DE2115410C3 - Transmission system for images - Google Patents

Description

of the complex transfer factor is selected over the frequency.

7. System according to claim 5, characterized in that a function | F _U | = M ₁ (O)) I is provided, in which the magnitude of the transfer factor in db over the frequency is half as fast

ίο decreases as with the noise evaluation curve for the eye.

8. System according to claim 5, characterized in that a function | F _1S | = Μ »( ^ω ) Ι is provided, which is the noise evaluation curve for

the eye corresponds.

9. System according to claim 6 and 7, characterized in that a function | F ₁₃ | = M ₃ (a>) | is provided, which in the area between the functions | F _U ! = M ₁ (O)) I and IF ₁₄ 1 = \ Α _ζ (ω) \ ver

ao runs.

10. System according to one of claims 5, 7 to 9, characterized in that a pre-emphasis filter is provided whose phase response is non-linear.

11. System according to claim 5, 7 to 9, characterized in that an all-pass filter with a non-linear phase response is provided as a pre-emphasis filter.

12. System according to one or more of the preceding claims, characterized in that that a device is provided, the one for Synchronization of the switch (7) to the scanning device (1) additively the information required on the transmit side to the analog signal before the subtraction circuit (2) and on the receive side behind the demodulator (8, 9) recognizes.

13. System according to one of the preceding

Claims, characterized by its use for the transmission of television images, faknimile images or radar images.

Transmission system for moving images in particular, in which the original image is transmitted from the original image to the formation of a first image (n = 2, 3, 4, ...) only

/ I

every nth raster image point is scanned offset from raster line to raster line with the inclusion of the interlace method, in which to form the further η - 1 piece - pictures after the same

/ i

Method, the not yet scanned raster image points of the η − 1 following original images are scanned and each of them is scanned at the receiving end -i-image one after the other together with all -image η η

the «- 1 temporally preceding original images is reproduced. For transmission using pulse code modulation is it known the original image in a sampling time that is usually about a thirtieth of a second, to be sampled once that one after the other all Raster pixels of the odd-numbered and then all of the raster pixels of the even-numbered lines scanned, transmitted and reproduced. The scanning of the original image is then repeated ongoing. The absolute value of the sample is quantized in each case, so that a code word from 6 to

gBits length P ^ro sample comes about. In the representative code words around the sampling time for the sampling time for the original image, which is usually a third, the field, which is usually a thirtieth of a second, carries one for each pixel. Every transmitted code word is transmitted to the demodulator. Estimation error by means of a synchronous to the sampling clock

From the magazines "The Bell System Technical 5 switching switch alternately direct or Journal", May / June 1966, pp. 689 to ^ 21, and September about the delay memory for the duration of a December 1969, pp. 2583 to 2599, it is known, fed with a delay in the scanning duration of a field and the scanning and reproducing system adds the same Schatz conference to these estimation errors by means of differential pulse code modulation, which are used when calculating the peeling errors. _{The OK} transmission side provided for this purpose was used for transmission. The output signal of the auantized estimation error casts only 2 until the demodulator then contains as many pixels in 4 bits per code word. The number of image points to be transmitted in the sampling time of an original image, such as the original sampling time for the original image.

Code words is here again equal to the number of image For the transmission of the quantized estimation errors

Points. The specification of 2 to 4 bits per code word i ₅ in the solution according to the invention is only 2 to is based on experience. 4 bits per code word and only one transmission

to the magazine The Bell System Technical Codewords that are 1 times the number

Journal ", January 1967, op. 167 to 198, is the entrance «

described system. Which corresponds to it based on pixels of the original image, in the underlying method, 20 sampling time of the original image is required as a low-resolution method. The arrangement designates and requires 6 to 8 bits per code word for each quantitative delay memory to be transmitted in front of the demodulator. This memory capacity for the ⁿ - ^ th

Method exploits the fact that the sampling ^{r r} "

Because of the flickering of the original image, part of a full image at 2 to 4 bits per code word must follow faster than the fastest recognizable movement 25, whereas the original low-resolution requirement. In contrast to the previously mentioned methods _{, storage capacity for} the ^ i-len part

