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Abstract

In this article, three test methods are described to measure the water spreading behaviour of textiles such as rate of absorbency and total absorbent capacity. The methods described are manual method, commercial image analysis method using Photoshop and embedded image analysis method using digital signal processor through MATLAB software (EIAS). With these methods the rate of absorbency and total water absorbent capacity were analysed in 12 different knitted/woven fabrics. In order to compare the three test methods, the correlation among the methods were analysed. A very good correlation (more than 0.9) was found between the manual water spreading tests and commercial image analysis method using Photoshop when compared to manual versus EIAS method. Also Photoshop versus EIAS method correlation was found better than manual versus EIAS method.

Keywords

Transverse wicking horizontal spreading image analysis drop test embedded digital image processing

Introduction

Clothing comfort is an important aspect for any garment used for sportswear and leisurewear. Every human being sweats during different kinds of activities. Das et al. [1] have stated that in sweating conditions, wicking is the most effective process to maintain a feel of comfort. In case of clothing with high wicking properties, moisture coming from the skin is spread throughout the fabric and may offer a dry feeling; the spreading of the liquid enables moisture to evaporate easily.

According to Mahadevan [2] wicking is the ability of a fabric to take in moisture. Kissa [3] has stated that liquid moisture transfer through a textile material consists of two processes – wetting and wicking. In the wetting process, the fibre–air interface is replaced with a fibre–liquid interface and wicking starts as the liquid enters into the capillary formed by two adjacent fibres or yarns. Ghali et al. [4,5] and Hanett et al. [6] have reported that wickability is the ability to sustain capillary flow whereas wettability describes the initial behaviour of a fabric, yarn or fibre when it comes in contact with liquid.

Wicking of a drop can be divided into two phases of different kinetics [7,8]. At first, the drop spreads on the substrate and penetrates the porous substrate underneath. During the second phase of the capillary penetration process, all of the liquid is contained within the substrate and spreads radially under the influence of capillary forces.

As per AATCC 198 [9], horizontal or transverse wicking is the ability of horizontally aligned fabric specimens to transport liquid along and/or through them by capillary action.

Sampath et al. [10] have stated that the analysis of transverse wicking characteristics of the fabric is also as important as the longitudinal wicking because the perspiration (sweat) transfer from skin involves its movement through the lateral direction of the fabric. The influence of longitudinal gravity is not considered in horizontal wicking but being multi-directional, it eliminates the directional effect and the results will be most effective for developing fabrics for sportswear.

Therefore objective measurement of the moisture transfer properties of clothing is important to apparel product development. As per AATCC 198 [9], there are two parameters most commonly used to characterise the properties of liquid moisture management performance of fabrics, which are the rate of absorbency and the total absorbent capacity. The former determines the rapidity with which fluid is imbibed while the latter determines the total capacity of the material to absorb and hold fluid.

Many authors have tried to find the moisture transfer properties of textile objectively using different test methods. Kissa [11] has measured the spreading area of a drop on textile fabric as a function of time. The area of a spreading liquid was photographed at uniform time intervals with an instant-picture camera. The area depicting the spreading liquid was cut out from the dried photograph and weighed. Kissa found that assuming that the fabric was impermeable to the liquid, the spreading rate could be represented by equation (1)

A = K (γ / η)^{u} V^{m} t^{n}

(1)

where A is the area of the liquid drop at time t, V the volume of the drop, γ the surface tension, η the viscosity, and K the capillary sorption coefficient.

In this study, the equations developed by Kissa are applied to a more rigorous measurement of spreading behaviour using the image analysis of frames captured at fast rates, especially in the initial stages. Measurements of the dynamic change of shape of the spreading area of the liquid are also made.

Hu et al. [12,13] have developed another method based on the change of the electrical resistance of the fabric with its water content. It consists of six concentric rings (sensors) of different sizes which are then placed on both the surfaces of the fabric. The distance between two consecutive rings is 5 mm except the first one which is at 1.5 mm from the centre.

A similar instrument has been developed by Adams et al. [14] to measure the in-plane flow of fluids in a fibrous network. They have used an image analysis technique to obtain the shape and position of a radially advancing fluid front, which can define the directional permeabilities in the plane.

