Low-Resolution TV: Subjective Effects of Frame Repetition and Picture Replenishment

Brainard, R. C.; Mounts, F. W.; Prasada, B.

doi:10.1002/j.1538-7305.1967.tb02451.x

Cited by 17 publications

(2 citation statements)

References 2 publications

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“…Pseudorandom scanning of CRT displays consists of dividing the display into a matrix of cells in which the beam scans one or more points in one cell and then jumps randomly to a different cell (Brainard, Mounts, and Prasada, 1967;Deutsch, 1965). The 11 different pseudorandom scan orders were based upon the matrix size into which the screen was divided (2 X 2, 6 X 6, 10 X 10, 20 X 20) and the number of randomly determined points that were scanned consecutively in one cell (1, 4, or maximum number in the cell) before the beam passed to another cell.…”

Section: Scan Orders On P-12 Phosphormentioning

confidence: 99%

“…However, they used regeneration rates no greater than 3 fps, which must have resulted in display flicker. Brown (1967) also studied various scan orders, not in an attempt to determine the required regeneration rate for each (this was fixed at 60 fps), but rather to determine how they affected perceived resolution . Brainard, Mounts, and Prasada (1967) studied the effect of several different scan orders on the perceived continuity of image motion for a picture telephone, but they report no flicker data.…”

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Flickerless Regeneration Rates for CRT Displays as a Function of Scan Order and Phosphor Persistence

Dill

Gould

1970

Hum Factors

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The effects of two variables on the regeneration rates required to prevent flicker on CRT displays were investigated in this computer-automuted experiment. The two variables were the sequential order in which the display was scanned ( e g , horizontal, vertical, or pseudo-random scanning) and the persistence of the phosphor on the display. Twenty-one different scan orders and two phosphors (P-12 and P-38) were used. Results showed that flickerless regeneration rates depended principally upon phosphor persistence; scan order had only a minor influence. The main effect of random and pseudorandom scanning was to reduce the disturbing effects of display flicker when it did occur, rather than to reduce significantly the regeneration rate at which flicker did not occur.The cathode ray tube (CRT) is used as a display device in several systems that receive information conveyed over lines rather than information that is broadcasted, e.g., picture telephone and computer terminals. The required bandwidths of such systems (or rates at which information is conveyed from its source to the display) are closely related to system costs. A reduction in bandwidth can lead to a reduction in display system costs. Accordingly, bandwidth reduction is often advantageous, especially if it does not lead to deterioration in system performance. Display bandwidth is proportional to the product of two variables: the resolution of the display multiplied by the regeneration rate of the display. Consequently, a reduction in either the regeneration rate, which is presently 40-60 frames per second (fps) (Adams Associates, 1967), or resolution of a display are two ways to accomplish a reduction in display bandwidth. A reduction in the flicker-free regeneration rate of a display is especially attractive because unlike a reduction in display resolution, it does not detract from the usefulness of the display. "Flicker-free'' means that the viewer does not observe the temporal luminance changes on an otherwise homogeneous luminance field caused by the fading and subsequent regeneration of that field on the display.This study evaluated the effect of two variables on the flicker-free regeneration rate of a CRT display. One variable was the order in which the display was scanned. "Scan order" refers to the temporal sequence in which spots on the face of the screen are illuminated, Scan order was originally considered in the design of broadcast television (Engstrom, 1935). At that time two-line horizontal interlace (odd raster lines are scanned, then even raster lines scanned) was chosen over progressive horizontal scan (consecutive raster lines scanned sequentially) to provide a flicker-free picture. Since then, other types of scan orders in addition to line scans have been discussed, e.g., pseudorandom or dot-line interlace (defined below). A general characteristic of these latter scan orders is that consecutively scanned points, instead of being very close to each other, are relatively widely separated across the display screen. The superiority of these...

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Section: Scan Orders On P-12 Phosphormentioning

confidence: 99%

mentioning

confidence: 99%

Flickerless Regeneration Rates for CRT Displays as a Function of Scan Order and Phosphor Persistence

Dill

Gould

1970

Hum Factors

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Low-Resolution TV: An Experimental Digital System for Evaluating Bandwidth-Reduction Techniques

Mounts¹

1967

Bell System Technical Journal

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An experimental digital television system has been constructed for evaluating digital techniques which involve storage and which may be used to reduce the bandwidth required for the transmission of television signals. The basic configuration of this system is presented. The system is composed of a television camera chain, synchronizing generator, 8‐digit analog‐to‐digital Gray code converter, Gray to natural‐binary code translator, high‐speed large capacity ultrasonic delay‐line memory, digital control logic, 8‐digit digital‐to‐analog converter, television display monitors, and video‐tape recording equipment. The picture format consists of 160 lines per frame sequentially scanned at 60 frames per second. The video signal is band‐limited to less than 768 kHz, corresponding to a horizontal resolution of 160 samples per line. The required timing and synchronization signals for all equipment are derived from a common clock source.

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Low-Resolution TV: Subjective Effects of Noise Added to a Signal

Brainard¹

1967

Bell System Technical Journal

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The visibility of noise in a television presentation is related to the spatial‐frequency and flicker‐frequency components of the noise display. The visibility of sine wave interference, which generates a sine wave grating on a TV screen, demonstrates remarkable linearity by giving a good approximation to the visibility function measured with narrow bands of noise. A difference in visibility between moving and stationary gratings produces a difference between noise visibility in TV and photographs. This fact is important in evaluating the computer simulation of a system by calculations for a single TV frame. The variation of visibility with motion predicts increased visibility for additive noise in a television frame repeating system. Applications to predistortion and reconstruction filters for transmission of analog and digital TV signals are discussed.

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Low-Resolution TV: Subjective Effects of Frame Repetition and Picture Replenishment

Abstract: Using the experimental television facility described in a companion

Cited by 17 publications

References 2 publications

Flickerless Regeneration Rates for CRT Displays as a Function of Scan Order and Phosphor Persistence

Flickerless Regeneration Rates for CRT Displays as a Function of Scan Order and Phosphor Persistence

Low-Resolution TV: An Experimental Digital System for Evaluating Bandwidth-Reduction Techniques

Low-Resolution TV: Subjective Effects of Noise Added to a Signal

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