^{driving is only v} " in the sampling time for an original image

to transmit a number of code words which is equal to i of the picture points of the original picture at 6 to 8 bits per code word of a frame. _{3o ^ It is advantageous if the delay memory is the object of} the invention as a tapped chain of items to implement a transmission system that are designed to store the estimation errors compared to the known systems for transmission _{dJ D ines} J_ _Bi , _{of delay} . both with short Codewortern and with a η. ". ,,, a" lens number in the sampling time for an original image 35 Advantageously, it is further if manages the modulator and m üb> rtraeender code values and thus the demodulator according a Schätzwertbildner is provided , Vnrtriie of the two last-mentioned methods grain design estimate for each raster image point from wvorraueu * e. This task will be derived from the estimation error invented at least from a temporally preceding, quanti-external from a transmission system of the type described and assigned to an adjacent pixel. This is because the SchatzdS is solved in accordance with the fact that an error on the transmission side can be precoded with conventional Bildsignaennut fewer bits stlator for differential pulse code modulation per code word than the absolute value Xn and that on the receiving side a demodulator is provided for if the same quality reduction of the reproduced differential pulse code modulation is provided, the picture is assumed.

For the practical implementation of the switching object that switches to the sampling rate, it is advantageous if a shift register is provided as a delay directly and one after the other via η - 1 delay memory, since this memory is supplied with a delay time of in comparison to other stores easy, safe and easy

the duration of a ^ -image starting respectively around the _jo ¹ ^ ⁸ j _{uf the} receiving side, reproduced image

,. . differs from the original image, because the

Duration of an image increases and the correspondingly described processing method is system-related

The selected transmission-side scanning scheme is queried. Falsifications are made. The error exists

"" .Fr on the one hand in the quantization error, which

i ^ fn on the one hand in the quantization error,

^eren ·! . ₅₅ stands that the estimation error in quantized

The duration of a picture is equal to the sampling time, the _{porm transmitted w} j _r d and the quantized one

^ t Modulator for diligence buffer code modulation. Sampling process not changed, d. h "whom camera Delay memory delays the estimation errors.

fc <iiig cmsiciH, wira suDjeKtiv mitigated when the beweetpn RiiH <»ii» n ty -ca ι · · · j

Described here? Get lost mri ow! these

aas ^ ¹ VM ₁ -S-Ata °°

J- »ie hig. 1 shows a transmission system according to the invention for β = 2 with a scanning device device 1, a subtracting circuit 2, a quanti-

^FtTB ~ j7T ^S i ^erer ^ enon sending-side estimated value partner 4,

^{Α {ω)} * ° ^ ¹ ? ¹¹¹ transmission channel 5, a delay

spachei 6, a switch 7, a receiving J? ⁸ ? S ^ towetMdner 8 i Sihl

, nm receive

of the complex transfer factor over the Fr ^ J? ⁸ ? S ^ towetMdner 8, a summing sequence is chosen ^ ⁶ " ¹¹⁸⁵¹ ^ ^{015 over the function} 9 ^ d a low-pass filter 10. Furthermore, a pre-

It is advantageous after this if a function

'ÜÄfl S

to obtain a second

gd ^ ATgeSts ^ ch? _a SSJ ^^? * "**» »" ** "-

A Geräuschbewertangskurve for black W ^ t ^^ LJ ^ · ^Mese "mpötndenmodn-white television, for example, in denTlS JSt ^ S * ^ ^6" ^^ t ^ 2 etschaltung to-"Nachrichtenüberlragung" H ö 1 ζ le r / Th fe r IhT ^ S * r every amphtu-modiilated pulse

bach.Sprmger.VeS ^ Sdddb ^ N ^ YorV " ^ JS ^ S ™ * ¹ **" ⁴ * "* *" ^ ¹ "** ¹ " 1966, shown on pp. 251 and 252 ^ **** - S2L "^ OtaWgBHgeBm quantized Schatz-It is also advantageous to subtract ^ nTdne function ^ ^^^^ ^{& Μ} ^? *. The IF ₁₈ ] = _{] Α} , {ω)] is provided in the BerSS ^ SPSäiKf ^ ³ ? ^ ** M * ™ d
see the functions jF "| and | F _M j runs. riSte ^ StfiT ¹¹ "?? ³ """ ⁰¹

