JPS6247025B2 - - Google Patents
Info
- Publication number
- JPS6247025B2 JPS6247025B2 JP56123109A JP12310981A JPS6247025B2 JP S6247025 B2 JPS6247025 B2 JP S6247025B2 JP 56123109 A JP56123109 A JP 56123109A JP 12310981 A JP12310981 A JP 12310981A JP S6247025 B2 JPS6247025 B2 JP S6247025B2
- Authority
- JP
- Japan
- Prior art keywords
- image quality
- scanning line
- scanning lines
- signal
- scanning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000034 method Methods 0.000 claims description 12
- 238000011156 evaluation Methods 0.000 claims description 11
- 230000005540 biological transmission Effects 0.000 claims description 6
- 238000012372 quality testing Methods 0.000 claims description 2
- 230000001629 suppression Effects 0.000 claims description 2
- 238000012795 verification Methods 0.000 claims description 2
- 230000002950 deficient Effects 0.000 claims 1
- 230000006866 deterioration Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/40—Picture signal circuits
- H04N1/407—Control or modification of tonal gradation or of extreme levels, e.g. background level
Description
本発明は冗長度抑圧符号化伝送を行なうフアク
シミリの受信画像品質を自動検定する方式におい
て、走査線ごとの符号誤りの有無を検出し、符号
誤りの含まれる走査線の連続数に応じた重みづけ
加算を行なうことによつて受信画像品質を判断す
る画品質の検定方式に関するものである。
冗長度抑圧符号化伝送を行なうフアクシミリで
は、送信側で走査線単位のランレングス符号化を
行ない伝送し、受信側でランレングス復号化を行
ないもとの画像信号を再生することによつて、伝
送効率を高めている。このため伝送路で符号誤り
が発生すると、誤りの含まれる走査線は受信側で
もとの画像信号に復元することができなくなり、
通常はすでに再生が行なわれている直前の走査線
信号を置き換えて使用する方法が用いられてい
る。
従つて、伝送路の符号誤りが増加すると、前走
査線置き換えの回数が増加し、画像品質が使用に
耐えないまでに劣化してしまう場合が発生する。
画像品質が悪い場合には、受信側より送信側へ再
送要求を出し、再度画像を送りなおすことにな
る。
このため、受信側では画像品質の良否を自動的
に判断することが必要となり、従来は符号誤りの
含まれる走査線の数を計数し、一画面中の計数値
があらかじめ決められた閾値以上となつた場合に
は画像品質不良と判断し、画面を再度伝送するこ
ととしていた。
しかし、この計数値と画像品質とは近似的な対
応関係であるために、計数値が閾値以下であつて
も画像品質が不良であつたり、閾値以上であつて
も画像品質が良好であつたりするという欠点を有
していた。
本発明はこの欠点を除去するため画像品質との
対応が良い符号誤りを含む走査線の連続数とその
頻度に着目した画像品質の検定方式を提供するも
ので、以下図面について詳細に説明する。
一般に走査線信号を他の走査線信号で置き換え
ることによつて発生する画像品質の劣化は、２つ
の走査線が近い程小さく、遠い程大きいことが容
易に推察できる。従つて連続した走査線の置き換
えでは、連続数の増加につれて急速に品質劣化を
発生することになる。すなわち、連続ｍ走査線置
換の第ｎ走査線の品質劣化に及ぼす寄与をｆ
（ｎ）とすれば、ｆ(1)＜ｆ(2)＜……となり、全体
では
The present invention detects the presence or absence of code errors for each scanning line and weights them according to the number of consecutive scanning lines containing code errors in a method for automatically testing the received image quality of a facsimile that performs redundancy suppression coding transmission. The present invention relates to an image quality verification method for determining received image quality by performing addition. In facsimile systems that perform redundancy reduction coding transmission, the transmitting side performs run-length encoding for each scanning line, and the receiving side performs run-length decoding to reproduce the original image signal. Improving efficiency. Therefore, when a code error occurs on the transmission path, the scanning line containing the error cannot be restored to the original image signal on the receiving side.
