STOIK Imaging announces the release of PictureMan 5.0 PRO – the first application with a complete set of image processing and editing functions available in 48 bit (16 bit per channel) color mode. Image editing, including filtering, retouching, and multi-layering in 48 bit color offers multiple advantages over conventional image editing in 24 bit (8 bit per channel) color mode. STOIK products with full support of 48 bit color will allow users to enjoy the benefits provided by 48 bit–enabled scanners and modern digital cameras offering more than 8 bits per channel color.
This is an established fact, accepted by customers and hardware manufacturers, that image processing in color space where color data is represented with 16 bits per channel (48 bits RGB) has multiple advantages over conventional processing in 8 bits per channel (24 bits). The simple fact that almost all scanners sold today in all market segments output digital images with 48 bit color resolution speaks for itself. The major benefit of image processing in 48 bits is the possibility of avoiding loss of color information during digital retouching and color correction operations. When processing is done with 24 bit image each channel (e.g. R,G, or B) has 256 possible values or levels, but each edit such as a levels tweak, a contrast curve, a color balance change, or a conversion to another color space subtly degrades the image and the resulting image will have fewer than 256 levels per channel. The color histogram of the resulting image will have holes and spikes, which in turn manifest themselves in potential posterization or banding clearly visible in low-saturation and continuous-tone regions of digital photos. When processing is done in 48 bits, each channel contains 65,536 possible levels. The same levels tweak or color balance change will similarly lead to fewer levels in resulting image, but the sheer number of values present in the original data guarantees that there will be no holes in 256-levels histogram. In practice it means that if the image is further downsampled to 24 bit representation for printing or viewing, each channel would still have data at each of the 256 levels. Thus processing in 48 bits allows one to apply color correction – for example to enhance color contrast in under- or overexposed photos without artifacts such as posterization or banding. The benefits of image processing in 48 bits can be summarized as follows:
Gamma correction and histogram expansion in 24 bits (PictureMan tool Levels). Significant posterization, small details in shadows are not resolved.
The same enhancement operation applied in 48 bit mode. Less posterization, more detail revealed in shadows.
The realm of 48-bits image processing today is limited by TWAIN drivers of scanners and basic functions provided by professional-grade image editing. The 48 bits functionality of Photoshop, for example, includes acquisition of 48-bit images from a TWAIN-compliant scanner, import-export of 48 bit TIFF, and several operations such as Auto Levels, Curves, Blur. Typically, a Photoshop user acquires 48-bit image from a scanner, stores the original as a TIFF file, adjusts colors using Auto Levels command (expands histogram), and converts the image to a 24-bit RGB to do all further retouching and composition in 24 bit representation. Software typically bundled with scanners, does not provide even limited processing in 48 bit which makes 48 bits color resolution provided by all present-day scanners effectively meaningless to a customer.
Very limited 48 bit functionality provided by professional-grade software does not allow users to take advantage of high color resolution of scanners and digital cameras since the only possible workflow requires the conversion of color mode to 24 bit in the initial step of editing – thus allowing for color degradation in further steps. Processing of images in 48 bits on all editing steps will bring significant customer benefits:
Proper color adjustment - color correction and conversion can be done at the final step of retouching workflow.
It is well-known to graphic designers that color correction should be done after all other retouching manipulations with an image. Most widely used color adjustment tools such as Expand, Auto Levels, and Equalize generate output based on the analysis of image histogram, and histogram changes when operations such as smoothing and common enhancement filters are applied to the image.
When image processing is done in 48 bits colors, it can be corrected multiple times during editing, unlike the in the 24 bit situation where each successive color adjustment adds to color detail loss.
Adjust layer colors in multi-layer composition without quality loss
Multi-layer compositions are used by photographers and designers to create photo collages, when objects are cut from photos and placed over various backgrounds. Studios typically use a collection of background images so that one background image is used in multiple compositions. The visual quality of the composition requires color tone and brightness matching between foreground and background. In a sample composition shown below, the foreground subject is too light-colored for the background image used. To correct for the mismatch, the background colors are adjusted using Levels and Gamma correction. If color correction is done in 24 color mode, then the resulting image features visible posterization in the shadow areas. PictureMan 5.0 PRO is the only software today which allows multi-layer composition of 48 bit images. Color correction applied to 48 bit background in multi-layer composition resulting in much lower degradation of colors.
