JP2000059609A - Network scanner device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To compress image data by switching a compression algorithm for each page in accordance with a read image of a document, so that even if a page including a photographic image exists in the read document, Provided is a network scanner device capable of transmitting image data while reducing a load on a network. SOLUTION: It is determined for each page whether or not a photographic image portion exists in a document image read by a reading section 10, and image data of a document image of a page where a photographic image portion exists is determined by a lossy compression circuit 120. After lossy compression, the image data is transmitted over a network, and image data of a document image of a page having no photographic image portion is losslessly compressed by a lossless compression circuit 110 and transmitted over the network.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a network scanner for transferring read image data to a computer or the like via a network.

[0002]

2. Description of the Related Art In a conventional network scanner device, that is, a scanner device having a function of communicating with other devices such as a computer via a network, image data of a read document image is converted into a document image regardless of the presence or absence of a photographic image.
Each job was compressed by a certain compression algorithm and sent over the network. Therefore, if lossless (Lossless) compression is specified as the above compression algorithm, if there is a page containing a photographic image in the original, even the compressed data will be very large data.
There is a problem that it takes a long time to transmit the data. Lossless compression is a compression algorithm used for data that must be restored without loss of one bit, such as programs and numerical values, without limiting the type of data to be compressed. This is because it cannot be compressed. In addition, the network scanner device unilaterally distributes the processed data regardless of the degree of network traffic congestion or the processing capability of the distribution destination terminal. By doing
It is conceivable that the load (traffic amount) of the network becomes excessive due to the data communication, which hinders communication between other devices. Further, the transfer data size may exceed the receivable capacity of the distribution destination.

[0003]

As described above, in the conventional network scanner apparatus, the image data of the read original image is compressed by a predetermined compression algorithm for each job, regardless of the presence or absence of a photographic image. If the document contains a photo image in the scanned document, it takes a long time to transmit the data, and the network load becomes excessive, preventing communication between other devices. There was such a problem. SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the above-described conventional technology. In accordance with an image of a read original, a compression algorithm is switched for each page to compress image data, thereby enabling the read original to be read. It is an object of the present invention to provide a network scanner device capable of reducing the load on a network and transmitting image data even when a page including a photographic image exists.

[0004]

According to a first aspect of the present invention, there is provided an image processing apparatus having a function of communicating with another device via a network, and obtaining image data obtained by reading a document image. A network image scanner for transferring a photograph image portion to another device via a network, wherein the photograph image judging means judges for each page whether a photograph image portion exists in the read document image, and a photograph image portion. And lossy compression means for lossy-compressing the image data of the document image in which the image data exists in page units. According to a second aspect of the present invention, there is provided the network scanner according to the first aspect, further comprising a lossless compression unit that performs lossless compression of image data of a document image having no photographic image portion in page units. And

[0005]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing an example of an embodiment of a network scanner device according to the present invention. As shown in the figure, the network scanner device includes a reading unit 10 that optically reads an image of a document as a group of dots and converts the image into a video signal, and two compression units having different compression algorithms, that is, a lossless compression circuit 1.
10 and the lossy compression circuit 120, and a network interface (I /
F) 130, the image data read by the reading unit 10 is compressed by the lossless compression circuit 110 or the lossy compression circuit 120, and then transferred to a host device on a network (not shown) via the network I / F 130. It has become. The image data input from the reading unit 10 is a scanner video (VIDEO) I / F2
At the same time, the data is transferred to the main storage device 40 via a data transfer method such as DMA, and is also input to the change point counter 60. The change point counter 60 is for detecting a point at which adjacent dots in the image input from the reading unit 10 change in black and white, and performs real-time processing on the read line specified in the count line specification register 70. The black-and-white change point is counted by the
Send to The comparing circuit 90 compares the count value sent from the change point counter 60 with the threshold value set in the threshold value register 80, and when the count value exceeds the threshold value, the fact is notified. The given signal shown is given to the interrupt status circuit 100. That is, in this example, the photographic image determination means in this embodiment is composed of the above-mentioned change point counter 60, counting line designation register 70, comparison circuit 90, comparison circuit 90, etc. Utilizing the feature that the number is overwhelmingly greater than that of a text, a CAD drawing, or the like, a comparison is made between the count value of the change point and a threshold value to easily determine whether or not a photographic image portion exists.

