 Method and apparatus for selecting image data to skip when encoding digital video |
| A block and frame skipping technique decides which image regions, blocks or frames in a video frame ... |
|
| Loudspeaker having a two-part diaphragm for use as a car loudspeaker |
| In order to obtain a frequency response characteristic with a broadened dip, the loudspeaker in ... |
|
| Horizontal synchronizing system |
| In accordance with an embodiment of the present invention, a phase control circuit for the ... |
|
| Multiple scanning type television receiver |
| The above problem is overcome by the present invention which is intended for use in combination ... |
|
| Selective efficiency videofrequency non-linearity correction device |
| The invention provides a selective efficiency video frequency nonlinearity correction device, for ... |
|
| Compression of data on status of remote equipment |
| The environment of this invention is a communication system in which each of a number of ground ... |
|
| Digital-analog converter |
| In accordance with the present invention, there is provided a novel digital-analog converter ... |
|
| Digital equalizer for data-transmission system |
| We claim: 1. An equalizer for digital messages insertable between a transmission channel and a load,... |
|
| A/D and D/A converter using C-2C ladder network |
| It is therefore an object of the present invention to provide A/D and D/A converters employing a ... |
|
|
Data processor for image data using orthogonal transformation
| Details |
Inventors: Nakatani, Munehiro; Suzuki, Hiroyuki; Sakatani, Kazuomi;
Assignee: Minolta Camera Kabushiki Kaisha (Osaka, JP)
Primary Examiner: Coles, Sr.; Edward L.
Assistant Examiner: Lee; Thomas D.
Attorney, Agent or Firm: Willian Brinks Hofer Gilson & Lione
In a data processor, image data of a pixel matrix is subjected to orthogonal transformation to coefficient data, the coefficient data is quantized with a first quantization table for character image and a second quantization table for half-tone image, and the image data is discriminated to be character image data or half-tone image data according to the quantization data. The selected data is then coded. In another processor, image data are divided into first and second processing blocks of m*m and M*M pixel matrices wherein M>m and the second processing block includes one of first processing blocks and adjacent pixels. Image data in a first and second processing block are subjected to orthogonal transformation to coefficient data. It is discriminated according to the coefficient data of the second processing block if the image is a character, dot, or half-tone image to select an appropriate quantization table, and image data of the first block is quantized according to the selected table and the quantized data are coded. In a further processor, two discrimination windows are provided, the first having coefficient data around the DC component and the second having the other data. Orthogonal transform coefficients of image data in a processing block are calculated, and maximum of absolute values in the windows are obtained. An image is discriminated to be a dot image if the maximum of the first window is larger than the second and larger than a threshold value. |
|
DETAILED DESCRIPTION An object of the present invention is to provide a coding apparatus which can performs discrimination of a character image and a half-tone image more precisely and efficiently in a short time.
Another object of the present invention is to provide a coding apparatus which can performs discrimination of a character image, a dot image and a half-tone image more precisely and efficiently in a short time.
A different object of the present invention is to provide a coding apparatus which can discriminate a dot image more precisely.
In one aspect of the present invention, in order to perform coding efficiently, image data of a prescribed size of pixel matrix is subjected to orthogonal transformation to be transformed to coefficient data.
A first quantization table for character image and a second quantization table for half-tone image are provided.
The coefficient data is quantized with the first quantization table and with the second quantization table.
Then, the quantized data are used to discriminate a character image data and a half-tone image.
Then, quantized data in correspondence to the discrimination result is selected or subjected to entropy coding.
In a further aspect of the invention, in order to discriminate a kind of image in a processing block fast and correctly, image data are divided into first processing blocks of m*m pixel matrices and second processing blocks of M*M pixel matrices wherein M>m.
A second processing block includes one of first processing blocks and adjacent pixels around it.
For example, m=8 and M=16.
Image data in a first processing block and image data in a second processing block including the first processing block are subjected to orthogonal transform to send coefficient data, respectively.
It is discriminated according to the coefficient data of the second processing block if the image is a character image, a dot image or a half-tone image to select an appropriate quantization table.
Then, image data of the first processing block is quantized according to the selected quantization table and quantized data are coded
|
|
Image Analysis 
