Application of Hyperspectral Imaging: Color Difference Testing of Gray Fabric

色差值是指兩個顏色之間的差異(yì)，是(shì)衡(héng)量兩(liǎng)個顏色差(chà)異的重要指標，隻(zhī)要(yào)涉及(jí)到(dào)顏色的行(háng)業，幾乎(hū)都會用到(dào)。色(sè)差可(kě)用ΔL，Δa，Δb和(hé)ΔE表示，其中ΔE值(zhí)越大表示(shì)色(sè)差(chà)越明(míng)顯。常用(yòng)的色差(chà)公式包(bāo)括(kuò)L*a*b色差公式(shì)和ΔE公(gōng)式(shì)。

本次實(shí)驗采用(yòng)高光譜相(xiāng)機，對(duì)灰色布(bù)料樣品(pǐn)進行色差檢測(cè)，通過(guò)測量(liáng)和分析樣(yàng)品的(dí)顏色差異(yì)來(lái)驗證該技術的應(yīng)用(yòng)效果(guǒ)。

Color Difference refers to the difference between two colors and serves as a key metric for evaluating color variations. It is widely used in industries where color accuracy is critical. Color differences can be expressed using ΔL, Δa, Δb, and ΔE, where a higher ΔE value indicates a more noticeable color difference. Common color difference formulas include the Lab* color difference formula and the ΔE formula.

In this experiment, a hyperspectral camera was employed to test the color difference of gray fabric samples. By measuring and analyzing the color variations of the samples, the effectiveness of this technology was validated.

「測(cè)試設備介紹(shào) / Test Equipment」

測試(shì)采用(yòng)的高(gāo)光(guāng)譜相機具(jù)備400~1000nm的光譜(pǔ)範圍檢測能力(lì)，配合綫性(xìng)推(tuī)掃成(chéng)像方案和(hé)鹵(lǔ)素光源照明係(xì)統，將樣(yàng)品置於傳(chuán)送帶上進(jìn)行精(jīng)準(zhǔn)測(cè)量(liáng)。

The hyperspectral camera used in this test features a spectral range of 400–1000 nm. Combined with a line-scan imaging setup and a halogen light source illumination system, the samples were placed on a conveyor belt for precise measurement.

高光譜相機(jī)參(cān)數 / Hyperspectral Camera Specifications

·光譜(pǔ)範圍 / Spectral Range
：400~1000nm

·光譜(pǔ)分辨率(shuài) / Spectral Resolution
：≤2.8nm

·光譜波段(duàn)數(shù) / Number of Spectral Bands
：300

·F數(shù) / F-Number
：F/2.0

·空間像(xiàng)素數 / Spatial Pixels
：480

·探測(cè)器類(lèi)型 / Detector Type
：CMOS

·探(tàn)測器接口 / Detector Interface
：GigE

·有效位(wèi)深(shēn) / Effective Bit Depth
：12bits

「高(gāo)光譜(pǔ)圖(tú)像(xiàng) / Hyperspectral Image」

「光譜(pǔ)曲(qū)綫(xiàn) / Spectral Curve」

「Lab值 / Lab Values」

計(jì)算(suàn)出(chū)的Lab值(zhí)和ΔE色(sè)差值如(rú)下圖(tú)所示
：

通過(guò)分析獲(huò)得(dé)的(dí)高光譜(pǔ)圖像(xiàng)和光譜曲綫(xiàn)數(shù)據，我們計算出Lab值和(hé)ΔE值(zhí)。

其(qí)中1號(hào)標(biāo)樣區(qū)的(dí)數據作(zuò)為基(jī)準參考值，以(yǐ)ΔE=0.5為(wéi)判定閾值。

The calculated Lab values and ΔE color difference values are shown below:

By analyzing the acquired hyperspectral image and spectral curve data, we calculated the Lab values and ΔE values.

The data from the reference area (Sample 1) was used as the benchmark, with a threshold of ΔE = 0.5 for judgment.

測試(shì)結論“OK"表示計(jì)算(suàn)的ΔE值(zhí)小於判(pàn)定閾(yù)值(zhí)（即(jí)ΔE≤0.5），測試(shì)結論“NG"表示計算(suàn)的ΔE值大於(yú)判(pàn)定(dìng)閾(yù)值(zhí)（即ΔE>0.5）。

Test Conclusion "OK": Indicates that the calculated ΔE value is less than or equal to the threshold (ΔE ≤ 0.5). Test Conclusion "NG": Indicates that the calculated ΔE value exceeds the threshold (ΔE > 0.5).

「總(zǒng)結 / Summary」

測(cè)試結(jié)果顯示(shì)，雖然最大(dà)ΔE值達到0.83，但(dàn)仍(réng)處於(yú)人眼(yǎn)難(nán)以辨別的細微(wēi)差異(yì)範圍(wéi)內，這充(chōng)分體現了高(gāo)光譜技術在捕(bǔ)捉細微(wēi)色差(chà)方(fāng)麵的優勢。

The test results show that although the maximum ΔE value reached 0.83, it still falls within the range of subtle differences that are difficult to discern with the naked eye. This fully demonstrates the unique advantage of hyperspectral technology in detecting minute color variations.