Affiliation:
1. Scientific and Technical Center LEMT of the BelOMO
2. Belarusian State University of Informatics and Radioelectronics
Abstract
The problem of reducing the dynamic range and improving the quality of infrared (IR) images with a wide dynamic range for their display on a liquid crystal matrix with 8-bit pixels is considered. To solve this problem in optoelectronic devices in real time, block algorithms based on local equalization of the histogram are widely used, taking into account their relatively low computational complexity and the possibility of taking into account local features of the brightness distribution. The basic adaptive histogram equalization algorithm provides reasonably high image quality after conversion, but may result in excessive contrast for some types of images. In a modified algorithm of adaptive histogram equalization, the contrast is limited by a threshold by truncating local maxima at the edges of the histogram. This leads, however, to a deterioration in other indicators of image quality. This disadvantage is inherent in many algorithms of local histogram equalization, along with limited control over the characteristics of image reproduction quality. To improve the quality and expand the control interval for the characteristics of the reproduction of infrared images, the article proposes an algorithm for double reduction of the dynamic range of the image with intermediate control of the shape of its histogram. This algorithm performs: preliminary reduction of the dynamic range of the image based on adaptive equalization of the histogram, control of the shape of the histogram based on its linear or nonlinear compression, linear stretching of its central part and linear stretching (compression) of its lateral parts, final reduction of the dynamic range based on linear compression of the entire histograms. The characteristics of the proposed algorithm are compared with the characteristics of known algorithms for reducing the dynamic range and improving the image quality. The dependences of the characteristics of the quality of image reproduction after a decrease in their dynamic range on the control parameters of the proposed algorithm and recommendations for their choice taking into account the computational complexity are given.
Publisher
Publishing House Belorusskaya Nauka
Reference12 articles.
1. Liu S. C., Liu S., Wu H., Rahman Md. A., Ching-Feng Lin S., Wong C. Y., Kwok N., Shi H. Enhancement of low illumination images based on an optimal hyperbolic tangent profile. Computers & Electrical Engineering, 2018, vol. 70, pp. 538–550. https://doi.org/10.1016/j.compeleceng.2017.08.026
2. Zhi N., Mao S., Li M. An enhancement algorithm for coal mine low illumination images based on bi-Gamma function. Journal of Liaoning Technical University, 2018, vol. 37, no. 1, pp. 191–197. https://doi.org/10.11956/j.issn.1008-0562.2018.01.034
3. Nithyananda C. R., Ramachandra A. C., Preethi. Review on Histogram Equalization based Image Enhancement Techniques. 2016 International Conference on Electrical, Electronics, and Optimization Techniques (ICEEOT). Chennai, 2016, pp. 2512–2517. https://doi.org/10.1109/ICEEOT.2016.7755145
4. Kim T. K., Paik J. K., Kang B. S. Contrast enhancement system using spatially adaptive histogram equalization with temporal filtering. IEEE Transactionson Consumer Electronics, 1998, vol. 44, no. 1, pp. 82–87. https://doi.org/10.1109/30.663733
5. Reza A. M. Realization of the contrast limited adaptive histogram equalization (CLAHE) for real-time image enhancement. The Journal of VLSI Signal Processing-Systems for Signal, Image, and Video Technology, 2004, vol. 38, no. 1, pp. 35–44. https://doi.org/10.1023/B:VLSI.0000028532.53893.82
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献，注册后可以免费订阅5篇论文的施引文献，订阅后可以查看论文全部施引文献