An Improved Image Contrast Assessment Method

Yuanyuan Fan, Yingjun Sang, Guang Hu, Zaijin Zhou, Yunrong Hao
2014 TELKOMNIKA Indonesian Journal of Electrical Engineering  
Abstrak Kontras merupakan faktor penting yang mempengaruhi kualitas gambar. Untuk mengatasi masalah lokal kontras-band terbatas, diusulkan sebuah metode baru penilaian kontras berdasarkan sifat HVS. Pertama, gambar dengan low-pass filter dilakukan dekomposisi wavelet cepat. Kedua, semua tingkat band-pass disaring sesuai gambar dan citra low-pass filter yang diperoleh dengan mengolah koefisien wavelet. Ketiga, kontras lokal band terbatas dihitung, dan band-terbatas entropi kontras lokal dihitung
more » ... tras lokal dihitung sesuai dengan definisi entropi. Akhirnya, entropi kontras gambar diperoleh dengan rata-rata entropi kontras-band lokal terbatas ditimbang menggunakan koefisien CSF. Hasil percobaan menunjukkan bahwa kontras gambar terbaik dapat diidentifikasi secara akurat dalam gambar urutan diperoleh dengan menyesuaikan waktu paparan dan peregangan abu-abu masing-masing, hasil penilaian sesuai dengan karakteristik visual manusia dan membuat kurangnya lokal kontras-band terbatas. Abstract Contrast is an important factor affecting the image quality. In order to overcome the problems of local band-limited contrast, a novel image contrast assessment method based on the property of HVS is proposed. Firstly, the image by low-pass filter is performed fast wavelet decomposition. Secondly, all levels of band-pass filtered image and its corresponding low-pass filtered image are obtained by processing wavelet coefficients. Thirdly, local band-limited contrast is calculated, and the local band-limited contrast entropy is calculated according to the definition of entropy. Finally, the contrast entropy of image is obtained by averaging the local band-limited contrast entropy weighed using CSF coefficient. The experiment results show that the best contrast image can be accurately identified in the sequence images obtained by adjusting the exposure time and stretching gray respectively, the assessment results accord with human visual characteristics and make up the lack of local band-limited contrast.
doi:10.11591/telkomnika.v12i3.3719 fatcat:g3gfk5nhevfyvko75b54hwopw4