JP3069249B2 - Image cropping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image data processing for cutting out only a part of an image (hereinafter, referred to as a partial image) from an image, for example, cutting out only a person image from an image including a person. The present invention relates to an image clipping device for performing the following.

[0002]

2. Description of the Related Art In a conventional image clipping apparatus, a partial image is clipped by the following procedure. First, data of an original image (for a color image, four color plates of Y, M, C, and K) is stored in an image data memory. Next, the original image data is converted into image data for display display (R, G, B).
(For three colors) and stored in the display image data memory and displayed on the display. On the other hand, the window display circuit displays a small frame called a window at a position on the display where the operator points with a mouse or the like. The operator operates the mouse or the like to place this window on the boundary between the partial image to be clipped and other images (hereinafter, referred to as background images). Then, the boundary line determining circuit reads the display image data corresponding to the inside of the window from the image data memory, determines the temporary boundary line in the window according to a predetermined algorithm, and displays the temporary boundary line on the display. This provisional boundary line determination algorithm includes a method of separating display image data corresponding to the inside of a window into a partial image and a background image by a predetermined threshold value and determining a boundary line, and a method of determining a boundary line by a differential value of image data. Various methods have been considered, such as a method of determining (see, for example, JP-A-2-40777).

If the temporary boundary line temporarily determined by the boundary line determination circuit does not match the expected boundary line, the operator changes parameters such as threshold values and re-enters the boundary line generation circuit. To create a temporary boundary line. When the operator moves the window to another location when the temporary boundary line created by the boundary line creation circuit matches the boundary line expected by the operator, the temporary boundary line created at the position of the immediately preceding window Is determined as a final boundary line (hereinafter, this is referred to as a determination boundary line). Note that the decision boundary line is generally generated as vector data, and stored in the memory as clipping boundary line data corresponding to the original image data. In this way, when the operator traces all the boundaries of the partial image in the window and determines all the determined boundaries, the cut-out boundary data is completed. Then, if you want to extract only the cropped image data,
An image extraction circuit extracts the image data of the partial image from the original image data based on the cut-out boundary data.

[0004]

As described above, it is the operator who ultimately determines the temporary boundary line created by the boundary line creation circuit of the image clipping device as the decision boundary line. However, for example, in a case where only an image of an object is to be extracted from an image in which a portion of the object that is not exposed to light (hereinafter, this is referred to as a shade portion) and a shadow of the object, a boundary line determining circuit is provided. The temporary boundary line is displayed on the display according to the above algorithm, but it is difficult to determine whether or not the boundary line between the two portions is a desired boundary line on the display.

The present invention has been made to solve such a problem, and an object of the present invention is to make it easy for an operator to determine a boundary line in such a case. Another object of the present invention is to provide an image clipping device with improved display on a display.

[0006]

According to the present invention, which has been made to solve the above-mentioned problems, a window which is moved by an operator along a boundary of a partial image to be cut out while looking at an image displayed on a display. In an image cropping apparatus that creates cropping boundary data based on image data corresponding to the inside, a) an original image data memory that stores original image data of an image including a partial image to be cropped, and b) an original image data memory. A display image data memory for storing display image data corresponding to the stored original image data, c) display means for displaying the display image data on a display, and d) display window data from the display image data. A) a window image data memory for reading and storing window image data corresponding to Conversion characteristic determining means for determining data conversion characteristics, f) data conversion means for converting window image data according to the determined data conversion characteristics, and g) the display image by the window image data converted by the data conversion means. Display image data rewriting means for rewriting the data of the window image data read out on the data.

[0007] The conversion characteristic determining means may determine the data conversion characteristic based only on the window image data of the pixels in the window frame.

[0008]

The display image data memory stores display image data corresponding to the original image data stored in the original image data memory. The processing performed by each of the following units is performed on the display image data, and has no effect on the original image data in the original image data memory.

