JPH08106536A - Extracting and compressing method for image, image transmission equipment, and image recorder - Google Patents

Abstract

PURPOSE: To efficiently transmit/record an image by slicing and compressing data of only a required part on the screen. CONSTITUTION: A boundary line to designate the range to be sliced is drawn on the screen by a pointing device, and bits corresponding to pixels in the designated range are set to '1' on a memory having bits corresponding to pixels on the screen. This memory is scanned, and frame memory addresses corresponding to bits set to '1' are obtained to take out and compress the data in the area to be segmented. Thus, image data is efficiently transmitted/ recorded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for extracting and compressing image data in an arbitrary area on a screen, and an apparatus for transmitting or recording image data extracted / compressed using the method.

[0002]

2. Description of the Related Art When a part of an image displayed on an image terminal device is cut out and transmitted / recorded, the cutout area is usually a rectangular area. Also, when an image is acquired from a video board or a scanner by a personal computer and recorded on a recording medium, a rectangle having an arbitrary position and size is designated and the image data therein is recorded.

[0003]

Depending on the figure, when the screen is cut out into a rectangle, many unnecessary parts are included, and even if compressed, the amount of information to be transmitted / recorded is larger than necessary. There was a problem that it was not efficient.

An object of the present invention is to extract and compress an image into an arbitrary shape, compress the data, and transmit or record with a small amount of data, and an image transmitting apparatus and image recording method using the method. To provide the equipment.

[0005]

The above-mentioned object is to display an original image to be cut out on the screen of the display means, and see a boundary line drawn on the screen by a pointing device while seeing a part of the screen by the boundary line. It is achieved by designating a cutout area by enclosing it, extracting only the image data in the cutout area from the frame memory for displaying the original image, and compressing it. Further, in the designation of the cutout area, the boundary line is closed. If not, it is achieved by designating which side of the boundary line should be cut out, and by setting the area surrounded by the boundary line and the periphery of the screen as the cutout area. This is achieved by transmitting and recording the data that is cut out and compressed by using.

[0006]

Since only the image data of the arbitrarily shaped area can be cut out by the pointing device, if it is compressed and transmitted or recorded, the image data can be transmitted and recorded efficiently.

[0007]

EXAMPLES The present invention will be described in detail below with reference to examples. FIG. 2 shows an embodiment of the image transmission device according to the present invention. In FIG. 2, the transmission device includes a CPU 1 that controls the operation of the entire device, an image input unit 2 such as a video camera, a frame memory 3 that holds an image, and a handwriting input unit 4 such as a mouse, pen, or tablet. A memory 5 for holding handwritten graphic data and a frame memory 3
Display control unit 6 for synthesizing the image of FIG.
And a display 7 for displaying the image combined by the display controller 6.
A memory 8 having a work area for determining a coding block of an image by a handwritten figure, an image coding unit 9 for coding the image data as an information source, and one or more transmitted from the image coding unit 9. Coding block and memory 8
From the CPU 1 to collect the encoded block numbers to generate a transmission block and transmit the block.

On the other hand, the receiving apparatus shown in FIG. 2 has a CPU 20 for controlling the operation of the entire apparatus, a communication section 21 for receiving a transmission block, a memory 22 for holding a coding block, an image decoding section 23, and a decoding section. A frame memory 24 for holding the image data, a display controller 25 for converting the image data in the frame memory 24 into an image signal in the NTSC or PAL format, and a display 26 for displaying the image data from the display controller 25. Has been done.

