<title>Digital Information Optical Recording In Pictorial Format</title>

Abstract

AbstractAn optical recording technique which permits high bit packing densities, extension ofrecording media dynamic range and most importantly, the recording and retrieval ofextremely large digital pixel word values within a human readable /machine readablepictorial format has been formulated for imagery recording applications with conventionalsilver based film, electro- static materials and metallized film materials.IntroductionLaser recording systems have demonstrated the capability to record large blocks ofinformation at high recording rates. The recorded information is either in a machinereadable digital format or the human -readable pictorial format. In the former, digitizedimagery is stored in bit sequential fashion by appropriate encoding techniques and maylater be retrieved to reconstruct the original scene image. The later method provides avisual analog presentation of imagery with a loss of digital data dynamic range.This loss of digital data is due to the inability of continuous -tone recording media torecord the dynamic range normally encountered in advance sensors. To combat this, therecording and storage of large dynamic range pixel values is usually done in the digitaldomain while a separate image recorder reconstructs the pictorial format. Other opticaldata recording techniques for digitized imagery allow high bit packing densities, but thestored information remains in the digital domain and as such is less accessible thanpictorial data. By formatting the digital data base into quantized pixel values, however,image recording and digital storage can be simultaneously merged together to form acomposite data base which is both human and machine readable. The advantages of thisstorage and retrieval system are that information can be stored in a high- density mannerand be read out in either an analog or a digital format, while preserving the full dynamicrange of the digital collection device. The digital storage technique lends itself to theselective fusion of collateral information into the primary sensor data.Reconnaissance Imagery Data RecordingPresent electronic information gathering systems are capable of generating immenseamounts of data that must be processed, stored, and reconstructed to allow timelyintelligence exploitation and data dissemination. Most of the information gathered is inthe form of sampled data, i.e., the electronic gathering system time samples and digitizesthe sensed information. Enhancement or extraction of specific data contained in theinformation gathered can be extremely useful.Large numbers of electronic transducers (linear or area arrays) operating in either thevisible, infrared or radio portions of the electromagnetic spectrum and which can be readout in parallel or series -parallel combinations have necessitated systems which record,process, display and /or extract information at very high data rates.Optical recording techniques offer the capability of high density, high rate informationstorage. Conventional optical recording techniques limit the analog recording of digitaldata to the dynamic range of the recording media, i.e., less than 6 -bits (digital values)are recoverable from the recorded data.New recording techniques and materials which provide practical solutions for opticalimagery information storage and retrieval, including a technique for recording andretrieving digital data whose dynamic range is much larger than that of the recording mediahave been developed. Figure 1 is a block diagram of a Digital imagery recording system.Incoming digitized sample data from any one of several possible electronic imagingsensors is reformatted and recorded using a scanning laser recorder. After processing,with conventional recording materials or immediately with metallized films, the data isavailable for visual screening by an interpreter. If targets or objects of interest to theinterpreter are spotted their location is cued on the recording. The recorded image isthen scanned by detector or array of detectors, to extract the digital value of each pixelin the area of interest. Then, using digital computing techniques, the data may be