Experiments in Iterative Enhancement of Linear Features

Lines and curves in an image are detected locally by a template-matching process which determines the line-ness value of the image at each point, in a set of orientations. The output of the detection process is the strongest of these values at each point, and the orientation that gave rise to this value. The results of this approach tend to be noisy, but their noisiness can be reduced by examining, for each point, the values at nearby points, in the direction defined by the preferred orientation, and increasing the point\u27s value if the nearby points have high values and similar orientations. Iteration of this reinforcement process leads to further noise reduction. Several variations on this scheme are presented. The preferred orientations can also be sharpened by examining the orientation at nearby points (in the preferred direction) and biasing it toward their average. Experimental results using these methods are obtained for LANDSAT and SKYLAB images containing many linear features

Outline bibliography, and KWIC index on mechanical theorem proving and its applications

Bibliography and KWIC index on mechanical theorem proving and its application

The effect of bystander CPR on survival of out-of-hospital cardiac arrest victims

The effect of bystander cardiopulmonary resuscitation (CPR) was studied in 2142 emergency medical service (EMS) cardiac arrest runs. When bystander CPR was administered to cardiac arrest victims, 22.9% of the victims survived until they were admitted to the hospital and 11.9% were discharged alive. In comparison, the statistics for cardiac arrest victims who did not receive bystander CPR were 14.6% and 4.7%, respectively (p < 0.001). A critical factor in patient survival was the amount of time that elapsed before the EMS personnel arrived and administered CPR. Patients who received bystander CPR were more likely to have ventricular fibrillation when the EMS arrived. Other factors relating to patient survival were the location of the victim at the time of the cardiac arrest and the age of the victim. Understanding these factors is important in developing community strategies to treat patients with cardiac arrest out of hospital.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25928/1/0000491.pd

Analysis of cardiac symptoms preceding cardiac arrest

Prodromal symptoms and cardiac history were examined in 227 patients with coronary artery disease who were successfully resuscitated after out-of-hospital cardiac arrest. Cardiac arrest was sudden--with either no symptoms or symptoms for less than 1 hour--in 71% of the patients. Nonsudden death--death occurring after more than 1 hour of symptoms--occurred in 29% of the patients. A history of cardiovascular disease was present in 85% of patients with sudden cardiac arrest and in 83% with nonsudden arrest. Cardiac arrest occurred without symptoms in 38% of the patients with sudden cardiac arrest and was the first expression of coronary artery disease in 4% of the entire study group. This study indicates that cardiac arrest usually occurs with symptoms and almost always in the setting of a history of cardiovascular disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25967/1/0000033.pd

Effect of empiric antiarrhythmic therapy in resuscitated out-of-hospital cardiac arrest victims with coronary artery disease

The effect of empiric antiarrhythmic therapy with quindine and procainamide on long-term mortality was examined in 209 patients with coronary artery disease resuscitated after out-of-hospital cardiac arrest. The antiarrhythmic agent used was determined by the patient's private physician without knowledge of the study ambulatory electrocardiogram. Of the 209 patients, procainamide was prescribed in 45 (22%), qiinidine in 48 (23%) and no antiarrhythmic therapy in 116 (55%). Digoxin therapy was initiated in 101 patients. The 2-year total survival rate for the quinidine, procainamide and nontreated patients was 61, 57 and 71% (p &lt; 0.05), and for sudden death was 69, 69 and 89% (p &lt; 0.01), respectively. These observations suggest that empiric antiarrhythmic therapy in survivors of out-of-hospital cardiac arrest did not affect total mortality and was associated with an increased frequency of sudden death.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28573/1/0000376.pd

Line Detection in Satellite Imagery

Three algorithms for line detection, the linear detector, the nonlinear detector, and the semilinear detector are examined. Experiments are conducted on detecting linear features in terrain on LANDSAT-1 images, and on detecting suburban roads on Skylab images

Towards Reliable Evaluation of Algorithms for Road Network Reconstruction from Aerial Images

Existing connectivity-oriented performance measures rank road delineation algorithms inconsistently, which makes it difficult to decide which one is best for a given application. We show that these inconsistencies stem from design flaws that make the metrics insensitive to whole classes of errors. This insensitivity is undesirable in metrics intended for capturing overall general quality of road reconstructions. In particular, the scores do not reflect the time needed for a human to fix the errors, because each one has to be fixed individually. To provide more reliable evaluation, we design three new metrics that are sensitive to all classes of errors. This sensitivity makes them more consistent even though they use very different approaches to comparing ground-truth and reconstructed road networks. We use both synthetic and real data to demonstrate this and advocate the use of these corrected metrics as a tool to gauge future progress