A MICROCOMPUTER -BASED ELECTRON MICROSCOPE 
DIGITAL IMAGE 3D PROCESSING SYSTEM 
Lixin SUN 
Department of photogrammetry, Harbin College of Surveying, 
No. 97 Zhong Shan Road, Harbin, China 
Commission No.: V 
ABSTRACT 
A Microcomputer-based Electron Microscope Digital Image 3D Processing System (EM3DPS) is described in 
this paper. The system mainly includes some basic image processing functions and some procedures for 
obtaining various electron microscope 3D data such as contrast enhancement, false color enhancement, edge 
enhancement, image sharping, image smoothing, image segment, relative orientation and absolute 
orientation based on parallel projection, the display of stereoscopic pair on the microcomputer screen, the 
measurement of length, angle, area, volume, digital surface model(DSM) and contour line, etc. 
Since the system just needs a general microcomputer(IBM PC/AT, 80286, 80386 or its compatibles just 
with VGA or TVGA) instead of a conventional photogrammetric plotters or a special image processing 
computer, so it is more accessible to electron microscope users. In addition, the friendly user interface 
based on windows and on-line help system make it easier and more convinent to operate the software. 
Key Words: Close-range, Electron microscope, Digital processing system, Photogrammetry, 
3D, Microcomputer -based, Biostereomatric 
1. INTRODUCTION 
Many papers have reported the principles and methods 
of obtaining electron microscope 3D data by using 
photogrammetry, and in some scientific fields, a lot of 
practical problems have been solved by means of these 
techniques.But all of the current electron microscope 
3D surveying systems are based on some special 
photogrammetric instruments (analogic or analytic). 
Although many kinds of electron microscope 3D data 
can be gotten on these instruments, they cann't be 
widely applied in the electron microscope fields widely, 
because it is impractical for a general electron 
microscope user to purchase a special photogrammetric 
instrument to acquire some microcosmic 3D data. 
Recently, as a result of the advances in semiconductor 
technology and micro-electronics and consequent 
reduction in prices, microcomputers not only have been 
available in many scientific fields but also have 
powerful functions, thus making it possible to design a 
microcomputer-based electron microscope digital image 
3D processing system. 
This paper is concerned with some pricinples, 
characteristics and performance of a Microcomputer- 
based Electron Microscope Digital Image 3D Processing 
System (EM3DPS) designed by the author. 
2. MATHMETICAL MODELS 
2.1 PARALLEL PROJECTIVE EQUATIONS 
Theoretically speaking, the EM imaging system is 
central projection, but as regards extremely small 
specimen and extremely large magnifications, an 
electron microscope has an extremely small field 
angle. So the EM imaging system should be 
regarded as a parallel(or near parallel) projection. 
According to the features of the parallel projection, 
the parallel projective equations can be expressed as: 
X = a; X-Xo)+az(Y-Yo)+az(Z-Zo) 
y = kb 1X -Xo) +kb 2(Y -Yo) +kb 3(Z -Zo) (QD 
where x,y are the photo coordinates of photo point; 
X,Y,Z are the object space coordinates of the 
specimen; Xo, Yo,Zo are the coordinates of the 
original of the photo coordinate system in the object 
space coordinate system; ai,bi(i=1,2,3)are the 
parameters of rotation matrix; k is the scale factor 
along Y direction, taking scale factor along X direction 
as 1. 
On current electron microscopes, the various possible