From patchwork Mon Aug 10 20:19:53 2026 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Milan Zamazal X-Patchwork-Id: 27746 Return-Path: X-Original-To: parsemail@patchwork.libcamera.org Delivered-To: parsemail@patchwork.libcamera.org Received: from lancelot.ideasonboard.com (lancelot.ideasonboard.com [92.243.16.209]) by patchwork.libcamera.org (Postfix) with ESMTPS id 3E4B3BDE4C for ; Mon, 10 Aug 2026 20:20:53 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id C9C406821C; Mon, 10 Aug 2026 22:20:52 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="ft5UAv37"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 9E7A968226 for ; Mon, 10 Aug 2026 22:20:51 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1786393250; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=E286z2yTCNyPpCzTYWQaatOya1tbi2pBWNrdZR6/69M=; b=ft5UAv37a7ddcdFRgy+hsgAXEMBr3nWN2qTdW+wiR76AEVWA84HeAIIe8ArzqgqZCkRfQf rmVVRbt/WN1p4OMOUVkJU6JjcwrJDOq1nQvRxjkhy1aSb0b9JZ0W/kJ3OoE9U6X59t0ecY Lpm0ZzS140PcbffX2lm2/0uBLomM1R0= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-222-dwJv9_--PgqkH3r3m2zd9g-1; Mon, 10 Aug 2026 16:20:41 -0400 X-MC-Unique: dwJv9_--PgqkH3r3m2zd9g-1 X-Mimecast-MFC-AGG-ID: dwJv9_--PgqkH3r3m2zd9g_1786393240 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id ED80A1956047; Mon, 10 Aug 2026 20:20:39 +0000 (UTC) Received: from mzamazal-thinkpadp1gen7.redhat.corp (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 90E6619560AB; Mon, 10 Aug 2026 20:20:37 +0000 (UTC) From: Milan Zamazal To: libcamera-devel@lists.libcamera.org Cc: Xander Pronk , Bryan O'Donoghue , Hans de Goede , Laurent Pinchart , Robert Mader , =?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= , Rick ten Wolde , Milan Zamazal Subject: [PATCH v13 3/7] ipa: simple: Add LSC algorithm Date: Mon, 10 Aug 2026 22:19:53 +0200 Message-ID: <20260810201957.19623-4-mzamazal@redhat.com> In-Reply-To: <20260810201957.19623-1-mzamazal@redhat.com> References: <20260810201957.19623-1-mzamazal@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: c2UQ-tJ-bWqa_NlVskRbFBMn-x65nalOHSy4yCc0rL0_1786393240 X-Mimecast-Originator: redhat.com content-type: text/plain; charset="US-ASCII"; x-default=true X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" From: Xander Pronk The algorithm is based on the common libipa lens shading correction implementation. The grid values obtained from the libipa algorithm are passed to the debayer algorithm as an array and used as an an RGB texture. Notes on the implementation: - The overall idea is to keep things simple, to not make the LSC computation unnecessarily expensive. - LscAlgorithm accepts only quantised types. UQ<2,6> is used, to be converted to float in debayering. - The limit of 100 degrees to consider a temperature change noticeable is arbitrary. Co-developed-by: Rick ten Wolde Signed-off-by: Rick ten Wolde Signed-off-by: Xander Pronk Signed-off-by: Milan Zamazal --- .../internal/software_isp/debayer_params.h | 12 ++- src/ipa/simple/algorithms/lsc.cpp | 96 +++++++++++++++++++ src/ipa/simple/algorithms/lsc.h | 55 +++++++++++ src/ipa/simple/algorithms/meson.build | 1 + src/ipa/simple/ipa_context.h | 5 + src/ipa/simple/soft_simple.cpp | 2 + src/libcamera/software_isp/debayer.cpp | 8 ++ 7 files changed, 178 insertions(+), 1 deletion(-) create mode 100644 src/ipa/simple/algorithms/lsc.cpp create mode 100644 src/ipa/simple/algorithms/lsc.h diff --git a/include/libcamera/internal/software_isp/debayer_params.h b/include/libcamera/internal/software_isp/debayer_params.h index 93dcf42e6..b7860c9dd 