Image information signal transmitting system with selective transmission of input data or extracted data

• US 4,994,911 A
• Filed: 03/20/1989
• Issued: 02/19/1991
• Est. Priority Date: 03/28/1988
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Takahashi, Koji, Ishikawa, Hisashi, Nakayama, Tadayoshi, Nagasawa, Kenichi, Sasatani, Tomohiko, Yoshimura, Katsuji, Kozuki, Susumu
• Primary Examiner(s): Kostak, Victor R.
• Application Number:
  US07/325,549
• Time in Patent Office: 701 Days
• Field of Search: 358/133, 358/141, 358/135, 358/136, 358/138
• US Class Current: 375/240.24
• CPC Class Codes: H04N 7/0152 using spatial or temporal subsampling

Abstract

A transmission system, of the type wherein input data to be transmitted is stored in blocks and less than all stored data is extracted from the blocks for transmission and the extracted data is subjected to interpolation to restore all of the data, includes computing circuits for obtaining respective differences between input data and restored data and between input data and stored data and the sums of such differences, and further computing and comparison circuits operating with such differences sums to effect selective transmission of the input data or the extracted data.

Claims

1. An image information signal transmitting system comprising:

(a) input means for inputting an image information signal composed of a plurality of picture element data corresponding to one picture;

(b) storing means for storing the plurality of picture element data inputted by said input means by blocks each of which is composed of a predetermined number of picture element data;

(c) extracting means for dividing the plurality of picture element data inputted by said input means into the blocks, for extracting from each of the blocks a fewer number of picture element data than the predetermined number of picture element data of which each of the blocks is composed, and for outputting the extracted picture element data;

(d) interpolating means for interpolating picture element data which has not been extracted by said extracting means by using picture element data which has been extracted by said extracting means to restore the plurality of picture element data;

(e) first computing means for comparing the plurality of picture element data inputted by said input means with the plurality of picture element data restored by said interpolating means for every one of the blocks to obtain differences therebetween, and for computing the sum of the differences for every one of the blocks to output the sum as first computed data;

(f) second computing means for comparing the plurality of picture element data inputted by said input means with the plurality of picture element data stored by said storing means for every one of the blocks to obtain differences therebetween, and for computing the sum of the differences for every one of the blocks to output the sum as second computed data;

(g) third computing means for computing and outputting third computed data by multiplying the first computed data output from said first computing means by a first constant, adding the result of multiplication to the second computed data output from said second computing means, subtracting a second constant from the result of addition and, after that, multiplying the result of subtraction by a third constant;

(h) fourth computing means for computing and outputting fourth computed data by multiplying the second computed data output from said second computing means by a fourth constant and adding the result of multiplication to the first computed data output from said first computing means;

(i) comparing means for comparing a level of the second computed data output from said second computing means with that of fifth computed data obtained by multiplying the first computed data output from said first computing means by a fifth constant and adding a sixth constant to the result of multiplication, and for outputting discrimination data indicative of the kind of computed data which is found to be at a lower level as a result of comparison;

(j) output switching means for selectively outputting one of the third- computed data output from said third computing means and the fourth computed data output from said fourth computing means according to the discrimination data output from said comparing means;

(k) transmission mode determining means for determining a transmission mode to be selected for every one of the blocks, according to the discrimination data output from said output switching means, from between a transmission mode in which all the predetermined number of picture element data of which each of the blocks is composed are transmitted and a transmission mode in which not all of the predetermined number of picture element data are transmitted; and

(l) selective output means for selectively outputting, in accordance with a transmission mode determined by said transmission mode determining means, one of the plurality of picture element data inputted by said input means and the picture element data extracted by said extracting means.

2. A system according to claim 1, wherein a transmission mode information signal indicating a transmission mode determined by said transmission mode determining means is arranged to be transmitted along with picture element data.

3. A system according to claim 1, wherein said storing means is so arranged that a content stored therein concerning a specific picture element data is not changed, said specific element data corresponding to the block as to which said transmission mode determining means assigns the transmission mode in which all of the predetermined number of picture element data constituting the respective blocks are transmitted.

4. An image information signal transmitting method comprising:

(a) a first step of inputting an image information signal composed of a plurality of picture element data corresponding to one picture;

(b) a second step of storing the plurality of picture element data inputted by said input means in blocks each of which is composed of predetermined number of picture element data;

(c) a third step of dividing the plurality of picture element data inputted in said first step into the blocks, extracting from each of the blocks a fewer number of picture element data than the predetermined number of picture element data constituting the respective blocks and outputting the extracted picture element data;

(d) a fourth step of interpolating picture element data which has not been extracted in said third step by using picture element data which has been extracted in said third step to restore the plurality of picture element data;

(e) a fifth step of comparing the plurality of picture element data inputted in said first step with the plurality of picture element data restored in said fourth step for every one of the blocks to obtain differences therebetween, and computing the sum of the differences for every one of the blocks to output the sum as first computed data;

(f) a sixth step of comparing the plurality of picture element data inputted in said first step with the plurality of picture element data stored in said second step for every one of the blocks to obtain differences therebetween and computing the sum of the differences for every one of the blocks to output the sum as second computed data;

(g) a seventh step of computing and outputting third computed data by multiplying the first computed data outputted in said fifth step by a first constant, adding the result of multiplication to the second computed data outputted in said sixth step, subtracting a second constant from the result of the addition and, after that, multiplying the result of the subtraction by a third constant;

(h) an eighth step of computing and outputting fourth computed data by multiplying the second computed data outputted in said sixth step by a fourth constant and adding the result of the multiplication to the first computed data outputted in said fifth step;

(i) a ninth step of comparing a level of the second computed data outputted in said sixth step with that of fifth computed data obtained by multiplying the first computed data outputted in said fifth by a fifth constant and adding a sixth constant to the result of the multiplication, and outputting discrimination data indicative of the kind of computed data which is found to be at a lower level as a result of the comparison;

(j) a tenth step of selectively outputting one of the third computed data outputted in said seventh step and the fourth computed data outputted in said eight step according to the discrimination data outputted in said seventh step;

(k) an eleventh step of determining a transmission mode to be selected for every one of the blocks, according to the data outputted in said tenth step and the discrimination data outputted in said ninth step, from between a transmission mode in which all the predetermined number of picture element data constituting the blocks are transmitted and a transmission mode in which not all of the predetermined number of picture element data are transmitted for each of the blocks; and

(l) a twelfth step of selectively outputting, in accordance with the transmission mode determined in said eleventh step, one of the plurality of picture element data inputted in said first step and the picture element data extracted in said third step.

5. A method according the claim 4, wherein said image information signal transmitting method further comprises a thirteenth step of transmitting a transmission mode information signal indicative of the transmission mode determined in said eleventh step.

6. A method according to claim 4, wherein in said second step, a content stored in said second step concerning specific picture element data is not changed, said specific picture element data corresponding to the block as to which said transmission mode determining means assigns the transmission mode in which all of the predetermined number of picture element data constituting said block are transmitted.