GB2159363A - Method and apparatus for image processing - Google Patents

Abstract

The invention entails feeding image information in analogue form obtained by a pixel by pixel scan of a picture area (pixels 1 to 9) into a delay line providing a delayed output (@ to @) for each pixel of the area except the last pixel (pixel 1) thereof to be scanned, such that all the delayed outputs are provided simultaneously and at the same time as the signal for said last pixel of the area. <IMAGE>

Description

SPECIFICATION Method and apparatus for image processing The present invention relates to a method and apparatus for image processing.

Image processing heretofore has entailed capturing the image on a grey scale with a camera typically using a frame of 256 X 256 pixels, digitising the data, storing the data in a frame store and processing the stored data by computer. This leads to long processing times e.g. four seconds. It also requires costly hardware. It would be desirable to reduce the processing time and the hardware cost and, indeed, in some instances, it would be essential to do this, to make electronic image processing practicable.

It is an object of the present invention to provide a more efficacious method and apparatus for image processing.

In accordance with the present invention, image information is fed in analogue form into a delay line providing delayed output for each pixel of an area of the picture to be scanned except for the last pixel thereof, such that all the delayed outputs are provided simultaneously and at the same time as the signal for said last pixel of the area.

All the picture information is therefore provided in analogue form and may be processed as such. This may entail quite sample hardware since the processing may require nothing more than e.g. summation, substraction or averaging, which can be achieved solely by passive circuit elements. However, the analogue information provided may be digitised for processing.

Preferably, the delay line is constituted by CCD hardware.

Since the picture scan is line by line, the delay line will need to be constructed to recognise the different time interval between scanning of adjacent lines and adjacent pixels in a line; and this is done by incorporating in the delay line elements providing different periods of delay.

The present invention will now be described, by way of example only, with reference to the accompanying drawing, in which: Figure 1 is a diagram of a delay line employed in an embodiment of the invention; and Figure 2 is a diagram of an arrangement by which picture information is accessed or scanned in the embodiment.

Referring now to the drawing, the embodiment entails feeding picture information to the delay line, generally indicated at 1, pixel by pixel in the sequence, in this instance, indicated in Fig. 2. In any one sequence, nine pixels are scanned in the form of a rectangle consisting of three lines each of three pixels, for convenience, numbered 1 to 9. Thus, pixels 1 to 3 constitute one line, pixels 4 to 6 a second line and pixels 7 to 9 a third line.

The delay line comprises eight delay elements DE 1 to 8 respectively, in this instance being COD elements, with the first, second, fourth, fifth, seventh and eighth elements providing a delay of 250ns equal to a scanning time interval between adjacent pixels, while the third and sixth elements provide a delay of 64 ys equal to the line scanning interval.

Consequently, as the picture information from pixels 9 to 2 sequence is fed to the delay line, the analogue signals representing that information will be presented at the respective outputs, indicated as tto ( > in Fig. 1, simultaneously and at the same time that the signal representing the information from pixel 1 being the last in the sequence is provided on output indicated as (3in Fig. 1; this signal being undelayed.

It will be understood in connection with the illustrated embodiment that the number of pixels scanned may vary and may be greater than nine e.g. 16 in a fqur by four array or 25 in a five by five array, and that the delay periods in the delay line may be varied to suit particular requirements.

Downstream of the delay line, as intimated, the analogue signals may be processed further in analogue form or converted to digital signals for digital processing.

An advantage of the present invention is that it provides a virtual real time processing of the picture information.

1. A method of image processing comprising feeding image information in analogue form obtained by scanning a picture area pixel by pixel, into a delay line providing a delayed output for each pixel of the area except for the last pixel thereof to be scanned such that all the delayed outputs are provided simultaneously and at the same time as the signal for said last pixel of the area.

2. A method according to Claim 1, wherein the picture information provided at the delayed outputs is processed in analogue form.

3. Apparatus for image processing comprising means for scanning a picture area pixel by pixel and a delay line to receive in sequence the analogue information provided by the scan; the delay line comprising a delayed output for each pixel of the area except for the last pixel thereof such that all the delayed outputs are provided simultaneously and at the same time as the signal for said last pixel of the area.