The second-mentioned adulteration, "the nuTbei be SsSSS !? *" £ - ^^ * ■
w ^ th original screen starts and then the scanning 6 _S ££ ZJk ££ ^ iJ ^ l * f? ⁰ ^ ⁸
can be recognized by the mentioned ° 5S- wSS ^? P "^ ⁰ ^^^ !! ^ implemented and anphase and de-emphasis also be modernized. TMnW S ^ i ^ changeover switch 7 again in the quan-

the receiving-side estimator 8 as well as the summing circuit 9 performed by the pre-emphasis filter 11 is compensated once directly via the change,
switch 7 and once, still in the pulse code modulated, it is advantageous, for example, if in the pre-form, via the delay memory 6, which has an emphasis filter 11, the amount of the transfer factor delay time of the sampling period of an original image 5 in dB decreases over the frequency half as fast as has, and the changeover switch 7 is supplied. The switching frequency for the noise evaluation curve for the eye and frequency of the switch 7 is synchronized with the sampling frequency when the phase response of the pre-emphasis filter 11 is not synchronized with the sampling device 1. In the sum linear, since the noise spectrum is subjectively empty circuit 9, the quantized estimation error is colored more favorably and the scanning pattern in an image reproduced in the estimator 8 from the at least one io cannot be recognized if temporally preceding quantized estimation error objects move in the image ,
derived estimate added. The sum is between the television camera and the input of the low-pass filter 10 t supplied, consisting of the wiedergewon- / or forms and between the output A and the Bildnenen amplitude samples to an analog signal, the playback device may be a transmission channel Fuei at the output A is applied. When arranged from picture frame to 15 analog signals or digital signals.
Image frame no extreme changes occur. So far, the system has been described in such a way that with dei this reconstructed image signal is of sufficient scanning on the transmission side every second pixel is of verQuality. The synchronization of the switch 7 is working. It is just as possible, there only the scanning device 1 is simple because both third or fourth or even more points to process the switch 7 and the scanning device 1 20, so that only after three, four or even more Ab with the PCM clock is coupled, which anyway when sampling an original image so many code words ge receiver is required. It is therefore only necessary to send the information about how the original image has points.

■ i-Image has just been transmitted. This can beispiels- ^Müs j ^s then repeatable at the receiving end as often

η 25 until a fresh one at this spatial place dei

wisely done in that the analog television picture belonging pixel is received. It is

signal on the sending side with every nth image change, more memory is required than with the in

a character faded into the image synchronization signal Example of the method described with η = 2.
which is recognized on the receiving side and used for The F i g. 2 and 3 show for the case η = 3, for the

Synchronization is used. 30 three thirds of the images are transmitted in succession

The analog image signal can be pre- the required delay memories 6 'and 6 "

Emphasis filter 11 in the transmission area differentiated as well as a triple changeover switch 7 '. The delay tangs

Borrowed attenuated and through the de-emphasis filter 12, the memory 6 'can be delayed by the duration one:

the magnitude of the transfer factor over the frequency third image, the delay memory 6 " by di <

are again attenuated so differently that 35 double the duration of a third picture.

1 sheet of drawings

Claims (6)

Patent claims: 1. Transmission system for moving pictures in particular, in which the transmission line is based on the original picture to form a first image (n = 2,3,4, ...) η in each case only every nth raster image point is scanned offset from raster line to raster line with the interlace method being used that for the formation of the further η - 1 piece - ■ images the not yet scanned raster image points of the η − 1 subsequent original images are scanned using the same method, in which on the empire side, each image successively to n lamb with all pictures of the n - l temporal previous original images is reproduced, characterized in that a modulator (2, 3, 4) for differential pulse code modulation is provided on the transmission line and that a demodulator (8, 9) for differential pulse code modulation is provided on the receiving side, to which each transmitted estimation error is synchronized to Sampling clock switching switch (7) is fed once directly and one after the other via η - 1 delay memory (6), the delay duration of which is the duration of one image starting in each case increases by the duration of an image and which are queried in accordance with the selected scanning scheme on the transmission side. 2. System according to claim 1, characterized in that the delay memory as a with taps provided chain of individual memories are formed, which delay the estimation errors in each case by the duration of an image. 3. System according to claim 1 or 2, characterized in that the modulator (2, 3, 4) and in the Demodulator (8, 9) an estimator (4, 8) is provided, which the estimated value for each Raster pixel from at least one temporally preceding, quantized estimation error associated with an adjacent pixel derives. 4. System according to one of claims 1 to 3, characterized in that a shift register is provided as the delay memory (6). 5. System according to one of the preceding claims, characterized in that the modulator (2, 3, 4) is preceded by a pre-emphasis filter (11) in which the magnitude of the transmission factor is in the frequency range of the to be transmitted Analog signals steadily decreases with increasing frequency, and that the demodulator (8, 9) a Dcemphase filter (12) is connected downstream, in which the amount of the transfer factor in the frequency range of analog signals to be transmitted increases steadily with increasing frequency. 6. System according to claim, characterized in that with a function F ₁ = A (ω) of the complex transfer factor over the frequency in the pre-emphasis filter (11), a function in the de-emphasis filter (12) A (ω)