accuracy. Fraunhofer diffraction was a classic phenomenon in optical physics that arises from fairly simple a well-understood mechanism [7]. Fig. 1 showed the Fraunhofer diffraction schematic diagram. The system consisted of a light source emitting the monochromatic parallel light, and a lens, and linear CCD. The linear CCD was located behind a convex lens and on its focal plane. CCD detected and recorded the intensity distribution of diffraction fringe. If one cotton fiber replaced the slot, the ribbon width of cotton fiber can be obtained according Eq. (1): d=
2m f, Xm + X−m
m = 1, 2, 3, . . .
(1)
Z.-f. Zhang et al. / Optik 124 (2013) 3876–3879
1
3877
3
2
X
θ
d
f
Monochromatic parallel light
Fig. 1. Schematic diagram of the simple diffraction: 1, slot; 2, convex lens; and 3, linear CCD plane.
where d was the cotton ribbon width; m was the diffraction fringe order; Xm is the minimum diffraction fringes to the center; X−m is the same order minimum to the center on the other side; and f is the focal length of the convex lens. The standard fineness (Hs ) of the cotton fiber was given by the following Eq. (2): Hs =
0.577 2 P 4
(2)
where was the cell–wall density in g/cm3 ( = 1.52 g/cm3 ) and P was the outside perimeter of the cotton fiber. Typical fiber cross sections were converted to a circular type having the same perimeter and wall thickness [8]. The perimeter was related to an effective circular diameter or ribbon width (RW). The ribbon width of the fiber can be expressed as a function of the fiber standard fineness as follows:
RW = 1.11
Hs
(3)
Therefore, the mean ribbon width (RWmean ) of cotton variety can be estimated by direct measurement for the fiber fineness. Cotton’s fineness had not direct relation to fiber’s maturity. However, mature cotton variety generally had more change and wider cross-section width. So maturity ratio (MR) of the variety cotton fiber can be obtained from Eq. (4): MR = RWSD × RWmean
(4) 2
2
2
where RWSD = ((RW1 −RWmean ) +(RW2 − RWmean ) + · · · + (RWn − RWmean ) )/n, and RWmean = (RW1 + RW2 + · · · + RWn )/n. 2.2. Measuring system’s composition The experimental setup to measure the cotton fiber was shown in Fig. 2. It was composed of a 0.8 mW polarized and stabilized He–Ne laser (EDMUND J61-374) with wavelength 632.8 nm, and the diameter of the radiated beam (1/e2 ) 0.48 mm, and an iris (EDMUND J56-276) to avoid the scattering light to He–Ne laser 10 mm, and a polaroid (DHC GCL-05) used to avoid the scattering light and reduce the incident beam power to avoid the saturation to the linear CCD to the iris 100 mm, and a fiber holder fixed on the linear stage (DHC GCMH-1284) with 1 m resolution to the polaroid 200 mm, and convex lens (DHC GCL-010615) with focal length 100 mm to the holder 15 mm, and the central block before the center part of the CCD to avoid the saturation with 4 mm, and the linear CCD (MIGHTEX TCN-1304-U) with 3648 pixels, of size 8 m located on the convex lens focal point. The length from the holder to lens could limit the diffraction fringe detected by CCD for the lens diameter limitation. The distance from the holder to the lens should be less 55 mm when the fifth-order dark fringe was
Fig. 2. Experimental setup for measuring the cotton fiber: 1, He–Ne laser; 2, iris; 3, polaroid; 4, cotton fiber; 5, fiber holder; 6, convex lens; 7, central block; and 8, linear CCD.
detected by CCD to the normal fiber (13.5 m) in our optical system. The quality of the diffraction pattern in the large-angle field became bad. The whole detection range of CCD cannot be used, so the fiber should be closest possible to the lens for detecting most minima and maxima. The distance, 17 mm, in our measurement system can meet the measuring requirement. The wavelet transform is prior to the traditional method in removing the noise from the signal [9–11]. Fig. 3 showed the principle of wavelet analysis. An original signal was decomposed to a high- and low-frequency component at several decomposition levels: fj,t =
M
hm Sj−1, ((2j−m)mod N/2j−1 )+1
(5)
m=1
Fj,t =
M
lm Sj−1, ((2j−m)mod N/2j−1 )+1
(6)
m=1
where h and l were high-pass and low-pass filters, respectively. fj,t and Fj,t were detail and approximation coefficients at level j, respectively. Reconstruction to the original signal can be performed by the detail coefficient and approximate coefficient as shown in Eq. (7), and repeating this process finally gave an original signal as S0,t : Sj,t =
M
hm f 0
j+1,((t+m−2)mod N/2j )+1
m=1
+
M
lm F 0
j+1,((t+m−2)mod N/2j )+1
m=1
(7)
Original Signal Level 1 Level 2 Level 3 Level N Fig. 3. Scheme of fast discrete wavelet transform. The symbol aj indicates the approximation coefficient from a low-pass filter and dj is a detail coefficient from the high-pass filter at level j (j = 1, 2, 3, . . ., N).
