JPH01189776A - Picture processing method - Google Patents

Abstract

PURPOSE:To detect an edge at high speed and with high accuracy by a software by using the correction of a preceding detecting edge position as an estimated edge position at this time after the edge position is detected at the time of starting of a detection. CONSTITUTION:When the edge of an object 3 to be detected moving vertically 4 to the scanning direction 2 of a picture detecting camera 1 is detected based on a luminance signal from a camera 1, a picture is processed on all luminance data initially at the time of starting the detection. Then, after the edge is detected, the position obtained by adding a value obtained by multiplying the change speed to the camera scanning direction 2 of the edge position by a sampling time to precedingly detected edge position is considered to be the estimated edge position of this time to process the picture centering the said estimated edge position. The picture is processed to the data of an effective data width capable of being changed by the software centering the said estimated edge position, thereby, the correct edge position can be detected in a short time to have a similar effect to that when the picture processing is executed to all the data. Thereby, a high speed processing can be executed by the software processing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image processing method in a device that detects edges of a detection target based on a luminance signal from an image detection camera.

[Conventional technology]

Conventionally, in this type of device, the method of detecting the edge of a detection target from the luminance signal from the image detection camera is to convert the luminance signal from the image detection camera into an analog-to-digital format, which can then be read out again. The edge position of the object to be detected is detected by storing the data in memory and performing various image processing such as noise removal and edge enhancement processing on the total luminance data.

[Problem to be solved by the invention]

By the way, in the conventional method as described above, in order to detect the edges of the detection target, a large amount of luminance data is
Since image processing such as noise removal and edge enhancement processing was performed, there was a problem in that it required a large amount of processing time when processed using software. Therefore, when an object is moving at high speed, image processing is performed using hardware (
The method of configuring it with electronic circuits was generally used, but
This method has a problem in that it cannot adequately handle changes/additions to processing contents.

The present invention aims to provide a new image processing method that solves the above-mentioned problems regarding image processing of a detection target having a simple shape such as a strip.

[Failure to solve the problem]

Therefore, the image processing method of the present invention is applicable to a device that detects the edge of a detection target based on the luminance signal from the image detection camera while the detection target moves in a direction perpendicular to the scanning direction of the image detection camera. At the start of detection, image processing is first performed on all luminance data, and after an edge is detected, the next step is to calculate the value obtained by multiplying the previous edge position by the rate of change in the camera scanning direction at the same position multiplied by the sampling time. The added position is regarded as the current estimated edge position, and image processing is performed on data with an effective data width of 8 minutes, which can be changed by software, around the estimated edge position.

[Operation] Image processing such as noise removal and edge enhancement processing is originally performed to accurately detect the edges of an object, but it is not necessary to perform it on all luminance data input from the image detection camera. There is no need for it to be done. In particular, when the object has a simple shape such as a band, it is only necessary to perform the process on data in a limited range near the edge.

There is a sufficient brightness difference between the detection target moving perpendicularly to the scanning direction of the image detection camera and its surroundings, and the amount of movement of the detection target in the camera scanning direction is sufficient compared to the camera detection width. If the edge is small, image processing is first performed on all luminance data at the start of detection, and after the edge is detected, the sampling time is multiplied by the rate of change in the camera scanning direction of the previously detected edge position. The position to which the value has been added is regarded as the current estimated edge position, and image processing is performed on the data with an effective data width of 8 minutes, which can be changed using software, with the estimated edge position as the center. The edge position can be detected in a short time, the same effect as when image processing is applied to all data can be obtained, and the software processing can also realize sufficiently high-speed processing.

By extracting effective data from a large amount of digitally converted luminance data, it is possible to reduce the number of luminance data that is subject to image processing after extraction, and it is possible to perform image processing using software. Even in cases where the image processing speed is sufficiently high compared to the moving speed of the detection target,
Moreover, it is now possible to maintain the same edge detection accuracy as when conventional image processing is performed on all data.

〔Example〕

The image processing method according to an embodiment of the present invention will be explained below with reference to Fig. 1. Fig. 1 shows the positional relationship between the image detection camera and the object to be detected (band-shaped), and the scanning direction of the camera and the movement of the object to be detected. This shows the relationship in direction. In FIG. 1, 1 is an image detection camera, 2 is a camera scanning direction, 3 is an object to be detected, and 4 is a moving direction of the object to be detected.

Figure 2 is a graph of the luminance signal from the image detection camera 1 installed at the position shown in Figure 1 converted from analog to digital, with the scanning direction of the camera 1 as the horizontal axis and the luminance as the vertical axis. It is.

In FIG. 2, 5 indicates the current estimated edge position determined from the previous edge position and the rate of change of the edge position in the camera scanning direction, and N is the effective data width set by software. To explain the effect of the present invention while comparing it with the conventional technology based on these figures 1 and 2, the steeply sloped part (edge part) of the luminance shown in the graph of Fig. 2 is usually found in the luminance signal from the camera. It is unclear where it exists. Therefore, conventionally, total brightness data has been subjected to image processing. For this reason, if the data length of luminance data is 8 bits and the resolution in the scanning direction is 512 points, then if we take the average of 10 lines of data to remove noise, it will be 512 points.
2X8X10=5120byte (lbyte =8
bij) had to be processed, which was a factor slowing down the processing speed.

Therefore, in the present invention, image processing is performed on all luminance data at the start of edge position detection, and after the edge position is detected, the previous edge position and the rate of change in the scanning direction of the edge position are multiplied by the sampling time. The current estimated edge position (5 in Figure 2) is assumed to be the current estimated edge position, and image processing is performed only on the luminance data for the effective data width N, which can be changed by software, with the estimated edge position as the center. The luminance data to be detected can be reduced by N x 2"i!, which is calculated based on the moving speed of the object to be detected in the scanning direction. Sufficient processing speed can be obtained even when processed by software, and edge detection accuracy can also be achieved. It is possible to maintain the same accuracy as when conventional image processing is applied to all luminance data.

〔Effect of the invention〕

As described above, according to the image processing method of the present invention, the following effects can be obtained.

(1) In the method of the present invention, in order to detect the edge of a detection target moving in a direction perpendicular to the scanning direction of the image detection camera, the previous detection edge position and the camera scanning direction of the edge position are By using the estimated edge position that has been corrected according to the rate of change as the current estimated edge position and performing image processing on only the luminance data for the valid data width N with the estimated edge position as the center, high-speed and high-accuracy edge positioning can be achieved using software. This made detection possible.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the relative arrangement of an image detection camera and a detection target according to an embodiment of the present invention, and FIG. 2 shows a luminance signal from the image detection camera converted from analog to digital. It is a graph explanatory diagram showing the scanning direction of the camera as the horizontal axis and the luminance as the vertical axis. 1... Image detection camera, 2... Camera scanning direction,
3... Detection target object, 4... Detection target object moving direction, 5
...Estimated edge position, N...Valid data width.

Claims (1)

[Claims] 1. In a device that detects the edge of a detection target based on a luminance signal from an image detection camera while the detection target moves in a direction perpendicular to the scanning direction of the image detection camera, After performing image processing on all luminance data and detecting edges, the next estimated edge position is the previous edge position plus the value obtained by multiplying the rate of change in the camera scanning direction at the same position by the sampling time. An image processing method characterized in that image processing is performed on data having an effective data width N that can be changed by software, with the estimated edge position as the center, which is regarded as a position.