[libcamera-devel,v3,2/5] ipa: rkisp1: Introduce Black Level Correction

15378 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>
Tested-by: Peter Griffin <peter.griffin@linaro.org>

---
v3: - return early when it is not the first frame anymore
    - add a todo to remember it may need a bit of rework later
    - Change the date of the copyright
---
 src/ipa/rkisp1/algorithms/blc.cpp     | 57 +++++++++++++++++++++++++++
 src/ipa/rkisp1/algorithms/blc.h       | 30 ++++++++++++++
 src/ipa/rkisp1/algorithms/meson.build |  1 +
 src/ipa/rkisp1/rkisp1.cpp             |  2 +
 4 files changed, 90 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, Feb 24, 2022 at 12:33:44PM +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>
> Tested-by: Peter Griffin <peter.griffin@linaro.org>

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

> ---
> v3: - return early when it is not the first frame anymore
>     - add a todo to remember it may need a bit of rework later
>     - Change the date of the copyright
> ---
>  src/ipa/rkisp1/algorithms/blc.cpp     | 57 +++++++++++++++++++++++++++
>  src/ipa/rkisp1/algorithms/blc.h       | 30 ++++++++++++++
>  src/ipa/rkisp1/algorithms/meson.build |  1 +
>  src/ipa/rkisp1/rkisp1.cpp             |  2 +
>  4 files changed, 90 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 00000000..0c5948ff
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/blc.cpp
> @@ -0,0 +1,57 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2021-2022, 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(IPAContext &context,
> +				   rkisp1_params_cfg *params)
> +{
> +	if (context.frameContext.frameCount > 0)
> +		return;
> +	/*
> +	 * 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;
> +}
> +
> +} /* 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 00000000..69874d8f
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/blc.h
> @@ -0,0 +1,30 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2021-2022, 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 a19c1a4f..27c97731 100644
> --- a/src/ipa/rkisp1/algorithms/meson.build
> +++ b/src/ipa/rkisp1/algorithms/meson.build
> @@ -2,4 +2,5 @@
>  
>  rkisp1_ipa_algorithms = files([
>      'agc.cpp',
> +    'blc.cpp',
>  ])
> diff --git a/src/ipa/rkisp1/rkisp1.cpp b/src/ipa/rkisp1/rkisp1.cpp
> index f119b3f3..bb3deb93 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 "libipa/camera_sensor_helper.h"
>  
>  #include "ipa_context.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>());
>  
>  	return 0;
>  }