The operation will be described below. FIG. 1 is an explanatory diagram of an image extraction / compression method according to the present invention. First, the image input unit 2 of the transmission device converts an analog signal from a video camera or the like into a digital signal and stores it in the frame memory 3. This is the original image to be cut out. Next, the user uses the pointing device such as a mouse to cut out the cut-out area from the handwriting input unit 4 with a curve C in FIG.
Enter as (outer line). (Display of the original image is omitted in FIG. 1) Further, the user marks which side of the input curve is cut out by double-clicking the mouse. These inputs are processed by the CPU 1, and the contents of the memory 5 corresponding to the pixels in the cutout area are set to "1" and the contents corresponding to other pixels are set to "0". However, the memory 5 corresponds to the image size 1
Frame capacity, for example display size 640 x 480
A pixel has 640 × 480 bits. In the example of FIG. 1, the inside of the curve C is designated as the cutout area and "1" is associated. The display control unit 6 synthesizes the image data of the frame memory 3 and the image data of the memory 5 and displays the synthesized data on the display unit 7. The user can input an outer peripheral line and mark with a pointing device while observing this screen.

FIG. 3 exemplifies various cases of specifying a cutout area. For each of Examples 1 to 3, the left end is the screen of the display 7 when the outer circumference of the cutout area is input, and which is next. The screen when the marking (x mark) that specifies whether to cut out the area is input, the right is the memory map of the memory 5 in which only the area specified by the marking is "1", the other is "0", the right end is described later It is explanatory drawing of the cut-out process of. Example 1 is when a closed curve is input as in FIG. 1, but Examples 2 and 3 are cases where the screen is divided into two parts and only one of the areas is cut out, and when the input curve is not closed in this way. Is processed by the CPU 1 so that a closed area is formed so that the periphery of the screen complements this.

When the input of the cutout area to the memory 5 is completed, the CPU 1 determines the cutout image area as follows according to the flowchart shown in FIG. First, the display size is Hm pixels horizontally and Vm pixels vertically. The memory is usually read in bytes, so CPU1
In order to read the vertical V-th and horizontal H-th pixel values of the screen, it is necessary to calculate the byte-wise memory address corresponding to the pixel value and the number of the bit in the byte.
Since this is a simple calculation, the illustration and description of such a mechanism is omitted in FIG. 4 for simplicity of description.

In step 401 of FIG. 4, the pixel position (H, V) is set to H = V = 0, which is smaller by 1 than the value (1,1) at the upper left corner of the screen. Then step 402, 4
In step 04, V and H are respectively incremented by 1 to set the screen to the value in the upper left corner, and the pixel value x0 previously read in step 403 between them is set to "0". This is because when the pixel value “1” suddenly appears from the left end of the screen as in Example 3 of FIG. 3, this left end position of the screen is added to the cutout area. Thus, in the next step 405, the position (H,
V) pixel value x is read.

In step 406, the previous pixel value x
It is checked whether 0 and the read pixel value x match. If they do not match, it means that the pixel value has changed from x0 = "0" to x = "1" or from x0 = "1" to x = "0".
Check in 7. If x0 = "0" in step 407, it means that the pixel is moved from outside the clipping area to inside the clipping area. Therefore, in step 308, the pixel position (H, V) is set to the start address of the first buffer provided in the memory 8. Store as. In step 407, x0 =
If it is "1", it means that the pixel has moved from the inside of the cutout area to the outside of the cutout area. Therefore, step 409
Then, the pixel position (H, V) at that time is stored in the first buffer as an end address. Since the end address is always detected after the start address, this is 1
The first buffer is managed as a pair.

When x0 and x match in step 406, it is checked in step 410 whether x = 1 and H = Hm at that time. If so, this is the case as in Example 2 in FIG. 3, which corresponds to the case where the cutout area extends to the right end of the screen, and is the cutout area end address that is not detected by the checks in steps 406 and 407. Therefore, when this is detected in step 410, the pixel position (H, V) is stored in the first buffer as the end address in step 409. FIG. 5 schematically shows the first buffer.

When the processing for one pixel value is completed as described above, the pixel value x at the current position (H, V) is substituted for the previous pixel value x0 in step 411, and step 4
At 12, it is checked if H = Hm, that is, if it is at the right end in the horizontal direction. If it is not at the right end, the process returns to step 404 and the same processing is performed for the next pixel value, but if it is at the right end, it moves to step 413 to check whether V = Vm, that is, the pixel value at the bottom end. If it is not at the bottom end, the process returns to step 402 to move to the scanning of the next horizontal line, and if it is at the bottom end, the process ends.