Lee et al. [15] have conducted horizontal wicking with a spectrophotometer in order to avoid using balances. They have determined the liquid weight wicked into the fabric by measuring the difference in colour depth between wet fabric and dry fabric. Various researchers like Morent et al. [16] and Perwuelz et al. [17] have proposed the image analysis instead of an analytical balance to determine the extent of horizontal wicking. In the study by Morent, the progression of the liquid front during wicking was recorded with a digital camera and an algorithm was used to calculate the area of the fabric wetted by fluid.

Petrulyte et al. [18] have measured the dynamic water absorption of terry woven fabrics using image analysis technique. They have found the terry woven fabrics absorption speed, influence of pile height with respect to liquid retention capacity and the impact of macerating process on absorption process.

Transverse wicking measurement is also as important as vertical wicking measurement for engineering and designing sportswear. Transverse wicking behaviour of the fabric or garment is more responsible for sweat evaporation during active sports events. Recent studies are focused on analysis of transverse wicking behaviour of fabric for active sportswear. Work still needs to be done in order to analyse transverse wicking behaviour of textiles quantitatively in the model.

Some standards and test methods can be employed to evaluate a fabric’s simple absorbency and wicking properties. However, the existing standards are unable to measure the behaviour of dynamic liquid transfer in clothing materials as the static test results will not serve the purpose of sportswear re-engineering. Dynamic liquid transfer analysis helps to re-engineer the active sportswear products. In this research work, dynamic transverse wicking test methods have been developed using image processing technique. Applying these new methods can be helpful for measuring the transverse wicking in textiles more accurately and cost effectively. Also comparison of the performance of the different test methods helps to understand the test results and the reliability of the test results and devices.

In image analysis method, using different software techniques helps find exact colour of pixels (wet area pixels) from the image. Still there is a further scope in terms of speed (using embedded image processing system using digital signal processor) and accuracy improvement in the image analysis method. Also the study of spreading measurement by image processing through commercial image processing software like Photoshop has not been done earlier.

In the present study, three test methods (two dynamic methods) are described and comparisons are made between three different test methods. The methods are: (i) Manual method; (ii) Commercial image analysis method through Photoshop; and (iii) Embedded image analysis technique using digital signal processor through MATLAB software. The reliability of the three methods is analysed using correlation coefficient analysis.

Material and methods

In order to measure the dynamic transverse liquid spreading behaviour (rate of absorbency and total absorbent capacity) using different test methods, 12 different grey fabric samples were procured from the industry. The fabric details are given in Table 1. The knitting machine used to produce the knitted fabrics is given in Table 2.

Table 1.

Fabric particulars.

Sample no.	Fibre	Structure	Count (Ne)	Thickness (mm)	Fabric construction details		GSM
Sample no.	Fibre	Structure	Count (Ne)	Thickness (mm)	EPC/WPC	PPC/CPC	GSM
1	Cotton	Derby	40 s	1.06	24	25	400
2	Cotton with Lycra	RIB 2X2	44 s	0.83	14	16	280
3	Cotton	Interlock	44 s	0.67	17	18	220
4	Polyester/Viscose	Plain	30 s	0.37	26	25	119
5	Polyester/Viscose	Matt	30 s	0.29	23	23	108
6	Polyester/Viscose	Sateen	30 s	0.26	23	23	106
7	Cotton-ring	Plain	60 s	0.20	30	26	70
8	Cotton-ring	Plain	40 s	0.29	28	24	100
9	Cotton-ring	Twill	60 s	0.27	30	26	80
10	Cotton-compact	Plain	40 s	0.28	28	24	90
11	Cotton-compact	Single jersey	2/40 s	0.51	24	20	160
12	Cotton-ring	Single jersey	2/60 s	0.42	26	24	140

EPC: ends per centimeter; WPC: wales per centimeter; PPC: picks per centimeter; CPC: courses per centimeter.

Sample no. 1–3, 11 and 12 are knitted fabrics; Sample no. 4–10 are woven fabrics.

Table 2.

