Contrast enhancement and details preservation of tone mapped high dynamic range images

Tone Mapped HDR Images Contrast Enhancement Using Piecewise Linear Perceptual Transformation

“…The results are compared to: (i) CEDP [8] with norm 1 and level 1; (ii) NUHA [7] with norm 1; (iii) NONSEP ENO-CA [6]; (iv) SEP ENO-CA [5] with parameters α 1 = 0.3, α 2 = 0.7; (v) Li TMO [11] with Haar multiscale; (vi) Fattal [4] using RBW method with parameters α = 0.8, β = 0.3, γ = 0.8; (vii) Duan [12] using β = 0.5; (viii) TMOs in HDR Toolbox: Drago [10], Reinhard [17], Ward [18], Durand [9], Schlick [20] using default parameters as given in the HDR Toolbox. The parameters are chosen so as to give the best results in terms of TMQI metric in all methods.…”

“…The more probability p i , the more value a i , and vice versa. The set of slopes satisfy the constraint condition given by (8). The unknown parameter b i is computed by the following formula: (1).…”

“…A piecewise linear perceptual quantizer modeling the "s-shaped" curve of the Human Visual Adaptation with getting more optional contrast by changing the norm space is proposed in [7]. Later, in [8], authors proposed a combination of a near optimal lifting scheme and perceptual quantizer to enhance the contrast and preserve more details in the tone mapped HDR images.…”

Performance Analysis of the Revisited Tone Mapped Quality Index for Tone Mapped HDR Images Evaluation

“…P LCC ranges from −1 and +1. Fifteen TMOs are used for the training such as "Drago" [7], "Reinhard" [8], "Ward" [9], "Durand" [10], "Tumblin" [11], "Schlick" [12], "Duan" [13], "Fattal" WRB [14], "Li" [15], "Husseis" [16], "NUHA" [19], "SEPENO" [17], "NONSEPENO" [18], "CEDP Lin" [20] with β = 0.25 and "CEDP Opt" [20] with adaptive β. The training TM HDR image database is based on 24 HDR images with different dynamic range (or contrast ratio) from 7 f-stops to 29 f-stops, namely "Lausanne1", "CraterLake1", "Shasta2", "Synagogue", "Anturium", "BowRiver", "Bridges", "Stairway1", "ArchRock", "DollDoll", "ClockBuilding", "OxfordChurch", "Bot-tlesSmall", "Montreal", "SmallOffice", "Light", "BridgeStudios2", "Memorial", "ClaridgeHotel", "Mistaya1", "BrookHouse", "Peace-Rocks", "GGpark2" and "AtriumNight".…”

“…Indeed this metric does not take into account the new distortions introduced by the new TMOs (e.g. "Duan" [13], "Fattal" WRB [14], "Li" [15], "Husseis" [16], "NUHA" [19], "SEPENO" [17], "NON-SEPENO" [18], "CEDP" [20]). That is why this paper addresses, in section III-C, the question of re-evaluating the TMQI parameters to be in accordance with the MOS.…”