JPH0583859U - Image target detection device - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain an image target detecting device capable of stably detecting a target even when the shape of the image of the target is different from the shape of the local region provided for measuring the density of the target. [Structure] First storage means 10 for storing pixel densities of a plurality of screens, second storage means 11 for storing pixel densities in a local area on a plurality of screens, and a plurality of screens on a plurality of screens. A third storage unit 12 for storing the densities of pixels in another same local area, a first order conversion unit 13, a first selection unit 14, a second order conversion unit 15, and a second order conversion unit 15. A selection unit 16, a subtraction unit 17, and a threshold value processing unit 6 are provided. [Effect] Eliminating the influence of noise that suddenly occurs on each screen, eliminating the influence of background pixels in the area provided for target density measurement, and eliminating the effect of background pixels in the area provided for background density measurement. The target object can be detected stably by eliminating the influence of the target pixel of.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an image target detecting device for detecting a target having a specific size from an image.

[0002]

[Prior Art]

 FIG. 2 is a block diagram of a conventional image target detection apparatus. In the figure, 1 is a fourth storage means for storing the density of pixels in a local area on the screen, and 2 is another local area on the screen. Fifth storage means for storing the densities of the pixels in the area, 3 is an output of the fourth storage means and is a first multiplication means for multiplying the density by a weighting coefficient, and 4 is an output of the fifth storage means. Is multiplied by a weighting coefficient by a second multiplication means, 5 is addition means for adding the output of the first multiplication means and the output of the second multiplication means, and 6 is a threshold for thresholding the output of the addition means. It is a value processing means.

Next, the operation will be described. FIG. 3 is a diagram showing a screen, 7 is a local area stored by the fourth storage means, 8 is a local area stored by the fifth storage means, and 9 is an image of a target to be detected. .. The fourth storage means 1 and the fifth storage means 2 scan the local area to be stored on the screen as shown in FIG. 3 while inputting the pixel densities in the order of raster scanning. The local area 8 is set so as to surround the local area 7. The first multiplication means 3 is provided in the local area 7 output from the fourth storage means 1 so that the average value of the density of the local area 7 is obtained when the density is added in the addition means of the next stage. Multiply the density of a pixel by a weighting factor. The second multiplication means 4 outputs the fifth storage means 2 so that a value obtained by multiplying the average value of the densities of the local regions 8 by -1 is obtained when the densities are added by the addition means of the next stage. The density of the pixel in the local area 8 is multiplied by a weighting coefficient. The adding means 5 adds the output of the first multiplying means 3 and the output of the second multiplying means 4 to obtain a value obtained by subtracting the average value of the densities of the local regions 7 from the average value of the densities of the local regions 7. Will be output. The output of the adding means 5 is thresholded by the threshold processing means 6, and if the output of the adding means 5 exceeds the threshold value, the threshold value processing means 6 outputs "1", otherwise. Outputs "0". When the local area 7 stored in the fourth storage means moves on the screen and overlaps the image 9 of the target object, if the size of the local area 7 is about the same as the size of the image 9 of the target object, Since the average value of the densities of the local area 7 becomes larger than the average value of the densities of the local area 8, it is assumed that the target object is present when the output of the threshold processing means 6 is "1". A target of a specific size can be detected from inside.

[0004]

[Problems to be solved by the device]

 Since the conventional image target detecting apparatus is configured as described above, when the shape of the image 9 of the target object differs from the shape of the local area 7 stored in the fourth storage means as shown in FIG. The average of the densities of 1 and 2 becomes small due to the influence of the background density, and the average of the densities of the local regions 8 becomes large due to the influence of the target density. At this time, the average of the densities of the local regions 7 is not sufficiently larger than the average of the densities of the local regions 8, so that the output of the adding means 5 does not exceed the threshold of the threshold processing means 6 and the target There was the problem of detecting and making mistakes.

The present invention has been made in order to solve the above problems, and even when the shape of the local area 7 is different from the shape of the image 9 of the target object, the target having the same size as the local area 7 is obtained. An object is to obtain an image target detecting device capable of stably detecting an object.

[0006]

[Means for Solving the Problems]

 The image target detecting device according to the present invention is provided with a storage means for simultaneously storing the densities of pixels in the same local area on a plurality of screens, and as a means for outputting a representative value of the densities in the local areas on the screen. An order conversion means for arranging the densities in descending order, a selection means for receiving the output of the order conversion means and outputting densities of a predetermined rank, and a subtraction means for subtracting the representative values of the densities of the two local regions are provided. It is a thing.

[0007]

The image target detecting apparatus according to the present invention inputs the densities of local regions over a plurality of screens, rearranges the densities in descending order as representative values of the densities of local regions, and outputs the densities in a predetermined order. Since the representative values of the densities of the two local regions are subtracted, the influence of background pixels in the region provided for the target concentration measurement is eliminated while eliminating the influence of noise that suddenly occurs on each screen. The target object can be detected stably by eliminating the influence of the target pixel in the area provided for measuring the background density.