Knitting machine details.

Sample no.	Knitted fabric structure	Machine make	Gauge	Diameter in inch	Feeders
1	Derby	Pai Lung	19	36	72
2	Interlock	Pai Lung	24	30	72
3	Rib	Mayer and Cie	19	30	52
11 and 12	Single jersey	Mayer and Cie	24	24	72

The knitted and woven fabrics were subjected to scouring and bleaching processes using winch and jigger machine, respectively with the following procedure.

Scouring: The bath containing 1.5% NaOH, 1% Na₂CO₃, and 1 g/L wetting agent was processed at the temperature of 90℃ for 60 min by maintaining pH at 10.5–11.

Bleaching: The bath containing 2.5% H₂O₂, 0.3% peroxide stabiliser was treated at 90℃ temperature for 60 min by maintaining pH 10.5–11. Then the samples were treated with hot water followed by treatment with 1 g/L peroxide killer followed by hot wash at 80℃ temperature for 15 min. Then the samples were neutralised with 0.5 g/L of acidic acid.

The polyester/viscose blended woven fabrics were subjected to scouring using 0.5% soap solution (Lisapol) at 80–90℃ temperature for 1 h and the fabrics were bleached using 4 g/L of hydrogen peroxide for 1 h at 90℃ at pH 10.5–11.

Contraction percentage of knitted fabric was measured and was noted as 5% in course wise and 4% in wale wise direction.

Sample measuring 10 cm× 10 cm and 25 cm× 25 cm (based on type of test) was prepared and then placed in climatic chamber at 20℃ and 65% RH. The 10 tests were conducted from each sample and the average test results were discussed.

Transverse liquid spread test

After full relaxation, the following tests were carried out for all the 12 samples.

Rate of absorbency

It is the ability of the fabric to transfer the water by spreading action. In this method, 50 µL of distilled water is allowed to fall on the fabric and the spreading area is recorded with respect to time. Rate of absorbency is calculated from the value of spreading area with respect to time. Sample size used for testing is 10 cm × 10 cm.

Total absorbent capacity

It is the ability of the fabric to transfer and retain the water by spreading action. In this method, 40 µL of distilled water is allowed to fall on the fabric continuously for every 2 s till the fabric reaches its saturation point. When the sample cannot absorb any more water, the excess water droplets falls down through the fabric. The experiment is stopped at this stage. Time taken from starting to saturation point is noted. Total volume of water retained by the fabric is calculated by multiplying the time taken in seconds for the test with amount of water (40 µL) falling on every 2 s.

Volume of water in mL = ((time taken for saturation point in seconds/2)*40 µL)/1000. Total area of water spread at the saturation point is also noted with respect to time. Sample size used for testing is 25 cm × 25 cm.

Different test methods of transverse wicking area measurement are correlated with Pearson correlation coefficient.

r = \frac{\sum (x - \bar{x}) (y - \bar{y})}{\sqrt{\sum (x - \bar{x})^{2} (y - \bar{y})^{2}}}

Method I: Measuring water spreading behaviour on the fabric by manual method

Apparatus description

As shown in Figure 1 in manual method, as per the type of test (rate of absorbency, total absorbent capacity) the fabric sample is mounted on an embroidery frame. The frame is fixed on a slot in the stand without any movement. For measuring total absorbent capacity, a burette is clamped vertically with the help of holder. Burette tip is positioned 6 mm above the surface of the fabric [19]. As per the testing procedure of AATCC method 198-2011, 40 µL of water is allowed to fall on the fabric continuously for every 2 s till the fabric reaches its saturation point. Water flow rate is controlled with the help of water flow rate controller knob. For measuring the rate of absorbency, a 50 µL micropipette is used to place one drop (50 µL) of water on the fabric and the area spread with respect to time is measured manually as per area calculation procedure.

Figure 1.

Investigating liquid spreading behaviour on the fabric. (a) Front view of transverse liquid spreading instrument; (b) Close view of liquid spreading after drop placed; (c) Marking and transferring of liquid spreading area using pencil (keep transfer sheet between graph sheet and the fabric); (d) Transferred line on the graph sheet; (e) Finding the area in mm² by counting.