As described above, when the pixel positions surrounding the cut-out area on the screen are obtained in the first buffer of the memory 8 by the processing of FIG. 4, the preliminary processing for compressing and transmitting / recording the pixels is next performed. I do. Generally, in the compression of image data, the screen is divided into vertical and horizontal sections by 8 × 8 pixels to form a quantized block, and the quantized block is used as a unit for compression processing. Therefore, now, the bitmap of the memory 5 corresponding to the screen is divided into the above quantization blocks, and the block numbers are assigned to the raster scan operation order as 0, 1, 2, ... As shown in FIG. . Then, as shown in the enlarged view of the rectangle A in the figure, it is checked whether or not the start / end address of the first buffer in FIG. 5 is included in the block, and if the start address is included, it is determined as the start block. If the end address is included, the number of the corresponding block is stored in the second buffer provided in the memory 8 as the end block as shown in FIG. Also in this case, the start / end blocks are recorded and managed in pairs in the horizontal direction.

Next, the CPU 1 cuts out the data in the frame memory 3 using the block number stored in the second buffer and sends it to the image coding unit 9. The image encoding unit 9 uses the CP
The data from U1 is compressed, source coded together with the corresponding block number, and sent to the communication unit 10. The communication unit 10 converts the data from the image encoding unit 9 into a transmission block suitable for the communication path and sends it to the communication path.

The communication unit 21 of the receiving device receives the data from the communication path, separates the encoded block number and the image encoded data from the transmission block, stores the encoded block number in the memory 22, and stores the image code. The decoded data is decoded by the image decoding unit 23. The decoded image data is CP
It is expanded to the address of the frame memory 24 obtained from the corresponding block number by U1. The display control unit 25
The image data stored in the frame memory 24 is displayed on the display unit 2.
Display in 6.

According to the present embodiment, image data of only a cutout area other than a rectangular area, for example, a triangular area or a circular area can be easily cut out, so that there is an effect that transmission can be performed efficiently. Further, if the communication unit 10 is replaced with a writing control unit for the recording device, it is possible to efficiently record only the necessary image data.

[0020]

According to the present invention, there is an effect that only a data portion desired to be transmitted or recorded is cut out and compressed, and efficient transmission / recording can be performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a cutting method that is a feature of the present invention.

FIG. 2 is a block diagram showing an embodiment of an image transmission device of the present invention.

FIG. 3 is an explanatory diagram of a cutout area specifying method.

FIG. 4 is a flowchart of a process of determining a designated cutout area.

FIG. 5 is an explanatory diagram of a first buffer that stores cut-out area addresses on a screen.

FIG. 6 is a diagram showing a correspondence between an address of a first buffer and a quantization block.

FIG. 7 is an explanatory diagram of a second buffer that stores start / end block numbers of a cutout area.

[Explanation of symbols]

 1 CPU 2 Image Input Section 3 Frame Memory 4 Handwriting Input Section 5 Memory 6 Display Control Section 7 Display 8 Memory 9 Image Encoding Section 10 Communication Section

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04N 1/41 Z 9365-5H G06F 15/62 322 B 15/66 470 A

Claims (4)

[Claims] 1. An original image to be cut out is displayed on a screen of a display means, and while observing a boundary line drawn on the screen by a pointing device, a part of the screen is surrounded by the boundary line to specify a cutout area, An image extracting / compressing method, wherein only image data in the cutout area is extracted from a frame memory for displaying an original image and compressed. 2. When specifying the cutout area, when the boundary line is not closed, by specifying which side of the boundary line is cut out, the area surrounded by the boundary line and the periphery of the screen is specified. The image extraction / compression method according to claim 1, wherein the extraction area is a cutout area. 3. An image transmission device for extracting and compressing image data using the image extraction / compression method according to claim 1 or 2, and transmitting the compressed data. 4. An image recording apparatus for clipping and compressing image data using the image extracting / compressing method according to claim 1 or 2, and recording the compressed data.