A COMPARISON OF LINE-SCAN AND PHOTOGRAPHIC IMAGES FOR TARGET IDENTIFICATION

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Document Number (FOIA) /ESDN (CREST): 
CIA-RDP79B00873A001600040027-5
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RIPPUB
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K
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25
Document Creation Date: 
December 28, 2016
Document Release Date: 
August 30, 2012
Sequence Number: 
27
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Publication Date: 
October 1, 1969
Content Type: 
MISC
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Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A00600-400277/5 Li A COMPARISON OF LINE-SCAN AND PHOTOGRAPHIC IMAGES FOR TARGET IDENTIFICATION STAT Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 r Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 LJ ? LIKAFT r- 1=J tzd A COMPARISON OF LINE-SCAN AND PHOTOGRAPHIC IMAGES FOR TARGET IDENTIFICATION October 1969 DRAFT STAT Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 STAT r Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 , ;infix r71 r" 1:=1 fl 1=1 1=i r- 1=i ri 1=1 ACKNOWLEDGMENTS We sincerely thank the photointerpreters who participated in this study and Mr STAT valuable assistance in evaluating the photography, obtaining the subjects, and gathering the data. riDA Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 - Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 r" 77. INTRODUCTION DRAFT TABLE OF CONTENTS Page METHOD Preparation of the Images 3 The Targets 5 Subjects 7 Experimental Design 7 Procedure 8 RESULTS 9 DISCUSSION APPENDIX A A-1 .iv 1:797P Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 ri Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 ri" r 1 La A COMPARISON OF LINE-SCAN AND PHOTOGRAPHIC IMAGES'FOR TARGET IDENTIFICATION 'INTRODUCTION There have been several studies of the effects of photo- graphic ground resolution on the intelligence output of photointerpreters (PIs) and intelligence analysts. There have been fewer studies of the effects of line-scan imagery on intelligence output. The purpose of the study reported here was to make an initial determination of the relation ber tween line-scan and photographic imagery in terms of PI target identification performance. The relations between the two types of imagery should be determined so that the de- signers of 'line-scan systems can use the results of the re- search on the effects photographic ground resolution has on the performance of different PI and analyst tasks. recently completed an experimental study to determine the informative value of static line-scan images as a function of two variables: (1) number of scans per target and (2) signar-to-noise ratio. Photographs were taken of 20 models: 10 tanks and 10 miscellaneous vehicles, such as trucks and armored cars. The photographs were transformed into line-scan transparencies so that there were either 16, 32, or 48 scans per target. Gaussian noise was added to the transparencies producing: 14 fl signal-to-noise ratios of 3, 5, 10, 20, and 30 for each of the three numbers of scans. There was also a noiseless image for each of the three numbers of scans. The subjects were 54 college students. Each subject was assigned randomly to one of six groups, and each group fliD A Vir STAT Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 Declassified in Part - Sanitized Copy Approved for Re-lease 2012/08/30: CIA-RDP79B00873A001600040027-5 Far IMP% F" fl r- 1=1 ^ viewed three transparencies that contained the same amount of noise but a different number of scans per target'. The,. targets were in different positions in the three transparen- cies. The models were mounted on a board in front_:of the subjects, and their task was to match each target image with each target model, a,task similar to matching a target image ? with the target as portrayed in a pI key. In the analysis, the tanks were treated as one class, of targets .and the miscellaneous vehicles were treated as another. Matching a target image with the target model was. considered a correct "identification," and the percentage of correct identifications was computed class and each experimental condition. The results study. were reported in for each target. of the The informative value of line-scan images as a function nal and noise characteristics (white, Gaussian, independent noise) 1969 . of sig- signal- March, METHOD The method used in the study reported here was similar STAT STAT to that used by However, PIs not STAT only viewed, the line-scan imagery used in the previous study, they also viewed conventional photographic transparencies of the same targets at five different ground resolutions. Their task was to match the line-scan target images and conventional photographic target images with the target models. The percentage of correct identifications*was com- puted both As a function of number of scans per target and signal-to-noise ratio in the line-scan images, and as a function of photographic ground ,resolution. 11R A 071 Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 um. A 111111.111111111 irk Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 III 11.-16 ? in Preparation of the Images Following are descriptions of how the line-scan and photographic transparent images were prepared line-scan images used in the study reported here same ones used and a plete description of the image preparation is report. The line-scan images. The model targets were placed on a uniform background and the position of each was random. They were placed so that all of them extended an equal dis- tance in the direction perpendicular to the scan direction. This was done so that each image would be formed by approxi- mately the same number of scan lines. A diffuse light source was used to simulate the illumi- nation of the sky, and another point light source was used to simulate the sun at 50? aboVe the horizon. Three different random arrangements of the models were photographed with Kodak High Definition Aerial Film, Type 3404, in a 35mm camera. Each photograph was enlarged so ' that the subsequent conversion into line-scan images would result in 16, 32, and 48 scans per target. 'The enlarged photographs were transformed into line- scan images using the Line-Scan Image Generatorl and The were the more corn- given in their 0 associated Digital Tape Memory System2. The sampling and reconstruction spots were identical and circularly symmetri- cal; they had Gaussian intensity distributions with half- amplitude diameters of 0.55mm. The scan spacing was 0.55mm. Scott, F. A line-scan image generator, Photo Sci. & Eng., Vol. II, 5, 1967. STAT STAT STAT STAT - Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 I Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 i'riri ,The photographs were sampled at intervals of 0,55mm, the half-amplitude of the spot diameter, The sampled trans- mittance was quantized into 12 bits (virtually analog imagery) and recorded digitally on tape. Noise Was added to the quantized transmittance pro:- ducing an output image with the desired noise characteristics. The noise elements were generated using a random-number- generator subroutine on an SDS 9,30 computer. The noise had a Gaussian transmittance distribution, and different standard deviations of the distribution were Used to produce signal-to-noise ratios of 3, 5, 10, and 203,. The signal-to-noise ratio was'defined as the.ratio of the, standard deviation of the signal to the standard, deviation of the noise, ' Fourteen line-scan image transparencies were produced with the characteristics shown in Table 1. Each cell in the table.represents a line-scan transparency characterized by the, column and row values'. (Note that a transparency was not made to represent 48 scans and a signal-to-noise ratio of 20, because it would have been almost identical to the noiseless -imagery.) Each transparency contained the images of the 20 model . targets. The position of the vehicles was the same in all transparencies in each row in the table but differed from one row to the next. 3A signal-to-noise ratio of 30 was also used in the study. It was nOt used in the study reported here because identification performance with it was? not significantly different from performance with noiseless line-scan imagery. 4 Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 Ile IMAM 11- I :11 1=1 171 171 TABLE 1 CHARACTERISTICS OF THE LINE-SCAN TRANSPARENCIES, NUMBER OF SCANS PER TARGET SIGNAL-TO-NOISE RATIO 3 5 10 20 . (Noiseless) 16 32 48 * *A transparency was not made to represent this cell. The photographic images. The photographic images used in the study were made by from the original negative used STAT in making the 48 scan; line-scan images. The method used is described in detail report submitted t in Appendix A, which is a cppy of the with the photographs. he ground resolution of the five photographs was de- termined from the average of the three-bar target readings made by three photographic tions were: The Targets scientists. The ground resolu- Figure 1 is a photograph of the models used as targets in the study. 