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A novel nonlinear image encryption scheme based on a fully phase nonzero-order joint transform correlator architecture (JTC) in the Gyrator domain (GD) is proposed. In this encryption scheme, the two non-overlapping data distributions of the input plane of the JTC are fully encoded in phase and this input plane is transformed using the Gyrator transform (GT); the intensity distribution captured in the GD represents a new definition of the joint Gyrator power distribution (JGPD). The JGPD is modified by two nonlinear operations with the purpose of retrieving the encrypted image, with enhancement of the decrypted signal quality and improvement of the overall security. There are three keys used in the encryption scheme, two random phase masks and the rotation angle of the GT, which are all necessary for a proper decryption. Decryption is highly sensitivity to changes of the rotation angle of the GT as well as to little changes in other parameters or keys. The proposed encryption scheme in the GD still preserves the shift-invariance properties originated in the JTC-based encryption in the Fourier domain. The proposed encryption scheme is more resistant to brute force attacks, chosen-plaintext attacks, known-plaintext attacks, and ciphertext-only attacks, as they have been introduced in the cryptanalysis of the JTC-based encryption system. Numerical results are presented and discussed in order to verify and analyze the feasibility and validity of the novel encryption–decryption scheme. 相似文献
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A cascaded Fresnel digital hologram (CFDH) is proposed, together with its mathematical derivation. Its application to watermarking has been demonstrated by a simulation procedure, in which the watermark image to be hidden is encoded into the phase of the host image. The watermark image can be deciphered by the CFDH setup, the reconstructed image shows good quality and the error is almost closed to zeros. Compared with previous technique, this is a lensless architecture, which minimizes the hardware requirement. 相似文献
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We propose a modified encryption joint transform correlator scheme that introduces an additional random phase mask. The positions of both the conventional and the new mask are crucial for successful recovery of the original data. Although the two random phase masks are 2D, variation of their relative distance constitutes an additional dimension. Consequently by including this notion, both random phase masks act as a 3-dimensional (3D) key code increasing thereby the security with respect to the conventional JTC encryption scheme. We employ this scheme to multiplex encrypted data, displacing the encoding masks. During decryption of the multiplexed information, we only reconstruct the object that matches the correct predetermined 3D key code, i.e. that matches the random masks positions in the encryption step. We present actual experimental results, by using BSO crystal as recording medium, as well as their respective analysis. 相似文献
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John Fredy Barrera Edgar Rueda Myrian Tebaldi Roberto Torroba 《Optics Communications》2011,284(19):4350-4355
We develop an experimental protocol to visualize decrypted images that otherwise would have been barely recognizable, while keeping the standard security levels. This image deterioration is partly due to the natural speckle noise as well as the practical limitations arising from the optical elements composing the setup. This protocol is based on an optical image synthesis with digital holography using enlarged sub-samples of an entire image together with a multiplexing technique. We implement the process using a Mach-Zehnder interferometer with a joint transform correlator encrypting architecture. As a result, we get smaller speckle patterns on the final assembled image and a spatial frequency enhancement with respect to the decoded image obtained with the conventional procedures. 相似文献
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Ruijia Wang Yi Zhang Prof. Wei Lu Baoyi Wu Shuxin Wei Shuangshuang Wu Prof. Wenqin Wang Prof. Tao Chen 《Angewandte Chemie (International ed. in English)》2023,62(23):e202300417
Many living organisms have the superb structure-editing capacity for better adaptation in dynamic environments over the course of their life cycle. However, it's still challenging to replicate such natural structure-editing capacity into artificial hydrogel actuating systems for enhancing environment-interactive functions. Herein, we learn from the metamorphosis development of glowing octopus to construct proof-of-concept fluorescent hydrogel actuators with life-like structure-editing capacity by developing a universal stepwise inside-out growth strategy. These actuators could perform origami-like 3D shape deformation and also enable the postnatal growth of new structures to adapt additional actuating states for different visual information delivery by using different environment keys (e.g., temperature, pH). This study opens previously unidentified-avenues of bio-inspired hydrogel actuators/robotics and extends the potential uses for environment-interactive information encryption. 相似文献
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Jiahong Yu Zhiyu Sun Huili Ma Chengyun Wang Wenbin Huang Zikai He Wenjun Wu Honglong Hu Weijun Zhao Wei-Hong Zhu 《Angewandte Chemie (International ed. in English)》2023,62(52):e202316647
The development of ultra-long room-temperature phosphorescence (UL-RTP) in processable amorphous organic materials is highly desirable for applications in flexible displays, anti-counterfeiting, and bio-imaging. However, achieving efficient UL-RTP from amorphous materials remains a challenging task, especially with activation by visible light and a bright afterglow. Here we report a general and rational molecular-design strategy to enable efficient visible-light-excited UL-RTP by multi-esterification of a rigid large-plane phosphorescence core. Notably, multi-esterification minimizes the aggregation-induced quenching and accomplishes a ′four birds with one stone′ possibility in the generation and radiation process of UL-RTP: i) shifting the excitation from ultraviolet light to blue-light through enhancing the transition dipole moment of low-lying singlet-states, ii) facilitating the intersystem crossing process through the incorporation of lone-pair electrons, iii) boosting the decay process of long-lived triplet excitons resulting from a significantly increased transition dipole moment, and iv) reducing the intrinsic triplet nonradiative decay by substitution of high-frequency vibrating hydrogen atoms. All these factors synergistically contribute to the most efficient and stable visible-light-stimulated UL-RTP (lifetime up to 2.01 s and efficiency up to 35.4 % upon excitation at 450 nm) in flexible films using multi-esterified coronene, which allows high-tech applications in single-component time-delayed white light-emitting diodes and information technology based on flashlight-activated afterglow encryption. 相似文献
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A mixed scrambling operation is defined by the use of Arnold transform and Baker mapping. Following a designed sequence, the combined scrambling operation is utilized for changing the pixel position of secret image under the control of a random matrix. At the same time, the pixel value is altered by random bit shift for obtaining an encrypted image encoded in N-bit data. The operations mentioned above are employed for all pixels of original secret image. Finally an encrypted image is obtained and encoded into N-bit data being from the input image. Some numerical simulations have been achieved for checking the performance of the image hiding scheme. 相似文献
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在大量的彩色图像处理工作中,已研究和发展了许多方法和技术对光谱颜色进行定量的控制、变换。无论失真彩色复现,还是假彩色合成,均能做到颜色的定量描述。本论文阐述用彩色光谱的三维属性进行编码演算,在浩瀚的颜色空间中进行线性和非线性的颜色参量映射变换,形成难以辨认和难以破解的密码图,对文本、图像的传递实现加密,是一个创新的技术。 相似文献