A wide range of users will find this guide useful for maintaining image quality in electronic displays. This professional reference book begins with overviews of display systems and types of displays, then covers such topics as physical and perceptual quality measurement, human visual performance, display system performance requirements, monitor selection and setup, pixel processing, and digitizer and printer operation. An accompanying CD-ROM provides image test targets to demonstrate applications described in the text.
Since the 1950s, numerous studies have been performed within the surveillance and reconnaissance (S&R) and target acquisition (TA) communities in an attempt to predict information extraction performance as a function of image collection and quality parameters. In general, the work followed two separate paths. The TA community developed models to predict probabilities of detection, recognition, and identification as a function of target size, range, and collection system design/performance parameters (e.g., MRT, FLIR92,NVTHERM,MRC). The S&R community developed models to predict National Imagery Interpretability Ratings (NIIRS) as a function of system design and collection parameters (e.g. IR GIQE). More recently, efforts have linked the two approaches such that NIIRS can be predicted from TA models and probabilities of identification can be predicted from NIIRS. With both approaches, resolution is a dominant term. A considerable amount of variability and uncertainty results from target differences. The criteria used to define the NIIRS generalize target type, size, and level of identification specificity. The TA predictions use the Johnson recognition criteria to relate lines on the target to recognition performance. A recent paper found that TA predictions differed substantially between the visible and IR. Further, the paper reported substantial differences among vehicles in terms of a confusion matrix. This finding was not surprising in light of other research, but suggested the need for a more detailed examination and explanation of results. Accordingly, the current effort was undertaken. Data from a variety of past studies dealing with target recognition were examined relative to the Johnson criteria, along with a more detailed analysis of data from two recent TA studies. A hypothesis of target recognition performance was generated and partially validated using available data.
A study was performed to assess the ability of five objective quality measures to predict perceptual quality difference ratings. The objective measures included peak signal-to-noise ratio (PSNR), root-mean-square error (RMSE), maximum absolute difference (MAD), the Image Quality Metric (IQM), and the just-noticeable-difference (JND) metric. Perceptual difference ratings used the National Image Interpretability Rating Scale (NIIRS). NIIRS data from four previous studies of bandwidth compression and image processing were compared to values of the five objective measures to determine whether any of the objective metrics could be used as a substitute for the labor-intensive NIIRS ratings.
The display is a key element in the softcopy image chain. If the display is not optimized, information is lost. Studies seeking to assess the effects of bandwidth compression and image enhancement will reach false conclusions unless the display system is optimized. Although standards exist for the display of text and symbology, no such standards exist for continuous tone imagery. To help remedy this situation, a series of studies were conducted to help define guidelines for the effective display of continuous tone imagery, with emphasis on surveillance and reconnaissance imagery. Imagery of various types (visible, IR, multispectral, SAR) was displayed on cathode ray tube (CRT) and active matrix liquid crystal displays (AMLCD) that varied in luminance and spatial resolution performance. Over a series of eight studies, trained imagery analysts provided National Imagery Interpretability Ratings (NIIRS) and Briggs target ratings (a measure of minimum discriminable target size as a function of contrast) to assess the impact of display variations. From these studies, recommendations were derived for display pixel density, contrast modulation, and luminance measures including dynamic rang, ambient light level, color temperature, and perceptual linearization. This paper defines the display performance measures used, performance measurement procedures, and presents guidelines for display optimization. Results of studies supporting the guidelines are summarized. Use of the guidelines is recommended in any study involving softcopy display of continuous tone imagery.
Four perceptually based metrics were compared for use in studies of video bandwidth compression in a military context. They include the National Imagery Interpretability Rating Scale (NIIRS), a task satisfaction confidence scale (TSC), an information conveyance scale (IC), and an artifact rating (AR) scale. The metrics were used in two compression studies using both MPEG-2 and frame decimation. The studies used video imagery collected with an unmanned aerial vehicle (UAV). The metrics were compared in terms of sensitivity and reliability. Results were also compared to those from other studies employing the ITU-R BT. 500-9 double-stimulus continuous quality-scale (DSCQS) in terms of both findings and metric performance. DSCQS is the metric commonly used in studies of bandwidth compression for commercial applications. It was concluded that for studies of video quality for military applications, NIIRS was the preferred perceptual metric. It was shown to be applicable to video, was comparable to DSCQS in reliability and sensitivity, and is a metric most familiar to the intelligence community.
Video systems have seen a resurgence in military applications since the recent proliferation of unmanned aerial vehicles (UAVs). Video system offer light weight, low cost, and proven COTS technology. Video has not proven to be a panacea, however, as generally available storage and transmission systems are limited in bandwidth. Digital video systems collect data at rates of up to 270 Mbs; typical transmission bandwidths range from 9600 baud to 10 Mbs. Either extended transmission times or data compression are needed to handle video bit streams. Video compression algorithm have been developed and evaluated in the commercial broadcast and entertainment industry. The Motion Pictures Expert Group developed MPEG-1 to compress videos to CD ROM bandwidths and MPEG-2 to cover the range of 5-10 Mbs and higher. Commercial technology has not extended to lower bandwidths, nor has the impact of MPEG compression for military applications been demonstrated. Using digitized video collected by UAV systems, the effects of data compression on image interpretability and task satisfaction were investigated. Using both MPEG-2 and frame decimation, video clips were compressed to rates of 6MPS, 1.5 Mbs, and 0.256 Mbs. Experienced image analysts provided task satisfaction estimates and National Image Interpretability Rating Scale ratings on the compressed and uncompressed video clips. Result were analyzed to define the effects of compression rate and method on interpretability and task satisfaction. Lossless compression was estimated to occur at approximately 10 Mbs and frame decimation was superior to MPEG-2 at low bit rates.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.