3878
Z.-f. Zhang et al. / Optik 124 (2013) 3876–3879
Avearge Ribbon Width - System (um)
18.5 START
READ-IN CCD SIGNAL
LEFT SIGNAL
18.0 17.5
COTTON VARIETY R = 0.98788 SD = 0.19081 N=8
Sample 3 Sample 4 Sample 5
17.0
Sample 2 Sample 1
16.5
Sample 8
16.0
Sample 7
15.5 15.0 14.5
RIGHT SIGNAL
Sample 6 14.0 14.5
15.0
15.5
16.0
16.5
17.0
17.5
Average Ribbon Width - Microcope (um)
WAVELET DE-NOISE (SYM8, 6)
Fig. 5. Average ribbon widths of eight cotton varieties with system and microscope measurement.
WAVELET DE-NOISE (SYM8, 6)
20
20
MICROSCOPE R = 0.68234 SD = 0.63274 N=8
FIND THE POSITION (FIRST BRIGHT AND SECOND DARK)
ERROR LESS THAN 10% (DIAMETER OF BRIGHT AND DARK)
19
18
18
17
17
16
16
System R = 0.68121 SD = 0.89162 N=8
15
14 2
YES
3
4
15
System Measurement (um)
NO
Microscope Measurement (um)
19 FIND THE POSITIONS (FIRST BRIGHT AND SECOND DARK)
14
5
6
Micronaire Value
Fig. 6. Relation between micronaire and ribbon width of different cotton varieties.
SAVE
COTTON VARIETIES R = 0.95587 SD = 0.33203 N=8
5.0
Fig. 4. Program flowchart based on wavelet analysis.
Fig. 4 showed the program flowchart measuring the cotton fiber diameter based on wavelet transform denoising. The wavelet was sym8 and the level was 6. Firstly, the program was started and the data CCD detected were read in. Next, the signal was divided into two parts from the center. Then, the two parts were de-noised with wavelet analysis respectively and the maxima and minima were found. Finally, the cotton fiber diameter and fineness and maturity can be calculated according to Eqs. (1), (3) and (4). The measuring results were saved in the computer.
System Maturity Ratio
4.5
Sample 3 Sample 4 Sample 1
4.0
Sample 2 3.5
Sample 5 Sample 8
3.0
Sample 7
2.5 2.0
Sample 6
1.5 1.5
2.0
2.5
3.0
3.5
4.0
Microscope Maturity Ratio
3. Results and discussion Fig. 7. Maturity ratio between microscope measurement and system measurement.
Cotton samples were selected randomly from eight varieties. The ribbon width of cotton samples were measured with the measuring system and the microscope respectively. Table 1 showed the average ribbon widths and micronaire values of eight cotton samples varieties. Fig. 5 showed the linear fit results of two measuring methods that linear fit was 0.98788, and standard Table 1 Average ribbon widths and micronaires of eight cotton varieties. Variety
System (m)
Microscope (m)
Micronaire
Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8
16.8 17.0 18.1 17.8 16.8 14.5 16.3 15.9
16.0 16.4 17.1 16.9 16.2 14.6 16.0 15.4
3.1 3.3 3.9 5.47 4.1 2.6 3.5 3.7
deviation was 0.19081. Fig. 6 showed the relation of ribbon widths measured by the microscope and diffraction methods respectively and micronaire value. RWmean measured by the microscope and the diffraction had a fairly low correlation with the micronaire data; this was because a micronaire value was a combined measurement of both fineness and maturity. Fig. 7 showed the maturity ratios of eight cotton fiber varieties had the relation between the optoelectronic technique measurement and the microscope measurement. The linear fit result of two measuring methods was 0.95587, and standard deviation was 0.33203. The optoelectronic system can estimate the cotton fiber qualities. 4. Conclusion The fine and mature cotton fibers can make it possible to spin a finer yarn, and fineness and maturity of cotton fibers were essential qualitative characteristic, however, there was no direct or indirect
Z.-f. Zhang et al. / Optik 124 (2013) 3876–3879
measurement method that was both fast and reliable to estimate them. In this paper, a novel method was put forward to assess cotton fiber fineness and maturity based on the optical diffraction. At present, this method can be done in the lab and be used in the industry adherent to the present measurement instruments, for example AFIS, after improved. The experimental results were compared between the microscope measurement and diffraction measurement and the linear fit results of two measuring methods of that linear fit was 0.98788, and standard deviation was 0.19081. RWmean measured by the microscope and the diffraction had a fairly low correlation with the micronaire data; this was because a micronaire value was a combined measurement of both fineness and maturity. The linear fit result of the fiber maturity ratio of two measuring methods was 0.95587, and standard deviation was 0.33203. Acknowledgments This research work is supported by Doctoral Foundation of Zhengzhou University of Light Industry, and Science and Technology Department of Henan Province of China (No. 122102210436), Foundation of Henan Educational Commission (No. 2011B510019), and Key Members of the Outstanding Young Teacher of Zhengzhou University of Light Industry (No. 2011XGGJS).
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