Arducam libcamera低分辨率下画质差问题求助

问题概述 #

在树莓派4上使用Arducam 16MP自动对焦相机，通过libcamera获取1920x1080及其他非最高分辨率的视频/图像时，画质极低。libcamera已按官方指南完成安装。

相机支持模式 #

执行libcamera-still --list-cameras得到以下支持模式：

0 : imx519 [4656x3496] (/base/soc/i2c0mux/i2c@1/imx519@1a)
    Modes: 'SRGGB10_CSI2P' : 1280x720 [120.00 fps - (1048, 1042)/2560x1440 crop]
                             1920x1080 [60.05 fps - (408, 674)/3840x2160 crop]
                             2328x1748 [30.00 fps - (0, 0)/4656x3496 crop]
                             3840x2160 [18.00 fps - (408, 672)/3840x2160 crop]
                             4656x3496 [9.00 fps - (0, 0)/4656x3496 crop]

测试验证 #

执行以下命令拍摄两张对比图片：

libcamera-still --immediate --shutter 50000 --gain 1.5 --width 2328 --height 1748 -e png -o org_2328x1748.png && libcamera-still --immediate --shutter 50000 --gain 1.5 --width 4656 --height 3496 -e png -o org_4656x3496.png

现象 #

• 将4656x3496的图片在电脑上缩放到2328x1748后，画质远优于相机直接输出的2328x1748图片
• 4656x3496图片文件大小为15.6 MiB，远大于2328x1748图片（2.7 MiB）的4倍

Arducam技术支持表示需通过调整libcamera参数解决此问题。

命令执行输出 #

pi@rpi:~ $ libcamera-still --immediate --shutter 50000 --gain 1.5 --width 2328 --height 1748 -e png -o org_2328x1748.png && libcamera-still --immediate --shutter 50000 --gain 1.5 --width 4656 --height 3496 -e png -o org_4656x3496.png
Preview window unavailable
[3:26:37.815366618] [4847]  INFO Camera camera_manager.cpp:293 libcamera v0.0.0+3730-67300b62
[3:26:37.851216285] [4849]  WARN CameraSensorProperties camera_sensor_properties.cpp:174 No static properties available for 'imx519'
[3:26:37.851259785] [4849]  WARN CameraSensorProperties camera_sensor_properties.cpp:176 Please consider updating the camera sensor properties database
[3:26:37.868448913] [4849]  WARN RPI raspberrypi.cpp:1274 Mismatch between Unicam and CamHelper for embedded data usage!
[3:26:37.868923575] [4849] ERROR DelayedControls delayed_controls.cpp:87 Delay request for control id 0x009a090a but control is not exposed by device /dev/v4l-subdev0
[3:26:37.869202646] [4849]  INFO RPI raspberrypi.cpp:1398 Registered camera /base/soc/i2c0mux/i2c@1/imx519@1a to Unicam device /dev/media3 and ISP device /dev/media0
[3:26:37.870104137] [4847]  INFO Camera camera.cpp:1029 configuring streams: (0) 2328x1748-BGR888 (1) 2328x1748-SRGGB10_CSI2P
[3:26:37.870498504] [4849]  INFO RPI raspberrypi.cpp:763 Sensor: /base/soc/i2c0mux/i2c@1/imx519@1a - Selected sensor format: 2328x1748-SRGGB10_1X10 - Selected unicam format: 2328x1748-pRAA
Still capture image received
Preview window unavailable
[3:26:39.086635744] [4855]  INFO Camera camera_manager.cpp:293 libcamera v0.0.0+3730-67300b62
[3:26:39.123343254] [4858]  WARN CameraSensorProperties camera_sensor_properties.cpp:174 No static properties available for 'imx519'
[3:26:39.123386606] [4858]  WARN CameraSensorProperties camera_sensor_properties.cpp:176 Please consider updating the camera sensor properties database
[3:26:39.140987785] [4858]  WARN RPI raspberrypi.cpp:1274 Mismatch between Unicam and CamHelper for embedded data usage!
[3:26:39.141479410] [4858] ERROR DelayedControls delayed_controls.cpp:87 Delay request for control id 0x009a090a but control is not exposed by device /dev/v4l-subdev0
[3:26:39.141723259] [4858]  INFO RPI raspberrypi.cpp:1398 Registered camera /base/soc/i2c0mux/i2c@1/imx519@1a to Unicam device /dev/media3 and ISP device /dev/media0
[3:26:39.142604010] [4855]  INFO Camera camera.cpp:1029 configuring streams: (0) 4656x3496-BGR888 (1) 4656x3496-SRGGB10_CSI2P
[3:26:39.142994210] [4858]  INFO RPI raspberrypi.cpp:763 Sensor: /base/soc/i2c0mux/i2c@1/imx519@1a - Selected sensor format: 4656x3496-SRGGB10_1X10 - Selected unicam format: 4656x3496-pRAA
Still capture image received

解决方案建议 #

• 强制使用全分辨率传感器输出后缩放：避免传感器自身降采样，指定传感器输出最高分辨率，再由ISP缩放到目标分辨率。以2328x1748为例：

  libcamera-still --immediate --shutter 50000 --gain 1.5 --mode 4656:3496:10:P --width 2328 --height 1748 -e png -o scaled_2328x1748.png
  

• 更新相机传感器属性数据库：命令输出提示No static properties available for 'imx519'，建议安装Arducam提供的libcamera补丁或更新官方libcamera配置，确保传感器参数被正确识别。
• 指定对应传感器模式而非仅宽高：直接使用--mode参数调用相机支持的模式，例如拍摄1920x1080时：

  libcamera-still --immediate --shutter 50000 --gain 1.5 --mode 1920:1080:10:P -e png -o 1920x1080.png
  

内容的提问来源于stack exchange，提问作者Robin