Most image analysis programs handle 8 bit per channel images (8 bit greyscale and 24 bit RGB images) but have limited or no capability to handle 16 bit per channel (16 bit greyscale and 48 bit RGB) images. Prior to Photoshop CS (Photoshop 8) many of the internal functions do not work with 16 bit per channel images. It wasn't until Photoshop CS2 (Photoshop 9) that multichannel images could also be 16-bit.

These high-depth images are essential for many scientific imaging tasks, and are provided by some microscopes (atomic force microscopes, confocal microscopes, etc.), cooled digital cameras, and flat bed scanners. These images typically have 10, 12 or 14 bits of actual data, which are stored and processed in the computer as 16 bit images. Processing and measuring high-depth images is superior to 8 bit images for many tasks, especially surface images, intensity or density calibration, and images requiring multiple processing steps.

The higher bit depth is vital in applications with a high dynamic range and with detail in both the bright and dark regions (e.g., astronomy, fluorescence microscopy, scanned probe microscopy, etc.).

Fovea Pro provides a comprehensive set of tools for working with these high bit depth images, including standard and state of the art image processing algorithms, and extensive measurement capabilities (including measurement of surface roughness parameters from scanned probe microscopes). The software operates as a set of plug-ins within the familiar environment of Adobe Photoshop, and comes with utilities that convert specialized file formats used by many scientific instruments. With Fovea Pro operating within the familiar environment of Photoshop CS2 (running on either the Mac or Windows computers) you will have access to analytical power and functionality that exceeds many "professional" dedicated image analysis programs that cost ten times more!

16 bit tips and tricks

Understanding the use of 16 and 8 bit per channel images and the way that Photoshop handles these images allows users to manipulate the images in many useful ways. The extensive tutorial includes many tips for these operations. A few examples:

Region selections in 16 bit images

Photoshop has several tools for selection of regions of interest, including freehand and polygon lasso, rectangular and round marquee selection, and the magic wand which is uses a seed-fill algorithm and is often very useful. This latter tool only functions with Photoshop CS and CS2 with 16 bit per channel images. With older versions you can still employ this tool by duplicating the image, converting the copy to 8 bits per channel, selecting the regions of interest using the wand and any operations under the Select menu to modify the region or select additional similar areas. Then transfer the region of interest back to the 16 bit per channel image to limit processing or measurement.

Conversion from 16 bits down to 8 bits

Photoshop converts 16 bit per channel images to 8 bit per channel images by adding a half a bit of noise, which visually eliminates banding problems. It is also possible using Fovea Pro to get exact conversion from 16 bit to 8 bit depth, because the second image buffer (used in math and logical operations using two images) stores both depths automatically. Saving a 16 bit image in the buffer and recalling it into an 8 bit image will generate the exact 8 bit conversion.

Additional Capabilities using Fovea Pro

Many of the built-in Photoshop functions do not function for 16 bit images. Fovea Pro includes routines that provide general math capabilities and custom filters, with added capabilities for optional autoscaling and accepting floating point values.

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