Showing papers on "Image compression published in 1979"
TL;DR: In this paper, a new technique for image compression called block truncation coding (BTC) is presented and compared with transform and other techniques, which uses a two-level (one-bit) nonparametric quantizer that adapts to local properties of the image.
Abstract: A new technique for image compression called Block Truncation Coding (BTC) is presented and compared with transform and other techniques The BTC algorithm uses a two-level (one-bit) nonparametric quantizer that adapts to local properties of the image The quantizer that shows great promise is one which preserves the local sample moments This quantizer produces good quality images that appear to be enhanced at data rates of 15 bits/picture element No large data storage is required, and the computation is small The quantizer is compared with standard (minimum mean-square error and mean absolute error) one-bit quantizers Modifications of the basic BTC algorithm are discussed along with the performance of BTC in the presence of channel errors
823 citations
TL;DR: Results obtained indicate this two-dimensional image model is formulated using a seasonal autoregressive time series and could be used to code textures for low bit rates or be used in an application of generating compressed background scenes.
87 citations
TL;DR: Discusses the image compression technology where the aim is to narrow the transmitted band-width as much as possible to reduce the cost of transmission and for military use it reduces the susceptibility to interference.
Abstract: Discusses the image compression technology where the aim is to narrow the transmitted band-width as much as possible. Such compression reduces the cost of transmission and for military use it reduces the susceptibility to interference, but the problem is that the higher the compression, the greater the loss of image quality.
25 citations
TL;DR: A new data compression algorithm for a binary image which has a hierarchical format for describing a macroscopic image structure and can be applied for the image data storage, image edition and image transmission.
17 citations
01 Jan 1979
TL;DR: Application of BARC image data compression to the Galileo orbiter mission of Jupiter is considered and it is noted that the compressor can also be operated as a floating rate noiseless coder by simply not altering the input data quantization.
Abstract: A block adaptive rate controlled (BARC) image data compression algorithm is described. It is noted that in the algorithm's principal rate controlled mode, image lines can be coded at selected rates by combining practical universal noiseless coding techniques with block adaptive adjustments in linear quantization. Compression of any source data at chosen rates of 3.0 bits/sample and above can be expected to yield visual image quality with imperceptible degradation. Exact reconstruction will be obtained if the one-dimensional difference entropy is below the selected compression rate. It is noted that the compressor can also be operated as a floating rate noiseless coder by simply not altering the input data quantization. Here, the universal noiseless coder ensures that the code rate is always close to the entropy. Application of BARC image data compression to the Galileo orbiter mission of Jupiter is considered.
14 citations
01 Jun 1979
TL;DR: A new technique for image compression and/or enhancement is presented that comprises dividing the two-dimensional spectrum into low- and high-frequency components and digitizing the latter with a tapered, randomized quantizer.
Abstract: A new technique for image compression and/or enhancement is presented. The method comprises dividing the two-dimensional spectrum into low- and high-frequency components and digitizing the latter with a tapered, randomized quantizer. A version of the system in which the highs component is adaptively adjusted gives improved picture quality.
8 citations
28 Dec 1979
TL;DR: Conditional Replenishment is an interframe video compression method that uses correlation in time to reduce video transmission rates and computer simulations have demonstrated that data rates of 2 to 4 Mega-bits/second can be achieved while still retaining good fidelity in the image.
Abstract: Conditional replenishment is an interframe video compression method that uses correlation in time to reduce video transmission rates. This method works by detecting and sending only the changing portions of the image and by having the receiver use the video data from the previous frame for the non-changing portion. The amount of compression that can be achieved through this technique depends to a large extent on the rate of change within the image, and can vary from 10 to 1 to less than 2 to 1. An additional 3 to 1 reduction in rate is obtained by the intraframe coding of data blocks using a 2-dimensional variable rate Hadamard transform coder. A further additional 2 to 1 rate reduction is achieved by using motion prediction. Motion prediction works by measuring the relative displacements of a subpicture from one frame to the next. The subpicture can then be transmitted by sending only the value of the 2-dimensional displacement. Computer simulations have demonstrated that data rates of 2 to 4 Mega-bits/second can be achieved while still retaining good fidelity in the image.
4 citations
28 Dec 1979
TL;DR: It is seen that convolutional coders incorporating definite decoders can do several desirable things, normally associated only with block coders, such as noncausal coding; and, in addition, traditional applications of single channel convolutionals, suchAs linear prediction and estimation, are also possible in multi-channel systems.
