Digital pathology refers to the digitizing of glass slides to provide image-based information for diagnostic, analytical and educational purposes. Telepathology is pathology that is performed at a distance, usually using digital pathology. Therefore, these two practices are closely interlinked and enjoy considerable overlap.
Imaging constitutes the core aspect of any digital pathology application. The captured images act as useful materials for teaching, documentation, publication, archiving and in the case of telepathology, they offer real-time consultation. The digital cameras used in pathology therefore need to be extremely reliable to ensure patients’ safety and protect against adverse outcomes. These are requirements that consumer-type cameras often fail to meet.
Outlined here are the key features a camera used in digital pathology camera needs to incorporate.
Life science researchers, clinical pathologists and industrial technicians count on our exceptional color reproduction, high quality microscopy cameras, complete with user friendly software packages. Select from Lumenera’s cost-effective CMOS cameras, our HD camera with full 1080p60 preview, or our CCD solutions with high dynamic range and outstanding color fidelity.
Color Reproduction and Consistency
Unlike the grey images generated in digital radiology, color plays an important perceptual role in pathology, helping to identify visual clues as to what action may need to be taken.
The colors captured by the camera need to match human perception as closely as possible as well as remaining consistent between cameras and from frame to frame. Therefore, the fidelity and consistency of color capture is an essential factor in digital pathology applications.
Important choices over which hardware design to use, such as whether to opt for a mosaicing filter or different pixel sensors, can have significant effects on color quality. In the case of software too, the algorithms developed for a particular pathology must be meticulously designed and tested. Furthermore, the quality and consistency of color is affected by the type of monitor that is used to display the image.
Wide Dynamic Range
The camera’s dynamic range refers to the range of light intensity that it can capture in a single frame. Cameras often fail to generate low noise images that can match the dynamic range of the human eye. In pathology applications, particularly those that use fluorescence specimens, it is important that both high- and low-intensity signals are captured and displayed.
Additionally, the dynamic range is also affected by the size of individual pixels. Although smaller pixels increase spatial resolution, they also limit how many photons hit the image sensor, restricting the dynamic range of the final image.
All digital cameras are affected by a degree of noise that affects the quality of images. In order to create images of acceptable quality for use in medical diagnosis and/or training, cameras must have a high signal-to-noise ratio. Camera noise may be either fixed-pattern noise which is produced by variability between pixels or temporal noise, which is produced during the image capture process.
High Spatial Resolution
A high spatial resolution is a key desired feature of most imaging applications, but certain types of tissue processing demand stringent resolution for visual cues, which can push against the theoretical optical resolution limit of visible light.
Pixel pitch or the size of each pixel sensor is perhaps the most important element in spatial resolution. However, as pixels decrease in size, the performance demands of the image sensor becomes more difficult to meet, placing considerable limitations on the size of individual pixels.
The sensitivity of a camera refers to the lowest light intensity a camera can capture where the noise level is still below the true light signals.
High sensitivity is important in digital pathology. Fluorescence imaging, in particular, needs to produce high-quality images under difficult conditions.
Physical components, such as the darkening effects of the magnifying optics and the size of the aperture, can affect the sensitivity of the imaging system. With respect to the camera itself, pixel size is the most significant factor that affects sensitivity.
Large Optical Sensor
In many types of digital pathology, it is necessary to capture the same field of view as much as possible. For whole-slide imaging, the larger the field of view is, the more quickly the slide can be imaged. For the optical sensor to match the microscope’s field of view, it must be a medium- or large-format sensor. In static imaging, this enables the pathologist to see the same amount of sample area as they would see directly when using the microscope.
Fast Frame Rates
High frame rates of 90 fps or higher are needed in whole-slide imaging, to ensure the digital scanning process is as fast as possible. To match these fast frame rates, the image sensor needs to be of a quality high enough to perform effectively under these fast conditions.
High-Speed Data Interface
A high-speed data interface must available to enable rapid transfer of the image data. An industry standard data interface can enable a laboratory to mix-and-match modules and upgrade its system more easily in the future. Here, USB 3.0 interface is suitable for pathology applications as it is readily available on almost all desktop PCs and enables applications of almost 4Gbps.
The software utilized in a telepathology system must be able to reliably import, stitch, and compress images as well as being intuitive to use. The system must also offer image measurement and annotation features.
Lumenera provides a general purpose software solution that is integrated into most INFINITY microscopy cameras. Figure 1 shows the images obtained with Lumenera’s megapixel cameras.
Figure 1. A selection of images taken with Lumenera’s scientific megapixel cameras. With 5 series of cameras ranging from 1.3 to 32 megapixel, Lumenera cameras are ideal for digital pathology
Figure 2. INFINITY microscopy camera
The INFINITY microscopy camera (Figure 2) with INFINITY ANALYZE software enables advanced image acquisition and analysis. In addition, an intuitive user interface INFINITY CAPTURE includes all the basic features required to control the camera and capture images.
INFINITY ANALYZE software allows users to quickly process, archive and save images in a wide range of formats; to easily apply and recreate customized annotations and measurements; and to effortlessly manage and recover images within the integrated database.
Additional highlights of the software include real time video preview, single capture and time lapse, automatic/manual exposure and white balance, advanced image processing, hue, saturation, contrast, brightness, gain and gamma controls, context sensitive help for all functions, thumbnail worksheet, save and restore camera settings, interactive color composition, optional focus enhancement, etc.
INFINITY Cameras with Hands-free Operation
At times, a hands-free operation is necessary for sterilising procedures, for carrying out certain types of laboratory research or for examining fragile electronic components, for example.
In these cases, the INFINITY camera’s application software could be used to add a footswitch to the computer, allowing the operator to perform keyboard functions via foot pedals. These devices come with a standard PS/2 connection or a USB interface.
In addition, keyboard shortcuts can significantly enhance efficiency when performing repetitive sequences. The INFINITY CAPTURE and INFINITY ANALYZE software packages contain menu shortcuts that can be activated by means of the <Alt> key and a corresponding keyboard character.
Lumenera offers a wide range of cameras, such as INFINITY2-1R, INFINITY3-1UR, INFINITY4-11, INFINITYHD, Lt365R INFINITY3-3UR.
Figure 3. INFINITYHD
Figure 4. Lt365R
Clinical pathologists can meet their imaging needs with Lumenera’s USB 2.0 INFINITY cameras. These research-grade cameras set the benchmark for uncooled cameras. Advanced thermal management enables extended exposure times and the resulting images display dark and bright areas that are not usually seen in lower dynamic range cameras. Lumenera offers CMOS cameras with fast frame rates, CCD cameras with high dynamic range and unparalleled color fidelity, and HD cameras with full 1080p60 preview and excellent color reproduction.
About Lumenera Corporation
Lumenera Corporation, a division of Roper Industries, and headquartered in Ottawa, Canada, is a leading developer and manufacturer of high performance digital cameras and custom imaging solutions. Lumenera cameras are used worldwide in a diverse range of industrial, scientific and security applications.
Lumenera solutions provide unique combinations of speed, resolution and sensitivity in order to satisfy the most demanding digital imaging requirements. Lumenera customers achieve the benefit of superior price to performance ratios and faster time to market with the company's commitment to high quality, cost effective product solutions. For further information about Lumenera, please visit www.lumenera.com or call 613-736-4077.
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