Area calculation

The centimeter graph sheet should be kept between transfer sheet and the fabric surface, and the boundary of the water spread area should be traced by using a pencil as shown in Figure 1. From the marked graph sheet the area in mm² can be found. A total of 10 samples are tested. This method took 10 min to measure water spread area in mm² for each sample (depends upon the area of manual counting from graph sheet).

Method II: Measuring water spreading behaviour on the fabric by commercial image processing method using Photoshop

As shown in Figures 2 and 4, a high resolution Logitech HD Pro webcam c910 with Carl Zeiss optics autofocus facility camera is used to measure the dynamic movement of the liquid over the fabric surface. The camera has the facility to produce razor-sharp images of high-definition 10-megapixel video capture quality and automatic brightness adjustment and colour compensation. The camera is mounted on a stand, equipped with a LED light, and connected to personal computer via its USB port. The distance between the camera and fabric sample is calculated as per the calibration procedure.

Figure 2.

Schematic diagram of commercial image processing method.

Figure 3.

Digital processing of captured water spreading image. (a) Raw image received from digital video camera; (b) Quality improved image after adjusting (brightness/contrast); (c) Cropped image; (d) Resized image (resolution: 10 pixels/cm); (e) Dark pixels selected through magic wand selection tool with the help of grow option.

Figure 4.

Experimental setup of embedded image processing method using DSP.

Figure 5.

Schematic diagram for assessing water spreading area.

For measurement of dynamic liquid spreading rate, the fabric sample (as per the type of test) was mounted on an embroidery frame. The frame was fixed on a slot in the stand without any movement. For measuring total absorbent capacity, a syringe was connected with water reservoir through water flow rate controller knob and it was positioned 6 mm above the surface of the fabric. 40 µL of water was allowed to fall on the fabric continuously for every 2 s till the fabric reached its saturation point. Water flow rate was controlled with the help of water flow rate controller knob. For measuring the rate of absorbency, a 50 µL micropipette was used to place one drop (50 µL) of water on the fabric and the area spread on the fabric was captured as image with respect to time. The interval of image capture can be set in camera control software as per the requirement. The camera is compatible with image analysis software. The captured image was stored in a separate folder for processing it in Adobe Photoshop tool.

Calibration

Before starting the new test, the position of the camera height from the fabric stand was calibrated. For this a black solid circle (20 mm diameter) was drawn on a white paper and it was placed over the embroidery ring where the camera captures the image.

Total area of 20 mm diameter solid circle in mm²

= π r^{2} where, r = 10 mm = 3.14 \times 10 \times 10 = {314 mm}^{2}

The captured image was transferred into Photoshop and the image resolution was changed into10 pixels/cm. Then the area of circle (as per the procedure mentioned below) was found in terms of pixels. The total pixels were compared with calculated value (314 mm²), when it did not match with the result, the camera height was adjusted and a new image snap was taken. This process was repeated until the Photoshop method result matched with the calculated result.

Area calculation

As shown in Figure 3, the required raw image is opened to find the area in commercial image processing software Photoshop. The image quality is adjusted by correcting brightness and contrast (Image menu – Adjustment option). The unwanted areas are removed by cropping the image using crop tool. The image is calibrated by changing the image resolution value into 10 pixels/cm. The darken pixels (water spread area) are selected using magic wand selection tool with the help of tolerance property. The magic wand selection tool from the tool box is taken and clicked over the water spread area and then grow option is used from select menu for further exact selection of water spread area. After exact selection of water spread area, histogram option is used from window menu to know the number of pixels in the selected area, i.e. water spread area in mm². This method took less than 3 min to measure water spread area in mm² for each sample.

Method III: Measuring water spreading behaviour on the fabric by EIAS

Apparatus description

Basic instrument setup procedure is same as method II (Photoshop method). Instead of image processing setup, the new instrument was developed with embedded coding in digital signal processor (DSP) with MATLAB tool (EIAS).