Usually, a method is used in which the immediately preceding scanning line signal that has already been reproduced is used instead. Therefore, when the number of code errors in the transmission path increases, the number of times the previous scanning line is replaced increases, and the image quality may deteriorate to the point where it is unusable.
If the image quality is poor, the receiving side issues a retransmission request to the transmitting side, and the image is sent again. For this reason, it is necessary for the receiving side to automatically judge whether the image quality is good or bad. Conventionally, the number of scanning lines containing code errors is counted, and if the counted value in one screen is equal to or greater than a predetermined threshold, it is necessary to automatically judge the quality of the image. If the image quality deteriorated, it was determined that the image quality was poor and the screen was transmitted again. However, since this count value and image quality have an approximate correspondence relationship, the image quality may be poor even if the count value is below the threshold value, and the image quality may be good even if the count value is above the threshold value. It had the disadvantage of In order to eliminate this drawback, the present invention provides an image quality testing method that focuses on the number and frequency of consecutive scanning lines containing code errors, which corresponds well with image quality.The present invention will be described in detail with reference to the drawings below. In general, it can be easily inferred that the degradation in image quality caused by replacing a scanning line signal with another scanning line signal is smaller as the two scanning lines are closer, and larger as the two scanning lines are farther apart. Therefore, when replacing consecutive scanning lines, quality deterioration occurs rapidly as the number of consecutive scanning lines increases. In other words, the contribution of continuous m scanning line replacement to the quality deterioration of the nth scanning line is expressed as f
(n), then f(1)<f(2)<..., and overall
【式】の寄与となる。
そこで、画面がＮ走査線で構成され、第ｉ走査
線がｎi番目の連続置換走査線であるとすると、It becomes the contribution of [formula]. Therefore, if the screen is composed of N scanning lines and the i-th scanning line is the n i- th continuous replacement scanning line, then
【式】を画面全体の品質劣化に対応させる
方法が考えられる。誤りの含まれない走査線はｎ
i＝０であり、ｆ（０）＝０とすれば良い。
第１図はこの方法の一実施例を示す受信機のブ
ロツク図である。受信された符号化データは端子
１より入力され、復号器２により画信号に再生さ
れ端子３より出力される。一方、復号器２では一
走査線の終わりを示す同期信号を検出すると、信
号４および一走査線に符号誤りの含まれない場合
には信号５を出力する。信号４，５はカウンタ６
のクロツク、リセツト端子に接続される。すなわ
ちカウンタ６は符号誤りの含まれない正常な走査
線信号が受信されると計数値が０となり、符号誤
りの含まれる走査線信号が受信されると、その都
度正常な走査線が入力されるまでカウントアツプ
し、符号誤りの含まれる走査線の連続数を示すこ
とになる。カウンタの出力７は読み出し専用メモ
リ（ROM）８のアドレスに接続される。ROM８
の出力９には、誤りの含まれる走査線の連続数ｎ
に対応した評価値ｆ（ｎ）が出力される。９は次
段の累算器１０へ入力される。累算器１０では走
査線の終了を信号４により識別し、評価値ｆ
（ｎ）を累算する。ただし、画面の開始時点でカ
ウンタ６、累算器１０は、リセツト信号１１によ
り０に初期設定しておく。１画面の電送が終了す
ると、累算器の出力１２は端子１４から供給され
る閾値と比較器１３により比較され、その大小関
係によつて画品質の良否を端子１５より出力す
る。端子１４の閾値は目標とする画品質に対応す
る値をあらかじめ求めておき、設定すれば良い。
ROM８の内容はｆ（ｎ）の形状によつて変わる
が、例えばｆ（ｎ）＝ｎなる評価値を用いる場合
にはROM８を省略することができる。
第２図はｆ（ｎ）＝ｎの場合の各部の動作例を
示す。走査線はｉ＝１より順次入力される。カウ
ンタ出力値ｎiは符号誤りの含まれる走査線ｉ＝
４、５では１、２と変化する。この値を累算器で
加えることにより、評価値は３まで増加する。以
下同様に、ｉ＝９、ｉ＝14、15、16、17の走査線
で評価値は加算され、最終評価値は14となる。仮
りに評価閾値が10であれば、画品質は不良と判断
される。
以上説明したように本発明によれば符号誤りの
含まれる走査線の分布に関し、連続した走査線の
誤りを孤立した走査線の誤りより大きな値で評価
して加算するので、単純に走査線の誤り数をカウ
ントする方法に比較して、画像品質との対応が良
いという特徴がある。