100644 --- a/include/libcamera/internal/software_isp/debayer_params.h +++ b/include/libcamera/internal/software_isp/debayer_params.h @@ -35,7 +35,17 @@ struct DebayerParams { static constexpr unsigned int kLscValuesPerCell = 4; using LscLookupTable = std::array; - LscLookupTable lscLut{}; + static constexpr auto identityLscLut = [] { + LscLookupTable lut = {}; + /* lut.fill(64) could be used, but it fails with older gcc versions */ + for (size_t i = 0; kLscValuesPerCell * i < lut.size(); i++) { + lut[i * kLscValuesPerCell + 0] = 64; /* == UQ<2, 6>(1.0f).quantized() */ + lut[i * kLscValuesPerCell + 1] = 64; + lut[i * kLscValuesPerCell + 2] = 64; + } + return lut; + }(); + LscLookupTable lscLut = identityLscLut; uint64_t lscLutVersion = 0; }; diff --git a/src/ipa/simple/algorithms/lsc.cpp b/src/ipa/simple/algorithms/lsc.cpp new file mode 100644 index 000000000..d515be3c2 --- /dev/null +++ b/src/ipa/simple/algorithms/lsc.cpp @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Lens shading correction + */ + +#include "lsc.h" + +#include + +namespace libcamera { + +namespace ipa::soft::algorithms { + +LOG_DEFINE_CATEGORY(IPASoftLsc) + +int Lsc::init(IPAContext &context, const ValueNode &tuningData) +{ + static constexpr unsigned int kGridSize = DebayerParams::kLscGridSize; + + for (unsigned int i = 0; i < kGridSize; i++) + gridPos_.push_back(static_cast(i) / (kGridSize - 1)); + + return lscAlgo_.init(tuningData, context.ctrlMap, + { .keys = { "r", "g", "b" }, + .numHSamples = kGridSize, + .numVSamples = kGridSize, + .sensorSize = context.sensorInfo.activeAreaSize }); +} + +int Lsc::configure(IPAContext &context, + [[maybe_unused]] const IPAConfigInfo &configInfo) +{ + return lscAlgo_.configure(context.activeState.lsc, + context.sensorInfo.analogCrop, + gridPos_, gridPos_); +} + +void Lsc::prepare([[maybe_unused]] IPAContext &context, + [[maybe_unused]] const uint32_t frame, + IPAFrameContext &frameContext, + DebayerParams *params) +{ + unsigned int ct = frameContext.awb.colourTemperature; + constexpr unsigned int minTemperatureChange = 100; + + if (!frameContext.lsc.enabled) { + if (lastAppliedCt_ != 0) { + params->lscLut = DebayerParams::identityLscLut; + lastAppliedCt_ = 0; + } + return; + } + + if (utils::abs_diff(ct, lastAppliedCt_) < minTemperatureChange) + return; + + const auto &set = lscAlgo_.interpolateComponents(ct); + + const auto &red = set.at("r"); + const auto &green = set.at("g"); + const auto &blue = set.at("b"); + + DebayerParams::LscLookupTable &lut = params->lscLut; + constexpr unsigned int gridSize = DebayerParams::kLscGridSize; + for (unsigned int i = 0, j = 0; i < gridSize * gridSize; i++) { + lut[j++] = red[i]; + lut[j++] = green[i]; + lut[j++] = blue[i]; + lut[j++] = 0; /* padding */ + } + params->lscLutVersion++; + + lastAppliedCt_ = ct; +} + +void Lsc::queueRequest(IPAContext &context, [[maybe_unused]] const uint32_t frame, + IPAFrameContext &frameContext, const ControlList &controls) +{ + lscAlgo_.queueRequest(context.activeState.lsc, frameContext.lsc, + controls); +} + +void Lsc::process([[maybe_unused]] IPAContext &context, + [[maybe_unused]] const uint32_t frame, + IPAFrameContext &frameContext, + [[maybe_unused]] const SwIspStats *stats, + ControlList &metadata) +{ + lscAlgo_.process(frameContext.lsc, metadata); +} + +REGISTER_IPA_ALGORITHM(Lsc, "Lsc") + +} /* namespace ipa::soft::algorithms */ + +} /* namespace libcamera */ diff --git a/src/ipa/simple/algorithms/lsc.h b/src/ipa/simple/algorithms/lsc.h new file mode 100644 index 