As shown in Figure 4, the DSP kit is connected via RS232 in to the USP port. The DSP kit receives main supply and this power supply is reduced into 12 V using step down transformer. The developed software through MATLAB is capable of adjusting to record number of frames per second. The software has the provision to change interval time (seconds) of image capture. For each sample, the recording is started approximately 1 s before drop falling. This is for the purpose of taking reference frame.

From the experimental system (Figure 4), the captured videos are transferred and stored simultaneously in the computer. The stored videos are converted into individual frames using MATLAB coding. Individual frames are transferred into embedded Blackfin ADSP-BF532 DSP kit through RS-232 cable. Using background subtraction algorithm (Figure 5) the processor will subtract reference frame with successive frame and the resulting output image is the difference image. The difference image is the binary image, which is obtained by thresholding. The area of spreading is calculated based on the number of the white pixels for each successive frame.

The thresholding process may vary depending on the lighting conditions, so there should be constant lighting conditions. The final calculated areas are sent back to computer for plotting the graph with the help of MATLAB software. This method took less than a minute to measure water spread area in mm² for each sample.

EIAS method is used to measure the transverse wicking area in each and every second, i.e. continuous measurement and similar to the Photoshop method images can be captured continuously with a fixed delay. Due to continuous measurement both the method can be referred to as dynamic method.

Results and discussion

Rate of absorbency test

Ten tests were conducted in all the three methods for the above sample to compute the average values. Comparison was done between manual method, commercial image analysis method using Photoshop, and EIAS method. The water spreading area was measured for 5 s, 10 s, 30 s, 60 s and 120 s and was noted immediately after 50 µL of water was allowed to fall on the fabric as shown in Table 3. The rate of spreading or the rate of absorbency in mm² per second (Table 4) can be calculated from water spreading area with respect to time.

Table 3.

Measured liquid spreading area in mm² in three methods.

Sample no.	Liquid spreading area in mm² with respect to time
	Manual					Photoshop					EIAS
	5 s	10 s	30 s	60 s	120 s	5 s	10 s	30 s	60 s	120 s	5 s	10 s	30 s	60 s	120 s
1	63	105	124	131	149	67	107	127	136	155	61	98	135	145	158
2	104	173	243	285	305	127	203	257	275	296	141	221	266	301	353
3	125	194	254	286	315	135	216	269	298	314	122	221	261	289	387
4	162	312	492	589	623	167	332	518	597	636	142	328	401	705	621
5	216	396	534	621	712	220	411	567	643	719	231	295	472	468	585
6	184	342	497	601	695	192	381	538	619	690	202	462	561	584	623
7	341	593	895	986	1089	351	615	921	1011	1129	470	593	802	923	962
8	301	503	692	820	911	279	498	734	848	940	218	421	604	688	855
9	421	638	943	1098	1187	467	747	995	1153	1257	478	737	821	1201	1447
10	205	318	694	777	841	239	382	715	787	831	222	410	625	725	752
11	271	361	398	473	548	291	382	454	527	627	345	443	576	632	682
12	362	497	587	673	801	393	563	643	734	810	405	567	655	811	992

Table 4.

Rate of absorbency measured in three methods.

Sample no.	Rate of absorbency in mm²/s
	Manual					Photoshop					EIAS
	5 s	10 s	30 s	60 s	120 s	5 s	10 s	30 s	60 s	120 s	5 s	10 s	30 s	60 s	120 s
1	2.52	1.05	0.14	0.04	0.01	2.68	1.07	0.14	0.04	0.01	2.45	0.98	0.15	0.04	0.01
2	4.16	1.73	0.27	0.08	0.02	5.08	2.03	0.29	0.08	0.02	5.64	2.21	0.30	0.08	0.02
3	5.00	1.94	0.28	0.08	0.02	5.40	2.16	0.30	0.08	0.02	4.88	2.21	0.29	0.08	0.03
4	6.48	3.12	0.55	0.16	0.04	6.68	3.32	0.58	0.17	0.04	5.68	3.28	0.45	0.20	0.04
5	8.64	3.96	0.59	0.17	0.05	8.80	4.11	0.63	0.18	0.05	9.24	2.95	0.52	0.13	0.04
6	7.36	3.42	0.55	0.17	0.05	7.68	3.81	0.60	0.17	0.05	8.08	4.62	0.62	0.16	0.04
7	13.64	5.93	0.99	0.27	0.08	14.04	6.15	1.02	0.28	0.08	18.78	5.93	0.89	0.26	0.07
8	12.04	5.03	0.77	0.23	0.06	11.16	4.98	0.82	0.24	0.07	8.73	4.21	0.67	0.19	0.06
9	16.84	6.38	1.05	0.31	0.08	18.68	7.47	1.11	0.32	0.09	19.12	7.37	0.91	0.33	0.10
10	8.20	3.18	0.77	0.22	0.06	9.56	3.82	0.79	0.22	0.06	8.87	4.10	0.69	0.20	0.05
11	10.84	3.61	0.44	0.13	0.04	11.64	3.82	0.50	0.15	0.04	13.80	4.43	0.64	0.18	0.05
12	14.48	4.97	0.65	0.19	0.06	15.72	5.63	0.71	0.20	0.06	16.18	5.67	0.73	0.23	0.07

