640hx480v, to conserve storage space [31]. The original image for Fig. 6 is in full color, requiring only 118 kBytes of digital
storage space. This demonstrates the powerful image compression schemes employed, and the pressing need to minimize the
amount of image data to be stored in cost-sensitive consumer applications. Such an electronic camera, currently available for $650,
is considered to be sufficient for many computer applications, but also for journals and magazines, providing that the final full-
resolution reproduction size does not exceed about 6 cm [32].
The large-scale replacement of conventional film-based still cameras by electronic cameras, is expected once higher resolution
image sensors and higher-capacity storage media at a lower price are available. At the turn of the century, small and inexpensive
HDTV color CCD image sensors will be available with about 2000hx1100v pixels, showing a resolution comparable to
photographic film. Although the cost of such electronic photography systems will still be higher than that of conventional film-
based cameras, it is expected that the added conveniences of higher sensitivity, immediate picture viewing, direct link to image
processing and hard-copying on PCs, etc. will lead the customer to shift to electronic photography within the next 5-10 years.
Fig. 6 : Black-and-white reproduction of a color image taken with a commercially available electronic still camera (Apple
QuickTake [29]), which offers a resolution of 640hx480v pixels. The camera's built-in data compression reduces the
amount of image data to just 118 kByte per color image.
The situation is different in professional applications, where the advantages of electronic photography do already outweigh the cost
considerations in many cases. All major manufacturers of professional photographic equipment, such as Kodak, Sony, Nikon, Fuji,
Hasselblad, Sinar, etc. already offer electronic photography products. Image sensors with a minimum number of 1200hx1000h
color pixels are employed, with sensitivities equivalent up to ISO 800/1600 film speed. This pixel number is barely sufficient for
most applications. If affordable, high-resolution image sensors developed specifically for electronic photography applications will
be employed [32]. A case in point is Kodak's recently demonstrated M6 CCD image sensor chip with 3kx2k color pixels on an area
of 36x24 mm”, finding its way into professional studio and reporting cameras. This is an alternative to existing solutions
employing scanning CCD line sensors, requiring tens of seconds for exposure. Most professional applications, such as in the
graphics arts, publication and reporting work, catalogue photography, etc. call for such a high-resolution color image sensor, with a
resolution of at least 2kx2k pixels digitized to 12 or 16 bits, capable of taking flash exposures (one-shot exposure instead of
scanning), and mounted in a precision-engineered custom camera back taking suitable new lens systems [32]. Such a camera is still
IAPRS, Vol. 30, Part 5W1, ISPRS Intercommission Workshop "From Pixels to Sequences", Zurich, March 22-24 1995
de
to
cal
bu
pr
str
[34
of
chi
ad
ele
ma
co-
dir
[37
CN
CC
sen
for
pra
10,
can
inc
nec
fun
sen
itse
CC
Size
[40
sen
env
of
has
syn
moi
“Lo
spe
det:
bac
ligh
inte
inte
tech
con
com
kerr
The
opti
char
ima;
IAP