Comparison of Advanced Compression for Bitonal Images

Comparison of Advanced Compression for Bitonal Images

This study extends the example tables for JBIG2-compressed PDF at both the Adobe and CVision websites, and then also adds a study of typical technical papers. Use this study to see for yourself the relative merits of advanced compression technologies for both DjVu and PDF, as applied to bitonal scanned images.

Use the displayed sizes to compare the compression effectiveness. Click the size hyperlinks to open files to compare actual performance.

Adobe Study - Extended

A comparison by James Rile, PlanetDjVu, Sept. 19, 2002, updated Oct. 22, 2002

...a DjVu and CVision JBIG2-PDF extension of...

http://www.adobe.com/products/acrcapture/agentpack/main.html

Document	PDF Image with G4 Comp- ression	PDF Image with JBIG2 Comp- ression (Capture)	PDF Image with JBIG2 Comp- ression (CVision)	DjVu Image using JB2 Comp- ression	Searchable Image with Group 4 Comp- ression	Searchable Image with JBIG2 Comp- ression (Capture)	Searchable Image with JBIG2 Comp- ression (CViison)	Searchable Image DjVu using JB2 Comp- ression
Contract	58k	14k	10k	10k	72k	28k	12k	12k
Annual Report	2.89M	511k	384k	396k	2.0M	755k	464k	527k
Technical Report	2.02M	431k	393k	368k	2.15M	582k	427k	419k
Patent	815k	153k	134k	123k	908k	240k	152k	162k
Total	5.84M	1.11M	921k	897k	5.13M	1.61M	1.055M	1.12M
Average	100%	19%	16%	15%	100%	31%	18%	22%

Comparison Notes:

All Adobe and CVision PDF files have been copied to the PlanetDjVu server, so you can make a good comparison of the relative performance and speed of PDF and DjVu files.

Remember, it is not just file size that is a factor in web performance, it is also file format design and the file viewer plug-in design. I notice a short lag time in the decoding of JBIG2-compressed PDF pages from Capture, while there is barely any lag time at all PDF pages from CVIision and in DjVu. Check for yourself!

DjVu files were produced (and OCRed) at the Any2DjVu conversion server.

CVision JBIG2-PDF files were produced by CVIsion using the latest Build 19 of their compressor.

CVision has introduced some clever text compression in addition to JBIG2 compression, which is why their OCRed JBIG2-PDF is actually smaller than DjVu!

CVision Study - Extended

A comparison by James Rile, PlanetDjVu, May 14, 2002, updated Oct. 4, 2002

...a DjVu and Acrobat Capture JBIG2-PDF extension of...

http://www.cvisiontech.com/jbig2_samplelinks.html

Reports

	TIFF Group IV size (bytes)	PDF size (bytes)	JBIG2 size (bytes)	JBIG2-PDF size (bytes) Capture	JBIG2-PDF size (bytes) cVision	DjVu size (bytes)
Starr report page 39	96,814	96,942	8,589	14,416	10,170	8,643

Patents

	TIFF Group IV size (bytes)	PDF size (bytes)	JBIG2 size (bytes)	JBIG2-PDF size (bytes) Capture	JBIG2-PDF size (bytes) cVision	DjVu size (bytes)
US Patent #US06122289	1,348,726	1,422,311	155,982	153,215	169,589	135,681

Books

	TIFF Group IV size (bytes)	PDF size (bytes)	JBIG2 size (bytes)	JBIG2-PDF size (bytes) Capture	JBIG2-PDF size (bytes) cVision	DjVu size (bytes)
Page1	172,700	178,132	19,624	52,679	22,206	13,031

Legal

	TIFF Group IV size (bytes)	PDF size (bytes)	JBIG2 size (bytes)	JBIG2-PDF size (bytes) Capture	JBIG2-PDF size (bytes) cVision	DjVu size (bytes)
Legal Page 1	69,432	72,285	11,335	19,637	12,890	12,216

Financial

	TIFF Group IV size (bytes)	PDF size (bytes)	JBIG2 size (bytes)	JBIG2-PDF size (bytes) Capture	JBIG2-PDF size (bytes) cVision	DjVu size (bytes)
Financial Contract 1	800,704	842,347	150,757	183,411	163,893	135,437

Fax

	TIFF Group IV size (bytes)	PDF size (bytes)	JBIG2 size (bytes)	JBIG2-PDF size (bytes) Capture	JBIG2-PDF size (bytes) cVision	DjVu size (bytes)
CCITT image 4	72,144	72,664	11,792	19,652	13,408	12,360

Totals

	TIFF Group IV size (bytes)	PDF size (bytes)	JBIG2 size (bytes)	JBIG2-PDF size (bytes) Capture	JBIG2-PDF size (bytes) cVision	DjVu size (bytes)
Size	2,560,520	2,684,641	358,079	443,010	392,156	317,448
Percent	100%	105%	14%	17.3%	15.3%	12.4%

NOTE: You need Adobe Acrobat Reader 5.0 or later to view JBIG2-encoded PDF files.

Technical Paper Comparison from JRA

This is a set of 59 technical papers presented at a symposium. The scanned text is clean and only one or two fonts are used. This study demonstrates compression levels that can be achieved with the scanning and conversion of clean, laser-printed scientific and technical papers.

Notes:

To view CIF files, you need the CVista Viewer Plug-in, available from: http://www.cvisiontech.com/cvista_viewer.html

To view DjVu files, you need the DjVu Web Browser Plugin, available from:

http://www.planetdjvu.com/djvu_plugin.htm

To view JBIG2-PDF files, you need Acrobat Reader 5.0 or above.