Results show (Table 5) that the rate of absorbency measurement through manual and Photoshop methods have Pearson correlation coefficient R² to be 0.978, 0.974, 0.995, 0.996 and 0.993 for rate of absorbency at 5, 10, 30, 60 and 120 s, respectively. The dynamic transverse liquid spreading measurements done by the commercial image analysis method (Adobe Photoshop®) are in parallel with the manual transverse water spreading method.

Table 5.

Three test methods correlation coefficient value.

Correlation coefficient R² value
Method	Rate of absorbency
Method	5 s	10 s	30 s	60 s	120 s
Manual vs. Photoshop method	0.978	0.974	0.995	0.996	0.993
Manual vs. EIAS method	0.879	0.849	0.884	0.880	0.864
Photoshop vs. EIAS method	0.910	0.915	0.910	0.901	0.887

For manual and EIAS methods the correlation coefficient R² was 0.879, 0.849, 0.884, 0.88 and 0.864 for rate of absorbency at 5, 10, 30, 60, 120 s, respectively. The dynamic transverse liquid spreading measurements done by the EIAS are also in parallel with the manual transverse spreading method.

Similarly, between Photoshop and EIAS methods the correlation coefficient R² was 0.910, 0.915, 0.901 and 0.887 for rate of absorbency at 5, 10, 30, 60, 120 s, respectively. The dynamic transverse liquid spreading measurements done by the Photoshop are also in parallel with the EIAS transverse spreading method.

Total absorbent capacity

After fabric reaches the saturation point, the area and total volume of water falling on the fabric are calculated with respect to time. Ten tests are conducted in all the three test methods for the above sample to compute the average value as shown in Table 6. Total volume of water in mL absorbed by the fabric is calculated from number of seconds taken by the fabric to reach saturation point and the total number of drops (40 µL) falling on the fabric till it reaches the saturation point. Volume of water in mL = ((time taken for saturation point in seconds/2)*40 µL)/1000.

Table 6.

Time taken to reach saturation and total absorbent capacity measured in three methods.

Sample no.	Time taken to reach saturation						Total absorbent capacity in mL
	Manual		Photoshop		EIAS		Manual		Photoshop		EIAS
	No. of seconds	Area in cm²	No. of seconds	Area in cm²	No. of seconds	Area in cm²	Total vol. of liquid	Area in cm²	Total vol. of liquid	Area in cm²	Total vol. of liquid	Area in cm²
1	441	431.2	449	410.5	570	376.4	8.82	431.2	8.98	410.5	11.40	376.4
2	372	346.5	388	337.9	317	306.2	7.44	346.5	7.76	337.9	6.34	306.2
3	253	374.4	249	348.5	238	235.0	5.07	374.4	4.99	348.5	4.75	235.0
4	46	23.8	52	25.3	45	25.9	0.92	23.8	1.03	25.3	0.91	25.9
5	67	89.2	64	92.4	69	124.6	1.34	89.2	1.28	92.4	1.39	124.6
6	62	122.1	64	133.1	67	138.3	1.23	122.1	1.28	133.1	1.34	138.3
7	28	64.2	26	67.3	24	78.2	0.55	64.2	0.53	67.3	0.48	78.2
8	95	96.5	91	95.7	86	123.6	1.90	96.5	1.82	95.7	1.72	123.6
9	74	84.6	78	84.3	65	104.2	1.48	84.6	1.56	84.3	1.29	104.2
10	112	104.7	114	109.6	108	133.7	2.24	104.7	2.27	109.6	2.16	133.7
11	150	128.4	162	123.4	128	157.5	3.01	128.4	3.25	123.4	2.56	157.5
12	98	78.3	102	76.8	94	83.5	1.95	78.3	2.03	76.8	1.87	83.5