4After they were prepared, the photographs were cut and the targets rearranged so that their position would not be the same as their position in the 48 scan, line-scan images. 5 DRAFT STAT STAT Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 Declassified in Part - Sanitized Copy Approved for7-Release -2012/08/30 : CIA-RDP79B00873A001600040027-5 PO Ft". F I 1 ? ? OOOOOOOOOOO ? - ? I ... ? ? 7'.***-1 . * ? id: 0 ? 77. 0 ? 0 t ? ? . i 0 1 ? ? ? VV. ? . 8', t.H .10.? ? ? . . ........ d.C.Y.'fV4.k: V.6 ? I ? t' ? .1 .12. 1. 2. 3. 4. .. .. Russian T-54 Tank 11. U. S.. Medium Sherman M4, 12. A4 Tank 13. German Tank IV/H German Tiger (1) Tank 14. 5. Joe Stalin III Tank 15. 6. U. S. Medium M-60 Tank 16. 7. British Centruion Tank 8. U. S. Medium Patton M-47 17. Tank 18. 9. Medium Tank AMX30 10. .French U. S. Light "Walker Bull- 19. dog" M-41 Tank 20. Figure 1. Tank Recovery Vehicle 1-119 Tank Recovery Vehicle 1-120 (1) U. S. 1-120 Tank Recovery Vehicle German 234/1 Armored Car U. S. M-106 Mortar Carrier German Half Track Rocket Carrier Half Track - Munition Carrier U. S. M-62, 5-Ton Wrecker Truck German Sound Detector U. S. La-Cross Missile XM 4 E2 The model targets. 6 1) A Irr Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 gm.- 10i. A UAW ANY Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 Oil 1111i1FM? ? TABLE. 2 EXPERIMENTAL DESIGN NUMBER OF SCANS PER TARGET SIGNAL-TO-NOISE RATIO 3 5 10 20 m 16 G1 05 G3 G4 G5 32 01 G2. G3 04 05 48 01 .02 03 * 05 *This cell was not represented in the study. Subjects The subject's were 50 professional PIs. Their.mean experience was 5..3 years. Eight of them were from IAS, 24 from IEG, 8 from SPAD,. and 10 from Nineteen of the subjects specialized in ground order-of-. battle (GOB) targets. Experimentai Design Each subject was randomly .assigned to one of five groups with the restriction that about the same number of GOB specialists be in each group of 10: . the 19 specialists were distributed 4, 4, 4, 4, 3 in the five groups. . The subjects in Groups 1, 2, 3, and 5 viewed...three . line-scan transparencies and A photographic transparency. The subjects in Group 4 viewed.two line-scan transparencies 7 STAT STAT rtr? A VT 7Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 .Alk 1111111111111111 Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 11109 Mir-% III ? and a photographic transparency. All subjects viewed line- scan transparencies that differed in the number of scans per vehicle, but had the same signal-to-noise ratio. Table 2 shows the experimental design. Procedure Each subject was seated .at a light-table and given a loop and a microscope with which to view the imagery. A set of the 20 model vehicles arrayed in 4 x S,matrix on a board was placed in convenient viewof the subjects. Each model was identified by a number ranging from 1 to 20. The purpose of the experiment and rules for the task were explained to the subjects. The rules were as follows: 1. Match the images to the models in the order they appear in the transparency proceeding from the upper left-hand corner of the trans- parency to the lower right. Do not skip any images; respond to them in order. 2. Match each image to a model and write the num- ber of the model on your answer sheet. 3. Consider each match independently of all other matches.. You:may match the same model to more than one image. Your initial selection is considered as final; do not 'change your answer unless you get per- mission to do so. 5. Use any magnification you wish. fi. Work at your own pace: and takebreaks when you wish. The subjects were given the appropriate transparencies in the predetermined orders. Each subject completed the matching task for a given transparency before the next one was given to him. The average time taken to complete the task was about one-and-one-.half hours. 8 rita A rare Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 L Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 DRAFT z=1 fl RESULTS ? The results of the study are shown in Table 3 and Figure. 