CN1175317C - camera magnification correction method - Google Patents

Abstract

A camera magnification correction method, capture a fixed distance correction sample image with the camera, move the zoom lens to the marginal end and carry out the automatic focusing of the correction sample first, in moving the zoom lens and increasing the process of the magnification, calculate the evaluation value of the image data captured in CCD sampling area; carrying out automatic focusing when the evaluation value suddenly drops, and then continuously moving the zoom lens to increase the magnification and calculate the evaluation value; and recording the position of the zoom lens when all the evaluation values suddenly drop, wherein the position is the position which is required by the stepping motor or the voltage motor to drive the zoom lens to reach when the magnification is reached.

Description

Camera magnification correction method

technical field

The present invention relates to a camera magnification correction method, especially to automatically and rapidly correcting the camera magnification.

Background technique

The autofocus device of a general digital camera or a traditional optical camera uses a stepping motor (Pulsemotor) or a voltage motor (Dc motor) to drive the zoom lens to move to the focusing position to obtain a clear image. When obtaining an image with a certain magnification, it is necessary to calibrate the camera magnification first, so as to know the position where the zoom lens needs to be moved to obtain an image with this magnification. The position data of the zoom lens can be used to drive the zoom lens to move It is represented by the number of steps of the stepping motor or the voltage value of the voltage motor.

The previous calibration method of camera magnification is to move the zoom lens to the edge to capture the corrected image in Figure 10 as shown in Figure 1, and adjust the distance between the camera and the corrected figure 10 so that the outer frame 11 of the corrected image in Figure 10 is exactly at the On the frame of the image display screen, fix the distance between the camera and the correction figure 10; manually control the stepping motor or voltage motor to drive the zoom lens to move, so that the middle frame 12 or inner frame 13 of the correction figure 10 is just at the frame of the image display screen On the screen, record the number of steps of the stepping motor, or the voltage value of the voltage motor, and you can confirm the number of steps the stepping motor needs to turn, or the voltage value of the voltage motor when the camera is at a certain magnification. Move the zoom lens to a position where that magnification is obtained. The manual correction of camera magnification described above is quite time-consuming and prone to human error, making the correction of magnification inaccurate. There is another way to correct the magnification of the camera using optical instruments, which requires equipment with optical instruments, and its cost is relatively high. In order to solve the problem of requiring equipment and funds when using optical instruments for camera magnification correction, or the problem that manual correction is time-consuming and prone to errors, the inventor finally completed the present invention after repeated research.

Contents of the invention

The main purpose of the present invention is to provide a camera magnification calibration method, which can conveniently, time-saving and correct calibrate the camera magnification.

A method for correcting camera magnification of the present invention is characterized in that it comprises the following steps:

A. Move the zoom lens to the edge, capture the image of the calibration sample and perform focusing;

B. Move the zoom lens to change the magnification, and calculate the evaluation value of the image data captured by the CCD sampling area;

C. When detecting a sudden drop in evaluation value, record the position of the zoom lens and perform focusing; and

D. Repeat steps B and C to record the position of the zoom lens when all evaluation values suddenly drop;

Wherein the position of the zoom lens is indicated by the number of rotation steps of the stepping motor driving the zoom lens.

A method for correcting camera magnification of the present invention is characterized in that it comprises the following steps:

A. Move the zoom lens to the edge, capture the image of the calibration sample and perform focusing;

B. Move the zoom lens to change the magnification, and calculate the evaluation value of the image data captured by the CCD sampling area;

C. When detecting a sudden drop in evaluation value, record the position of the zoom lens and perform focusing; and

D. Repeat steps B and C to record the position of the zoom lens when all evaluation values suddenly drop;

The position of the zoom lens is represented by the voltage value of the voltage motor driving the zoom lens.

Wherein moving the zoom lens in the step B is to increase the magnification.

Description of drawings

For other purposes, effects and embodiments of the present invention, please refer to the drawings and detailed descriptions as follows, wherein:

FIG. 1 is a schematic diagram of an existing camera magnification correction map;

Fig. 2 is a schematic diagram of a camera magnification correction sample of the present invention;

Figure 3 is a schematic diagram of the image of the calibration sample enlarged by the camera;

Figure 4 is a schematic diagram of the blurred image of the calibration sample enlarged by the camera and not yet in focus;

FIG. 5 is a schematic diagram of the relationship between the evaluation value of the CCD sampling area and the position of the zoom lens.

