oring 
1g them 
Lity 
ce to 
ulated 
ıminan- 
d. by 
if 
if thc 
istic 
gi 
where í is the slope of the linear region, i is the time of ex 
position and C is the film sensitivity. 
The luninance has three main sources which nave to be taken 
in consideretion; nanely aj reflected sunlight, b) reflected 
skylight and c) scattered sunlight by particles benssth the 
ocean surface (15). Under the assumption of a calm sea, b) and 
c) are roughly equal uhen visued vertically but a) is larger 
than the other sources at any surface roughness condition. That 
makes that the use of reflected sunlight for imaging waves may 
overemphasize a particular slope, introducing a error in the 
evaluation of the imagery. Hence that reflected sunlight should 
be avoided. 
B) Optical Analysis 
The two dimensional power spectrum is obtained by optical 
processing of information on surface waves, using the hologra- 
phic method, The optical processor consists of two parts: an 
optical transform computer and a photochemical equidensity con- 
touring by which the power of the spectrum of the Fraunhofer 
patterns on the film are determined. 
In the revieued literature abundant references uere found 
on optical Fourier transformates, 5vz cnly tuo sugossted vaguely 
a method for improving the Fraunhofer images (12),(15). The 
main problem that  arised uhen following tne indications of 
other authors (10), (11), (12), (14), (15), (16), (17), (19), (20) was 
the strong limitation imposed by the size of the Fraunhofer 
image. SUGIMCRI .(12)-suggested the reduction of scale of the 
photograph, sc that the transformed image is ameliorated for 
the analysis. Eventhough this is a rather simple method for 
improving the information content of the photograpn, it might 
become twofold disadventageous: i) the very high freauencies may 
be overlooked, for the reduction causss a loss of definition, 
and ii) the reduction of the photograph may mask some aspects 
due to slight developing and/o- copying defects which are not 
always obsarveble or avoidable. Thus that the usual configurat- 
ion of the optical processor(figure 2) has been disregarded, 
modifying it to an optimal and more simple design in uhich the 
experimenter may control the scale of the Fourier transform. 
This configuration is shown in figure 3. The modified optical 
transform computer consists of a coherent light source (He-Ne 
laser, A =6328 A), a microscope's objective (10/0.25) which 
expands the laser beam, and a focusing lens (Vivitar 300mm,1:5.6). 
The transparency to be analyzed is set on plane P, after the 
lens L, and the diffraction pattern is registered by a convention 
al ref ox camera (Asahi Pentax) without ob jective, located on 
plane P, where the transformated image of P appears. ‘The peak 
amplitude of the wave at L5 is A and at P, 1s impinging d'.A/d 
in the geometrical-optics approximation (1s). If the beam dia- 
meter at L, is D, than a circular region of diameter d.D/d' is 
illuminated in the transparency plane. Using a paraxial eppro- 
ximation to the spherical wave that illuminates P4 , the field