CN110887455A

CN110887455A - Tree electronic altimeter jitter error eliminating method based on mode

Info

Publication number: CN110887455A
Application number: CN201911186459.4A
Authority: CN
Inventors: 李建华; 谢晓宇; 倪瑞强
Original assignee: Shandong Agricultural University
Current assignee: Shandong Agricultural University
Priority date: 2019-11-20
Filing date: 2019-11-20
Publication date: 2020-03-17
Anticipated expiration: 2039-11-20
Also published as: CN110887455B

Abstract

The invention discloses a mode-based method for eliminating treetop jitter error. According to the method, through the application of delay measurement, automatic counting, mode calculation and programming processing technologies, in the actual measurement process aiming at the tip angle, the trunk distance and the base angle respectively, a certain number of instantaneous parameters are measured respectively to form a parameter group, then the mode is calculated for the parameter group, and then the mode is substituted into a model formula by taking the mode of the parameter group as an ideal parameter to calculate the height of the tree. The method utilizes the mode principle to automatically eliminate the jitter data by a program, improves the determination precision, has low cost and feasible method, and also plays a certain reference role in the aspect of error elimination design of other related measuring instruments.

Description

Tree electronic altimeter jitter error eliminating method based on mode

Technical Field

The invention belongs to the technical field of tree electronic height measurement, and particularly relates to a method for eliminating dithering errors of a tree electronic height meter based on a mode, which is solved by means of a software technology.

Background

At present, height meters used in forestry, whether mechanical or electronic, are designed according to the tangent theorem of trigonometric relation, and the basic principle and algorithm thereof is h-Ltan a (fig. 4), and the general principle and algorithm thereof is h-L (tan α + tan β) (fig. 5). therefore, one more β angle parameter is added in the general algorithm, because fig. 4 is only an ideal state, and in actual situations, people cannot lie on water like fig. 4Measuring on a flat ground; due to the high forest density and uneven ground, the most appropriate measurement method is only to divide the tree height h into h by a horizon line as shown in fig. 5₁And h₂The two parts are measured respectively and finally pass through h₁+h₂The method of (1) calculates the total height h of the tree.

As a theoretical basis and a practical basis for tree height measurement, the method and the process are realized by a tree electronic height measuring instrument which integrates laser distance measurement, angle sensing and program calculation. When the electronic height indicator for trees is used for height measurement, the tree height value can be directly displayed through the display screen only by aiming at the treetop, the trunk and the tree base respectively and pressing the keys to acquire data, so that the electronic height indicator for trees is a rapid and efficient future height measuring instrument. However, although the scientific and technological advantages of the tree electronic altimeter are obvious, the products of the tree electronic altimeter have been on the market for more than ten years, but the popularization and application of the tree electronic altimeter are very slow. The reason is mainly because the design and manufacture of the tree electronic altimeter only pay attention to the basic principle and appearance in the past, but the research on countermeasures is lacked in the aspects of user experience, convenience, error elimination and precision improvement, so that the basic level investigators lack trust and are unwilling to use the tree electronic altimeter.

In order to change the situation, a patent application (201921447957.5) of a three-key type tree electronic height measuring instrument is proposed in 2019, namely xueyu, li jianhua and the like, and a three-key control technology is adopted, so that the usability, the credibility and the reliability of the tree electronic height measuring instrument are greatly improved, and a good technical support is provided for the updating and updating of the tree electronic height measuring instrument in the forestry industry.

Disclosure of Invention

Aiming at the problems, the invention discloses a mode-based method for eliminating treetop jitter errors. The method solves the problem by taking time delay measurement, automatic recording, mode calculation and logic programming as lines, and comprises the following specific steps:

(1) aiming at a target, pressing a measuring button, and keeping the measurer in an aiming state for a period of time t in situ;

(2) in time t, the measuring circuit continuously and automatically acquires n instantaneous readings, the interval time is t/n, and the acquired n instantaneous readings are automatically stored as a measured value array;

(3) calculating the mode of the measurement value array;

(4) taking the obtained mode as an ideal measurement value;

(5) after the ideal measured values of the tip angle α, the trunk distance L and the base angle β are respectively and completely obtained according to the steps, a subsequent calculation program is started, the tree height is calculated according to the mathematical method of the formula h-L (tan α + tan β), and the measurement process is completed.

In the invention, the t value setting of the 'measurer keeps the aiming state for a period of time in situ' is related to the sensitivity and the precision of the used hardware, and the t value range can be set between 1 and 3 seconds under the prior art condition. In addition, in the invention, a buzzer is arranged in the height indicator, and the height indicator can synchronously emit buzzing prompt sound which is working within a period of measurement time t when the measurer keeps the aiming state in situ.

Theoretical explanation about the use of the mode for the elimination of the jitter error of the tree electronic altimeter:

(1) because the hand-held shaking phenomenon objectively exists, parameter measurement errors are inevitable when the hand-held electronic tree height indicator carries out one-time aiming measurement, and the traditional instrument cannot solve the problem;

(2) if the measurement is changed to a continuous measurement within a period of time t, and the computer automatically collects n data within the period of time t, the interval time is t/n, then it will be found that: as long as the surveyor aims at the target and does not move all the time t, the n data continuously collected by the computer have jitter change, but the most frequent data is the target value (or the data interval extremely close to the target value) required by the surveyor, because the target | is the target when the surveyor tries to aim in the time t!

