What Resolution Should Your Images Be?
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Exploring the .BMP File Format
Exploring the .BMP File Format Don Lancaster Synergetics, Box 809, Thatcher, AZ 85552 copyright c2003 as GuruGram #14 http://www.tinaja.com [email protected] (928) 428-4073 The .BMP image standard is used by Windows and elsewhere to represent graphics images in any of several different display and compression options. The .BMP advantages are that each pixel is usually independently available for any alteration or modification. And that repeated use does not normally degrade the image. Because lossy compression is not used. Its main disadvantage is that file sizes are usually horrendous compared to JPEG, fractal, GIF, or other lossy compression schemes. A comparison of popular image standards can be found here. I’ve long been using the .BMP format for my eBay and my other phototography, scanning, and post processing. I firmly believe that… All photography, scanning, and all image post-processing should always be done using .BMP or a similar non-lossy format. Only after all post-processing is complete should JPEG or another compressed distribution format be chosen. Some current examples of my .BMP work now do include the IMAGIMAG.PDF post-processing tutorial, the Bitmap Typewriterthat generates fully anti-aliased small fonts, the Aerial Photo Combiner, and similar utilities and tutorials found on our Fonts & Images, PostScript, and on our Acrobat library pages. A few projects of current interest involving .BMP files include true view camera swings and tilts for a digital camera, distortion correction, dodging & burning, preventing white punchthrough on knockouts, and emphasis vignetting. Mainly applied to uncompressed RGBX 24-bit color .BMP files. -
Free Lossless Image Format
FREE LOSSLESS IMAGE FORMAT Jon Sneyers and Pieter Wuille [email protected] [email protected] Cloudinary Blockstream ICIP 2016, September 26th DON’T WE HAVE ENOUGH IMAGE FORMATS ALREADY? • JPEG, PNG, GIF, WebP, JPEG 2000, JPEG XR, JPEG-LS, JBIG(2), APNG, MNG, BPG, TIFF, BMP, TGA, PCX, PBM/PGM/PPM, PAM, … • Obligatory XKCD comic: YES, BUT… • There are many kinds of images: photographs, medical images, diagrams, plots, maps, line art, paintings, comics, logos, game graphics, textures, rendered scenes, scanned documents, screenshots, … EVERYTHING SUCKS AT SOMETHING • None of the existing formats works well on all kinds of images. • JPEG / JP2 / JXR is great for photographs, but… • PNG / GIF is great for line art, but… • WebP: basically two totally different formats • Lossy WebP: somewhat better than (moz)JPEG • Lossless WebP: somewhat better than PNG • They are both .webp, but you still have to pick the format GOAL: ONE FORMAT THAT COMPRESSES ALL IMAGES WELL EXPERIMENTAL RESULTS Corpus Lossless formats JPEG* (bit depth) FLIF FLIF* WebP BPG PNG PNG* JP2* JXR JLS 100% 90% interlaced PNGs, we used OptiPNG [21]. For BPG we used [4] 8 1.002 1.000 1.234 1.318 1.480 2.108 1.253 1.676 1.242 1.054 0.302 the options -m 9 -e jctvc; for WebP we used -m 6 -q [4] 16 1.017 1.000 / / 1.414 1.502 1.012 2.011 1.111 / / 100. For the other formats we used default lossless options. [5] 8 1.032 1.000 1.099 1.163 1.429 1.664 1.097 1.248 1.500 1.017 0.302� [6] 8 1.003 1.000 1.040 1.081 1.282 1.441 1.074 1.168 1.225 0.980 0.263 Figure 4 shows the results; see [22] for more details. -
Invention of Digital Photograph
Invention of Digital photograph Digital photography uses cameras containing arrays of electronic photodetectors to capture images focused by a lens, as opposed to an exposure on photographic film. The captured images are digitized and stored as a computer file ready for further digital processing, viewing, electronic publishing, or digital printing. Until the advent of such technology, photographs were made by exposing light sensitive photographic film and paper, which was processed in liquid chemical solutions to develop and stabilize the image. Digital photographs are typically created solely by computer-based photoelectric and mechanical techniques, without wet bath chemical processing. The first consumer digital cameras were marketed in the late 1990s.[1] Professionals gravitated to digital slowly, and were won over when their professional work required using digital files to fulfill the demands of employers and/or clients, for faster turn- around than conventional methods would allow.[2] Starting around 2000, digital cameras were incorporated in cell phones and in the following years, cell phone cameras became widespread, particularly due to their connectivity to social media websites and email. Since 2010, the digital point-and-shoot and DSLR formats have also seen competition from the mirrorless digital camera format, which typically provides better image quality than the point-and-shoot or cell phone formats but comes in a smaller size and shape than the typical DSLR. Many mirrorless cameras accept interchangeable lenses and have advanced features through an electronic viewfinder, which replaces the through-the-lens finder image of the SLR format. While digital photography has only relatively recently become mainstream, the late 20th century saw many small developments leading to its creation. -
