From patchwork Tue Apr 5 06:57:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Naushir Patuck X-Patchwork-Id: 15620 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 08646C0F1B for ; Tue, 5 Apr 2022 06:58:03 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id 51D7665642; Tue, 5 Apr 2022 08:58:02 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=libcamera.org; s=mail; t=1649141882; bh=9wx/f1nPYlXISgf5B4OXSb6hRCIE5SFPK+T6gK1ZacI=; h=To:Date:Subject:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=cuMc05hxsq1U9bNrftW8JXJCgKZccR/AXHej6CqMx0hwFQyxZP6sgobVVwI7qGoop 4L34mxFg4MgOVtHEvCq+TxxD8YTv3IekMaMVvg2vQcSrtgciJnDZw/oQT1+KuOjuE3 0ZZtRWXxDCUoS2btAzKkHAOrOwEo96jqKmSoAI0o+kSYK5INTs9uBPMdeI3aPgx9Sf vMfDaWpwj8JmhttuTJxw1aoEJDAwup3ekicR1qprhccyVxs17EbuDz3IYTrUWIQsO5 4/Cp9nYpxnBVtsNQVBhVQdS+KV8m9KpE62MNx3594KQ8KfXESMN161pxoVDRDcsCzr HmGMm8GPf6Aiw== Received: from mail-wm1-x331.google.com (mail-wm1-x331.google.com [IPv6:2a00:1450:4864:20::331]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 7D28F604B7 for ; Tue, 5 Apr 2022 08:58:01 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (2048-bit key; unprotected) header.d=raspberrypi.com header.i=@raspberrypi.com header.b="Z9r3F+jw"; dkim-atps=neutral Received: by mail-wm1-x331.google.com with SMTP id r7so7321719wmq.2 for ; Mon, 04 Apr 2022 23:58:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=raspberrypi.com; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=l/jWLiW6ENeSmmXY5+OIgXwFe0cuM4EmajkCFaLVpso=; b=Z9r3F+jwpqF1OnE+5y40IU6eJFyNBC8HSI96b6b+3JSxFFjv+T5Axzkck28iYcgHWu 2MfD1B//QIk4iHnmGz5j/j9Lt90iCQ9ZWYCcP9IcUK58C4yY95EoEnApd1TcZ3LSnjak agpjiWyv5mAadtTjleSzgWzVDmdNIxkhnvgYl3Qd4eXErof0IGko+R5FxPlHXz7uRITM UiQcQez74Le4nsrgAsfCB3UGkZh0O01V91Iv43EO4zRRUyhXgU24Iak04ecb663J62d5 fTGWXeoztynal14jVHcgxzOh/u9rbFksNaTwLHl3EqvvlSC5gpJw8Sk48SKxvLc1K4H9 Rf7g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=l/jWLiW6ENeSmmXY5+OIgXwFe0cuM4EmajkCFaLVpso=; b=eo58adT8wNgSSXTJuzQzVcWwLJCcTJb0Htz1QQSdnupFytYLysPA9bsletD5DH5dHy lSxCDdHWRiR2kyeJW6pPl8be0mMhhmT878QWci2j1jcy+NizOlmYUBPfORxP0/p0j4T0 lNgIHtuwH0brOMHYeJMvZlyd5ra9SqrL3EmTTeIXNyh6NQQ8Zp2GqneNLS+dI/M0Blup ZmP3/jt4ufXAsUXSKYPWO/u+P85uKXQW1TGr4dNDiQoDYQX74nqa/GpUwRRAdXcfZLpK cek3q8soz4Y1zCkuz7BoDkKVRH87pPXSH588DzOl5XLvAgyD5jOFDLjGxZFyptv948tL 4kww== X-Gm-Message-State: AOAM531Xig79+CgjZk4tmzUzGLFJENqm8B0Uw1VgTnJlsWKKcrZA5KK9 tSCSNSSuOC+FvLvbaaWzyd62gqHHfZ2h9A== X-Google-Smtp-Source: ABdhPJz0jautWFJ3t5LegSLg7CssPjyDwv+ry8uAqC2Tp1PYvyvQSUUHP/90Z7BdCSUXbSp9QDXMOw== X-Received: by 2002:a1c:7219:0:b0:38c:a4f8:484f with SMTP id n25-20020a1c7219000000b0038ca4f8484fmr1654395wmc.99.1649141880857; Mon, 04 Apr 2022 23:58:00 -0700 (PDT) Received: from naush-laptop.pitowers.org ([2a00:1098:3142:14:547b:2a10:726e:d9e0]) by smtp.gmail.com with ESMTPSA id f1-20020a1c6a01000000b0038c9f6a3634sm1183373wmc.7.2022.04.04.23.58.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Apr 2022 23:58:00 -0700 (PDT) To: libcamera-devel@lists.libcamera.org Date: Tue, 5 Apr 2022 07:57:58 +0100 Message-Id: <20220405065758.2166956-1-naush@raspberrypi.