(3) Even if slight deviation of the aiming position exists when the target is aimed, the deviation is inevitable in the handheld state, and the mode can still reflect the optimal measuring position and parameter measuring result in the handheld state;

(4) the mode method can thoroughly solve accidental errors caused by handheld shaking in the conventional measurement, because the measured value with large deviation cannot become a mode when a measurer carefully aims, and can be automatically rejected by an algorithm.

Compared with the prior art, the key point of the invention is that the problem of hand-held shaking error of the tree electronic height indicator is solved by using a mathematical algorithm, the technology can be used for the traditional single-key tree electronic height indicator and a new generation of three-key tree electronic height indicator, and has the outstanding advantages of low cost and easy realization as a pilot technology for improving the performance of the tree electronic height indicator because no special requirements are required on hardware.

Drawings

FIG. 1 is a schematic side view of an electronic altimeter in accordance with the present invention;

in FIG. 1, 1-tip angle (α) key, 2-stem length (L) key, 3-base angle (B) key, 4-measurement circuitry, 5-buzzer, 6-handle;

FIG. 2 is a right side view of FIG. 1; displaying the structure of the display screen and the positions of an on-off key and a tree height key;

FIG. 3 is a logic block diagram of the method for eliminating dithering errors of the tree electronic altimeter based on the mode, which is disclosed by the invention, and shows the working process of tree altimeter, and the processes of obtaining an array, solving the mode and assigning the array to corresponding α, L and β as ideal values in the measuring process of a tip angle (α), a trunk distance (L) and a base angle (β);

FIG. 4 is a basic schematic diagram of tree height measurement;

FIG. 5 is a diagram of the tree height measurement process, showing the process of measuring the tree height by dividing the tree height into two parts according to the horizontal line of sight.

In fig. 4 and 5: o-measuring point; ab (h) -tree height; AC (h)₁) -a height above the horizon; CB (h)₂) -a height below the horizon.

Detailed Description

The following description of the present invention is provided in connection with the accompanying drawings.

1. Referring to fig. 1, the implementation of the present invention still depends on the tree height measuring instrument of the prior art as a basis, and although the main subject of the present invention is a program control problem, since the intermediate process needs to temporarily collect and temporarily store a large amount of data, the problem of increasing data storage units should be properly considered when configuring the measurement circuit system (4), and the capacity is preferably 20000 tree height data.

2. A buzzer (5) is additionally arranged in the height indicator and is electrically connected with the measuring circuit system (4) at the same time.

3. The program is written according to the logic block diagram shown in fig. 3 and implements the following functions:

(3) calculating the mode of the measurement value array;

(4) taking the obtained mode as an ideal measurement value;

In the program design, the t value setting of the 'measurer keeps the aiming state for a period of time in situ' is related to the sensitivity and the precision of the used hardware, and under the condition of the prior art, the t value range can be set between 1 and 3 seconds.

In addition, the programming should make the buzzer (5) sound synchronously within t time after the measurer presses the key, so as to remind the height indicator to automatically measure and count within the time, and the measurer must keep the corresponding time of the measuring state carefully.

The application method of the tree electronic altimeter manufactured by the invention comprises the following steps:

1. selecting a survey station location (see fig. 5):

firstly, selecting a measuring point O beside a measured tree (according to the traditional tree measurement requirement, in order to reduce the measurement error, the distance from the point O to the trunk should be as close to the tree height as possible during point selection);

2. measurement of tree height (see fig. 5 and 3):

(1) the handheld height finder aims at the treetop, the screen is used for main breathing, the tip angle key (1) is pressed by a forefinger and kept for a certain time, and an ideal tip angle α can be obtained when the buzzing sound is finished;

(2) aiming at a relatively flat and smooth place on a trunk, carrying out screen main breathing, pressing a trunk distance key (2) by using a middle finger and keeping for a certain time, and obtaining an ideal trunk distance L when the buzzing sound is finished (because a height measuring instrument can automatically flatten, the aiming position of the trunk is not required, but the smooth surface position of the trunk near an apparent flat line is aimed as much as possible, so that the measurement precision is improved favorably);

(3) aiming at the base of the trunk, shielding the main breath, pressing by a ring finger and keeping for a certain time, and obtaining an ideal base angle β when the buzzer is finished;

(4) pressing the tree height key (see fig. 2) causes the tree height value h to be displayed on the screen along with the tip angle α, the stem length L, and the base angle β.

It is worth emphasizing that: the method can eliminate or greatly reduce the jitter error, improve the measurement precision of the tree electronic height measuring instrument, and ensure stable and reliable results by applying the mode principle, thereby having important significance for improving the field investigation speed and ensuring the accuracy of forestry resource data.

Claims

1. A mode-based method for eliminating dithering errors of an electronic tree altimeter comprises the following five steps:

(3) calculating the mode of the measurement value array;

(4) taking the obtained mode as an ideal measurement value;

2. The mode-based tree electronic altimeter jitter error elimination method of claim 1, wherein: the time t ranges from 1 to 3 seconds.

3. The mode-based tree electronic altimeter jitter error elimination method of claim 1, wherein: the height indicator is internally provided with a buzzer, and the height indicator can synchronously emit buzzing prompt tones which work within a period of measurement time t when a measurer keeps an aiming state in situ.