U.S. Philips Corporation

Leonardus A Verhoeven

Peter J Janssen

Maarten Rutger De Haan

Otto E Scheltema

Walter E Carels

A line structure correction circuit for reducing the visibility of the raster line structure of a television picture which is to be photographed. The picture information associated with each raster line in the television picture signal is repeated n-times, n being an integer at least equal to two. The raster-line information is applied to a television display device operated at the same line period as the picture signal but with an n-times longer picture or frame period, respectively, depending on whether the television picture is interlaced. A further improvement in the quality of the recording is obtained by forming the information in each raster line of the television picture from different combinations of the information associated with consecutive raster lines in the picture signal.

Arrangement for making a photographic slide or cine-film recording of a

In an X-ray image intensifier-television pickup tube apparatus for displaying an image with a small contrast difference, the beam current of the television camera tube can be temporarily increased. As a result, images can be displayed with an increased signal-to-noise ratio. The television camera can then be switched, preferably automatically between this form of image production and the usual production of fluoroscopic images.

X-ray examination apparatus

The method and the device in accordance with the present invention utilizes a recursive filter for forming a composite image from a short series of X-ray images with the weighting factor .alpha. used in the filter being a function of the number of X-ray images processed and to be processed. When .alpha. is suitably chosen, the amplitude of the composite image is always constant, such as a constant image brightness, and each X-ray image makes an equally large contribution to the composite image. The noise level in the composite image decreases as the number of processed X-ray images is larger.

Method of and device for X-ray processing

The invention relates to a method of and a device for generating differential images in which the effect of fluctuations of the X-ray pulse or the gain of the images intensifier/image pick-up tube network on the differential image is eliminated. To this end, the peak value is determined for each X-ray image in order to be stored in a fixed location in a memory. The difference between the logarithms of the peak values is added to the differential image, so that said fluctuations are compensated for.

Method of a device for generating differential images

A device for and method of X-ray processing in which a constant adjustable signal value is subtracted from a video signal of an X-ray image in order to correct the video signal for the effects of inherent scatter. The adjustable signal value depends on the X-ray tube voltage, the nature of the object to be examined, the field size etc. so that it is preferably dependent on the X-ray exposure parameters. The video signal is preferably converted into a logarithmic value by means of a logarithmic table which is dependent on the adjustable signal value (or actually on the exposure parameters).

Device for and method of X-ray image processing

Two image processing devices having different time delays are used to generate time difference images having high signal-to-noise ratios. The image processing devices may be real time image processors having only one image memory wherein consecutive images are sequentially fed in digital form to a recursive filter. In such devices the memory is employed in the recursive filter as a 'delay element', as a result of which noise integration and differential image determination between consecutive images takes place.

Device for differential image determination

A real-time image processing device having only one image memory. Consecutive images are sequentially fed in digital form to a recursive filter. The memory is employed in the recursive filter as a 'delay element', as result of which noise integration and differential image determination between consecutive images take place.

A color television system for transmitting a color television signal, specifically for recording on and subsequently reproducing from a record carrier. The color television signal to be transmitted contains a first carrier which is frequency-modulated with the luminance information and a second carrier which is modulated with the chrominance information, whose frequency lies between zero and the first-order lower side band of the modulated first carrier which corresponds to the highest modulation frequency. Said second carrier does not have a fixed frequency, but is locked to the instantaneous frequency of the modulated first carrier by a constant integral ratio. Depending on the characteristics of the transmission medium and the signal processing equipment said ratio is preferably two or three.

Color television recording system employing frequency modulation and

Color television system in which the chrominance subcarrier is locked to

A television camera tube having a conductive gauze behind the target plate, the parallel wires of which cross each other at an acute angle which has been suitably chosen to minimize interference in decoded colour signals.

Growing community of inventors

Eindhoven, Netherlands

Leonardus A Verhoeven