Showing papers on "Channel (digital image) published in 1987"

A Video-Rate CCD Two-Dimensional Cosine Transform Processor

Abstract: The need for transmitting an image through a low data rate channel has led to the development of various image data compression techniques. Recently, transform image coding based on the discrete cosine transform (DCT) algorithm has been proven to be a near optimum method for good quality, low data rate image transmission [1],[2]. In this paper, a CCD two-dimension DCT [3] device structure based on the recently developed one dimension CCD DCT device [4] will be reviewed. The CCD DCT device computes a 16-point cosine transform in 100 ns. The device structure is based on the vector-matrix product algorithm and implemented by using a bank of 256 fixed-weight multipliers. 60-dB dynamic range, -40-dB harmonic distortion has been achieved by the DCT device. Clocked at 10 MHz, the device is performing 5 billion computations per second and dissipates only 700 mW. The speed, power, weight and through-put rate advantages offered by the CCD technology make it ideal to be used in a low cost image transform CODECL [2].

Image display device displaying a composite character and graphic color image

Abstract: An image display apparatus wherein an existence of a plurality of color factors which constitute pixels of a character image (1) and a graphic image (2) which have corresponding pixels is expressed by a logical value rotation, the logical values of the color factors of the character image (1) and the graphic image (2) for the corresponding pixels are operated logically, and a composite image (3) consisting of the character image and the graphic image is displayed, comprises a logical operation circuit wherein when at least one color factor of the character image (1) exists for pixels, not all the color factors of the graphic image (2) for the pixels are displayed. By using this apparatus, the character image is easily distinguished from the background image.

An image coding technique using a human visual system model and image analysis criteria

Abstract: Recently, ways to obtain a new generation of image-coding techniques have been proposed. The incorporation of the human visual system (HVS) models and tools of the image analysis, such as segmentation, are two defining features of these techniques. In this paper, a new image coding technique is presented which utilizes a human visual system model and a image analysis criteria together with the technique of projection onto convex sets (POCS). The human visual system model is used to determine the most probable perceptual information of an image and the removal of irrelevant information. The projection onto convex sets operation is used as a restoration technique aimed at correcting the degradations caused by the conventional coders in the transmitter part of the channel. And finally, the image analysis based technique is used as an interpolator in order to predict the unknown regions of the received image. This new technique can be used in single frame image coding applications to obtain acceptable images at extremely high compression rates.

Workstation for use with a digital image communications network

Abstract: A workstation for use with a digital image communications network. The workstation has a data processing section and an image section. The data processing section includes a central processing unit (CPU) connected to a bus structure within the data processing section. The CPU uses the bus to communicate with a memory and a disk drive controller. Two interface modules, a communication interface module and an image controller module are also connected to the bus structure allowing the data processing section to communicate with a communications control channel and the image section. The CPU in the data processing section, via the communication module handles all communications between itself and all other nodes on the network. The image control module allows the CPU to control the receipt of images by the image section from the image channel of the images using hardware, prior to their display.

Method for extracting specific color area

Abstract: PURPOSE:To improve accuracy in processing and analysis by converting level information at every channel into vector information representing color attributes (color brightness, hue and saturation degree). CONSTITUTION:The output of an primitive signal generator 1 is applied to an RGB, an I(brightness) converter 2, an H(hue) converter 3 for RGB to H(hue) and a converter 4 from RGB to P(saturation degree) through digital lines 1R, 1G and 1B. Outputs from respective converters 2-4, that is, one-dimensional data equivalent to brightness, hue and saturation degree and the corresponding reference levels of said brightness, hue and saturation degree are impressed to window comparators 5i, 5h and 5p, and only areas having color attributes in a desired area are made 'true' among original pictures in terms of their outputs. The outputs of the comparators are all impressed on an AND circuit 6. Accordingly all the outputs consider color attributions.

Filter circuit for influencing the resolution of a video recording luminance signal reproduced on a screen

Abstract: In the playback channel (15) for the frequency-modulated luminance signals (YFM) of a video playback device, a filter circuit (14) with two parallel branches (22, 30) is placed between the video head (2) which scans a video medium (1), and an FM demodulator (11). The first branch (22), with the input- and output-side impedances (25, 26), forms an acceptor circuit (27), the low-frequency half of the resonance curve of which extends over the frequency bands of the video medium which are assigned to the luminance signal (YFM). The LR serial circuit (30) raises the lower-frequency part of the resonance curve to a step value, and bends the phase response of the filter circuit so that it removes the phase errors of the frequency-modulated luminance signal to a large extent, so that with a simple circuit design a high luminance resolution of the reproduced video picture is achieved, without reflections or intermittent sputters at the luminance boundaries.

Single channel masking camera & projector for improved image enhancement

Abstract: An optical imaging system for producing and applying image masks consisting of an original object holder, an image forming optical system, recording means for the image formed, processing means for the recorded image, means for maintaining the recorded image in precise register with the original object. The recorded image is projected back on the original in a modified form by means of adding and controlling optical flare in the imaging system to control image contract and by well known means control image color and sharpness. This modified projected image in register with the original objects acts as a mask for image enhancement. The resulting enhanced image can then be recorded by photographic film or paper and other ray recording devices.

Automatic channel selection using template correlation

Abstract: A new technique for automatic channel characterisation and selection in spectrally congested environments, known as ‘template correlation’, is described. Its performance under simulated conditions is illustrated. Modification of the basic technique to reduce the computational load, via a thresholding algorithm, is also discussed.