FigSpec line scanning hyperspectral identification of authentic and printed books test case

In the field of calligraphy and painting identification, it is crucial to accurately distinguish between authentic calligraphy and printed text. Traditional calligraphy and painting identification methods rely on observing the texture of lines, ink color levels, paper characteristics, etc., combined with touch, smell, and textual research, but this method is too subjective and too dependent on experience, and cannot be scientifically and effectively judged. Hyperspectral identification technology is based on advanced technology to obtain the reflection spectrum information of calligraphy and painting at different wavelengths. It has the advantages of non-contact, high resolution, and objectivity, which can effectively improve the accuracy of identification.

1. DN value

DN value: pixel brightness value. It has no unit and is an integer value. The value is related to the radiation resolution of the sensor, the sample emissivity and scattering rate, etc.

2. Principle of Hyperspectral Imaging

Dispersive hyperspectral camera - grating dispersion type: use dispersive elements (gratings or prisms) to split light, and then image it on the detector through the

imaging system. The above figure shows the specific principle of the grating dispersion hyperspectral camera.

If we want to measure the hyperspectral data of each point of the leaf in the picture, the incident light is reflected on the grating surface, and the incident light of

this point is decomposed into energy distribution at different wavelengths, and then the energy at specific different wavelengths is measured through multiple

sensor pixels. This figure shows that a reflection grating or a transmission grating is needed to split the light.

The advantage of this method is that all points on a line can be processed at one time. Then the energy at different wavelengths of each point can be measured

once. Therefore, most grating hyperspectral cameras are designed as line scan cameras. Obtain the spectral data of all wavelengths of each point on a line at one

time. Since the spectral data at different wavelengths of each point are obtained at the same time, the spectral data at different wavelengths of this point can be

calculated simultaneously. This is a very important feature of the grating type. Grating-type hyperspectral cameras are particularly suitable for applications in

color measurement, fruit classification and quality, sugar content detection, and plastic classification in plastic waste recycling, because these applications require

simultaneous calculation of different wavelength data at each point to calculate the desired results.

3. Experimental test

3.1. Experimental purpose: to identify authentic calligraphy and printed calligraphy

3.2. Experimental test equipment list

3.3 Experimental content

The external push-scan detection of the 400-1000nm hyperspectral camera on the curve characteristics of the authentic and printed body

The experimental measurement process is shown in the figure below: the printed body is smooth and has no characteristic peaks, while the authentic body has characteristic peaks.

4. Conclusion