When the interrupt status circuit 100 receives the signal from the comparison circuit 90, the interrupt status circuit 100 sends to the CPU 30 interrupt information notifying that the count value has exceeded the threshold value. The CPU 30 controls the entire network scanner according to a program stored in a ROM (not shown). If the interrupt information is not sent between the time when the reading unit 10 starts reading one page and the time when the transfer of the one page of image data to the main storage device 40 is completed, If the flag indicating data is not set, it is determined that the photographic image is not included in the document image of the page, and the image data stored in the main storage device 40 is transferred to the lossless compression circuit 110. After lossless compression, the data is stored in the temporary storage device 50 in page units with a header indicating that the data is lossless compressed data. On the other hand, if the interruption information notifying that the count value has exceeded the threshold value is sent without waiting for the end of the transfer of one page, or if a flag indicating that the data is photographic image data is set, C
PU 30 determines that a photographic image is included in the document image of the page. Then, after transferring the image data stored in the main storage device 40 to the lossy compression circuit 120 and performing lossy compression, the image data is stored in the temporary storage device 50 in page units with a header indicating that the data is lossy compressed data.

The CPU 30 repeats the above operation for each page. The compressed data is transmitted to the host device on the network page by page regardless of whether the image data of the document for one job, that is, all pages is stored in the temporary storage device 50, and the final page When the compressed data is transmitted, the operation for one job is completed. As described above, it is determined for each page whether or not a photo image portion exists in the document image read by the reading unit 10, and the image data of the document image of the page where the photo image portion exists is determined by the lossy compression circuit 120. Is transmitted over the network after lossy compression, so even if there are pages containing photo images in the scanned original, the amount of transmitted data can be reduced and the load on the network can be reduced. It is not necessary to apply an unnecessary load that exceeds the processing capacity to the destination terminal. Further, since the image data of the document image of the page having no photographic image portion is lossless-compressed by the lossless compression circuit 110 and transmitted over the network, the data can be distributed without deteriorating the image quality. In other words, if lossy compression is performed uniformly throughout one job, characters and ruled lines may be very difficult to identify, but lossless compression is performed on image data of a document image consisting of only characters and ruled lines. , Such a problem can be suppressed. In addition, since these operations are automatically performed by the network scanner device, the user does not need to perform extra operations such as switching the compression algorithm according to the image data. In the above-described example, the apparatus configuration including the dedicated hardware (110, 120) for lossless compression or lossy compression of image data has been described. However, instead of these dedicated hardware, a ROM (not shown) or the like is used. , Programs for lossless compression and lossy compression may be stored, and the CPU 30 may selectively execute these programs to perform data compression processing.

[0008]

As described above, the present invention has the following excellent effects. In the invention according to claim 1,
Since it is determined on a page-by-page basis whether or not a photo image portion exists in the read document image, the image data of the document image of the page where the photo image portion exists is lossy-compressed and then transmitted over the network. Even when a page including a photographic image exists in the read original, the load on the network can be reduced, and an unnecessary load that exceeds the processing capacity of the distribution destination terminal can be avoided.
According to the second aspect of the present invention, image data of a document image of a page having no photographic image portion is losslessly compressed and transmitted over a network, so that data can be distributed without deteriorating image quality.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of an embodiment of a network scanner device according to the present invention.

[Explanation of symbols]

10: reading unit, 60: change point counter (photo image determination means), 70: counting line designation register (photo image determination means), 80: threshold value register (photo image determination means), 90: comparison circuit (photo image) Judgment means), 100:
Interrupt status circuit, 110: lossless compression circuit,
120: Lossy compression circuit, 130: Network interface.

Claims (2)

[Claims] 1. A network scanner device having a function of communicating with another device via a network, and transferring image data obtained by reading a document image to another device via a network. Photographic image determining means for determining, on a page basis, whether or not a photographic image portion is present in the original image, and lossy compressing means for performing lossy compression of image data of the original image having the photographic image portion in page units. A network scanner device, comprising: 2. The network scanner according to claim 1, further comprising a lossless compression unit for performing lossless compression of image data of a document image having no photographic image portion in page units.