The graph shown in Figure 6 compares the volume of water in mL absorbed per unit volume of fabric (mL/mm³) in all the three methods. Manual and Photoshop method results are well correlated than the EIAS method. The results are obtained from total volume of water absorbed in mL with respect to saturation point area in cm² (from Table 6). Fabric volume in mm³ was calculated by multiplying saturation point area in mm² with fabric thickness in mm.

Figure 6.

Comparison of fabric absorbent capacity in ‘volume of water (in mL) absorbed per unit volume of the fabric’ (mL/mm³).

Results show (Table 7) that the total absorbent capacity measurement through manual and Photoshop methods has the correlation coefficient R² to be 0.9985 and the area to reach saturation correlation coefficient R² to be 0.9982. The total absorbent capacity measurements done by the commercial image analysis method (Adobe Photoshop®) are in parallel with the manual method.

Table 7.

Three test methods correlation coefficient value.

Method	Correlation coefficient R² value
Method	Total water absorbent	Area to reach saturation
Manual vs. Photoshop method	0.9985	0.9982
Manual vs. EIAS method	0.934	0.916
Photoshop vs. EIAS method	0.937	0.928

For manual and EIAS method the correlation coefficient R² was 0.934 for the total absorbent capacity measurement and correlation coefficient R² was 0.916 for the total area to reach saturation results. The total absorbent capacity measurements done by the EIAS are in parallel with the manual method.

Similarly, between the Photoshop and EIAS method the correlation coefficient R² was 0.937 for the total absorbent capacity measurement and correlation coefficient R² was 0.928 for the total area to reach saturation results. The total absorbent capacity measurements done by the Photoshop are in parallel with the EIAS method.

Conclusion

Three test methods namely manual, commercial image analysis method using Photoshop software, embedded image analysis system using digital signal processor methods were described. The commercial image analysis method using Photoshop and EIAS method can be used to measure the rate of absorbency and total absorbent capacity of the fabric objectively. When compared to commercial analysis method, the EIAS method takes less time for testing because of fully automatic calculation through MATLAB coding with DSP. Three test methods were compared for its rate of absorbency and total absorbency statistically. A good correlation (more than 0.9) was found between manual and commercial image analysis method. Commercial image analysis test result has shown good correlation with manual method as compared with manual versus EIAS method. Also Photoshop versus EIAS method correlation was found better than manual versus EIAS method. Comparison of the performance of the different devices helps to understand the test results of the devices and ensures the reliability of the instrument and its results. The two new developed methods can be useful for the industry to measure the dynamic transverse wicking behaviour of the fabrics to design a new active sportswear.

Footnotes

Acknowledgements

We thank the management of Sona College of Technology, Salem for their valuable suggestions and providing necessary facilities for carrying out this research work.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

References

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Comparison of different methods to measure the transverse wicking behaviour of fabrics

Abstract

Keywords

Introduction

Material and methods

Transverse liquid spread test

Rate of absorbency

Total absorbent capacity

Method I: Measuring water spreading behaviour on the fabric by manual method

Apparatus description

Area calculation

Method II: Measuring water spreading behaviour on the fabric by commercial image processing method using Photoshop

Calibration

Area calculation

Method III: Measuring water spreading behaviour on the fabric by EIAS

Apparatus description

Results and discussion

Rate of absorbency test

Total absorbent capacity

Conclusion

Footnotes

Acknowledgements

Funding

References