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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2021, Google inc.
*
* blc.cpp - IPU3 Black Level Correction control
*/
#include "blc.h"
#include <string.h>
/**
* \file blc.h
* \brief IPU3 Black Level Correction control
*/
namespace libcamera {
namespace ipa::ipu3::algorithms {
/**
* \class BlackLevelCorrection
* \brief A class to handle black level correction
*
* 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 ImgU 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.
*/
BlackLevelCorrection::BlackLevelCorrection()
{
}
/**
* \brief Fill in the parameter structure, and enable black level correction
* \param[in] context The shared IPA context
* \param[in] frame The frame context sequence number
* \param[in] frameContext The FrameContext for this frame
* \param[out] params The IPU3 parameters
*
* Populate the IPU3 parameter structure with the correction values for each
* channel and enable the corresponding ImgU block processing.
*/
void BlackLevelCorrection::prepare([[maybe_unused]] IPAContext &context,
[[maybe_unused]] const uint32_t frame,
[[maybe_unused]] IPAFrameContext &frameContext,
ipu3_uapi_params *params)
{
/*
* The Optical Black Level correction values
* \todo The correction values should come from sensor specific
* tuning processes. This is a first rough approximation.
*/
params->obgrid_param.gr = 64;
params->obgrid_param.r = 64;
params->obgrid_param.b = 64;
params->obgrid_param.gb = 64;
/* Enable the custom black level correction processing */
params->use.obgrid = 1;
params->use.obgrid_param = 1;
}
REGISTER_IPA_ALGORITHM(BlackLevelCorrection, "BlackLevelCorrection")
} /* namespace ipa::ipu3::algorithms */
} /* namespace libcamera */
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