Original multilayer image with too dark background layer
Histogram expansion and gamma correction applied to background
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result for background in 24 bit color mode |
result for background in 48 bit color mode |
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Note posterization and gaps in histogram |
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When a user imports an image from a 48 bit scanner to an image editing application, image colors are converted in accordance with color profiles of the scanner, monitor, and printer. The colors will be converted again by a color management system when, for example, a user wants to output the image to a different printer. The successive conversions, if done in 24 bit color space, will lead to the loss of color detail. There will be no problem if the image is kept in 48 bit color space.
Precise and powerful enhancement - 48 bit color information allows for improved performance of enhancement filters and new algorithms.
Image processing in 48-bit color space allows for creation of new and improvement of existing image enhancement algorithms such as Dust and Scratch removing, Red Eye Removing, Green screen color keying, etc. This allows for automation of enhancement and retouching operations and for better quality of resulting images.
Improved productivity – original can be stored in 48 bits with all time-consuming retouches already applied.
In order to reuse a scanned image, it should be stored in 48 bits format (48 bit original). Today the original is to be saved BEFORE any application of enhancement filtering which is typically needed to correct image defects such as fuzziness, scratches, etc. That means that next time, when the original is to be used, enhancement filtering – usually requiring extensive manual work - will be repeated. When retouching filters become available in 48 bit mode, the original can be stored AFTER manual retouching, and immediately available for future use.
Color correction is the most difficult task of image editing, and most errors occur when users try to adjust color or brightness balance. Image processing in 24 bits leaves no room for error, while color levels adjustment in 48 bits can be redone and corrected many times without visible degradation of colors in the resulting image.
PictureMan 5.0 PRO introduces the first truly automatic Red Eye removal filter and improved automatic Scratch removal filter. All image processing filters of PictureMan can be allied in batch mode using scripting engine and OLE automation.
PictureMan has numerous enhancement and retouching tools, much more than any other image editor, mostly grouped under menu TOOLS-ENHANCEMENT and TOOLS-PROCESSINGS. The most recently updated filters are:
menu TOOLS-ENHANCEMENT-RED EYE REMOVAL
Totally automatic, parameter-free filter. PictureMan Red Eye removal filter
has a very low error rate, but you can further improve its precision by
manually selecting part of the image.
menu TOOLS-ENHANCEMENT-SCRATCH REMOVAL
Automatically detects scratches in images scanned from film. User interaction is
only required to let program know if the image was scanned from a negative (typically)
or from positive (photo slides). Since the algorithm takes into account grain noise
of the photo film, it works differently in these two cases.
menu TOOLS-ENHANCEMENT-DUST CLEANER
Corrects defects caused by dust on the surface of scanned film. It may need some
adjustment of GAP and STRENGTH parameters (default values are gap=21,
strength=4).
menu TOOLS-ENHANCEMENT-JPEG DENOISE
Removes most common defects of highly compressed JPEGs - blocking and ringing.
PictureMan 5.0 PRO offers JPEG2000 (free of JPEG artifacts) compression
including import-export of JPEG2000-compressed 48 bit color images.
menu TOOLS-ENHANCEMENT-DE-INTERLACE
Corrects the interlacing pattern in captured video frames. Automatically calculates the
necessary
shift of lines.
menu TOOLS-ENHANCEMENT-TRUE DESPECKLE
Corrects impulse noise in pictures with unsurpassed effectiveness.
PictureMan 5.0 has dozens of other more common enhancement filters (Sigma, Median, Gaussian, etc) under TOOLS-ENHANCEMENT and TOOLS-PROCESSING, all of them can be applied either to selection or manually with brush using Selection/Brush switch button in the upper left corner of each tool dialog.
More info and software download:
http://www.stoik.com/pictureman
STOIK Imaging