[0008]

【Example】

 Embodiment Next, an embodiment of the invention will be described with reference to the drawings. In FIG. 1, 10 is a first storage means for storing the densities of pixels on a plurality of screens, 11 is a second storage means for simultaneously storing the densities of pixels in the same local area on a plurality of screens, 12 Is a third storage means for simultaneously storing the densities of pixels in another same local area on a plurality of screens, and 13 is a first order conversion for receiving the output of the second storage means and rearranging the densities in descending order. Means, 14 is first selection means for receiving the output of the first order conversion means and outputting the densities of a predetermined rank, and 15 is a second order for receiving the output of the third storage means and rearranging the densities in descending order. Conversion means, 16 is second selection means for receiving the output of the second order conversion means and outputting the density of a predetermined rank, and 17 is a subtraction for subtracting the output of the second selection means from the output of the first selection means. Means, 6 thresholds the output of the subtraction means It is a threshold processing hand stage.

Next, the operation will be described. The first storage means 10 stores the pixel densities for a plurality of predetermined screens while inputting the pixel densities in the order of raster scanning. The second storage unit 11 inputs the densities of pixels of a plurality of screens in the order of raster scanning and simultaneously stores the densities of pixels in the same local area on a plurality of screens. The third storage means 12 stores the densities of pixels in a plurality of screens at the same time while inputting the densities of pixels in a plurality of screens in the order of raster scanning. The local area to be stored is scanned on the screen as shown in FIG. The local area stored by the third storage means is set so as to surround the local area stored by the second storage means. The first order conversion means 13 rearranges the densities of the pixels in the local area output from the second storage means 11 in descending order, and the first selection means 14 selects the densities in a predetermined order. Output. When the local area 7 moves on the screen and overlaps the image 9 of the target object, it is output even if the background pixel exists in the local area 7 provided for measuring the target density as shown in FIG. If the order of the densities is set appropriately, the output of the first selecting means 14 is not affected by the densities of the background pixels. Further, since the densities of pixels in the local area are input over a plurality of screens, it is possible to eliminate the influence of noise that suddenly occurs on each screen. For example, if the rank of the density to be output is set to 1/2 of the number of pixels in the local area 7, most of the pixels in the local area 7 are pixels constituting the target. The output of the selection means of 1 becomes the target density. Next, the second order conversion means 15 rearranges the densities of the pixels in the local area output by the third storage means 12 in descending order, and the second selection means 16 sets the density of a predetermined rank. Select and output. When the local area 7 moves on the screen and overlaps the image 9 of the target, even if the target pixel exists in the local area 8 provided for measuring the background density as shown in FIG. 4, it is output. If the order of the densities is set appropriately, the output of the second selecting means 16 will not be affected by the densities of the target pixels. In addition, since the pixel density in the local area is input over multiple screens, it is possible to eliminate the effect of noise that suddenly occurs on each screen. For example, if the output density order is set to 1/2 of the number of pixels in the local area 8, most of the pixels in the local area 8 are pixels that form the background. The output of the second selection means is the background density. The output of the subtracting means 17 for subtracting the output of the second selecting means 16 from the output of the first selecting means 14 is thresholded by the threshold processing means 6 so that the output of the subtracting means 17 becomes the threshold value. If the threshold value is exceeded, the threshold value processing means 6 outputs "1", and otherwise outputs "0". As described above, when the local area 7 stored in the second storage means 11 moves on the screen and overlaps the image 9 of the target object, the size of the local area 7 becomes the same as the size of the image 9 of the target object. As long as the shape of the image 9 of the target differs from the shape of the local region 7 as shown in FIG. 4, the output of the first selecting unit correctly represents the target density and the output of the second selecting unit Since the output correctly represents the density of the background, when the output of the threshold value processing means 6 is "1", it is considered that the target exists, so that the target of a specific size can be stably detected from the image. You can

[0010]

[Effect of the device]

 As described above, according to the present invention, the densities of local regions are input over a plurality of screens, the densities are rearranged in descending order as representative values of the densities of local regions, and the densities of a predetermined rank are output. Since the representative values of the densities of the local areas are subtracted, the effect of background pixels in the area provided for the target density measurement is eliminated while eliminating the effect of noise that suddenly occurs on each screen. The target object can be stably detected by eliminating the influence of the target pixel in the area provided for measuring the background density.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional embodiment.

FIG. 3 is a diagram showing a screen.

FIG. 4 is a diagram illustrating a problem.

[Explanation of symbols]

 6 Threshold value processing means 10 1st storage means 11 2nd storage means 12 3rd storage means 13 1st order conversion means 14 1st selection means 15 2nd order conversion means 16 2nd selection means 17 Subtraction means

Claims (1)

[Scope of utility model registration request] 1. An image target detecting apparatus for detecting a target object having a specific size from an image, wherein a first storage means for storing the densities of pixels of a plurality of screens and the same local area on a plurality of screens. Second storage means for simultaneously storing the densities of pixels inside the same, and third storage means for simultaneously storing the densities of pixels within another same local area on a plurality of screens;
First order conversion means for receiving the output of the storage means and arranging the densities in descending order, and first selecting means for receiving the output of the first order conversion means and outputting the densities of a predetermined rank,
Second order conversion means for receiving the output of the third storage means and rearranging the densities in descending order; and second selection means for receiving the output of the second order conversion means and outputting the densities of a predetermined rank. An image comprising: subtraction means for subtracting the output of the second selection means from the output of the first selection means; and threshold processing means for thresholding the output of the subtraction means. Target detection device.