Abstract: The special class of convolutional, or nonblock, coding systems which employ both FIR encoders and FIR decoders, or definite decoders, is proposed for real-time processing of sampled data. Fully definite multi-dimensional systems and partially definite, i.e. definite in some dimensions but not in others, are seen to exist. Since such a coding system is necessarily a multi-channel system, for signals of any dimension, some of the properties of multi-channel systems are considered as well as their applications. It is seen that convolutional coders incorporating definite decoders can do several desirable things, normally associated only with block coders, such as noncausal coding; and, in addition, traditional applications of single channel convolutional coders, such as linear prediction and estimation, are also possible in multi-channel systems. Color television image coding is seen to be a natural application for multi-channel coding because of the inherent separation of luminance and chrominance into separate channels. An important property of definite coding systems affecting the economy of 2 and 3 dimensional processing systems, which are used for bandwidth compression, is that the decoder uses only the compressed data, thereby significantly reducing the memory requirements for storage of data corresponding to previous lines and frames. Examples are presented of definite systems which separate color signals into their components, noncausal coders, doders which reduce the visability of noise bursts, and linear predictors with feedback quantizers.
2 citations
01 Aug 1979
TL;DR: Conventional imagery differing in resolution, digitized and treated to represent four levels of bandwidth compression was interpreted by 12 experienced image interpreters and significant decreases were found in the number of correct identifications due to bandwidth compression.
Abstract: : Conventional imagery differing in resolution (8-inch ground resolved distance GRD, 16-inch GRD, and 24-inch GRD), digitized and treated to represent four levels of bandwidth compression (1:1=no compression, 4:1, 8:1, and 10:1) was interpreted by 12 experienced image interpreters. A Greco-Latin square design was used to control for differences between interpreters, imagery subsets, and period effects at each GRD and to test the effects of bandwidth compression. The dichotomized image variables of sun angle, image contrast, and target obscurity were distributed equally across all conditions, but could be analyzed only for the 24-inch GRD imagery. Significant decreases were found in the number of correct identifications due to bandwidth compression; the largest decrease occurred between 4:1 and 8:1 bandwidth compression ratios. System developers should make careful trade-off evaluations in using bandwidth compression. More research in this area is required on the search function of interpretation and interactions of image variables.
2 citations
20 Aug 1979
TL;DR: The Night Vision & Electro-Optics Laboratory has initiated funding of separate studies to access the feasibility of obtaining 1000 to 1 and 10,000 to 1 compression ratios.
Abstract: Bandwidth compression schemes have found useful application in preventing the jamming of transmitted information. Such data reduction methods are particularly needed in the case of RPV imagery transmission. The Night Vision & Electro-Optics Laboratory has initiated funding of separate studies to access the feasibility of obtaining 1000 to 1 and 10,000 to 1 compression ratios. The achievement of such ratios necessitates a considerable degree of local intelligence in which specially selected scene information only, is transmitted. The 1000 to 1 concept involves sending with fidelity, just such information that is deemed to be of probable value to the RPV mission. In the case of 10,000 to 1 ratio the image is segmented, classified and only coordinates and image descriptors are transmitted.© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
1 citations
01 Jan 1979
TL;DR: In this article, a globally adaptive image compression structure has been developed for use in the tactical environment of a remotely piloted vehicle, based on an image compression algorithm RM2 but can be easily extended to standard algorithms.
Abstract: A globally adaptive image compression structure has been developed for use in the tactical environment of a remotely piloted vehicle. The control structure is based on an image compression algorithm RM2 but can be easily extended to standard algorithms. It is shown that this structure provides an operator with the flexibility to dynamically maximize the usefulness of a limited and changing bit rate and should significantly improve overall system performance in tactical environments.
01 May 1979
TL;DR: In this article, a number of image coding methods were implemented and applied to aerial reconnaissance photos for relative ranking evaluations by experienced photo-analysts, including two-dimensional transform, one-dimensional hybrid, and spatial.
Abstract: : In this study a number of image coding methods were implemented and applied to aerial reconnaissance photos for relative ranking evaluations by experienced photo-analysts. These coding methods were of three broad types: two-dimensional transform, one-dimensional hybrid, and spatial. The compression rates used were 1.6 and 0.5 bits/pixel. The effects of channel errors at a .001 error rate were also simulated and evaluated.