From d0478c41f432b1c733f7a49ca35614017f3ec33e Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Mon, 28 Oct 2024 03:00:10 +0200 Subject: libcamera: Rename "shutter speed" to "exposure time" The terms "shutter" and "shutter speed" are used through libcamera to mean "exposure time". This is confusing, both due to "speed" being used as "time" while it should be the inverse (i.e. a maximum speed should correspond to the minimum time), and due to "shutter speed" and "exposure time" being used in different places with the same meaning. To improve clarity of the code base and the documentation, use "exposure time" consistently to replace "shutter speed". This rename highlighted another vocabulary issue in libcamera. The ExposureModeHelper::splitExposure() function used to document that it splits "exposure time into shutter time and gain". It has been reworded to "split exposure into exposure time and gain". That is not entirely satisfactory, as "exposure" has a defined meaning in photography (see https://en.wikipedia.org/wiki/Exposure_(photography)) that is not expressed as a duration. This issue if left to be addressed separately. Signed-off-by: Laurent Pinchart Reviewed-by: Naushir Patuck Acked-by: Kieran Bingham --- src/ipa/ipu3/ipu3.cpp | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'src/ipa/ipu3/ipu3.cpp') diff --git a/src/ipa/ipu3/ipu3.cpp b/src/ipa/ipu3/ipu3.cpp index 89c3192c..44c98cbf 100644 --- a/src/ipa/ipu3/ipu3.cpp +++ b/src/ipa/ipu3/ipu3.cpp @@ -112,7 +112,7 @@ namespace ipa::ipu3 { * blue gains to apply to generate a neutral grey frame overall. * * AGC is handled by calculating a histogram of the green channel to estimate an - * analogue gain and shutter time which will provide a well exposed frame. A + * analogue gain and exposure time which will provide a well exposed frame. A * low-pass IIR filter is used to smooth the changes to the sensor to reduce * perceivable steps. * @@ -215,13 +215,13 @@ void IPAIPU3::updateSessionConfiguration(const ControlInfoMap &sensorControls) /* * When the AGC computes the new exposure values for a frame, it needs - * to know the limits for shutter speed and analogue gain. + * to know the limits for exposure time and analogue gain. * As it depends on the sensor, update it with the controls. * - * \todo take VBLANK into account for maximum shutter speed + * \todo take VBLANK into account for maximum exposure time */ - context_.configuration.agc.minShutterSpeed = minExposure * context_.configuration.sensor.lineDuration; - context_.configuration.agc.maxShutterSpeed = maxExposure * context_.configuration.sensor.lineDuration; + context_.configuration.agc.minExposureTime = minExposure * context_.configuration.sensor.lineDuration; + context_.configuration.agc.maxExposureTime = maxExposure * context_.configuration.sensor.lineDuration; context_.configuration.agc.minAnalogueGain = camHelper_->gain(minGain); context_.configuration.agc.maxAnalogueGain = camHelper_->gain(maxGain); } -- cgit v1.2.1