KR940013153A - Camcorder auto focusing device and method - Google Patents

Abstract

The present invention relates to an auto focusing device and a method for automatically adjusting lens focus in a camcorder.

The conventional camcorder auto focusing apparatus and method need to spend a lot of time for the control of the lens driving motor, which requires a separate dedicated microcomputer, which complicates the circuit configuration, and passes a series of vertices after the vertex for focusing. Since the operation is repeated, the image change caused by the overshoot appears to be visually burdened, and the focusing time becomes long.

The present invention tracks and monitors the sweep of the detection data caused by the lens motor driving during focus adjustment to determine the inclination, and changes the filter before reaching the peak while controlling the lens motor driving speed variably according to the inclination. It is possible to adjust the focus at high speed while proceeding with the adjustment, to prevent unnecessary overshoot images, and to provide a simple circuit configuration auto focus control device and method, which is applied to the camcorder.

Description

Camcorder auto focusing device and method

As this is a public information case, the full text was not included.

4 is a block diagram of a camcorder automatic focusing apparatus of the present invention,

5 is a flowchart of a method for automatically focusing a camcorder according to the present invention;

6 is a graph showing an automatic focus adjustment process of the present invention;

7 is a flowchart of an embodiment of the automatic focus adjustment method of the present invention.

Claims (5)

A high pass filter 13 and 14 for filtering the amplified image signals photographed by the subject with different characteristics, and a screen splitter and a digital integrator which selects the filtered image signals and performs screen division and digital integration. 15), a low pass filter 16 for low pass filtering the selected signal, an A / D converter 17 for converting the filtered video signal into a digital signal and supplying it to the integrator, and monitoring the digital video signal level. Automatic focusing of a camcorder comprising a microcomputer 18 that performs lens motor driving control to a vertex, and a lens motor driving unit 12 that drives and controls the lens 1 under the control of the microcomputer 18. Regulator. A first step of driving the lens driving motor to determine the inclination while moving to the peak of the detected image signal level, and variably controlling the moving speed to the vertex according to the determined inclination; Compare the set value to detect whether the vertex is reached near the vertex, select the sharply filtered detection image signal for fine focus at the point of decreasing below the set value, and change the lens driving motor to 1 step / feed. And a second step of searching, and a third step of checking a peak and monitoring whether the peak is changed by reciprocating the front / rear points of the found vertex in the process. The method of claim 2, wherein the first process compares the magnitude of the current input data and the previous input data of the detected image signal, and reverses the driving direction of the lens driving motor if the current input data> previous input data. For the previous input data, the process of calculating the slope by dividing the difference between the current input data and the previous input data by the moving speed and comparing the calculated slope with a set value set to detect whether the vicinity of the vertex is reached before passing the vertex. And if the slope calculated as a result of the comparison is greater than or equal to the set value, driving the moving speed to the vertex at a high speed until reaching the set value and decelerating and moving as the set value is approached. Auto focusing method of the camcorder consisting of. The method of claim 2, wherein in the second process, when the inclination calculated in the first process is equal to or less than a predetermined set value, the filter output image signal having a sharp filtering characteristic near a vertex is selected as detection data and the speed of the lens driving motor is set. The step of calculating the reference value of the vertex search from the current input data after changing to one step / feed, and comparing the difference between the calculated reference value and the current input data and the previous input data until the difference value is greater than the reference value The automatic focus adjustment method of the camcorder consisting of the steps of increasing the vertex position counter value while repeating the procedure. 3. The method of claim 2, wherein the third process comprises: comparing the input data difference value closer to the reference value of the vertex search with respect to the vertex found in the second process; and if the difference value is equal to or greater than the reference value, driving the lens. A method for automatically focusing a camcorder comprising reversing the driving direction of a motor, moving a lens by a vertex position counter value, and setting a vertex check mode. ※ Note: This is to be disclosed by the original application.