As is the case with many other aspects of our lives here in the twilight years of the twentieth century, the computer is having an evermore pervasive role in the daily endeavors of the electron microscopist. And as I contemplate the little button on the microwave that allows me to burn popcorn the exact same way, time after time, I am led to wonder “where is it all going?”…the technology that is. I know where the burnt popcorn will end up. Whether we like it or not, the computer is a tool that can drastically improve our productivity, and typically such productivity gains occur precisely within those tasks where mistakes are the most likely to creep in, to wit: the mundane and repetitive.

As an example, consider the task of indexing a diffraction pattern for a known crystal. In the far distant and superstitious past of the mid to late 1960's, this task required all sorts of strange alchemy.

Recent advances in digital image processing hardware providing very high pixel resolutions can be exploited to solve problems in correlating high magnification feature analysis with specimen macrostructure. In neuroscience, for instance, analyses such as neuron counting which are performed at high magnification often need to be correlated with the overall structure of the specimen. Typically these procedures involve tediously moving between very low and very high power objectives. Once at high power, the positional knowledge of the objects of interest can be difficult to maintain.

By integrating high resolution image capture with precise microscope automation, a digital composite image of the specimen can be created. Such composite images show the researcher a high resolution “map” of the specimen, facilitating the analysis of both macro- and microstructure characteristics from a single view.

The Confocal microscopy listserver discussion group was put on the air over 5 years ago by Don Parsons (Albany), Steve Paddock (Wisconsin), P.C. Cheng (Buffalo) and me at the suggestion of Parsons that there should be an open discussion forum for this rapidly developing technology. Parsons is an expert in infomatics (among other things) and appreciated the potential of the “mail reflector” concept at an early stage in its development.

Listserver groups were pretty uncommon then but we figured that since we were dealing with digital microscopists, most of those interested would have computers and access to Bitnet or Internet. For the first month or so Parsons, Paddock, Cheng and I corresponded with one another to work wrinkles out of the system and we then began to publicize the existence of the group at meetings, symposia and through the commercial manufacturers of confocal microscopes and associated hardware.

To adequately microscopically characterize opaque particles, and some finely divided, high refractive index, and transparent particles, one must use top light. This can be done with a built-in or accessory vertical illuminator. It can also be done without a vertical illuminator using any PLM with any separate microscope illuminator focusable to a small bright spot. Aimed downward onto the slide preparation at a steep angle, but missing the objective, and with the transillumination subdued or turned off, the color and surface texture of opaque particles can be readily discerned. The objective must have a long working distance, usually, therefore, a 10X or lower magnification.

Pseudo opaque particles (submicrometer particles of high index) are reaify transparent but hey may be colorless or any color. Top light brings out their true color - black, if opaque, but they may be red (Fe2O3), green (CR2O3), yellow (lead-tin yellow) or white (TiO2).

We have acquired and made available for loan a durable, easy-to-use, though expensive video-probe microscope. This hand-held, automatically focussing instrument can be used by a 5 year-old and provides instant, excellent, in-focus images of 50X to 200X on a video screen visible simultaneously to all students in the class.

The probe consists of a miniature video camera with interchangeable magnifying “objective” lenses which are surrounded with built-in, cool, fiber-optic illumination. Each lens is capped with a “contact tip” which corresponds to the focal length of the lens and which, when touching the sample, provides automatic focus of the image on the monitor. The images can be videotaped in the normal fashion.

Part 1 of this series, in the August '94 issue of this newsletter, contained an overview of digital imaging for TEM. The key point was that digital imaging systems are getting better and costing less. This article contains a brief summary of the pro's and con's of digital imaging for TEM.

Although different laboratories have different situations, there are common issues that all can consider when evaluating the value of a digital imaging system for TEM.

Information Density: As things stand today, atypical 1024 pixel by 1024 pixel digital imaging system cannot compare with film! Typical film used for EM can display feature sizes as small as 10 μm. This is like having a film negative made up of 10,400 pixels by 7,800 pixels. Put this way it's tough to see how a factor of between 7 and 10 can be ignored.

When most of us use a microscope, we are looking through a specimen, or more and more frequently, at the “top” surface. It usually doesn't occur to us to look sideways. But that is what was done recently in the laboratory of Charles Lieber at Harvard University. As reported by Daniel Frisbie, Lawrence Rozsnyai, Aleksandr Nay, Mark Wrighton, and Prof, Lieber, an atomic force microscope (AFM) was modified to perform as a “chemical force microscope” (CFM). With the CFM they were able to precisely measure adhesive and frictional forces. These forces can be thought of as acting parallel to the surface of the specimen, whereas most observations are made perpendicular to the surface.

This familiar saying may be a little too risque for sober scientists but surely all of us can accept a substitution of the word humor for the word nonsense. For humor is based on a sense of proportion and fitness of relationships, which is the very essence of the scientific obligation to interpret what we observe. In fact, many of our colleagues insert humorous slides in their very serious talks to help wake up the audience and give them an association for remembering a key point. Do we also remember to use this power of humor when teaching, or otherwise communicating with, a lay audience?

Like it or not we are all required to be teachers to our own circle of support people and should furthermore take advantage of any opportunity to educate the world at large about our work. I should like to give a few examples from my own experience in teaching electron optical practice.

Advances in camera technology and digital instrument control have meant that in modern microscopy, the image that was, in the past, typically recorded on a piece of film is now recorded directly into a computer. The transfer of the analog image seen in the microscope to the digitized picture in the computer does not mean, however, that the problems associated with recording images, analyzing them, and preparing them for publication, have all miraculously been solved. The steps involved in the recording of an image to film remain largely intact in the digital world. The image is recorded, prepared for measurement in some way, analyzed, and then prepared for presentation.

The Information Superhighway, Email, The Internet, FTP, BBS, Modems,: all buzz words which are becoming more and more routine in our daily life. Confusing terminology? Hopefully it won't be in a few minutes. All you need is to have a handle on a few basic concepts and terms and you will be on-line with the rest of the “telecommunication experts”. These terms all refer to some type or aspect of tools associated with a range of computer-based communication software and hardware. They are, in fact, far less complex than the instruments we use on a day to day basis as microscopists and microanalysts. The key is for each of us to know what each is and how to make use of the wealth of information which they can make available to us for the asking.