JPS58184874A - Band compressor - Google Patents

Abstract

PURPOSE:To attain ease of band compression, by performing compression after making the number of picture elements per one main scanning line constant. CONSTITUTION:The number of picture elements per one main scanning line is dispersed in picture information (m) outputted from a reader. A virtual original picture addition circuit 3a adds virtual picture information (v) to the original picture information by the number of deficient picture element number so that the number of picture elements per one main scanning line of the picture information is constant. The band compression is executed to picture information (n) where the number of picture elements per one main scanning line is constant. Since the band compression circuit is completed through normal operation to a prescribed number of picture elements by making the number of picture elements constant, a complicated processing circuit is not required. Thus the circuit is simplified and the operability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a band If compression # which performs band compression of an image IM obtained by scanning a two-dimensional image such as )r.

Efforts are being made to reduce the number of transmission codes as much as possible, that is, to increase the compression rate, in the FAX 7mm equipment (ζ), which uses band compression (bandwidth compression). In order to reduce the number of 11 people, it is generally done in the IDC, band (L line device 6,) outside circuit [, manual drawing information - Because of the code per Dokenmori line, Figure 1 shows the general configuration of a fac/millimeter/stem using a band compression device.An original image 1 is scanned by an image reading device 2 to obtain an image signal in units of main scanning lines. The read image signal is compressed and encoded by the band compression device 3, and then transmitted to the decompression device 6 via the transmission path 4.The decompression device 5 receives the compressed and encoded image signal, The image is restored to the original image signal, and the image recording device 6 records the reproduced image 7 based on the restored original image signal.

Since VT, the facsimile system shown in Figure 1 has achieved a high compression ratio when the image reading density and drum diameter of the image reading device 2 are changed, or when the main scanning line length of the original image 1 is changed. To avoid this, every time the number m of pixels per lifetime scanning line sent to the compression device 3 changes, the number n of pixels per lifetime scanning line processed by the compression device 3 and decompression device 5 is changed to the number m of pixels per lifetime scanning line of the original image. This had the disadvantage of having to be met.

On the other hand, the original image size and image signal reading device standards (image reading density per image,
Tram routes change frequently depending on the purposes and demands of users. Each time, the number n of pixels per scanning line of the compression device 3 and the y-source device 6 is read, and the number of pixels per main scanning line m
Not only does it significantly deteriorate the operability of the facsimile system, but also when changing the setting value n (if this error occurs, it will impede the operation of the entire facsimile system).

In addition, in the compression device 3 and decompression device 5, when the number n of pixels per main scanning line to be compressed changes, circuits related to this change in several tens of places, and the number of pixels per main scanning line to be compressed changes. Those with different specifications in number n (to change this, several dozen circuits must be changed).

The present invention addresses the above-mentioned drawbacks that have occurred in conventional compression/decompression devices. It is an object of the present invention to provide an operating device in which the number of pixels per scanning line is constant regardless of the lifetime number m of pixels per scanning line of information.

An embodiment of the present invention will be described below with reference to the drawings.

The following embodiments are facsimile machines that handle binary codes, and the present invention can also be applied to facsimile machines that compress halftone bands.

2A to 2C are diagrams illustrating the principle of the present invention, in which FIG. Image signals for a lifetime of scanning lines are compressed in a compression device in which a virtual original image of white or black (hereinafter referred to as white for convenience) is added. n is 1~. The true original image signal at the end of FIG. 2 is indicated by diagonal lines, and n < m.

The compression device of the present invention adds (−・−1) pixels of J.white virtual original image to the original image signal A read from the image signal reading device, forms an image signal port for compression processing, and then opens the image signal port. Compression encode and transmit. After adding the white virtual original image, the compression rate of the image signal port is lower than that of the original image signal because it cannot be compressed, but since there are fewer changing points in the added part, the compression rate is significantly higher. The number of postscript codes is 5000 or more
Even if the number of pixels is 10,000 pixels, the increase in the number of codes/II is 20 to 4 bits per line in a lifetime, so the compression ratio is extremely small. Tooling/mm/stem (
ζ A block diagram of one implementation example 1 of the present invention which is applicable to the present invention is shown in a small size.

From the image defect reading device 2, the compression device 3\kires the original picture 1d - well, virtual original picture) 10 circuits 3d performs compression processing.〇-The number of pixels in the main scanning line is n,! :Sa It, nmi shrink? *4
The compression encoding process is carried out by the transmission circuit 3b and sent to the transmission line 4. Original picture signal l at 5
(This is crushed. In the system shown in Fig. 3, the compression code f
The transmission circuit 3b and the Qi source device 5V'i compress the original image signal with a fixed number of pixels per scanning line n.
IF shrinkage process (it is enough to remove L, r1 end.')
7/LnThe circuit is simplified compared to the variable one.No.1
ing,.

For example, when the compression encoding of image information for main scanning lines is completed in the compression encoding transmission circuit 3b, the band compression device adds a certain special termination code to the end of the encoded data and sends it to the decompression device 5. Therefore, in the terminal code adding circuit 7J11 (shown) V, the compression/decompression device in which the number n of pixels per lifetime scanning line is fixed as in the present invention performs compression processing, and the code number of the image signal is Is it okay to keep the counting circuit fixed? In conventional compression/decompression devices where n changes to i, the circuit that counts the number of codes of the image signal must be changed each time n changes. The white virtual original image added by the JJI11 circuit 3a can be removed by the output terminal of the restoration device 6 or by the image recording device 6 to obtain the reproduced image 7. Even when recording, only a small white margin appears at the end of the reproduced image.
There is no problem in operating the tool/stem.