The display means displays the display image data stored in the display image data memory on a display. The operator positions the window at the boundary between the partial image to be clipped and another image while watching the image displayed on the display. When the position of the window is determined by the operator, display image data corresponding to the inside of the window is extracted as window image data and stored in the window image data memory. The conversion characteristic determining means, based on the window image data,
Determine data conversion characteristics.

Here, as the basic data for determining the data conversion characteristics, the window image data of all the pixels in the window may be used, or only the image data of the pixels in the window frame may be used. You may.

The data conversion means converts all window image data using the data conversion characteristics determined by the conversion characteristic determination means. The window image data after the data conversion is displayed in a window portion of the display by the window display means.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The image cutting device for plate making used in this embodiment is shown in FIG.
As shown in the figure, the input scanner 31 includes an image memory 33, a display memory 34, a save memory 36, a display control circuit 35, a color monitor 32, a CPU 40, and the like. The image memory 33 is connected to the input scanner 31 and the display memory 34
Is connected to the color monitor 32 via the display control circuit 35. The input scanner 31 and the display control circuit 35 are CPU
40, and operates under its control. The image memory 33, the display memory 34, and the save memory 36 are also C
Connected to PU40. CPU 40 and display control circuit 35
Between them, a window frame generation circuit 37, a temporary boundary line generation circuit 38, and a determined boundary line data creation circuit 39 are provided. A ROM 43 and a RAM 44 are connected to the CPU 40, and a keyboard 41 and a mouse 42 are connected as input devices.

A procedure for clipping an image by the image clipping apparatus having the above configuration will be described below. Here, it is assumed that the image 11 as shown in FIG. 1A is read by the input scanner 31 and stored in the image memory 33. The image to be clipped may be not only an image read by the input scanner 31 but also an image read from a medium such as an optical disk.

The image 11 is an image in a state where light is irradiated from the rear right of the ball 12, and there is a portion (shade portion) 12b on the near side of the ball 12 where light is not irradiated.
Further, a shadow 13 of the ball 12 is formed on the near side. In this embodiment, a case where only the ball 12 is cut out from the image 11 will be described.

The CPU 40 first reads out the data in the image memory 33 sequentially, converts the data into image data for color monitor display, and stores the image data in the display memory 34. When handling a color image, the image data in the image memory 33 is Y, M,
Since the data is stored for each of the colors C and K, the CPU 40 converts the data into data for each of the colors R, G and B suitable for display on the color monitor 32. In general, the image data for display has a lower resolution than the original image data. Therefore, if necessary, when the original image data is converted into the image data for display, the conversion of the resolution is also processed.

The display image data stored in the display memory 34 is displayed on the color monitor 32 by the display control circuit 35. The display on the color monitor 32 is also as shown in FIG. The window frame generating circuit 37 is configured as shown in FIG.
The data of the frame of the window 14 shown in (a) is generated and output to the display control circuit 35. The display control circuit 35 displays the frame of the window 14 by superimposing it on the image 11 on the color monitor 32 based on this data. The position of the window 14 is determined by the mouse 42 operated by the operator, and data on the position of the window 14 is supplied from the CPU 40 to the window frame generating circuit 37. The size of the frame of the window 14 is predetermined.

The general procedure of image clipping is as follows. The operator operates the mouse 42 to place the window 14 on the boundary 15 between the ball 12 to be cut out and other parts (that is, the outline of the ball 12). Then, the CPU 40 calculates the provisional boundary line 16 based on the data of the window image corresponding to the inside of the window 14 based on a predetermined algorithm. The temporary boundary line 16 is displayed in the window 14 by the temporary boundary line generation circuit 38. When the temporary boundary 16 displayed in the window 14 matches the desired boundary 15, the operator moves the window 14 to the next location. As a result of the movement of the window 14, the temporary boundary line 16 at the immediately preceding window position is set as the determined boundary line 17, is displayed in a manner superimposed on the image 11 on the color monitor 32, and is determined by the determined boundary line data creation circuit 39. The boundary data is stored in the RAM 44.