JPEG File Interchange Format Version 1.02
JPEG File Interchange Format Version 1.02 September 1, 1992 Eric Hamilton C-Cube Microsystems 1778 McCarthy Blvd. Milpitas, CA 95035 +1 408 944-6300 Fax: +1 408 944-6314 E-mail: [email protected] JPEG File Interchange Format Version 1.02 Why a File Interchange Format JPEG File Interchange Format is a minimal file format which enables JPEG bitstreams to be exchanged between a wide variety of platforms and applications. This minimal format does not include any of the advanced features found in the TIFF JPEG specification or any application specific file format. Nor should it, for the only purpose of this simplified format is to allow the exchange of JPEG compressed images. JPEG File Interchange Format features • Uses JPEG compression • Uses JPEG interchange format compressed image representation • PC or Mac or Unix workstation compatible • Standard color space: one or three components. For three components, YCbCr (CCIR 601-256 levels) • APP0 marker used to specify Units, X pixel density, Y pixel density, thumbnail • APP0 marker also used to specify JFIF extensions • APP0 marker also used to specify application-specific information JPEG Compression Although any JPEG process is supported by the syntax of the JPEG File Interchange Format (JFIF) it is strongly recommended that the JPEG baseline process be used for the purposes of file interchange. This ensures maximum compatibility with all applications supporting JPEG. JFIF conforms to the JPEG Draft International Standard (ISO DIS 10918-1). The JPEG File Interchange Format is entirely compatible with the standard JPEG interchange format; the only additional requirement is the mandatory presence of the APP0 marker right after the SOI marker. -
Foveon FO18-50-F19 4.5 MP X3 Direct Image Sensor
® Foveon FO18-50-F19 4.5 MP X3 Direct Image Sensor Features The Foveon FO18-50-F19 is a 1/1.8-inch CMOS direct image sensor that incorporates breakthrough Foveon X3 technology. Foveon X3 direct image sensors Foveon X3® Technology • A stack of three pixels captures superior color capture full-measured color images through a unique stacked pixel sensor design. fidelity by measuring full color at every point By capturing full-measured color images, the need for color interpolation and in the captured image. artifact-reducing blur filters is eliminated. The Foveon FO18-50-F19 features the • Images have improved sharpness and immunity to color artifacts (moiré). powerful VPS (Variable Pixel Size) capability. VPS provides the on-chip capabil- • Foveon X3 technology directly converts light ity of grouping neighboring pixels together to form larger pixels that are optimal of all colors into useful signal information at every point in the captured image—no light for high frame rate, reduced noise, or dual mode still/video applications. Other absorbing filters are used to block out light. advanced features include: low fixed pattern noise, ultra-low power consumption, Variable Pixel Size (VPS) Capability and integrated digital control. • Neighboring pixels can be grouped together on-chip to obtain the effect of a larger pixel. • Enables flexible video capture at a variety of resolutions. • Enables higher ISO mode at lower resolutions. Analog Biases Row Row Digital Supplies • Reduces noise by combining pixels. Pixel Array Analog Supplies Readout Reset 1440 columns x 1088 rows x 3 layers On-Chip A/D Conversion Control Control • Integrated 12-bit A/D converter running at up to 40 MHz. -
JPEG-Resistant Adversarial Images
JPEG-resistant Adversarial Images Richard Shin Dawn Song Computer Science Division Computer Science Division University of California, Berkeley University of California, Berkeley [email protected] [email protected] Abstract Several papers have explored the use of JPEG compression as a defense against adversarial images [3, 2, 5]. In this work, we show that we can generate adversarial images which survive JPEG compression, by including a differentiable approxima- tion to JPEG in the target model. By ensembling multiple target models employing varying levels of compression, we generate adversarial images with up to 691× greater success rate than the baseline method on a model using JPEG as defense. 1 Introduction Image classification models has been a highly-studied domain for adversarial examples. While adversarial images generated against these models are nevertheless very close to the original image according to L1 or L2 norm, unnatural high-frequency components or random-looking dot patterns are sometimes noticeable. As such, some proposed defenses to adversarial examples involve an initial input transformation step which attempts to remove such unnatural-looking additions. In particular, several papers [3, 2, 5] have proposed and evaluated JPEG compression as a potential method for preventing adversarial images. To summarize, they compress and then decompress an image using JPEG before providing it to the image classification model. Since JPEG is a lossy image compression method designed to preferentially preserve details important to the human visual system, the hope is that JPEG compression will keep the aspects of the image important for classification, but discard any adversarial perturbations. The method is appealingly simple and, according to the previous work, can reduce the attack success rate of adversarial examples. -
