From patchwork Sat Nov 13 08:49:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jean-Michel Hautbois X-Patchwork-Id: 14594 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 8D013BDB1C for ; Sat, 13 Nov 2021 08:49:59 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id 39BD860451; Sat, 13 Nov 2021 09:49:57 +0100 (CET) Authentication-Results: lancelot.ideasonboard.com; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="mKHVN0gY"; dkim-atps=neutral Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 939296036C for ; Sat, 13 Nov 2021 09:49:51 +0100 (CET) Received: from tatooine.ideasonboard.com (unknown [IPv6:2a01:e0a:169:7140:4d35:9445:6881:4ffd]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 4A2FB1490; Sat, 13 Nov 2021 09:49:51 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1636793391; bh=1+ZpyVr8E4p//ZS1A4+q8pMHMpddDrE2Nbise2ZoWj8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mKHVN0gYysefe1M5R0kGMIKBKWzJl2mhWqeEkGOiW4e5QfZofv8ZhA4RGn3YqjtnJ vRnU5ULJ88vLY+zDYjSD/lvvVZGsDrzYyiDNF1Vwg7I5E2OOBotKqHd5ecgnC6R67K LZmQPfZZvZ7mDlNl4j4UoHWT2Bi/qZOiYCSP4O7o= From: Jean-Michel Hautbois To: libcamera-devel@lists.libcamera.org Date: Sat, 13 Nov 2021 09:49:37 +0100 Message-Id: <20211113084947.21892-5-jeanmichel.hautbois@ideasonboard.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211113084947.21892-1-jeanmichel.hautbois@ideasonboard.com> References: <20211113084947.21892-1-jeanmichel.hautbois@ideasonboard.com> MIME-Version: 1.0 Subject: [libcamera-devel] [PATCH v5 04/14] ipa: ipu3: agc: Limit the number of saturated cells 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" When the histogram is calculated, we check if a cell is saturated or not before cumulating its green value. This is wrong, and it can lead to an empty histogram in case of a fully saturated frame. Use a constant to limit the amount of pixels within a cell before considering it saturated. If at the end of the loop we still have an empty histogram, then make it a fully saturated one. Bug: https://bugs.libcamera.org/show_bug.cgi?id=84 Signed-off-by: Jean-Michel Hautbois Reviewed-by: Kieran Bingham Reviewed-by: Paul Elder --- src/ipa/ipu3/algorithms/agc.cpp | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp index 5723f6f3..83aa3676 100644 --- a/src/ipa/ipu3/algorithms/agc.cpp +++ b/src/ipa/ipu3/algorithms/agc.cpp @@ -63,6 +63,12 @@ static constexpr uint32_t knumHistogramBins = 256; /* Target value to reach for the top 2% of the histogram */ static constexpr double kEvGainTarget = 0.5; +/* + * Maximum ratio of saturated pixels in a cell for the cell to be considered + * non-saturated and counted by the AGC algorithm. + */ +static constexpr uint32_t kMinCellsPerZoneRatio = 255 * 20 / 100; + Agc::Agc() : frameCount_(0), lastFrame_(0), iqMean_(0.0), lineDuration_(0s), minExposureLines_(0), maxExposureLines_(0), filteredExposure_(0s), @@ -124,7 +130,7 @@ void Agc::measureBrightness(const ipu3_uapi_stats_3a *stats, &stats->awb_raw_buffer.meta_data[cellPosition] ); - if (cell->sat_ratio == 0) { + if (cell->sat_ratio <= kMinCellsPerZoneRatio) { uint8_t gr = cell->Gr_avg; uint8_t gb = cell->Gb_avg; /* @@ -137,8 +143,14 @@ void Agc::measureBrightness(const ipu3_uapi_stats_3a *stats, } } + Histogram cumulativeHist = Histogram(Span(hist)); /* Estimate the quantile mean of the top 2% of the histogram */ - iqMean_ = Histogram(Span(hist)).interQuantileMean(0.98, 1.0); + if (cumulativeHist.total() == 0) { + /* Force the value as histogram is empty */ + iqMean_ = knumHistogramBins - 0.5; + } else { + iqMean_ = cumulativeHist.interQuantileMean(0.98, 1.0); + } } /**