At this time, for example, the window 14 is shown in FIG.
As shown at 14a in FIG.
When placed on the border 15 between b and the light background,
The difference between the two parts is clear, and the operator
Can be easily determined whether or not the calculated temporary boundary line 16 matches the desired boundary line 15. However, as described above, when the window 14 has the ball 1
2 (FIG. 1B is a slightly exaggerated image in the window at this time), the provisional boundary line 16 and the desired boundary line are placed. In spite of the difference, the difference between the two parts 12b and 13 is actually unclear, so the operator determines whether or not the temporary boundary line 16 calculated by the CPU 40 matches the desired boundary line 15. It is difficult to judge. Window 14 is 1
The same applies to the case where the light source is placed between the light-exposed portion 12a and the bright background as shown in FIG. 4c.

Therefore, in the image clipping device of this embodiment,
By improving the display in the window 14 on the color monitor 32 according to the procedure shown in the flowchart of FIG. First, when the window frame generating circuit 37 moves the position of the window 14 in response to the operation of the mouse 42 by the operator (step S1),
The CPU 40 reads the window image data in the save memory 36 and restores the window image data to the original position in the display memory 34,
The window image data at the new window position is read from the display memory 34 and written to the save memory 36 (step S2). The save memory 36 is a memory provided to save window image data before performing various clarification displays as described below. That is,
The data was clearly displayed by the data in the display memory 34,
The display of the image in the window at the previous position is performed in the save memory 3
The original display is restored by restoring the window image data in 6. In addition, the determined boundary line data creation circuit 39 outputs the temporary boundary line 1 calculated last in the window 14 at the previous position.
6 is used as a decision boundary line 17 to generate decision boundary line data (vector data and the like) and store it in the RAM 44. Further, the CPU 40 restores the window image data at that time to a corresponding position in the display memory, and the determined boundary is displayed (step S3).

In the window position after the movement, the CPU 4
0 determines whether the current window display mode is mode 1 or not. In the image clipping device of the present embodiment, there are five types of window display modes of mode 1 to mode 5,
The operator sets one of them in advance. The contents of each mode are as follows.

Mode 1: Mode in which the display in the window is not changed Mode 2: Shadow area enhancement mode Mode 3: Middle area enhancement mode Mode 4: Highlight area enhancement mode Mode 5: Automatic adjustment mode

If it is determined in step S4 that the current window display mode is mode 1, the process immediately jumps to step S11, where the CPU 40 temporarily sets a temporary algorithm according to a predetermined algorithm based on the window image data corresponding to the inside of the window 14. A boundary line 16 is calculated. The calculation result is sent to the temporary boundary generation circuit 38, and the temporary boundary 16 is displayed in the window 14. When the temporary boundary line 16 does not match the correct boundary line 15, the operator changes the parameter from a keyboard or the like to change the C
The PU 40 draws another temporary boundary line 16 (step S1).
2 → S13). When the temporary boundary line 16 matches the correct boundary line 15, as described above, the operator moves the window 14 to another location, so that the temporary boundary line 16 becomes the determined boundary line 17 (step S12). → S14). Of course, the determination boundary line 17 may be determined by separately performing a keyboard operation or the like. Thereafter, it is determined whether or not the boundary line determination has been completed for all the boundary regions (step S15), and if not, the process returns to step S1.

If it is determined in step S4 that the current window display mode is not mode 1, the CPU
40 reads out the display image data in the window 14 from the display memory 34 and stores it in the work area 45 in the RAM 44 (step S5), and also saves it in the save memory 36 (step S6). The work area 45 in the RAM 44 corresponds to the window image data memory of the present invention, but is converted as needed as described later. And
Window display mode is mode 2, mode 3, mode 4
Is determined (step S7).
If the current window display mode is one of these three modes, the process proceeds to step S9, and the data conversion function corresponding to the window display mode is stored in the ROM 43.
And converts the display image data in the work area 45 by the conversion function.