このため、フアクシミリ受信機において、画像
品質を自動検定する場合に有効である。なお本実
施例ではフアクシミリの走査線密度、符号化方
式、画面サイズは一定のものとして説明したが、
これらのパラメータの変化に対し前記閾値、ｆ
（ｎ）形状を変化させることもできる。また走査
線間隔が大きい場合には、等価的に間隔の小さい
走査線がｍ本挿入されたと考えて評価値を求める
こともできる。さらに、回線の瞬断等により、一
定時間ＴDだけ信号が欠損する場合、誤り走査線
数を一走査線平均時間ＴOによりｎ＝［ＴD／ＴO＋
１］（この［ ］はガウス記号）として推定する
ことも可能である。また第１図の処理はハードウ
エア上であつても、ソフトウエア上であつても良
い。One possible method is to make [Formula] correspond to the quality deterioration of the entire screen. The number of error-free scanning lines is n
i = 0, and it is sufficient to set f(0) = 0. FIG. 1 is a block diagram of a receiver illustrating one embodiment of this method. The received encoded data is input from terminal 1, is reproduced into an image signal by decoder 2, and is output from terminal 3. On the other hand, when the decoder 2 detects a synchronization signal indicating the end of one scanning line, it outputs a signal 4, and a signal 5 if one scanning line does not contain a code error. Signals 4 and 5 are counter 6
Connected to the clock and reset terminals. That is, when the counter 6 receives a normal scanning line signal containing no code error, the count value becomes 0, and when a scanning line signal containing a code error is received, a normal scanning line is input each time. This indicates the number of consecutive scanning lines containing code errors. The output 7 of the counter is connected to an address in a read only memory (ROM) 8. ROM8
The output 9 contains the number n of consecutive scanning lines containing errors.
An evaluation value f(n) corresponding to is output. 9 is input to the accumulator 10 at the next stage. In the accumulator 10, the end of the scanning line is identified by the signal 4, and the evaluation value f
Accumulate (n). However, at the start of the screen, the counter 6 and accumulator 10 are initialized to 0 by the reset signal 11. When the transmission of one screen is completed, the output 12 of the accumulator is compared with the threshold value supplied from the terminal 14 by the comparator 13, and the image quality is outputted from the terminal 15 based on the magnitude relationship. The threshold value of the terminal 14 may be set by determining a value corresponding to the target image quality in advance.
Although the contents of the ROM 8 vary depending on the shape of f(n), the ROM 8 can be omitted if, for example, an evaluation value of f(n)=n is used. FIG. 2 shows an example of the operation of each part when f(n)=n. The scanning lines are input sequentially starting from i=1. The counter output value n i is the scanning line i containing the code error =
4 and 5 change to 1 and 2. By adding this value in an accumulator, the evaluation value increases to 3. Similarly, evaluation values are added for scanning lines i=9, i=14, 15, 16, and 17, and the final evaluation value becomes 14. If the evaluation threshold is 10, the image quality is determined to be poor. As explained above, according to the present invention, regarding the distribution of scanning lines containing code errors, errors in consecutive scanning lines are evaluated and added up with a larger value than errors in isolated scanning lines. Compared to methods that count the number of errors, this method has a feature that it corresponds better to image quality. Therefore, it is effective when automatically verifying image quality in a facsimile receiver. In this example, the facsimile scanning line density, encoding method, and screen size are assumed to be constant.