To compare the different formats, you want to test performance and factor these results with the compression levels achieved. Performance is best measured using files that have not yet been opened, and are therefore not in the browser's cache - they are directly opened from the URL address. You have plenty of unopened file links to test with below.

We observe that JBIG2-PDF files from CVision display faster than JBIG2-PDF from Acrobat Capture, due to faster decoding in the Acrobat Reader Plugin. DjVu files display twice as fast as any PDF alternative, due to having a file and plugin that is designed specifically for web delivery.

Filename	TIFF-G4 300 dpi	PDF 300 dpi	PDF 240 dpi	JBIG2-PDF 300 dpi Capture	JBIG2-PDF 300 dpi CVision	CIF 300 dpi	DjVu 300 dpi
001	0.535	0.586	0.466	0.151	0.095	0.080	0.083
002	0.601	0.665	0.526	0.186	0.128	0.103	0.107
003	0.333	0.369	0.295	0.106	0.028	0.065	0.060
004	0.002	0.004	0.003	0.003	0.003	0.001	0.001
005	0.364	0.617	0.487	0.239	0.216	0.195	0.151
006	1.090	1.192	0.948	0.332	0.276	0.250	0.259
007	0.945	1.027	0.816	0.282	0.216	0.185	0.184
008	0.002	0.004	0.003	0.003	0.003	0.001	0.001
009	1.234	1.353	1.073	0.346	0.275	0.215	0.225
010	0.002	0.004	0.003	0.003	0.003	0.001	0.001
011	0.002	0.004	0.003	0.003	0.003	0.001	0.001
012	0.002	0.004	0.003	0.003	0.003	0.001	0.001
013	0.422	0.460	0.364	0.181	0.150	0.146	0.143
014	0.565	0.648	0.520	0.223	0.164	0.136	0.129
015	1.179	1.347	1.066	0.482	0.386	0.336	0.352
016	0.866	0.960	0.760	0.251	0.164	0.130	0.153
017	0.814	0.894	0.706	0.246	0.168	0.148	0.160
018	0.425	0.475	0.374	0.139	0.093	0.084	0.092
019	1.072	1.181	0.929	0.371	0.308	0.264	0.277
020	0.800	0.929	0.740	0.284	0.197	0.171	0.206
021	0.742	0.802	0.633	0.255	0.162	0.141	0.141
022	1.085	1.202	0.953	0.313	0.247	0.194	0.207
023	0.002	0.004	0.003	0.003	0.003	0.001	0.001
024	0.002	0.004	0.003	0.003	0.003	0.001	0.001
025	0.634	0.751	0.605	0.257	0.187	0.161	0.169
026	0.002	0.004	0.003	0.003	0.003	0.001	0.001
027	0.479	0.554	0.444	0.207	0.146	0.133	0.138
028	0.651	0.762	0.613	0.244	0.171	0.143	0.157
029	0.857	0.994	0.793	0.338	0.265	0.230	0.261
030	0.002	0.004	0.003	0.003	0.003	0.001	0.001
031	0.661	0.764	0.611	0.228	0.158	0.140	0.142
032	0.702	0.793	0.629	0.273	0.186	0.167	0.173
033	0.763	0.885	0.711	0.283	0.229	0.201	0.209
034	0.586	0.696	0.559	0.224	0.160	0.134	0.143
035	0.318	0.353	0.281	0.129	0.098	0.095	0.095
036	0.734	0.845	0.675	0.405	0.319	0.294	0.284
037	0.407	0.466	0.371	0.166	0.129	0.117	0.116
038	0.371	0.435	0.346	0.152	0.104	0.089	0.103
039	0.640	0.724	0.574	0.246	0.191	0.070	0.185
040	0.002	0.004	0.003	0.003	0.003	0.001	0.001
041	1.022	1.187	0.952	0.444	0.359	0.327	0.334
042	0.002	0.004	0.003	0.003	0.003	0.001	0.001
043	1.023	1.178	0.948	0.398	0.315	0.280	0.284
044	0.808	0.920	0.742	0.336	0.249	0.232	0.262
045	1.112	1.273	1.017	0.298	0.210	0.164	0.199
046	0.977	1.128	0.904	0.340	0.265	0.224	0.246
047	0.550	0.630	0.503	0.178	0.127	0.105	0.110
048	0.264	0.303	0.243	0.124	0.082	0.075	0.071
049	0.549	0.617	0.490	0.230	0.194	0.168	0.145
050	0.002	0.004	0.003	0.003	0.003	0.001	0.001
051	0.002	0.004	0.003	0.003	0.003	0.001	0.001
052	0.002	0.004	0.003	0.003	0.003	0.001	0.001
053	0.002	0.004	0.003	0.003	0.003	0.001	0.001
054	0.002	0.004	0.003	0.003	0.003	0.001	0.001
055	0.002	0.004	0.003	0.003	0.003	0.001	0.001
056	0.002	0.004	0.003	0.003	0.003	0.001	0.001
057	0.002	0.004	0.003	0.003	0.003	0.001	0.001
058	0.002	0.004	0.003	0.003	0.003	0.001	0.001
059	0.002	0.004	0.003	0.003	0.003	0.001	0.001
Total	27.222	31.049	24.73	9.95	7.48	6.413	6.776
Percent	100%	114%	91%	37%	27%	24%	25%
	TIFF-G4 300 dpi	PDF 300 dpi	PDF 240 dpi	JBIG2-PDF 300 dpi Capture	JBIG2-PDF 300 dpi CVision	CIF 300 dpi	DjVu 300 dpi