In the two-image reading device 2 described below, the time for scanning the 1 King's eclipse line is usually fixed, and this time is defined as T6.

This time T is shorter than T8. There are 1 pixels in the middle of .

If the time required to scan one pixel is Tp, then mT
, =Te is established. The number of pixels to apply 1 force is y (
y = n - m), and as the vTpQ value increases, (m + v)Tp, 4. Therefore, l of the band 1F compressor is
While the F compressed code 1 and the fi sending circuit 3b are scanning the image 1 and the imaging device 2 for the rest of their lives (when receiving n pixels, rl disappears (m+v)) +4. #"a when Tp<Ts The original image/JO circuit 3a simply adds a white virtual original image to the outside of the V pixel.
l −i if,, f: squid, (m tenv)T
p-Ts-') 4#←ko, -1, 1 stroke, ← correct time T
P is 1 pixel or 1t - Inafuyumi fhi Buddha sending circuit 3b\sending 7
14i1 City j' to the time Tc, virtual original drawing approaching 11 circuit 38, all connections and splits, Part 1 of ■
Tp is T so that (m+v)Tc T8 holds regardless of the directness.・＼Convert, convert, 't7[Bayoi.

Figure 4 shows this machine's 11-carrying W original picture υ1] Circuit 3
FIG. 5C and FIG. 5B are examples of the operation timing shown in FIG. In FIG. 4, the original picture <S number manually created by the picture 1ψ reading device is input into the line memory circuit 4a, and -
After completion of main scanning line capture, virtual original image addition signal control circuit 4
Under the control of b, the original image signal for a lifetime of scanning lines and subsequently the virtual original image signal are sent to the upper line encoding transmission circuit 3b as a data signal (2) via the gate circuit 4C. FIG. 6A shows the operation timing of the line memory circuit 4a, and FIG. 6B shows the operation timing when the original image signal bl read out from the line memory circuit 4a is converted into a data signal f to be compressed and encoded. ing.

The operation will be explained in detail using FIG. 4 and FIGS. 6A and 6B.

An original image signal b from an image l#' reading device, a strobe signal (period T) for sampling the original image signal, and
- The scanning signal a indicating that the main scanning line is being scanned is
The rights memory circuit 4aV is powered. While the light/memory circuit 4aid scanning signal a is off, the original image signal is written to the memory inside the light/memory circuit 4a.
RITE #1 work 9. .

□ When the scanning signal a is turned off, the original image signal is read out from the memory inside the write/memo 17 circuit 4a as the read data signal d (READ operation). It is read out in synchronization with the cycle T.).
iJ gJJ T. On Iτ, the period and ratio of the strobe signal ＼ is sufficiently high speed, and is set to (m+v)To(Ts holds true).

Virtual original picture IJ
When the output from the memory circuit 4a is output, the compression f1 signal f1 signal transmission circuit 3b-\IL@ outputs the enable signal C which crystallizes the operation, and also outputs the data signal f to the 00 gate circuit. 4C\Kate number e is manually operated 2, gate No. 16 e1-t retator signal d is output) Jsa71 and 0 times,
4, the enable signal is always on for 0 pixels, +fE
.

The compressed code fhi transmission circuit 3b has m as the code f.
Original picture 16 outside pixels and virtual original picture 1d outside (n-m) pixels
4. Receiving the signal 4, one-mari, ratio reduction A1 ratio jR circuit 3b←1 original image signal S, /)-number of pixels per main scanning line m,
Although the present invention has been described in detail by taking as an example a system that always receives data outside the pixels, the present invention is shown in FIG. Needless to say, the present invention can be applied to all devices that perform band compression processing on image signals obtained by scanning.

As described in detail below, the band compression device of the present invention keeps the number n of pixels per lifetime scanning line processed internally constant regardless of the number m of pixels per lifetime scanning line processed by the compression device. Accordingly, the circuit configuration of the band compression device can be simplified and the operability can be improved.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of l(), ri/mm/stem using band LL compression, the second factor I~/1 is the present invention, 7
) Figure 3 is a block diagram showing the band compression device according to an embodiment of the present invention, Figure 4 is a block diagram showing the main parts of the device, and Figures 6A and B are the FIG. 3 is a diagram showing the operation timing of the blocks in the figure. 1--Original image, 2--Image reading device a13-Compressing device, 4-Transmission line, 5-Reproducing C device, 6--Image recording device, 7--Reproducing image, 3a--Virtual original image addition JJI
T circuit, 3b...Compression encoding transmission circuit, 4a-...
Line memory circuit, 4b - Virtual original image addition signal control circuit, 4C... Gate circuit. Name of agent: Toshio Nakao and one other person...
18

Claims (1)

[Claims] Means for adding a white or black virtual original image to the original image information and making the number of pixels per main scanning line constant regardless of the length of the original image information; A band compression device characterized by comprising means for compressing information by 1F.