Method and system for transferring image data between two devices having different bandwidths

A method for transferring video data from an image input terminal to a host terminal, the host terminal having a transfer rate slower than a data transfer rate of the image input terminal, comprising the steps of:

• (a) selecting a scan rate and a line sampling rate;
• (b) scanning a document at the selected scan rate and producing N scanlines of valid image data therefrom, N being equal to two or more;
• (c) storing less than N scanlines of valid image data according to the selected line sampling rate;
• (d) skipping scanlines of valid image data not stored in said step (c) according to the selected line sampling rate;
• and
• (e) outputting the stored scanlines of image data to the host terminal.

A method for transferring video data from an image input terminal to a host terminal, the host terminal having a transfer rate slower than a data transfer rate of the image input terminal, comprising the steps of:

• p1 (a) generating a set of N scanlines of valid image data, N being two or more and being function of a size of a document being scanned, resolution and mode;
• (b) discarding N-1 scanlines of valid image data from the set of N lines of valid image data;
• (c) storing a scanline of valid image data from the set of N lines of valid image data;
• and
• (e) outputting the stored scanline of image data to the host terminal.

A system for transferring video data from an image input terminal to a host terminal, the host terminal having a transfer rate slower than a data transfer rate of the image input terminal, comprising:

• image means for generating a set of N scanlines of valid image data, N being equal to two or more and being a function of a size of a document being scanned, resolution, and mode;
• a buffer capable of storing the generated scanlines of valid image data;
• skip means for preventing said buffer from storing N-1 scanlines of valid image data from the set of N scanlines of valid image data;
• and
• interface means for outputting the stored scanlines of image data to the host terminal.

A system for transferring scanlines of valid video data from a first device to a second device, the second device having a transfer rate slower than a data transfer rate of the first device, comprising:

• counter means for counting a number of scanlines of valid video data in a set of scanlines of valid video data which has been generated for transfer and for generating a count therefrom;
• state decoder means, operatively connected to said counter means, for activating a sync signal when the count is equal to a predetermined number;
• buffer means for storing a scanline of the set of scanlines of valid video data when the sync signal is activated and for skipping scanlines of valid video data when the sync signal is not activated;
• and
• interface means for outputting the stored scanlines of video data to the second device;
• said buffer means transferring the scanline of valid video data to said interface means when the sync signal is not activated.

A system for transferring image data when a volume of the image data to be transferred exceeds a bandwidth characteristics of one of two devices comprising:

• control means for selecting a scan rate and a line sampling rate;
• image input means, in communication with said control means, for scanning an image at the selected scan rate and for producing a set of N scanlines of valid image data therefrom, N being equal to two or more;
• buffer means, in communication with said image input means and said control means, for storing the N scanlines of valid image data;
• and
• processing means for receiving the stored scanlines of valid image data and for image processing the received scanlines of valid image data;
• said buffer means storing less than N scanlines of valid image data when the volume of the image data to be transferred to said processing means exceeds a bandwidth characteristic of said processing means;
• said buffer means causing the non-stored scanlines of valid image data to be skipped, the number of scanlines of valid image data being skipped is proportional to the selected line sampling rate.