Related Experiment Video
Updated: Jul 7, 2026
06:50
Enabling High Grayscale Resolution Displays and Accurate Response Time Measurements on Conventional Computers
Published on: February 29, 2012
Perceptual coding of images for halftone display
1Dept. of Electr. Eng. and Comput. Sci., Michigan Univ., Ann Arbor, MI.
Summary
This study introduces a novel gray-scale image coding method for facsimile transmission, achieving higher compression rates. The receiver can customize the halftoning process for optimal laser printer output.
Area of Science:
- Image processing
- Data compression
- Computer vision
Background:
- Conventional gray-scale image transmission for facsimile uses halftoning before transmission.
- Existing methods like CCITT Group 3 and JBIG employ entropy coding on already halftoned images.
- This approach limits receiver control over the final printed image quality.
Purpose of the Study:
- To present a new technique for coding gray-scale images for facsimile transmission and laser printing.
- To enable higher compression rates compared to traditional methods.
- To allow receivers to adapt the halftoning process to specific printers.
Main Methods:
- A perceptually based subband coding approach is utilized.
- A perceptual masking model, empirically derived for printed images, is incorporated.
- The technique involves encoding the gray-scale image and converting it to a binary pattern only at the receiver.
Main Results:
- The proposed method achieves higher compression rates than standard facsimile techniques.
- It allows for printer-specific halftoning adjustments at the receiver.
- Lower data rates are required for nearly transparent coding of gray-scale images.
Conclusions:
- The new gray-scale image coding technique offers superior compression and flexibility for facsimile transmission.
- Adapting halftoning at the receiver improves print quality and efficiency.
- This method represents a significant advancement over conventional entropy coding of halftoned images.
Related Concept Videos
01:20Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...
01:32The Retina
The retina is a layer of nervous tissue at the back of the eye that transduces light into neural signals. This process, called phototransduction, is carried out by rod and cone photoreceptor cells in the back of the retina.
01:12Perceptual Constancy
Perceptual constancy is the ability to recognize that objects remain consistent and unchanged even when their appearance varies due to changes in sensory input. There are four main types of perceptual constancy: size constancy, shape constancy, color constancy, and brightness constancy.
Size constancy is the recognition that an object remains the same size, even when its image on the retina changes. For instance, a bus is perceived to be large enough to carry people, even if it looks tiny from...
Size constancy is the recognition that an object remains the same size, even when its image on the retina changes. For instance, a bus is perceived to be large enough to carry people, even if it looks tiny from...
01:24Color Vision
Color perception begins in the retina, the light-sensitive layer at the back of the eye. Two main theories explain how colors are seen: the trichromatic theory and the opponent-process theory. The trichromatic theory, proposed by Thomas Young in 1802 and extended by Hermann von Helmholtz in 1852, suggests that color vision is based on three types of cone receptors in the retina. These cones are sensitive to different but overlapping ranges of wavelengths corresponding to red, blue, and green.
01:20Parallel Processing
The brain processes sensory information rapidly due to parallel processing, which involves sending data across multiple neural pathways at the same time. This method allows the brain to manage various sensory qualities, such as shapes, colors, movements, and locations, all concurrently. For instance, when observing a forest landscape, the brain simultaneously processes the movement of leaves, the shapes of trees, the depth between them, and the various shades of green. This enables a quick and...
01:21Gestalt Principles of Perception
Gestalt principles provide a framework for understanding how humans perceive objects as unified wholes within their context. These principles are essential in explaining the cognitive processes that make sense of complex visual stimuli by organizing them into coherent groups. One fundamental principle is proximity, which posits that objects located close to each other are perceived as a collective group. For instance, when dots are positioned near one another, the visual system interprets them...