FIGS. 2A to 2C show data conversion functions corresponding to each of the window display modes of Modes 2 to 4. As shown in FIG. 2A, the data conversion function 21 used in the case of the shadow area emphasis mode which is the mode 2 has a density difference in a portion (shadow area) where the value of the input display image data is 50% or less. Has been expanded. As shown in FIG. 2B, the data conversion function 22 used in the intermediate region emphasis mode, which is the mode 3, has a density in a portion (intermediate region) where the value of the input display image data is 25 to 75%. The difference is being widened. Further, as shown in FIG. 2C, the data conversion function 23 used in the highlight area emphasis mode, which is the mode 4, is a part where the value of the input display image data is 50% or more (highlight area). ) Increases the density difference. The data conversion function may be stored in the ROM 43 in the form of a function, or may be stored in the form of a replacement table. As the data conversion function, various functions can be set as required in addition to the smooth curve shown in FIG.

Next, the CPU 40 overwrites the window image data in the work area 45 converted by the corresponding data conversion functions 21, 22, and 23 into an area of the display memory 34 corresponding to the current position of the window 14. (Step S10). Thus, the display in the window 14 is rewritten on the color monitor 32.

If it is determined in step S7 that the current window display mode is mode 5 (automatic adjustment mode), the process proceeds to step S8, in which the CPU 40 selects one of the window image data held in the work area 45. , The image data of the pixel to be determined is extracted, and it is determined which of the modes 2 to 4 is appropriate based on the value of the image data. In this embodiment, in order to shorten the determination time, only the pixels on the outer peripheral portion of the window 14 (that is, the frame portion of the window 14) are set as the determination target pixels. When the calculation for the determination does not impose a burden on the CPU 40, all the pixels of the window image data may be set as the determination target pixels.

A specific method of determining the window display mode will be described with reference to the flowchart of FIG. First, the values of the RGB data of the pixel to be determined (these values are R, G,
B) is calculated based on the following formula (step S81).

L = ｛max (R, G, B) + min
(R, G, B)｝ / 2 (where max (R, G, B) is the maximum value among R, G, B, and min (R, G, B) is between R, G, B) Function that takes the minimum value of

The above equation is equivalent to the H used in the Munsell color system.
Although only the calculation formula of the lightness L is extracted from the SL color conversion, the lightness may be calculated by another method.

Next, for each pixel to be determined,
The calculated lightness L is divided into two reference lightness values L1 and L2 (however,
L1 <L2) (step S82). Then, the number [n] of pixels whose brightness L is lower than the reference brightness value L1 which is lower.
If (L <L1)] is equal to or more than ／ of the number N of all the determination target pixels, the display mode is set to mode 2 (shadow area emphasis mode) (steps S83 → S85). Also, the lightness L
Is the number of pixels [n (L
≧ L 2)], the display mode is set to mode 4 (highlight area emphasis mode) (step S 84 → S 87). If neither of the above two conditions is satisfied, the display mode is set to mode 3 (intermediate area emphasis mode) (step S8).
6).

As described above, in the case of the mode 5, the window display mode is specifically set to any one of the modes 2 to 4 based on the value of the display image data in the window 14. Thereafter, the CPU 40 converts the window image data held in the work area 45 according to the data conversion function corresponding to the set window display mode (step S9), and stores it in the area of the display memory 34 corresponding to the current window position. (Step S10). At this time, the CPU 40 serves as display image data rewriting means of the present invention. Thus, the display in the window 14 on the color monitor 32 changes according to the set window display mode, and is clarified.

For example, when the window 14 is currently at the position 14b, the ball 1 is displayed on the color monitor 32.
It is assumed that the boundary between the shade portion 12b and the shadow 13 is unclear. In this case, even if the temporary boundary line is different from the desired boundary line in the display as it is, the operator does not notice it and may use it as the determined boundary line. For it,
In the image cropping device according to the present invention, the display in the window 14 is changed so as to be clearer by setting the automatic adjustment mode. That is, in the window position 14b, [L <L in steps S82 and S83.
Since the number of pixels determined to be [1] exceeds 3/4 of the total, the display image data in the window 14 is converted by the data conversion function in the shadow area emphasis mode in FIG. Thereby, as shown in FIG. 1C, the difference in brightness between the shade portion 12b and the shadow 13 in the window 14 is enlarged, and the boundary 15 between the two portions 12b and 13 becomes clear. In this state, the temporary boundary line 16 does not coincide with the desired boundary line 15, and the operator changes the temporary boundary line 16 to the true boundary line 15, for example, by appropriately changing the above-described threshold value. It is possible to clearly determine whether or not there is. FIG. 1C shows a state in which the boundary line thus obtained is obtained. 1 in FIG.
4C, the same applies to the case where the window 14 is placed on the boundary 15 between the portion of the ball 12 where the ball 12 is exposed to light and the bright background. In this case, the highlight region emphasis mode shown in FIG. Window 14 by the data conversion function
Is converted, and the boundary between both parts is clearly displayed.