2 for the tank targets and in Table 4 and Figure 3 for the miscellaneous vehicle targets. Some of the results are immediately apparent. The tanks were more difficult to identify coriectly than the miscellaneous targets in both the photographic and the line-scan images: distinguishing among the tanks is simply a more demanding perceptual task than distinguishing among the miscellaneous targets. For both classes of targets, higher per cent identi- fication measures were obtained with larger signal-to-noise ratios. For the tank targets, 48 scans per target resulted in higher per cent identification measures than 32, and 32 resulted in higher measures than 16. For the miscellaneous targets, 48 and 32 scans per target were better than 16 but there was little difference between 48 and 32. No effort has been made to smooth the functions shown in Figures 2 and 3 because additional work must be done to obtain the required reliability. Implied in that statement are more targets, more imagery, and more experimental subjects. Table 5 shows a few of the equivalences in terms of per cent correct identifications of tank targets between photographic ground resolution and line-scan image character- istics. The table was prepared to illustrate how data from studies like the one reported here can be used to determine the requirements and specifications of a line-scan system. 9 trti DACT Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 Fl Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 LI LintAt I TABLE 3 PER CENT CORRECT IDENTIFICATION OF TANKS NUMBER OF SCANS PER TARGET SIGNAL-TO-NOISE RATIO 3 5 10 20 . 16 18 20 27 32 56 32 31 38 52 60 83 ?48 32 43 75 * 98 *This cell was not represented in the study. TABLE 4 PER CENT CORRECT IDENTIFICATION OF MISCELLANEOUS TARGETS NUMBER OF SCANS PER TARGET SIGNAL-TO-NOISE RATIO 3 5 10 20 . 16 43 44 50 64 83 32 65 59 85 95 100 48 74 79 87 * 98 *This cell was not represented in the study. 10 DRAFT Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 STAT STAT Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 ILPKAIr I TABLE 5 EQUIVALENCES IN TERMS OF TARGET IDENTIFICATION PERFORMANCE AMONG LINE-SCAN AND PHOTOGRAPHIC IMAGES (Tank Targets Only) IMAGE SPECIFICATIONS PER CENT CORRECT IDENTIFICATIONS 16 SCANS/ TARGET 32 SCANS/ TARGET 48 SCANS/ TARGET 50 39.5 S/N* 9.5 S/N 6.0 S/N 60 ** 20 S/N 7.6 S/N 70 ** 31 S/N 9.3 S/N 80 ** 42 S/N 18.0 S/N 90 ** ** 32.1 S/N 98 ** ** 40.0 S/N * Signal-to-noise ratio **The imagery specified in these cells of the table will not yield the percent correct identifications indicated. STAT DR/14:0"1" Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 R Next 1 Page(s) In Document Denied Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 STAT Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 fl 1.$ 4=; fl DRAFT DISCUSSION The study reported here was the first effort designed to determine the relation between line-scan and photographic imagery. The usefulness of the results is limited because the samples of targets and subjects were small. However, an important first step has been made, and because it is obvious line-scan systems are going to be developed, add- itional steps must be made so that both collection and ex- ploitation systems can be properly designed. 14 Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 [0 Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 uprtmr Declassified APPENDIX A A- 1 rtp A CT in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 ?0 Ind Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 DRAFT VEHICLE GEM SET SPO 28919 July 1969 A-2 rip A rim Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 MII?a- MEM,- ? A& MIMI. Sat...6u ou Declassified in Part - Sanitized Copy Approved for Release 2012/08/30 : CIA-RDP79B00873A001600040027-5 111a191 IU A set of positive GEM photographs was generated by photographing a'negative original with controlled degrada- tion in a 1:1 optical system. The degradations were achieved by defocusing the optical system. The resulting GEMs fre- quency spectra are shown in Figure 2. The frequency spectra of the GEMs was measured by scanning edges in the scene with a microdens.itometer and processing, the data with a form of edge gradient analysis. A GEM master negative was not re- quired as the original negative supplied had a gamma o,f. 1.0. The choice of an optical..system for the generation of the GEMs.was based on the