JVC J-Log1 Formula
GY-HC500series
GY-HC900series
GY-LS300
JVCKENWOOD Corporation
Solution Business Unit
7thAugust 2020
0
J-Log1_J-GAMUT
• The primary color points of J-Log1 are below table 1.
• J-GAMUT called J-Log1_LS300 color gamut is red triangle line in below
chromaticity diagram.
• Rec.2020 cover ratio 80.3％.DCI-P3 cover ratio 93.8％.DCI-P3 area ratio 111.9％
Rec.2020 cover ratio is 80.3％, thereby It is able to convert to Rec.2020 with small
coefficients.
Table.1
J-Log1 Primary Color Point
x y z
R
G
B
W
0.67 0.32 0.01
0.22 0.75 0.03
0.13 0.08 0.79
0.3127 0.329 0.3583
1
Color space convert of J-GAMUT
0.5986
0.1781
0.1737
0.2859
0.6072
0.1069
0.0089
0.0243
1.0558
0.0000534
• Convert matrix formulas from J-GAMUT(J-Log1_LS300 gamut) to
others color space.
• J-Log1_J-GAMUT →XYZ
X = (
Y = (
Z = (
)( R
)( G
)( B
・ J-Log1_J-GAMUT →Rec2020 R,G,B
2020
R
= ( 0.923646 0.083636 -0.00728 )( R
2020
G
= ( 0.063214 0.863136 0.07365 )( G
2020
B
= ( 0.006748
0.993198 )( B
・ J-Log1_J-GAMUT →Rec709 R,G,B
709
R
= ( 1.496066 -0.36834 -0.12773 )( R
709
G
= ( -0.04348 0.967429 0.076053 )( G
709
B
= ( -0.01557 -0.08827 1.103845 )( B
J-Log1
J-Log
J-Log1
)
1)
)
J-Log1
J-Log1
J-Log1
J-Log1
J-Log1
J-Log1
)
)
)
)
)
)
2
J-Log1 gamma Formula
J-Log1 formula
・
In ＜ 11.34%
J-Log１ = 0.85・LOG10（（In＋0.86)/6.23＋0.73)+0.117
In ≧ 11.34%
J-Log1 = LOG10( ((In+0.86)/100)^0.786) + 1.2
* In = Scene Reflection（%）.ex. In＝18→ 10bit_code = 379
10bit code =round(((1023-64)/1.9221)×J-Log１+ 64)
=round( 498.9 ・J-Log1+64)
8bit code = Int (10bit code/4)
• J-Log1 Inverse formula
convert from 10BIT CV of J-Log1_10bit_code .
J-Log1 = (J-Log1_10bit_code-64)/498.9
if ( 10BIT CV ＜ 304.484) then
In（％）＝（10＾（（J-Log1-0.117）/0.85） - 0.73）×6.23-0.86
if(10BIT CV ≧ 304.484) then
In(%) ＝ 10＾（（J-Log1-1.2）/0.786＋2）-0.86
3
J-Log1 Characteristic graph.
0% (B LACK) Re ｆｌ e ction 2 % Re ｆｌe ction 18 % Re ｆｌe ction 90 % Re fｌe ction 80 0%
IRE 10bit Code 8Bit Code IRE 10bit Code 8Bit Code IRE 10bit Code 8Bit Code IRE 10bit Code 8Bit Code IRE 10bit Code 8Bit Code
3.7 % 96 24 10.3 % 154 39 35.9 % 379 95 66.5 % 646 162 108.8 % 1017 254
4
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