[0033]

For example, if the display image data in the window is entirely dark and the boundary between the part to be extracted and the other part does not clearly appear on the display, the image extracting apparatus according to the present invention employs both parts. The display image data in the window is converted so that the difference becomes clearer on the display. Thus, the operator can easily determine whether or not the temporary boundary line automatically created by the image extracting device is at the correct position. Similarly, when the display image data in the window is entirely bright or in other cases, the display on the display is converted by converting the window image data using a data conversion characteristic that eliminates obscurity. Clarify,
Help the operator decide.

The conversion characteristic determining means determines the data conversion characteristic not based on the window image data of all the pixels in the window but on the basis of only the window image data of the pixels in the window frame. By doing so, it is possible to reduce the calculation time until the data conversion characteristics are determined.

[Brief description of the drawings]

FIG. 1 is an overall view (a) of an image to be cut out in an embodiment, an enlarged view of an original display in a window (b), and an enlarged view of a display in a window after data conversion (c).

FIG. 2 is a graph of various data conversion characteristics.

FIG. 3 is a block diagram illustrating a configuration of an image clipping device according to the embodiment.

FIG. 4 is a flowchart of display clarification processing at the time of image clipping in the image clipping device of the embodiment.

FIG. 5 is a flowchart of a process for mode determination in an automatic adjustment mode.

[Explanation of symbols]

 11 ... Image 12 ... Ball 12a ... A part of the ball that is exposed to light 12b ... A part that is not exposed to the light of the ball (shade part) 13 ... A shadow of the ball 14 ... Window 15 ... A true boundary line (outline of the ball) 16 ... Temporary boundary line 17 ... Decision boundary line 21 ... Data conversion function in shadow area enhancement mode 22 ... Data conversion function in middle area enhancement mode 23 ... Data conversion function in highlight area enhancement mode 24 ... Curve data conversion function 31 ... Input Scanner 32 ... Color monitor 33 ... Image memory 34 ... Display memory 35 ... Display control circuit 36 ... Evacuation memory 37 ... Window frame generation circuit 38 ... Temporary boundary line generation circuit 39 ... Determined boundary line data creation circuit 40 ... CPU 41 ... Keyboard 42 ... Mouse 43 ... ROM 44 ... RAM 45 ... Work area (window image data memory)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F 1/00-1/16

Claims (2)

(57) [Claims] 1. An image cropping method for creating a cropping boundary data based on image data corresponding to an inside of a window which is moved along a boundary of a partial image to be cropped by an operator while watching an image displayed on a display. In the apparatus, a) an original image data memory for storing original image data of an image including a partial image to be clipped, and b) a display for storing display image data corresponding to the original image data stored in the original image data memory. A display image data memory; c) display means for displaying display image data on a display; d) a window image data memory for reading and storing window image data corresponding to the inside of the window from the display image data; ) A conversion characteristic determining means for determining a data conversion characteristic based on the value of the window image data; and f) the determined data. Data conversion means for converting the window image data according to the data conversion characteristics; andg) a display image for rewriting the data of the read window image data portion on the display image data by the window image data converted by the data conversion means. An image clipping device, comprising: data rewriting means. 2. The image clipping device according to claim 1, wherein the conversion characteristic determining means determines the data conversion characteristic based only on the window image data of the pixels in the window frame.