레노버 노트북 카메라가 너무 어둡거나 붉어요

v4l2-ctl 를 사용하여 카메라를 제어한다.

### v4l2-ctl 사용하기 위하여 v4l-utils를 설치한다.
jack@jack-ThinkPad-Edge-E540:~$ sudo apt-get install v4l-utils
### 카메라의 현재 설정보기
jack@jack-ThinkPad-Edge-E540:~$ v4l2-ctl -l
                     brightness 0x00980900 (int)    : min=-10 max=10 step=1 default=0 value=0
                       contrast 0x00980901 (int)    : min=0 max=20 step=1 default=10 value=10
                     saturation 0x00980902 (int)    : min=0 max=10 step=1 default=5 value=5
                            hue 0x00980903 (int)    : min=-5 max=5 step=1 default=0 value=0
                          gamma 0x00980910 (int)    : min=100 max=200 step=1 default=150 value=150
                           gain 0x00980913 (int)    : min=32 max=48 step=1 default=32 value=32
           power_line_frequency 0x00980918 (menu)   : min=0 max=2 default=1 value=1
                      sharpness 0x0098091b (int)    : min=0 max=10 step=1 default=5 value=5
         backlight_compensation 0x0098091c (int)    : min=0 max=2 step=1 default=1 value=1
                  exposure_auto 0x009a0901 (menu)   : min=0 max=3 default=3 value=3
              exposure_absolute 0x009a0902 (int)    : min=156 max=5000 step=1 default=512 value=200 flags=inactive
         exposure_auto_priority 0x009a0903 (bool)   : default=0 value=1
                  zoom_absolute 0x009a090d (int)    : min=0 max=10 step=1 default=0 value=0
### 밝기설정만 보기
jack@jack-ThinkPad-Edge-E540:~$ v4l2-ctl -C brightness
brightness: 0
### 밝기 조절해 가며 카메라의 밝기를 확인한다. (카메라 보기는 cheese 사용)
jack@jack-ThinkPad-Edge-E540:~$ v4l2-ctl -c brightness=10
jack@jack-ThinkPad-Edge-E540:~$ v4l2-ctl -c brightness=0
jack@jack-ThinkPad-Edge-E540:~$ v4l2-ctl -c brightness=2