Detailed ways

The present invention utilizes the sample correction shown in Figure 2 for the CCD sampling area of the digital camera to capture its image, and can obtain a clear image as shown in Figure 3 when focusing; when moving the zoom lens to increase the magnification, when not focusing , the image shown in Figure 4 is captured by the CCD sampling area, and the edges of its black stripes will be blurred (indicated in gray), and its visible range will gradually decrease; calculate the captured image of the CCD sampling area during the movement of the zoom lens Taking the evaluation value of the image data, the evaluation value of the focused image as shown in Figure 3 is relatively large, and in the process of increasing the magnification and not yet in focus, as shown in Figure 4, the image whose black stripe edge is gradually blurred has a higher evaluation value. The value will gradually decrease, and when the magnification increases until the outermost black-and-white boundary exceeds the sampling area, the evaluation value will suddenly drop. At this time, the position of the zoom lens is the position where the magnification is required to be recorded. Please refer to the schematic diagram of the relationship between the evaluation value of the CCD sampling area and the position of the zoom lens shown in Figure 5, where the evaluation value of the zoom lens drops suddenly at positions a and b, that is, the position where the camera can obtain images of certain two magnification ratios.

The camera magnification correction method of the present invention comprises the following steps:

A. Move the zoom lens to the edge, capture the image of the calibration sample and perform focusing;

B. Move the zoom lens to increase the magnification, and calculate the evaluation value of the image data captured by the CCD sampling area;

C. When detecting a sudden drop in evaluation value, record the position of the zoom lens and perform focusing; and

D. Repeat steps B and C to record the position of the zoom lens when all evaluation values suddenly drop.

The above method can use the internal micro-processing of the camera to calculate the evaluation value, and detect and record the position of the zoom lens when all the evaluation values suddenly drop, and automatically perform the correction of the magnification, without manual operation and correction, and without the need for other optical instruments Assisted, you can correct and quickly correct the camera magnification, and you can get the correct position of the zoom lens at a certain magnification.

If a general camera is equipped with a CCD, when the evaluation value of the image data captured by the CCD sampling area can be calculated, the method of the present invention can also be applied to correct the magnification of the general camera. The present invention can also record the number of rotation steps of the stepping motor, or the voltage value of the voltage motor instead of recording the position of the zoom lens, and can also make the stepping motor rotate a certain step, or when the voltage motor is at a certain voltage value, the The zoom lens is moved to a position where a certain magnification can be obtained, so that the camera can obtain an image with the required magnification. The invention can use different calibration samples to correct different magnifications, and can move the zoom lens to perform corrections of different magnifications by reducing the magnification.

The content described above is only the embodiment of the present invention, and any modifications and changes made by using the present invention belong to the patent scope claimed by the present invention, and are not limited to the content disclosed in the embodiment.

To sum up, the present invention is completely different from the correction method of the existing camera magnification, and has the enhancement of efficacy, which meets the conditions of the invention patent, so the patent is applied for according to the law.

Claims (3)

1, a kind of bearing calibration of amplifying ratio of camera is characterized in that, comprises the steps:

A, make zoom lens move to marginal end, the image of acquisition calibration samples is also carried out focusing;

B, zoom lens motionless zoom lens change magnification, and the evaluation of estimate of calculating CCD sampling area institute pick-up image data;

C, when detecting evaluation of estimate and descending suddenly, focusing is also carried out in the position of record zoom lens; And

D, repeating step B, C, the position of zoom lens when writing down all evaluations of estimate and descending suddenly;

Wherein the position of this zoom lens is to represent with the rotation step number of the step motor that drives zoom lens.

2, a kind of bearing calibration of amplifying ratio of camera is characterized in that, comprises the steps:

A, make zoom lens move to marginal end, the image of acquisition calibration samples is also carried out focusing;

B, zoom lens motionless zoom lens change magnification, and the evaluation of estimate of calculating CCD sampling area institute pick-up image data;

C, when detecting evaluation of estimate and descending suddenly, focusing is also carried out in the position of record zoom lens; And

D, repeating step B, C, the position of zoom lens when writing down all evaluations of estimate and descending suddenly;

Wherein the position of this zoom lens is to represent with the magnitude of voltage of the voltage motor that drives zoom lens.

3, the bearing calibration of amplifying ratio of camera according to claim 1 and 2 is characterized in that, wherein zoom lens motionless zoom lens is to increase magnification among this step B.

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