[libcamera-devel,v1,3/6] ipa: rkisp1: Introduce Black Level Correction

14997 diff mbox series

In order to have the proper pixel levels, apply a fixed black level
correction, based on the imx219 tuning file in RPi. The value is 4096 on
16 bits, and the pipeline for RkISP1 is on 12 bits, scale it.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
---
 src/ipa/rkisp1/algorithms/blc.cpp     | 55 +++++++++++++++++++++++++++
 src/ipa/rkisp1/algorithms/blc.h       | 30 +++++++++++++++
 src/ipa/rkisp1/algorithms/meson.build |  1 +
 src/ipa/rkisp1/rkisp1.cpp             |  2 +
 4 files changed, 88 insertions(+)
 create mode 100644 src/ipa/rkisp1/algorithms/blc.cpp
 create mode 100644 src/ipa/rkisp1/algorithms/blc.h

Hi Jean-Michel,

Thank you for the patch.

On Thu, Dec 02, 2021 at 07:04:07PM +0100, Jean-Michel Hautbois wrote:
> In order to have the proper pixel levels, apply a fixed black level
> correction, based on the imx219 tuning file in RPi. The value is 4096 on
> 16 bits, and the pipeline for RkISP1 is on 12 bits, scale it.
> 
> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
> ---
>  src/ipa/rkisp1/algorithms/blc.cpp     | 55 +++++++++++++++++++++++++++
>  src/ipa/rkisp1/algorithms/blc.h       | 30 +++++++++++++++
>  src/ipa/rkisp1/algorithms/meson.build |  1 +
>  src/ipa/rkisp1/rkisp1.cpp             |  2 +
>  4 files changed, 88 insertions(+)
>  create mode 100644 src/ipa/rkisp1/algorithms/blc.cpp
>  create mode 100644 src/ipa/rkisp1/algorithms/blc.h
> 
> diff --git a/src/ipa/rkisp1/algorithms/blc.cpp b/src/ipa/rkisp1/algorithms/blc.cpp
> new file mode 100644
> index 000000000..f27a8e439
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/blc.cpp
> @@ -0,0 +1,55 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2021, Ideas On Board
> + *
> + * blc.cpp - RkISP1 Black Level Correction control
> + */
> +
> +#include "blc.h"
> +
> +/**
> + * \file blc.h
> + */
> +
> +namespace libcamera {
> +
> +namespace ipa::rkisp1::algorithms {
> +
> +/**
> + * \class BlackLevelCorrection
> + * \brief RkISP1 Black Level Correction control
> + *
> + * The pixels output by the camera normally include a black level, because
> + * sensors do not always report a signal level of '0' for black. Pixels at or
> + * below this level should be considered black. To achieve that, the RkISP BLC
> + * algorithm subtracts a configurable offset from all pixels.
> + *
> + * The black level can be measured at runtime from an optical dark region of the
> + * camera sensor, or measured during the camera tuning process. The first option
> + * isn't currently supported.
> + */
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::prepare
> + */
> +void BlackLevelCorrection::prepare([[maybe_unused]] IPAContext &context,
> +				   rkisp1_params_cfg *params)
> +{
> +	/*
> +	 * Substract fixed values taken from imx219 tuning file.
> +	 * \todo Use a configuration file for it ?
> +	 */
> +	params->others.bls_config.enable_auto = 0;
> +	params->others.bls_config.fixed_val.r = 256;
> +	params->others.bls_config.fixed_val.gr = 256;
> +	params->others.bls_config.fixed_val.gb = 256;
> +	params->others.bls_config.fixed_val.b = 256;
> +
> +	params->module_en_update |= RKISP1_CIF_ISP_MODULE_BLS;
> +	params->module_ens |= RKISP1_CIF_ISP_MODULE_BLS;
> +	params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_BLS;

Same as previously, if the values are fixed, we shouldn't change them
for every frame.

Apart from that, this looks good.

> +}
> +
> +} /* namespace ipa::rkisp1::algorithms */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/rkisp1/algorithms/blc.h b/src/ipa/rkisp1/algorithms/blc.h
> new file mode 100644
> index 000000000..331a22097
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/blc.h
> @@ -0,0 +1,30 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2021, Ideas On Board
> + *
> + * blc.h - RkISP1 Black Level Correction control
> + */
> +
> +#pragma once
> +
> +#include <linux/rkisp1-config.h>
> +
> +#include "algorithm.h"
> +
> +namespace libcamera {
> +
> +struct IPACameraSensorInfo;
> +
> +namespace ipa::rkisp1::algorithms {
> +
> +class BlackLevelCorrection : public Algorithm
> +{
> +public:
> +	BlackLevelCorrection() = default;
> +	~BlackLevelCorrection() = default;
> +
> +	void prepare(IPAContext &context, rkisp1_params_cfg *params) override;
> +};
> +
> +} /* namespace ipa::rkisp1::algorithms */
> +} /* namespace libcamera */
> diff --git a/src/ipa/rkisp1/algorithms/meson.build b/src/ipa/rkisp1/algorithms/meson.build
> index 0678518d8..e6767aa5f 100644
> --- a/src/ipa/rkisp1/algorithms/meson.build
> +++ b/src/ipa/rkisp1/algorithms/meson.build
> @@ -2,5 +2,6 @@
>  
>  rkisp1_ipa_algorithms = files([
>      'agc.cpp',
> +    'blc.cpp',
>      'sdg.cpp',
>  ])
> diff --git a/src/ipa/rkisp1/rkisp1.cpp b/src/ipa/rkisp1/rkisp1.cpp
> index cd425a2e1..ec879ba37 100644
> --- a/src/ipa/rkisp1/rkisp1.cpp
> +++ b/src/ipa/rkisp1/rkisp1.cpp
> @@ -27,6 +27,7 @@
>  
>  #include "algorithms/agc.h"
>  #include "algorithms/algorithm.h"
> +#include "algorithms/blc.h"
>  #include "algorithms/sdg.h"
>  #include "libipa/camera_sensor_helper.h"
>  
> @@ -126,6 +127,7 @@ int IPARkISP1::init(const IPASettings &settings, unsigned int hwRevision)
>  
>  	/* Construct our Algorithms */
>  	algorithms_.push_back(std::make_unique<algorithms::Agc>());
> +	algorithms_.push_back(std::make_unique<algorithms::BlackLevelCorrection>());
>  	algorithms_.push_back(std::make_unique<algorithms::SensorDeGamma>());
>  
>  	return 0;