Tom Lane, Philip Gladstone, Luis Ortiz, Jim Boucher, Lee Crocker, Julian Minguillon, George Phillips, Davide Rossi, and Ge' Weijers, "The independent jpeg group's jpeg software release 6b," ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....from which our images came. Not counting repeated accesses to the same image, we found that the vast majority of the images in our collection (80 of GIFs and 77 of JPEGs) are from the .com domain. 3.2. 3 Implementation Details For our experiments, we used utilities from NetPBM [55] and libjpeg [77] to perform the various transcoding operations on GIF and JPEG images. 27 0 20 40 60 80 100 0 5 10 15 20 25 30 35 40 45 50 Cumulative Distribution ( Image Size (KBs) rounded down (0 to 1023 bytes is represented as 0 KB) GIF (actual) GIF (size #animations) JPEG Figure 3.1: ....

....31 3.3.3 JPEG Compression Metric Next we explore the JPEG compression metric. Lossy compression techniques such as JPEG define a way to specify the amount of lossiness using metrics such as the compression metric (also referred to as the JPEG Quality Factor by Independent JPEG Group [77]) In JPEG, the compression ratio of the output image is controlled solely by the quantization tables used in step 4 (Table 3.1) An all 1 s quantizer achieves a compression ratio that is comparable to a lossless compression algorithm. The JPEG specification [22] section K.1, provides standard ....

[Article contains additional citation context not shown here]

Tom Lane, Philip Gladstone, Luis Ortiz, Jim Boucher, Lee Crocker, Julian Minguillon, George Phillips, Davide Rossi, and Ge' Weijers. The independent JPEG group's JPEG software release 6b. ftp://ftp.uu.net/ graphics/jpeg/jpegsrc.v6b.tar.gz.

....referred to as the JPEG Quality Factor) Reconstructing the original Quality Factor used to produce the image is necessary so loss in quality becomes meaningful. Using the quantization tables stored in the JFIF [10] headers, we developed an algorithm to predict the Independent JPEG Group s (IJG) [12] equivalent of the JPEG Quality Factor for images compressed using popular JPEG compressors from IJG, Adobe PhotoShop TM and Paint Shop Pro TM . We utilized results showing that the information quality loss directly corresponds to the change in the JPEG Quality Factor [13] 14] Next, we ....

Tom Lane, Philip Gladstone, Luis Ortiz, Jim Boucher, Lee Crocker, Julian Minguillon, George Phillips, Davide Rossi, and Ge' Weijers, "The independent jpeg group's jpeg software release 6b," ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.

....we show that, for a transcoding that changes the JPEG compression metric (referred to as the JPEG Quality Factor) the change in JPEG Quality Factor directly corresponds to the information quality lost. To measure this change, we describe an algorithm to compute the Independent JPEG Group s (IJG) [15] equivalent of the JPEG Quality Factor of any JPEG image. To understand the overhead involved in performing a transcoding, we develop a predictor that predicts the computational overhead with a high degree of accuracy. We also develop a predictor for predicting if an image will transcode ....

....for the scaling factor, by specifying a compression metric called Quality Factor. This Quality Factor is an artifact of JPEG compression. Different software implementations use different values for Quality Factor. Quality Factors are not standardized across JPEG implementations. The IJG Library [15] uses a 0 100 scale, while Apple formerly used a scale running from 0 to 4. Recent Apple software uses an 0100 scale that is different from the IJG scale. Paint Shop Pro s scale uses a 100 0 scale, where lower numbers imply higher quality. Adobe Photoshop gives discrete maximum high medium low ....

T. Lane, P. Gladstone, L. Ortiz, J. Boucher, L. Crocker, J. Minguillon, G. Phillips, D. Rossi, and G. Weijers. The independent jpeg group's jpeg software release 6b. ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.

....by specifying a compression metric called Quality factor. This Quality factor is an artifact of JPEG compression. Different software implementations use different values for Quality factor. Quality factors are not standardized across JPEG implementations. The Independent JPEG Group s (IJG) Library[11] uses a 0 100 scale, while Apple formerly used a scale running from 0 to 4. Recent Apple software uses an 0 100 scale that is different from the IJG scale. Paint Shop Pro s scale uses a 100 0 scale, where lower numbers imply higher quality. Adobe Photoshop gives discrete maximum high medium low ....

Tom Lane, Philip Gladstone, Luis Ortiz, Jim Boucher, Lee Crocker, Julian Minguillon, George Phillips, Davide Rossi, and Ge' Weijers. The independent jpeg group's jpeg software release 6b. ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.

....cessed to some degree. Reconstructing the original Quality Factor that was used to produce the image is necessary so loss in quality becomes meaningful. Using the quantization tables stored in the JFIF [14] headers, we developed an algorithm to predict the Independent JPEG Group s (IJG) [26] equivalent of the JPEG Quality Factor for images compressed using popular JPEG compressors from IJG, Adobe Photoshop and Paint Shop Pro. We utilized results showing that the information quality loss directly corresponds to the change in the JPEG Quality Factor [12, 20] Next, we characterized ....

T. Lane, P. Gladstone, L. Ortiz, J. Boucher, L. Crocker, J. Minguillon, G. Phillips, D. Rossi, and G. Weijers. The independent JPEG group's JPEG software release 6b. ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.

....such as the JPEG Quality factor. Reconstructing the original Quality factor that was used to produce the image is necessary so loss in quality becomes meaningful. Using the quantization tables stored in the JFIF [10] headers, we developed an algorithm to predict the Independent JPEG Group s (IJG) [15] equivalent of the JPEG Quality factor for images compressed using popular JPEG compressors from IJG, Adobe Photoshop and Paint Shop Pro. We utilized results showing that the information quality loss directly corresponds to the change in the JPEG Quality factor [6, 13] Next, we characterize the ....