Using Graphics on the Web Keep Graphics Small Most Users Have Little Patience for Slow Loading Pages, and Will Rapidly Abandon a Slow Site
Using graphics on the web Keep graphics small Most users have little patience for slow loading pages, and will rapidly abandon a slow site. Remember that many of your audience will be using a dial up modem, and try to keep graphics file sizes under 40K. Be willing to sacrifice some image quality. Provide thumbnails for large graphics If you feel your site absolutely requires large graphics, to illustrate an experimental set-up for example, provide an in-line reduced thumbnail of the graphic on your main page, which will link to the larger graphic and a separate page. This way the user has a choice and can decide if she or he wants to view it then, at another time or at all. It's also a kindness to indicate the file size, so the user can estimate how long the display will take to load. Use the same motifs throughout your site Recycle graphics (icons, navigation bars), as they are cached locally once downloaded. Standardizing on a set of graphic arrows, bullets, logos etc. also provides your site with a characteristic "look and feel" that your audience can identify with. Provide alternative text for non-graphics browsers Use the [alt="" ] command to provide a text description for those with text-only browsers or those who may have graphics loading disabled on their browsers. This also follows guidelines for Americans with Disabilities Act (ADA) Compliance. Use the appropriate file format Graphics Interchange format - GIF - was originally developed for the rapid transfer of images. GIF compression works by encoding the identical repeating elements within any given graphic, storing the code in an attached table and using the data to display the image when called upon by the web browser. -
Printing Terms
Printing Terms Bitmap - Also called a BMP or a raster image. A digital image that is pixel based and resolution dependent. Bit-mapped images loose sharpness and clarity when reduced or enlarged. These files are specified as a number of pixels wide by the number of pixels high. The number of bits per pixel determines the number of shades of grey or colors it can represent. Bitmaps come in many file formats, a few are GIF, JPEG, TIFF, BMP, PICT, and PSD. These types of images are created in paint programs, by scanning and by digital cameras. Bit- mapped files can also be placed or imported into a vector based file, but they remain raster images. For the promotional products industry, bit-mapped or raster images are not usually the preferred type of art for vendors to work with as they are more difficult to make adjustments such as re-sizing. CMYK - A color model where all the colors are made up of a combination of four process colors. CMYK is an abbreviation for cyan (a blue color), magenta (a red color), yellow and key (black). Color Separations - The process of separating the areas of a piece of art to be printed into its component spot or process ink colors. Each color to be printed must have its own printing plate. For example, if a piece of art was to be printed in 3 spot colors, such as PMS 185C Red, PMS 288C Blue and Black, there would be 3 plates. Each of the 3 plates would contain only the elements to be printed in a specific color. -
Guide to Digital Art Specifications
Guide to Digital Art Specifications Version 12.05.11 Image File Types Digital image formats for both Mac and PC platforms are accepted. Preferred file types: These file types work best and typically encounter few problems. tif (TIFF) jpg (JPEG) psd (Adobe Photoshop document) eps (Encapsulated PostScript) ai (Adobe Illustrator) pdf (Portable Document Format) Accepted file types: These file types are acceptable, although application versions and operating systems can introduce problems. A hardcopy, for cross-referencing, will ensure a more accurate outcome. doc, docx (Word) xls, xlsx (Excel) ppt, pptx (PowerPoint) fh (Freehand) cdr (Corel Draw) cvs (Canvas) Image sizing specifications should be discussed with the Editorial Office prior to digital file submission. Digital images should be submitted in the final size desired. White space around the image should be removed. Image Resolution The minimum acceptable resolution is 200 dpi at the desired final size in the paged article. To ensure the highest-quality published image, follow these optimum resolutions: • Line = 1200 dpi. Contains only black and white; no shades of gray. These images are typically ink drawings or charts. Other common terms used are monochrome or 1-bit. • Grayscale or Color = 300 dpi. Contains no text. A photograph or a painting is an example of this type of image. • Combination = 600 dpi. Grayscale or color image combined with a line image. An example is a photograph with letter labels, arrows, or text added outside the image area. Anytime a picture is combined with type outside the image area, the resolution must be high enough to maintain smooth, readable text. -
