[{"id":34154,"web_url":"https://patchwork.libcamera.org/comment/34154/","msgid":"","date":"2025-05-07T17:34:13","subject":"Re: [PATCH v3 16/16] ipa: rkisp1: awb: Avoid division by zero","submitter":{"id":17,"url":"https://patchwork.libcamera.org/api/people/17/","name":"Paul Elder","email":"paul.elder@ideasonboard.com"},"content":"On Thu, Apr 03, 2025 at 05:49:21PM +0200, Stefan Klug wrote:\n> As the gains can also be specified manually, the regulation can run into\n> numeric instabilities by dividing by near zero. Mitigate that by\n> applying a small minium value.\n> \n> Signed-off-by: Stefan Klug \n> Reviewed-by: Kieran Bingham \n\nReviewed-by: Paul Elder \n\n> \n> ---\n> \n> Changes in v2:\n> - Collected tag\n> ---\n> src/ipa/rkisp1/algorithms/awb.cpp | 4 ++--\n> 1 file changed, 2 insertions(+), 2 deletions(-)\n> \n> diff --git a/src/ipa/rkisp1/algorithms/awb.cpp b/src/ipa/rkisp1/algorithms/awb.cpp\n> index 03449e87e1a0..84aa1d29419d 100644\n> --- a/src/ipa/rkisp1/algorithms/awb.cpp\n> +++ b/src/ipa/rkisp1/algorithms/awb.cpp\n> @@ -406,9 +406,9 @@ RGB Awb::calculateRgbMeans(const IPAFrameContext &frameContext, const rk\n> \t/*\n> \t * The ISP computes the AWB means after applying the colour gains,\n> \t * divide by the gains that were used to get the raw means from the\n> -\t * sensor.\n> +\t * sensor. Apply a minimum value to avoid divisions by near-zero.\n> \t */\n> -\trgbMeans /= frameContext.awb.gains;\n> +\trgbMeans /= frameContext.awb.gains.max(0.01);\n> \n> \treturn rgbMeans;\n> }\n> -- \n> 2.43.0\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id BA46FC3226\n\tfor ;\n\tWed, 7 May 2025 17:34:18 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 7539068B31;\n\tWed, 7 May 2025 19:34:18 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id E62D668B30\n\tfor ;\n\tWed, 7 May 2025 19:34:16 +0200 (CEST)","from pyrite.rasen.tech (unknown\n\t[IPv6:2001:861:3a80:3300:4f2f:8c2c:b3ef:17d4])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 6E7CDC59;\n\tWed, 7 May 2025 19:34:05 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"aC91nKl2\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1746639245;\n\tbh=Z3LyA93vHRiW4lU/gQwLeih3YGYGKDWf3O5xThK57b4=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=aC91nKl2xM6KaIpBGSMbpxl1Kq09qsU51ShJQvC/ZCFQwIn0/3A21I9QvNGUen8ik\n\tHjgo67iaSBby61cBXoUe0B9ihZvKKDcJwky5NwVa8zEYx75XhvHrHAJbCwRgXAt8lr\n\t+DMA7TfasEcvtQP9YvZ8vpRIDUa1srzRDD0aKiF0=","Date":"Wed, 7 May 2025 19:34:13 +0200","From":"Paul Elder ","To":"Stefan Klug ","Cc":"libcamera-devel@lists.libcamera.org,\n\tKieran Bingham ","Subject":"Re: [PATCH v3 16/16] ipa: rkisp1: awb: Avoid division by zero","Message-ID":"","References":"<20250403154925.382973-1-stefan.klug@ideasonboard.com>\n\t<20250403154925.382973-17-stefan.klug@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=us-ascii","Content-Disposition":"inline","In-Reply-To":"<20250403154925.382973-17-stefan.klug@ideasonboard.com>","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]