For changes in these parameters, the threshold value, f
(n) The shape can also be changed. Furthermore, when the scanning line interval is large, the evaluation value can be determined by considering that m scanning lines with equivalently small intervals are inserted. Furthermore, if the signal is lost for a certain period of time T D due to a momentary line interruption, etc., the number of error scanning lines can be calculated using the average time of one scanning line T O as n=[T D /T O +
1] ([ ] is a Gaussian symbol). Further, the processing shown in FIG. 1 may be performed on hardware or software.
第１図は本発明の一実施例を示すブロツク図で
ある。第２図は本発明における各部の動作例を示
す。
１……符号化データ入力端子、２……復号器、
３……復号化出力端子、４……走査線終了信号、
５……走査線正常信号、６……カウンタ、７……
カウンタ出力、８……読み出し専用メモリ
（ROM）、９……メモリ出力、１０……累算器、
１１……リセツト信号入力端子、１２……累算器
出力、１３……比較器、１４……閾値入力端子、
１５……画品質判定出力端子。
FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 shows an example of the operation of each part in the present invention. 1...Encoded data input terminal, 2...Decoder,
3...Decoding output terminal, 4...Scanning line end signal,
5...Scanning line normal signal, 6...Counter, 7...
Counter output, 8...Read-only memory (ROM), 9...Memory output, 10...Accumulator,
11...Reset signal input terminal, 12...Accumulator output, 13...Comparator, 14...Threshold value input terminal,
15... Image quality judgment output terminal.
Claims (1)
の受信画像品質を自動判定する方式において、ｉ
を走査線番号、Ｎを総走査線数、n1を第ｉ走査線
に連続した第ｉ走査線以前の連続誤り走査線数と
し、 評価関数ｆ（n1）を０＝ｆ（０）＜ｆ(1)＜ｆ(2)＜
……とし、評価値【式】があらかじめ設定 された閾値より小であれば画品質は良と判断し、
以上であれば不良と判断することを特徴とする画
像品質の検定方式。 ２ 前記評価関数ｆ（n1）＝n1としたことを特徴
とする特許請求の範囲１項記載の画像品質の検定
方式。[Claims] 1. In a method for automatically determining the received image quality of a facsimile that performs redundancy suppression coding transmission,
is the scanning line number, N is the total number of scanning lines, n 1 is the number of consecutive error scanning lines before the i-th scanning line following the i-th scanning line, and the evaluation function f(n 1 ) is 0=f(0)< f(1)＜f(2)＜
..., and if the evaluation value [formula] is smaller than the preset threshold, the image quality is judged to be good,
An image quality verification method characterized in that if the image quality is above, it is determined to be defective. 2. The image quality testing method according to claim 1, wherein the evaluation function f(n 1 )=n 1 .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56123109A JPS5825762A (en) | 1981-08-07 | 1981-08-07 | Inspecting system for picture quality |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56123109A JPS5825762A (en) | 1981-08-07 | 1981-08-07 | Inspecting system for picture quality |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5825762A JPS5825762A (en) | 1983-02-16 |
| JPS6247025B2 true JPS6247025B2 (en) | 1987-10-06 |
Family
ID=14852394
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56123109A Granted JPS5825762A (en) | 1981-08-07 | 1981-08-07 | Inspecting system for picture quality |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5825762A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06290673A (en) * | 1992-09-08 | 1994-10-18 | Fujitsu Ten Ltd | Pushbutton operating mechanism |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0787511B2 (en) * | 1985-06-07 | 1995-09-20 | 株式会社日立製作所 | Equipment |
| JPH0684565B2 (en) * | 1987-05-06 | 1994-10-26 | 帝人株式会社 | Synthetic fiber melt spinning equipment |
-
1981
- 1981-08-07 JP JP56123109A patent/JPS5825762A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06290673A (en) * | 1992-09-08 | 1994-10-18 | Fujitsu Ten Ltd | Pushbutton operating mechanism |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5825762A (en) | 1983-02-16 |
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