Showing papers on "Grayscale published in 1975"

Pattern recognition apparatus

Abstract: A pattern recognition apparatus for recognizing or identifying fingerprint images and the like is described The apparatus enables the determination of the coordinates and angular positions of characteritic points such as fingerprint minutiae The pattern recognition apparatus includes a high resolution scanner for scanning a fingerprint impression or image, an analog to digital converter to convert the scanner signals to a digitally encoded image having many levels of gray scale data, an image enhancer to eliminate imperfections in the imagery, pre-editing circuits to edit out areas of the image which should not be further processed, a minutiae detection system having high redundancy to reduce the probability of missed minutiae, and a post-editing subsystem to eliminate false minutiae detections

Real‐time color B‐scan ultrasonography

Abstract: The development and early clinical results of a real-time color B-scan ultrasonoscope are described. This instrument uses color to display detailed echo amplitude information more quantitatively than is possible with gray scale. With real time, dynamic changes are seen during the examination. Conversion of the amplitude information into binary coded decimal code permits separation into ten color steps and also eliminates "blooming" of the cathode ray tube, as seen in black and white. Integrated circuitry is used, providing a portable, relatively inexpensive unit. Early clinical work in ophthalmology is illustrated.

Specification of color image quality

Abstract: This thesis is concerned with the measurement and specification of color image quality. This includes the subclass of black-and-white images. The thrust of the work is the development of a bridge between the physical specification of quality provided by the Optical Transfer Function (OTF) and the subjective impressions of quality obtained from a panel of judges. The study was limited to OTF produced image degradations. The OTF's were varied in all spatial and spectral dimensions. Image magnification was also included. A large number of black-and-white and color still photographs were produced incorporating a wide variety of OTF defects. The images were produced using lenses, and analog and digital simulation methods. The quality samples used in our study were limited to grain-free isoplanotic images. The images were photographed to reproduce accurately the tone (gray scale) and color balance of the original. The result of the study was the definition of an Image Quality Merit Function (IQMF) which gives consistent predictions of the subjective quality of color images. The IQMF was developed by modeling the spatial and spectral properties of the visual system. The consideration of the visual system properties in the calculation of the quality merit has produced a practical image quality criterion which is easily calculated and directly measurable and which yields consistent predictions of system performance. The correlation between the predicted and measured subjective quality ratings exceeded 0.98 for all the conditions used in the study.

Image Improvement with Second Generation Gray Scale

Abstract: Ultrasound has proved extremely valuable in imaging human anatomy. Initially, the outline of various organs was of primary interest/ but there is increasing use of finer details of tissue structure such as distinguishing cystic from solid masses. Gray scale imaging has been developed to aid in displaying additional information continued in ultrasound echoes. Using the original processing schemes as a basis for explanation, this paper describes recent advances made in signal processing and display of ultrasound images.