An Improved Homomorphic Filtering Algorithm for Face Image Preprocessing

電腦學刊 ◽  
2021 ◽  
Vol 32 (6) ◽  
pp. 066-082
Author(s):  
Yi-Ting Han Yi-Ting Han ◽  
Guo-Jun Lin Yi-Ting Han ◽  
Liang-Jun Zhao Guo-Jun Lin ◽  
Xiao-Lin Tang Liang-Jun Zhao ◽  
Ye Huang Xiao-Lin Tang ◽  
...  

Author(s):  
Xiaolin Tang ◽  
Xiaogang Wang ◽  
Jin Hou ◽  
Huafeng Wu ◽  
Ping He

Introduction: Under complex illumination conditions such as poor light sources and light changes rapidly, there are two disadvantages of current gamma transform in preprocessing face image: one is that the parameters of transformation need to be set based on experience; the other is the details of the transformed image are not obvious enough. Objective: Improve the current gamma transform. Methods: This paper proposes a weighted fusion algorithm of adaptive gamma transform and edge feature extraction. First, this paper proposes an adaptive gamma transform algorithm for face image preprocessing, that is, the parameter of transformation generated by calculation according to the specific gray value of the input face image. Secondly, this paper uses Sobel edge detection operator to extract the edge information of the transformed image to get the edge detection image. Finally, this paper uses the adaptively transformed image and the edge detection image to obtain the final processing result through a weighted fusion algorithm. Results: The contrast of the face image after preprocessing is appropriate, and the details of the image are obvious. Conclusion: The method proposed in this paper can enhance the face image while retaining more face details, without human-computer interaction, and has lower computational complexity degree.


2021 ◽  
Vol 2074 (1) ◽  
pp. 012004
Author(s):  
Ling Cheng

Abstract To solve the massive noise contained in the images acquired under low illumination, we designed a digital video image Preprocessing device with the denoising function. Based on the embedded CPU and operating system, video images are acquired by the camera. The noise contained in the video images is filtered by the improved median filtering algorithm and wavelet image denoising. Subsequently, the images are transmitted through USB and network interface, and the storage function of image files is implemented. The device can remove the noise contained in videos effectively, which is conducive to performing more advanced processing on the images.


Author(s):  
I Nyoman Gede Arya Astawa ◽  
I Ketut Gede Darma Putra ◽  
I Made Sudarma ◽  
Rukmi Sari Hartati

One of the factors that affects the detection system or face recognition is lighting. Image color processing can help the face recognition system in poor lighting conditions. In this study, homomorphic filtering and intensity normalization methods used to help improve the accuracy of face image detection. The experimental results show that the non-uniform of the illumination of the face image can be uniformed using the intensity normalization method with the average value of Peak Signal to Noise Ratio (PSNR) obtained from the whole experiment is 22.05314 and the average Absolute Mean Brightness Error (AMBE) value obtained is 6.147787. The results showed that homomorphic filtering and intensity normalization methods can be used to improve the detection accuracy of a face image.


2011 ◽  
Vol 71-78 ◽  
pp. 4269-4273
Author(s):  
Jie Jia ◽  
Jian Yong Lai ◽  
Gen Hua Zhang ◽  
Huan Ling

To deal with the large amount of data and complex computing problems during high-speed image acquisition, the image acquisition and preprocess system based on FPGA is designed in the paper. In order to obtain continuous and integrity of image data streams, the design has completed the acquisition of CCD camera video signal and implementation of de-interlacing ping-pong cache. The fast median filtering algorithm is used for image preprocessing, and finally the preprocessed image data is displayed on CRT. Experiments indicate that the design meets requirements of image sample quality and balances the real-time demand.


2013 ◽  
Vol 433-435 ◽  
pp. 338-341
Author(s):  
Yue Ming Dai ◽  
Xi Jun Zhu

In this paper, based on the value measure of the Intermediary truth value, the Intermediary filtering algorithm is applied to the thenar palmprint image preprocessing. By using the Objective indicators of peak signal to noise ratio (PSNR), it can be seen that compared with the classical de-noising algorithm, the intermediary filtering algorithm is more effective and practicable.


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