LANE, T., GLADSTONE, P., ORTIZ, L., BOUCHER, J., CROCKER, L., MINGUILLON, J., PHILLIPS, G., ROSSI, D., AND WEI- JERS, G. The independent jpeg group's jpeg software release 6b. ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.

....such as the JPEG Quality factor. Reconstructing the original Quality factor that used to produce the image is necessary so loss in quality becomes meaningful. Using the quantization tables stored in the JFIF [9] headers, we developed an algorithm to predict the Independent JPEG Group s (IJG) [10] equivalent of the JPEG Quality factor for images compressed using popular JPEG compressors from IJG, Adobe Photoshop and Paint Shop Pro. We utilized results showing that the information quality loss directly corresponds to the change in the JPEG Quality factor [5] 6] Next, we characterize the ....

....web servers and stored on two separate, dedicated 21 GB IBM DeskStar 22GXP drives on separate Promise Ultra 33 IDE channels. Web Server: We modified the Apache Server [7] to offer differentiated service by choosing a number of transcoded image variants. We used the Independent JPEG Group s [10] JPEG library, along with the transcoding algorithm described in [3] to generate variations of the im 7 ages. We modified Apache server to keep track of the current bandwidth utilization for the different user classes. Since the request pattern and hence the bandwidth consumption is bursty, the ....

Tom Lane, Philip Gladstone, Luis Ortiz, Jim Boucher, Lee Crocker, Julian Minguillon, George Phillips, Davide Rossi, and Ge' Weijers, "The independent jpeg group's jpeg software release 6b," ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.

....of a transcoding that changes the JPEG [17] compression metric. We show that, for a transcoding that changes the JPEG compression metric, the change in JPEG Quality Factor directly corresponds to the information quality lost. We describe an algorithm to compute the Independent JPEG Group s (IJG) [12] equivalent of the JPEG Quality Factor of any JPEG image. Reconstructing the initial image quality is required in order to quantify the quality loss due to transcoding operations. To understand the overhead involved in performing a transcoding, we develop a predictor that estimates the ....

T. Lane, P. Gladstone, L. Ortiz, J. Boucher, L. Crocker, J. Minguillon, G. Phillips, D. Rossi, and G. Weijers. The Independent JPEG Group's JPEG Software Release 6b. ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.

....which our images came. Not counting repeated accesses to the same image, we have found that the vast majority of the images in our collection (80 of GIFs and 77 of JPEGs) are from the .com domain. 2. 3 Implementation Details For our experiments, we used utilities from NetPBM [16] and libjpeg [20] to perform the various transcoding operations on GIF and JPEG images. 3 Static Image Characteristics In order to understand the characteristics of images accessed on the internet today, we first analyze the static characteristics of the images. Static image characteristics such as image ....

....in our collection, 5 of the JPEG images were GrayScale. 3. 3 JPEG Compression Metric Lossy compression techniques such as JPEG define a way to specify the amount of lossiness using metrics such as the compression metric (also referred to as the JPEG Quality Factor by Independent JPEG Group [20]) The Quality Factor value that was used in encoding a JPEG image is not stored along with the image. In our earlier work [2] we developed an algorithm to accurately measure the initial JPEG Quality Factor 7 0 200 400 600 800 1000 0 200 400 600 800 1000 Height (in pixels) Width (in ....

Tom Lane, Philip Gladstone, Luis Ortiz, Jim Boucher, Lee Crocker, Julian Minguillon, George Phillips, Davide Rossi, and Ge' Weijers. The independent jpeg group's jpeg software release 6b. ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.

....such as the JPEG Quality factor [3] Reconstructing the original Quality factor that used to produce the image is necessary so loss in quality becomes meaningful. Using the quantization tables stored in the JFIF [8] headers, we developed an algorithm to predict the Independent JPEG Group s (IJG) [9] equivalent of the JPEG Quality factor for images compressed using popular JPEG compressors from IJG, Adobe Photoshop and Paint Shop Pro. We utilized results showing that the information quality loss directly corresponds to the change in the JPEG Quality factor [10] 11] Next, we characterized ....

....web servers and stored on two separate, dedicated 21 GB IBM DeskStar 22GXP drives on separate Promise Ultra 33 IDE channels. Web Server: We modified the Apache Server [6] to offer differentiated service by choosing a number of transcoded image variants. We used the Independent JPEG Group s [9] JPEG library, along with the transcoding algorithm described in [3] to generate variations of the images. We modified Apache server to keep track of the current bandwidth utilization for the different user classes. Since the request pattern and hence the bandwidth consumption is bursty, the ....

Tom Lane, Philip Gladstone, Luis Ortiz, Jim Boucher, Lee Crocker, Julian Minguillon, George Phillips, Davide Rossi, and Ge' Weijers, "The independent jpeg group's jpeg software release 6b," ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.

No context found.

Tom Lane, Philip Gladstone, Luis Ortiz, Jim Boucher, Lee Crocker, Julian Minguillon, George Phillips, Davide Rossi, and Ge' Weijers, "The independent jpeg group's jpeg software release 6b," ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.

No context found.

T. Lane, P. Gladstone, L. Ortiz, J. Boucher, L. Crocker, J. Minguillon, G. Phillips, D. Rossi, and G. Weijers, "The independent jpeg group's jpeg software release 6b." ftp://ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz.

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC