On the Quality of Color-Television Images and the Perception of Color Detail

Schade, Otto H.

doi:10.5594/j16981

Cited by 19 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The size of fixational eye movements is estimated to be as large as 10 arcmin.tv" The phase error between 632.8-and 514.5-nm interference fringes produced by an eye movement of 10 arcmin is -1. is approximately proportional to wavelength, as shown by Eq. (1), and thus the effect is smaller for shorterwavelength components.…”

Section: Effect Of Phase Error On Measured Contrast Sensitivitymentioning

confidence: 95%

Aberration-free measurements of the visibility of isoluminant gratings

1993

View full text Add to dashboard Cite

We developed a new apparatus and psychophysical technique to extend isoluminant contrast-sensitivity measurements to high spatial frequencies. The apparatus consists of two identical laser interferometers that are designed to produce phase-locked two-color interference fringes on the retina without the influence of diffraction and most aberrations in the eye. However, even with interferometry, transverse chromatic aberration of the eye can produce a wavelength-dependent phase shift in the interference fringes, which can be exaggerated by head movements. To reduce the effect of head movements, isoluminant red and green interference fringes of equal spatial frequency and orientation were drifted slowly in opposite directions to guarantee a purely isochromatic (in phase) and a purely isoluminant (out of phase) stimulus during each cycle of stimulus presentation. With this technique we found that observers could resolve red and green stripes at spatial frequencies higher than 20 cycles per degree (c/deg) (20-27 c/deg), substantially higher than has previously been reported. This places a lower bound on the sampling density of neurons that mediate color vision. At all spatial frequencies, even those above the isoluminant resolution limit, a relative phase of the red and the green components could be found that obliterated the appearance of luminance modulation at the fringe frequency. Above the resolution limit, red-green-isoluminant interference fringes are seen as spatial noise, which may be chromatic aliasing caused by spatial sampling at some stage in the chromatic pathway.

show abstract

Section: Effect Of Phase Error On Measured Contrast Sensitivitymentioning

confidence: 95%

Aberration-free measurements of the visibility of isoluminant gratings

1993

View full text Add to dashboard Cite

show abstract

“…Second, avoiding blurring allows us to extend our red-green-isoluminant contrastsensitivity measurements to 20-27 cycles per degree (c/deg), depending on the observer, substantially higher than has been measured previously. [15][16][17][28][29][30][31][32][33] This allows us to compare performance for isochromatic and isoluminant stimuli at high spatial frequencies, which is the focus of this paper.…”

Section: Introductionmentioning

confidence: 99%

Efficiency in detection of isoluminant and isochromatic interference fringes

1993

View full text Add to dashboard Cite

We examined the limitations imposed by neural factors on spatial contrast sensitivity for both isochromatic and isoluminant gratings. We used two strategies to isolate these neural factors. First, we eliminated the e~f~ct of blurring by the dioptrics of the eye by using interference fringes., Second, w~correc.ted our data for addl~lOnal sensitivity losses up to and including the site of photon absorption by applymg an Ideal-observer analysis described by Geisler [J. Opt. Soc. Am. AI, 775 (1984)]. Our measu~ementsind~cate t~at the.neural~isu~syst~m modifies the shape of the contrast-sensitivity functions for both isochromatic and isoluminant~tImuh at hlg.h spatial frequencies. If we assume that the high-spati~-~reque~cyperforman~e of the neural visual~ystem IS determined by a low-pass spatial filter followed by additive noise, then the VISUal system has a spatIal.bandwidth 1.8 times lower for isoluminant red-green than for isochromatic stimuli. On the other hand, we fmd no difference in bandwidth or sensitivity of the neural visual system for isoluminant red-green and S-coneisolated stimuli.

show abstract

“…In most studies, extrapolations have to be made by eye from threshold measurements obtained at lower spatial frequencies. Such procedures, using purity as the measure ofchromatic sensitivity suggest acuity values for red-green gratings that range from 25-30 cycles/deg (Van der Horst & Bouman, 1969) to 50 cycles/deg and equal to luminance acuity (Schade, 1958). Two studies which include measurements made using blue-yellow sine or square-wave stimuli suggest CONTRAST SENSITIVITY TO CHROMATICGRATINGS an acuity greater than 20 cycles/deg (Van der Horst et al 1967;Van der Horst & Bouman, 1969).…”

Section: Comparison Of Chromatic and Luminance Acuitymentioning

confidence: 99%

“…Schade, 1958;Van der Horst & Bouman, 1969;Granger & Heurtley, 1973;Kelly, 1983). Only one of these reports measurements using blue-yellow sinusoidal stimuli (Van der Horst & Bouman, 1969 (Van der Horst & Bouman, 1969;Kelly, 1983).…”

Section: Introductionmentioning

confidence: 99%

The contrast sensitivity of human colour vision to red‐green and blue‐yellow chromatic gratings.

Mullen¹

1985

The Journal of Physiology

879

485

View full text Add to dashboard Cite

SUMMARY1. A method ofproducing red-green and blue-yellow sinusoidal chromatic gratings is used which permits the correction of all chromatic aberrations.2. A quantitative criterion is adopted to choose the intensity match of the two colours in the stimulus: this is the intensity ratio at which contrast sensitivity for the chromatic grating differs most from the contrast sensitivity for a monochromatic luminance grating. Results show that this intensity match varies with spatial frequency and does not necessarily correspond to a luminance match between the colours.3. Contrast sensitivities to the chromatic gratings at the criterion intensity match are measured as a function of spatial frequency, using field sizes ranging from 2 to 23 deg. Both blue-yellow and red-green contrast sensitivity functions have similar low-pass characteristics, with no low-frequency attenuation even at low frequencies below 041 cycles/deg. These functions indicate that the limiting acuities based on red-green and blue-yellow colour discriminations are similar at 11 or 12 cycles/deg.4. Comparisons between contrast sensitivity functions for the chromatic and monochromatic gratings are made at the same mean luminances. Results show that, at low spatial frequencies below 0 5 cycles/deg, contrast sensitivity is greater to the chromatic gratings, consisting of two monochromatic gratings added in antiphase, than to either monochromatic grating alone. Above 0-5 cycles/deg, contrast sensitivity is greater to monochromatic than to chromatic gratings.

show abstract

On the Quality of Color-Television Images and the Perception of Color Detail

Cited by 19 publications

References 6 publications

Aberration-free measurements of the visibility of isoluminant gratings

Aberration-free measurements of the visibility of isoluminant gratings

Efficiency in detection of isoluminant and isochromatic interference fringes

The contrast sensitivity of human colour vision to red‐green and blue‐yellow chromatic gratings.

Contact Info

Product

Resources

About