4. Apparatus as claimed in Claim 3, wherein the delay line is constituted by CCD hardware.

5. A method for image processing substantially as hereinbefore described with reference to the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Method and apparatus for image processing The present invention relates to a method and apparatus for image processing. Image processing heretofore has entailed capturing the image on a grey scale with a camera typically using a frame of 256 X 256 pixels, digitising the data, storing the data in a frame store and processing the stored data by computer. This leads to long processing times e.g. four seconds. It also requires costly hardware. It would be desirable to reduce the processing time and the hardware cost and, indeed, in some instances, it would be essential to do this, to make electronic image processing practicable. It is an object of the present invention to provide a more efficacious method and apparatus for image processing. In accordance with the present invention, image information is fed in analogue form into a delay line providing delayed output for each pixel of an area of the picture to be scanned except for the last pixel thereof, such that all the delayed outputs are provided simultaneously and at the same time as the signal for said last pixel of the area. All the picture information is therefore provided in analogue form and may be processed as such. This may entail quite sample hardware since the processing may require nothing more than e.g. summation, substraction or averaging, which can be achieved solely by passive circuit elements. However, the analogue information provided may be digitised for processing. Preferably, the delay line is constituted by CCD hardware. Since the picture scan is line by line, the delay line will need to be constructed to recognise the different time interval between scanning of adjacent lines and adjacent pixels in a line; and this is done by incorporating in the delay line elements providing different periods of delay. The present invention will now be described, by way of example only, with reference to the accompanying drawing, in which: Figure 1 is a diagram of a delay line employed in an embodiment of the invention; and Figure 2 is a diagram of an arrangement by which picture information is accessed or scanned in the embodiment. Referring now to the drawing, the embodiment entails feeding picture information to the delay line, generally indicated at 1, pixel by pixel in the sequence, in this instance, indicated in Fig. 2. In any one sequence, nine pixels are scanned in the form of a rectangle consisting of three lines each of three pixels, for convenience, numbered 1 to 9. Thus, pixels 1 to 3 constitute one line, pixels 4 to 6 a second line and pixels 7 to 9 a third line. The delay line comprises eight delay elements DE 1 to 8 respectively, in this instance being COD elements, with the first, second, fourth, fifth, seventh and eighth elements providing a delay of 250ns equal to a scanning time interval between adjacent pixels, while the third and sixth elements provide a delay of 64 ys equal to the line scanning interval. Consequently, as the picture information from pixels 9 to 2 sequence is fed to the delay line, the analogue signals representing that information will be presented at the respective outputs, indicated as tto ( > in Fig. 1, simultaneously and at the same time that the signal representing the information from pixel 1 being the last in the sequence is provided on output indicated as (3in Fig. 1; this signal being undelayed. It will be understood in connection with the illustrated embodiment that the number of pixels scanned may vary and may be greater than nine e.g. 16 in a fqur by four array or 25 in a five by five array, and that the delay periods in the delay line may be varied to suit particular requirements. Downstream of the delay line, as intimated, the analogue signals may be processed further in analogue form or converted to digital signals for digital processing. An advantage of the present invention is that it provides a virtual real time processing of the picture information. CLAIMS

1. A method of image processing comprising feeding image information in analogue form obtained by scanning a picture area pixel by pixel, into a delay line providing a delayed output for each pixel of the area except for the last pixel thereof to be scanned such that all the delayed outputs are provided simultaneously and at the same time as the signal for said last pixel of the area.

2. A method according to Claim 1, wherein the picture information provided at the delayed outputs is processed in analogue form.

3. Apparatus for image processing comprising means for scanning a picture area pixel by pixel and a delay line to receive in sequence the analogue information provided by the scan; the delay line comprising a delayed output for each pixel of the area except for the last pixel thereof such that all the delayed outputs are provided simultaneously and at the same time as the signal for said last pixel of the area.

4. Apparatus as claimed in Claim 3, wherein the delay line is constituted by CCD hardware.

5. A method for image processing substantially as hereinbefore described with reference to the accompanying drawing.

6. Apparatus for image processing substantially as hereinbefore described with reference to the accompanying drawing.