Resolution and LPI
Resolution and LPI Pixels: Raster graphics are made up of a grid of pixels. When viewing 100% or less on a monitor (72 dpi resolution) the individual pixels are not visible to the eye. If the dpi is lower such as in Example 1 you can see the individual pixels and can't really tell what the image is. Similar to when you zoom in on an image. Images that are only going to be viewed on the screen can be created or scanned at 72 dpi DPI or PPI: Dots per Inch or Pixels per Inch. Monitor and Scanning DPI/PPI: You will hear these terms used interchangably and in this case they refer to monitor view perimeters or the scanning resolution you select. When scanning or creating an image to be viewed on a monitor or projection device the dpi/ppi should be the same as the monitor - thus 72 dpi or a 1:1 ratio. Printer DPI/PPI: Your output device has a dpi resolution also. This is the number of dots it can create within a square inch. Example 2 shows that on a laser Example 1: Pixels Enlarged printer a number of dots can make up a halftone dot depending on the line screen selected (more about that later). When scanning or creating images that will be printed you need to capture more information about the image due to the printing process. The ratio you utilize must then be higher. But how high is enough. If your dpi is very high the file is huge. -
Single-Pixel Imaging Via Compressive Sampling
© DIGITAL VISION Single-Pixel Imaging via Compressive Sampling [Building simpler, smaller, and less-expensive digital cameras] Marco F. Duarte, umans are visual animals, and imaging sensors that extend our reach— [ cameras—have improved dramatically in recent times thanks to the intro- Mark A. Davenport, duction of CCD and CMOS digital technology. Consumer digital cameras in Dharmpal Takhar, the megapixel range are now ubiquitous thanks to the happy coincidence that the semiconductor material of choice for large-scale electronics inte- Jason N. Laska, Ting Sun, Hgration (silicon) also happens to readily convert photons at visual wavelengths into elec- Kevin F. Kelly, and trons. On the contrary, imaging at wavelengths where silicon is blind is considerably Richard G. Baraniuk more complicated, bulky, and expensive. Thus, for comparable resolution, a US$500 digi- ] tal camera for the visible becomes a US$50,000 camera for the infrared. In this article, we present a new approach to building simpler, smaller, and cheaper digital cameras that can operate efficiently across a much broader spectral range than conventional silicon-based cameras. Our approach fuses a new camera architecture Digital Object Identifier 10.1109/MSP.2007.914730 1053-5888/08/$25.00©2008IEEE IEEE SIGNAL PROCESSING MAGAZINE [83] MARCH 2008 based on a digital micromirror device (DMD—see “Spatial Light Our “single-pixel” CS camera architecture is basically an Modulators”) with the new mathematical theory and algorithms optical computer (comprising a DMD, two lenses, a single pho- of compressive sampling (CS—see “CS in a Nutshell”). ton detector, and an analog-to-digital (A/D) converter) that com- CS combines sampling and compression into a single non- putes random linear measurements of the scene under view. -
1/2-Inch Megapixel CMOS Digital Image Sensor
MT9M001: 1/2-Inch Megapixel Digital Image Sensor Features 1/2-Inch Megapixel CMOS Digital Image Sensor MT9M001C12STM (Monochrome) Datasheet, Rev. M For the latest datasheet, please visit www.onsemi.com Features Table 1: Key Performance Parameters Parameter Value • Array Format (5:4): 1,280H x 1,024V (1,310,720 active Optical format 1/2-inch (5:4) pixels). Total (incl. dark pixels): 1,312H x 1,048V Active imager size 6.66 mm (H) x 5.32 mm (V) (1,374,976 pixels) • Frame Rate: 30 fps progressive scan; programmable Active pixels 1,280 H x 1,024 V • Shutter: Electronic Rolling Shutter (ERS) Pixel size 5.2 m x 5.2 m • Window Size: SXGA; programmable to any smaller Shutter type Electronic rolling shutter (ERS) Maximum data rate/ format (VGA, QVGA, CIF, QCIF, etc.) 48 MPS/48 MHz • Programmable Controls: Gain, frame rate, frame size master clock Frame SXGA 30 fps progressive scan; rate (1280 x 1024) programmable Applications ADC resolution 10-bit, on-chip Responsivity 2.1 V/lux-sec • Digital still cameras Dynamic range 68.2 dB • Digital video cameras •PC cameras SNRMAX 45 dB Supply voltage 3.0 V3.6 V, 3.3 V nominal 363 mW at 3.3 V (operating); Power consumption General Description 294 W (standby) Operating temperature 0°C to +70°C The ON Semiconductor MT9M001 is an SXGA-format with a 1/2-inch CMOS active-pixel digital image sen- Packaging 48-pin CLCC sor. The active imaging pixel array of 1,280H x 1,024V. It The sensor can be operated in its default mode or pro- incorporates sophisticated camera functions on-chip grammed by the user for frame size, exposure, gain set- such as windowing, column and row skip mode, and ting, and other parameters.