ease this method affords for con- trolled image degradation and by the?time and:cost'limits imposed on this program. A 1:1 camera system was set-up on an optical bench and consist6d of a 105mm Schneider Componon lens, target holder and film back. Defocusing was achieved by movement of the film back away from the target holder by a,micrometer stage adjustment. The original negative's frequency spectra did not contain high frequency information as is shown in Figure 1. This MTF curve was determined by scanning several edges throughout the original negative frame forMat and selecting a transfer function that was the? approximate center of the data spread. Thus phase shifts caused by defocusing was not a problem, 'due to the nature of the original 'scene., Tri-bar resolution was used to de- termine the' positions of the film back which gave resolutions of approximately 1/2, 1/4, 1/8, and 1/16 of that obtained at the prime focal position. These positions were then used to photograph the scenes, along with,aitarget array which consisted of an edge, high and low contrast tri-bar targets. Tlie addition of these targets was made necessary by the large amounts of defocus used. Measurements of edges within the scene could not be made for cases of low resolution due to the large. area required to properly measure the edges. The density.differences of the ?edge and background in the target array were selected to nearly match the density A-3 Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 Declassified in Part - Sanitized Copy Approved for Release 2012/08/30 : CIA-RDP79B00873A001600040027-5 - MilLORM differences in the scene. Listed in Table I are the density values for the. GEMs and the reference target array. Density measurements were made on vehicles in the four corners and in the center of the scene. The results of measurements made on the test .target control edges appear in Figure 2. Traces of reference edges contained in the S:cenes for which it was possible to measure the edges (num- ber 9, 1; and 2) are given in Figure 3 The image for the remaining GEMs could not be traced due to problem of the scan length required. The data given in both .these figures is uncorrected for the microdensitometer optics and slit, since this would only affect the level of the curves not their relative scaling to each other. The final GEM images were made on Kodak 5235 duplicat- ing film process in 0-76 at 68?.F. to give a gamma of 1.0. Exposures were adjusted so that the final scene densities remained approximately the same throughout the entire GEM set. A-4 EIRAPT Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 U. f-111 L II-11 1--11 Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 ? .8 10 20: 30 :40 Spatial Frequency cy/mm Figure 1. Selected Nominal Scene Transfer Function for GEM Original Negative Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 -111 11-1 1-111 11-11 1-111 1-1 r?m F-3 ? Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 20 30 Frequency ( Cycl es/ram) 40 50 Figure 2.. Target ?Edge Frequency Siectrum 60 Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 (TI1-11li 1-111 1-11 11-11 (?II Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 Transfer 10? 20 40 Frequency -(cycles/mm) 50 ,Figure 3. GEM Frequency Spectrum .60 70. Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 r Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5 11 Pah% I" I t.3 fl (-7 1=i TABLE 1. , DENSITY MEASUREMENTS ON GEM AND TARGET ARRAY Original Target Array D-Max D-Min Density Difference High Contrast 2.58 .04 2.54 Edge Target 1.07 .04 1.03 Low. Contrast .49 .04 .45 Target Array High contrast 1 ' 2 ' GEM 3 # 4 .5 D-MaxH 1.42 1:..38 1.40 1.36 1.40, D-Min .09 .09 .09 .09 .08 Density Difference 1.33 1.29 1.31 1.27 1.32 ' Target Array Low Contrast 1 2 GEM # 3 4 5 D-Max 1.34 1.31 1.35 1.32 1.34 D-Min .78 .74 .79 .78 .77 Density Difference . .56 .57 .56 .54 .57 Edge Target Array GEM # 1 2 3 4 5. D-Max 1.34 1.32 1.33 1.41 1.35 D-Min .37 .36 .36 .36 .36 Density Difference .97 .96 .97 1.05 .99 GEM-Array GEM # Density of. Background Density of Corner Vehicles Density of Center Vehicle .27 1.08 1.27 1.10 1.31 1.26 2 .25 1.04 1,25 1.14. 1.29 1.2.6 3, .24 1.06 1.28 1.13 1.32 1.23 ,4 .25 1.03 1.28 1.15 1.33 ' 1.28 5 .28 1.10 1.22 1.19 1.38. 1.25 A-8 111? A riT Declassified in Part - Sanitized Copy Approved for Release 2012/08/30: CIA-RDP79B00873A001600040027-5