Image data compression or expansion method and apparatus, and image transmission system and monitoring system using the method and device

• US 6,608,938 B2
• Filed: 03/04/2002
• Issued: 08/19/2003
• Est. Priority Date: 04/13/1998
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Michikawa, Yuichi, Kuroda, Masayoshi, Takamoto, Koichi, Honda, Toyota, Imanishi, Shinya
• Primary Examiner(s): Johns, Andrews W.
• Assistant Examiner(s): Dang, Duy M.
• Application Number:
  US10/086,711
• Publication Number:
  US 20020080881A1
• Time in Patent Office: 533 Days
• Field of Search: 382/232-236, 382/238, 382/244-246, 382/166, 348/14.11, 348/14.12, 348/14.13, 348/14.14, 348/14.15, 348/384.1, 348/387.1, 348/390.1, 358/426.01, 358/426.02, 358/426.03, 325/240.3, 325/240.5
• US Class Current: 382/236
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/137 Motion inside a coding unit, e.g. average field, frame or block difference
• CPC Class Codes: H04N 19/142 Detection of scene cut or scene change
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/587 involving temporal sub-sampling or interpolation, e.g. decimation or subsequent interpolation of pictures in a video sequence
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

An image data expansion apparatus including a decoder for decoding compressed image data at a frame rate controlled to be lower in a scene where the change is small than that in a scene where the change is large; an expander for expanding the compressed image data decoded by the decoder, the input image data being reproduced such that the frame rate is lower in a scene where the change between images is small than the frame rate in a scene where the change between images is large; and an image interpolator for generating an interpolation image from the input predetermined compressed image data in accordance with the information on the frame rate outputted with the compression image data. The reproduced input image data is interpolated with an interpolation image generated by interpolation processing by the image interpolator, and the interpolated image data is outputted.

Claims

1. An image data expansion apparatus, which inputs and expands compressed image data outputted from an image data compression apparatus having compression processing means for compression-processing input image data, image change detection means for detecting a change on image based on said input image data, frame rate control means for controlling a frame rate of outputted compressed image data obtained by compression-processing image data, means for controlling the frame rate of outputted compressed image data such that the frame rate is lower in a scene where the image change is small than the frame rate in a scene where the image change is large, in accordance with the situation of the change on image detected by said image change detection means, and synthesizing means for synthesizing information on the frame rate of the compressed image data, controlled by said frame rate control means, wherein the information on the frame rate is added to the compressed image data and the image data is outputted, said image data expansion apparatus comprising:

decoding means for decoding compressed image data at a frame rate controlled to be lower in a scene where the change is small, than that in a scene where the change is large;

expansion means for expanding the compressed image data decoded by said decoding means, wherein said input image data being reproduced such that the frame rate is lower in a scene where the change between images is small than the frame rate in a scene where the change between images is large;

and image interpolation means for generating an interpolation image from said input predetermined compressed image data, in accordance with the information on the frame rate outputted with said compression image data,

wherein said reproduced input image data is interpolated with an interpolation image generated by interpolation processing by said image interpolation means, and the interpolated image data is outputted.

2. An image data expansion method for inputting and expanding compressed image data, obtained by detecting a change on image based on input image data and compression-processing image data, while controlling a frame rate such that the frame rate in a scene where the image change is small is lower than that in a scene where the image change is large, in accordance with the situation of the detected change on image, comprising the steps of:

decoding the compressed image data at the frame rate controlled to be lower in the scene where the image change is small than in the scene where the image change is large;

reproducing said input image data by expanding said decoded compressed image data such that the frame rate in the scene where the image change is small is lower than that in the scene where the image change is large; and

generating an interpolation image from input predetermined compressed image data, in accordance with information on said frame rate, received with said compressed image data, and interpolating said reproduced input image with said generated interpolation image and outputting the interpolated image.

3. An image transmission system which performs image data communication by using an image data compression apparatus which compresses input image data and outputs compressed image data and an image data expansion apparatus,

said image data compression apparatus comprising:

compression processing means for compression-processing input image data;

image change detection means for detecting a change on image based on said input image data;

frame rate control means for controlling a frame rate of outputted compressed image data obtained by compression-processing image data;

and means for controlling the frame rate of outputted compressed image data such that the frame rate is lower in a scene where the image change is small than the frame rate in a scene where the image change is large, in accordance with the situation of the change on image detected by said image change detection means; and

synthesizing means for synthesizing frame rate information of compressed image data, controlled by said frame rate control means;

and wherein said image data expansion apparatus comprising;

encoding means for decoding compressed image data at the frame rate controlled to be lower in a scene where the change is small, than that in a scene where the change is large;

expansion means for expanding the compressed image data decoded by said decoding means, wherein said input image data is reproduced such that the frame rate is lower in a scene where the change between images is small, than that in a scene where the change between images is large; and

image interpolation means for generating an interpolation image from said predetermined compressed image data, in accordance with the information on the frame rate received with said compression image data, wherein said reproduced input image data is interpolated with an interpolation image generated by interpolation processing by said image interpolation means, and the interpolated image data is outputted,

said image transmission system comprising;

transmission means for transmitting compressed image data outputted from said image data compression apparatus on a predetermined line; and

reception means for receiving said compressed image data transmitted via said transmission means,

wherein said compressed image data received by said reception means is expanded by said image data expansion apparatus.

4. A monitoring system which performs image data communication by using an image data compression apparatus which compresses input image data and outputs compressed image data and an image data expansion apparatus,

wherein said image data compression apparatus comprising:

compression processing means for compression-processing input image data;

image change detection means for detecting a change on image based on said input image data;

frame rate control means for controlling a frame rate of outputted compressed image data obtained by compression-processing image data; and

means for controlling the frame rate of outputted compressed image data such that the frame rate is lower in a scene where the image change is small than the frame rate in a scene where the image change is large, in accordance with the situation of the change on image detected by said image change detection means; and

synthesizing means for synthesizing frame rate information of compressed image data, controlled by said frame rate control means;

and wherein said image data expansion apparatus comprising;

encoding means for decoding compressed image data at the frame rate controlled to be lower in a scene where the change is small, than that in a scene where the change is large;

expansion means for expanding the compressed image data decoded by said decoding means;

wherein said input image is reproduced such that the frame rate is lower in a scene where the change between images is small, than that in a scene where the change between images is large;

image interpolation means for generating an interpolation image from said input predetermined compressed image data, in accordance with the information on the frame rate received with said compression image data, wherein said reproduced input image data being interpolated with an interpolation image generated by interpolation processing by said image interpolation means, and the interpolated image data being outputted,

said image transmission system comprising;

image data output means for obtaining an image of a monitoring object and outputting image data;

means for transferring compressed image data, obtained by compressing input image data from said image data output means by said image data compression apparatus; and

display means for displaying image data, obtained by expanding said compressed image data, transferred via said transfer means, by said image data expansion apparatus.