USE OF IMAGE INTEf SIFIERS FOR REAL-TIME MULTISPECTRAL VIEWING

im experimental program has investigated the practicality of synchronized rotating filter wheels at the input and output of an image intensifier to produce a fieldsequential color image. Both military and commercial intensifier tubes were used. Reasonably true-color rendition was obtained, even with the limitations imposed by crude equipment and tar-from-optimum filters. Fundamental limitations result in rather large energy losses and hence preclude full-color operation at very low light levels (such as starlight). At intermediate light levels, color viewing may be practical and may be valuable in enhancing target contrast. With appropriately chosen sets of input and output filters, the spectral response of camouflage detection film can be duplicated. This makes the near-infrared reflectance of the scene visible by translating .hat portion of the spectrum to visible red. Red input energy is presented as green in the image, and green input is presented as blue. These translations make green vegetation appear in striking contrast to man-made objects which to the unaided eye seem to match closely. This suggests the possible use of this simple device for real-time reconnaissance, with appropriately chosen filters and spectral translations to enharce specific ta -get classes. The obvious advantage over camouflage detecUon film is that this device operates in real time. Also, the spectral translation characteristic may be readily varied. The promising experimental results suggest that a supplemental program should be supported: a better, more flexible, and more portable model should be built; and available spectral reflectance data should be analyzed to help select optimum filter combinations. WILLOW RUN LABORATORIES CONTENTS Foreword iii Abstract v List of Figures viii 1. Background 1 1.1. Imag« Tubes 1 1.2. Photocathode Materials 2 1.3. Phosphors 4 2. Experimental Program 6 2.1. True Color Display 7 2.2. Translated Color Systems 12 3. Recent Results 15 4. Future Program 16 References 17 Distribution List 24