000000000..13d9f2bca --- /dev/null +++ b/src/ipa/simple/algorithms/lsc.h @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Lens shading correction + */ + +#pragma once + +#include + +#include "libipa/fixedpoint.h" +#include "libipa/lsc.h" + +#include "algorithm.h" +#include "ipa_context.h" + +namespace libcamera { + +namespace ipa { + +namespace soft::algorithms { + +class Lsc : public Algorithm +{ +public: + Lsc() = default; + ~Lsc() = default; + + int init(IPAContext &context, const ValueNode &tuningData) override; + int configure(IPAContext &context, + const IPAConfigInfo &configInfo) override; + void queueRequest(IPAContext &context, [[maybe_unused]] const uint32_t frame, + IPAFrameContext &frameContext, const ControlList &controls) override; + void prepare(IPAContext &context, + const uint32_t frame, + IPAFrameContext &frameContext, + DebayerParams *params) override; + void process([[maybe_unused]] IPAContext &context, + [[maybe_unused]] const uint32_t frame, + IPAFrameContext &frameContext, + [[maybe_unused]] const SwIspStats *stats, + ControlList &metadata) override; + +private: + LscAlgorithm> lscAlgo_; + + std::vector gridPos_; + + unsigned int lastAppliedCt_ = 0; +}; + +} /* namespace soft::algorithms */ + +} /* namespace ipa */ + +} /* namespace libcamera */ diff --git a/src/ipa/simple/algorithms/meson.build b/src/ipa/simple/algorithms/meson.build index 73c637220..c9f6e5590 100644 --- a/src/ipa/simple/algorithms/meson.build +++ b/src/ipa/simple/algorithms/meson.build @@ -6,4 +6,5 @@ soft_simple_ipa_algorithms = files([ 'agc.cpp', 'blc.cpp', 'ccm.cpp', + 'lsc.cpp', ]) diff --git a/src/ipa/simple/ipa_context.h b/src/ipa/simple/ipa_context.h index ff312ae8f..23c2cfd0a 100644 --- a/src/ipa/simple/ipa_context.h +++ b/src/ipa/simple/ipa_context.h @@ -19,6 +19,7 @@ #include #include #include +#include "libipa/lsc.h" #include "core_ipa_interface.h" @@ -61,6 +62,8 @@ struct IPAActiveState { std::optional contrast; std::optional saturation; } knobs; + + ipa::lsc::ActiveState lsc; }; struct IPAFrameContext : public FrameContext { @@ -75,6 +78,7 @@ struct IPAFrameContext : public FrameContext { float gamma; std::optional contrast; std::optional saturation; + ipa::lsc::FrameContext lsc; }; struct IPAContext { @@ -89,6 +93,7 @@ struct IPAContext { FCQueue frameContexts; ControlInfoMap::Map ctrlMap; bool ccmEnabled = false; + ipa::lsc::ActiveState lsc; }; } /* namespace ipa::soft */ diff --git a/src/ipa/simple/soft_simple.cpp b/src/ipa/simple/soft_simple.cpp index 629e1a32d..f48ef76a5 100644 --- a/src/ipa/simple/soft_simple.cpp +++ b/src/ipa/simple/soft_simple.cpp @@ -163,6 +163,8 @@ int IPASoftSimple::init(const IPASettings &settings, params_->gamma = 1.0 / algorithms::kDefaultGamma; params_->contrastExp = 1.0; params_->gains = { { 1.0, 1.0, 1.0 } }; + params_->lscLutVersion = 0; + params_->lscLut = DebayerParams::identityLscLut; /* combinedMatrix is reset for each frame. */ } diff --git a/src/libcamera/software_isp/debayer.cpp b/src/libcamera/software_isp/debayer.cpp index 82cdf1dc2..6ebf7ed1a 100644 --- a/src/libcamera/software_isp/debayer.cpp +++ b/src/libcamera/software_isp/debayer.cpp @@ -66,6 +66,14 @@ namespace libcamera { * \brief Lens shading lookup table */ +/** + * \var DebayerParams::identityLscLut + * \brief Lens shading lookup table of identity mapping + * + * This table can be used to initialise the lens shading lookup table or to + * not apply any real lens shading correction. + */ + /** * \var DebayerParams::lscLutVersion * \brief Incremented on each \a lscLut change