X-GM-THRID: 1222419215961516802 X-Gmail-Labels: rsgb lf Delivered-To: daveyxm@gmail.com Received: by 10.70.56.11 with SMTP id e11cs371368wxa; Sun, 10 Dec 2006 14:30:10 -0800 (PST) Received: by 10.78.127.3 with SMTP id z3mr1053026huc.1165789810107; Sun, 10 Dec 2006 14:30:10 -0800 (PST) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.google.com with ESMTP id 31si2073552hub.2006.12.10.14.30.08; Sun, 10 Dec 2006 14:30:10 -0800 (PST) Received-SPF: neutral (google.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1GtX5k-000713-1U for rs_out_1@blacksheep.org; Sun, 10 Dec 2006 22:24:16 +0000 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1GtX5j-00070u-7I for rsgb_lf_group@blacksheep.org; Sun, 10 Dec 2006 22:24:15 +0000 Received: from imo-m18.mx.aol.com ([64.12.138.208]) by relay2.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1GtX5g-0004XS-3z for rsgb_lf_group@blacksheep.org; Sun, 10 Dec 2006 22:24:15 +0000 Received: from MarkusVester@aol.com by imo-m18.mx.aol.com (mail_out_v38_r7.6.) id l.3f5.12571ae4 (43930) for ; Sun, 10 Dec 2006 17:24:00 -0500 (EST) From: MarkusVester@aol.com Message-ID: <3f5.12571ae4.32ade2fe@aol.com> Date: Sun, 10 Dec 2006 17:23:58 EST To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 X-Mailer: 8.0 for Windows sub 6104 X-Spam-Flag: NO X-Spam-Score: 0.2 (/) X-Spam-Report: autolearn=disabled,AWL=-1.259,HTML_10_20=0.945,HTML_MESSAGE=0.001,NO_REAL_NAME=0.55 Subject: LF: Grabber image format Content-Type: multipart/alternative; boundary="part1_3f5.12571ae4.32ade2fe_boundary" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.7 required=5.0 tests=HTML_MESSAGE, HTML_TAG_BALANCE_HTML,NO_REAL_NAME autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false Status: O X-Status: X-Keywords: X-UID: 6732 --part1_3f5.12571ae4.32ade2fe_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Dear LF Group, today I have changed the 8-bit image format for my grabber from .gif to .png. This appears to save some 20% of volume, due to a more effective lossless compression algorithm. When I started grabber operation I had tried various flavours of .jpg first, but the halved colour resolution soon turned out inadequate for many fine details on the colour-DF display. With 256 colours and lossless compression, resolution looked much better, but very weak signals and noise details tended to get masked off by too few dark palette entries. I got around that by brightening the original bitmap (gamma=1.49 in IrfanView) before reducing to 8 bits, and then darkening the colour table again (gamma=0.67) before uploading. Please report if you find any difficulties displaying or downloading the .png images. 73 de Markus, DF6NM http://members.aol.com/df6nm/Grabber.htm --part1_3f5.12571ae4.32ade2fe_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Dear LF Group,

today I have changed the 8-bit image format for my grabber from .gif to .png= . This appears to save some 20% of volume, due to a more effective lossless=20= compression algorithm.

When I started grabber operation I had tried various flavours of .jpg first,= but the halved colour resolution soon turned out inadequate for many fine d= etails on the colour-DF display. With 256 colours and lossless compression,=20= resolution looked much better, but very weak signals and noise details tende= d to get masked off by too few dark palette entries. I got around that by br= ightening the original bitmap (gamma=3D1.49 in IrfanView) before reducing to= 8 bits, and then darkening the colour table again (gamma=3D0.67) before upl= oading.

Please report if you find any difficulties displaying or downloading the .pn= g images.

73 de Markus, DF6NM

http://members.aol.com/= df6nm/Grabber.htm
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