From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HTML_MESSAGE,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H3,RCVD_IN_MSPIKE_WL autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 1496 invoked from network); 29 Jan 2022 22:40:38 -0000 Received: from tb-ob0.topicbox.com (64.147.108.117) by inbox.vuxu.org with ESMTPUTF8; 29 Jan 2022 22:40:38 -0000 Received: from tb-mx0.topicbox.com (tb-mx0.nyi.icgroup.com [10.90.30.73]) by tb-ob0.topicbox.com (Postfix) with ESMTP id 7B335314D5 for ; Sat, 29 Jan 2022 17:40:37 -0500 (EST) (envelope-from bounce.mM9f60f8b5ffc2c3bb7b2c02d9.r522be890-2105-11eb-b15e-8d699134e1fa@9fans.bounce.topicbox.com) Received: by tb-mx0.topicbox.com (Postfix, from userid 1132) id 76DB81470536; Sat, 29 Jan 2022 17:40:37 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=9fans.net; h=to:subject :message-id:references:in-reply-to:date:mime-version :content-type:content-transfer-encoding:from:list-help:list-id :list-post:list-subscribe:reply-to:list-unsubscribe; s=dkim-1; bh=f1K79v5RSss+VcFHxPtGpgpn4OgRKK7D1hfD6MQATng=; b=XZAewmx0ArTX NT0mya/oig5U89XfIdhCnKblxzqT3KhWfxt2nutNNmZVHjIth2wwfB8KjXy4MVGD cvHi8GjmwCn2ZlHJVZOLtTv9yF2Wwur3YLJvy73ig2wNdxRayEl+okFjM5VCzEBg juoVqK6zuAPETaYezbzSLJcvKI4ui7Q= To: 9fans <9fans@9fans.net> Subject: Re: [9fans] licence question Message-Id: <16434960320.29d60.470765@composer.9fans.topicbox.com> References: <16433324650.ff90B.935638@composer.9fans.topicbox.com> <16433713090.e62E5Cc03.507002@composer.9fans.topicbox.com> <16434613850.BC38c.59069@composer.9fans.topicbox.com> <16434652910.557dFF03.267022@composer.9fans.topicbox.com> In-Reply-To: Date: Sat, 29 Jan 2022 17:40:32 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary=16434960321.7cF8.470765 Content-Transfer-Encoding: 7bit Topicbox-Policy-Reasoning: allow: sender is a member Topicbox-Message-UUID: 77c82cac-8154-11ec-a60c-33da212d11b0 Archived-At: =?UTF-8?B?PGh0dHBzOi8vOWZhbnMudG9waWNib3guY29tL2dyb3Vwcy85?= =?UTF-8?B?ZmFucy9UM2UwN2JmZGYyNjNhODNjOC1NOWY2MGY4YjVmZmMyYzNiYjdiMmMw?= =?UTF-8?B?MmQ5Pg==?= From: "ibrahim via 9fans" <9fans@9fans.net> List-Help: List-Id: "9fans" <9fans.9fans.net> List-Post: List-Software: Topicbox v0 List-Subscribe: Precedence: list Reply-To: 9fans <9fans@9fans.net> List-Unsubscribe: , Topicbox-Delivery-ID: 2:9fans:437d30aa-c441-11e9-8a57-d036212d11b0:522be890-2105-11eb-b15e-8d699134e1fa:M9f60f8b5ffc2c3bb7b2c02d9:1:xz3UaL-Xr2GMQOicbivXIHiODkHBaZrn11I8vaOSnk8 --16434960321.7cF8.470765 Date: Sat, 29 Jan 2022 17:40:32 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Saturday, 29 January 2022, at 11:14 PM, Bakul Shah wrote: > Note that djvu would compress things very nicely. A full page 300dpi magazine color page that may be 25MB uncompressed will compress down to 40K-80K or so and be very legible, much more so compared a similar sized jpeg compressed image. Thanks for your hint. I'm using djvu format for scanned book pages for my p= rivate use. The algorithm isn't easy to reimplement cause it uses pattern m= atching in an extensive way. You get the best results for scanned material = where as an example letters are matched quite often. It has superb compress= ion ratios but is slow regarding decompression or rendering. Regarding handwritten scans the best method I experienced is edge detection= filtering and color indexing to create a ppm image. Compression leads than= to smaller sizes than by using jpeg. Decompression is faster and when you = combine two lines to single one (subpixeling) you get smooth and clean imag= es. For printed sources djvu produces far smaller results. Thank you for this h= int. ------------------------------------------ 9fans: 9fans Permalink: https://9fans.topicbox.com/groups/9fans/T3e07bfdf263a83c8-M9f60f= 8b5ffc2c3bb7b2c02d9 Delivery options: https://9fans.topicbox.com/groups/9fans/subscription --16434960321.7cF8.470765 Date: Sat, 29 Jan 2022 17:40:32 -0500 MIME-Version: 1.0 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Saturday, 29 January 2022, at 11:14 PM, Bak= ul Shah wrote:
Note that djvu would co= mpress things very nicely. A full page 300dpi magazine color page that may be 25MB uncompressed will compress down to 40K-80K or so and be very legible, much more so compared a similar sized jpeg compressed image.
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Thanks for your hint. I'm using djvu format for scanned= book pages for my private use. The algorithm isn't easy to reimplement= cause it uses pattern matching in an extensive way. You get the best resul= ts for scanned material where as an example letters are matched quite often= . It has superb compression ratios but is slow regarding decompression or r= endering.

Regarding handwritten scans the = best method I experienced is edge detection filtering and color indexing to= create a ppm image. Compression leads than to smaller sizes than by using = jpeg. Decompression is faster and when you combine two lines to single one = (subpixeling) you get smooth and clean images.

=
For printed sources djvu produces far smaller results. Thank you for t= his hint.

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