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Subject: [libcamera-devel] [PATCH v2] ipa: raspberrypi: alsc: Limit the calculated lambda values 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: , X-Patchwork-Original-From: Naushir Patuck via libcamera-devel From: Naushir Patuck Reply-To: Naushir Patuck Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" Under the right circumstances, the alsc calculations could spread the colour errors across the entire image as lambda remains unbound. This would cause the corrected image chroma values to slowly drift to incorrect values. This change adds a config parameter (alsc.lambda_bound) that provides an upper and lower bound to the lambda value at every stage of the calculation. With this change, we now adjust the lambda values so that the average across the entire grid is 1 instead of normalising to the minimum value. Signed-off-by: Naushir Patuck Reviewed-by: David Plowman Reviewed-by: Laurent Pinchart --- src/ipa/raspberrypi/controller/rpi/alsc.cpp | 57 +++++++++++++++------ src/ipa/raspberrypi/controller/rpi/alsc.hpp | 1 + 2 files changed, 43 insertions(+), 15 deletions(-) diff --git a/src/ipa/raspberrypi/controller/rpi/alsc.cpp b/src/ipa/raspberrypi/controller/rpi/alsc.cpp index be3d1ae476cd..a88fee9f6d94 100644 --- a/src/ipa/raspberrypi/controller/rpi/alsc.cpp +++ b/src/ipa/raspberrypi/controller/rpi/alsc.cpp @@ -149,6 +149,7 @@ void Alsc::Read(boost::property_tree::ptree const ¶ms) read_calibrations(config_.calibrations_Cb, params, "calibrations_Cb"); config_.default_ct = params.get("default_ct", 4500.0); config_.threshold = params.get("threshold", 1e-3); + config_.lambda_bound = params.get("lambda_bound", 0.05); } static double get_ct(Metadata *metadata, double default_ct); @@ -610,30 +611,47 @@ static double compute_lambda_top_end(int i, double const M[XY][4], // Gauss-Seidel iteration with over-relaxation. static double gauss_seidel2_SOR(double const M[XY][4], double omega, - double lambda[XY]) + double lambda[XY], double lambda_bound) { + const double min = 1 - lambda_bound, max = 1 + lambda_bound; double old_lambda[XY]; int i; for (i = 0; i < XY; i++) old_lambda[i] = lambda[i]; lambda[0] = compute_lambda_bottom_start(0, M, lambda); - for (i = 1; i < X; i++) + lambda[0] = std::clamp(lambda[0], min, max); + for (i = 1; i < X; i++) { lambda[i] = compute_lambda_bottom(i, M, lambda); - for (; i < XY - X; i++) + lambda[i] = std::clamp(lambda[i], min, max); + } + for (; i < XY - X; i++) { lambda[i] = compute_lambda_interior(i, M, lambda); - for (; i < XY - 1; i++) + lambda[i] = std::clamp(lambda[i], min, max); + } + for (; i < XY - 1; i++) { lambda[i] = compute_lambda_top(i, M, lambda); + lambda[i] = std::clamp(lambda[i], min, max); + } lambda[i] = compute_lambda_top_end(i, M, lambda); + lambda[i] = std::clamp(lambda[i], min, max); // Also solve the system from bottom to top, to help spread the updates // better. lambda[i] = compute_lambda_top_end(i, M, lambda); - for (i = XY - 2; i >= XY - X; i--) + lambda[i] = std::clamp(lambda[i], min, max); + for (i = XY - 2; i >= XY - X; i--) { lambda[i] = compute_lambda_top(i, M, lambda); - for (; i >= X; i--) + lambda[i] = std::clamp(lambda[i], min, max); + } + for (; i >= X; i--) { lambda[i] = compute_lambda_interior(i, M, lambda); - for (; i >= 1; i--) + lambda[i] = std::clamp(lambda[i], min, max); + } + for (; i >= 1; i--) { lambda[i] = compute_lambda_bottom(i, M, lambda); + lambda[i] = std::clamp(lambda[i], min, max); + } lambda[0] = compute_lambda_bottom_start(0, M, lambda); + lambda[0] = std::clamp(lambda[0], min, max); double max_diff = 0; for (i = 0; i < XY; i++) { lambda[i] = old_lambda[i] + (lambda[i] - old_lambda[i]) * omega; @@ -653,15 +671,26 @@ static void normalise(double *ptr, size_t n) ptr[i] /= minval; } +// Rescale the values so that the avarage value is 1. +static void reaverage(double *ptr, size_t n) +{ + double sum = 0; + for (size_t i = 0; i < n; i++) + sum += ptr[i]; + double ratio = 1 / (sum / n); + for (size_t i = 0; i < n; i++) + ptr[i] *= ratio; +} + static void run_matrix_iterations(double const C[XY], double lambda[XY], double const W[XY][4], double omega, - int n_iter, double threshold) + int n_iter, double threshold, double lambda_bound) { double M[XY][4]; construct_M(C, W, M); double last_max_diff = std::numeric_limits::max(); for (int i = 0; i < n_iter; i++) { - double max_diff = fabs(gauss_seidel2_SOR(M, omega, lambda)); + double max_diff = fabs(gauss_seidel2_SOR(M, omega, lambda, lambda_bound)); if (max_diff < threshold) { LOG(RPiAlsc, Debug) << "Stop after " << i + 1 << " iterations"; @@ -675,10 +704,8 @@ static void run_matrix_iterations(double const C[XY], double lambda[XY], << last_max_diff << " to " << max_diff; last_max_diff = max_diff; } - // We're going to normalise the lambdas so the smallest is 1. Not sure - // this is really necessary as they get renormalised later, but I - // suppose it does stop these quantities from wandering off... - normalise(lambda, XY); + // We're going to normalise the lambdas so the total average is 1. + reaverage(lambda, XY); } static void add_luminance_rb(double result[XY], double const lambda[XY], @@ -737,9 +764,9 @@ void Alsc::doAlsc() compute_W(Cb, config_.sigma_Cb, Wb); // Run Gauss-Seidel iterations over the resulting matrix, for R and B. run_matrix_iterations(Cr, lambda_r_, Wr, config_.omega, config_.n_iter, - config_.threshold); + config_.threshold, config_.lambda_bound); run_matrix_iterations(Cb, lambda_b_, Wb, config_.omega, config_.n_iter, - config_.threshold); + config_.threshold, config_.lambda_bound); // Fold the calibrated gains into our final lambda values. (Note that on // the next run, we re-start with the lambda values that don't have the // calibration gains included.) diff --git a/src/ipa/raspberrypi/controller/rpi/alsc.hpp b/src/ipa/raspberrypi/controller/rpi/alsc.hpp index 9616b99ea7ca..d1dbe0d1d22d 100644 --- a/src/ipa/raspberrypi/controller/rpi/alsc.hpp +++ b/src/ipa/raspberrypi/controller/rpi/alsc.hpp @@ -41,6 +41,7 @@ struct AlscConfig { std::vector calibrations_Cb; double default_ct; // colour temperature if no metadata found double threshold; // iteration termination threshold + double lambda_bound; // upper/lower bound for lambda from a value of 1 }; class Alsc : public Algorithm