JP5167881B2 - Distance measuring device and program thereof - Google Patents

Description

  The present invention relates to a distance measuring device and a program thereof.

  There is a technique for selecting two points from a captured image and measuring the distance between the two points in an imaging apparatus, for example, a stereo camera.

JP Patent Publication No. 05-018748

  However, if there is no contrast between the two selected points, the distance between the two points is estimated from the surrounding contrast, so that an error increases and it is difficult to measure accurately. When considered as a consumer digital camera, it is necessary to be able to select two points with a simple operation method.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a distance measuring apparatus and a program for the distance measuring apparatus that can perform distance measurement with priority to highly accurate measurement with a simple operation.

To achieve the above object, image acquisition means for acquiring an image, detection means for detecting a plurality of feature points from the image obtained by the image acquisition means, and information indicating the feature points detected by the detection means are displayed. A display control means to be displayed on the means, a selection means for allowing the user to select two from the information displayed on the display means, and a feature point corresponding to the information indicating the feature point selected by the selection means A distance measuring means for obtaining a distance between the two points and a selection restricting means for restricting a feature point that can be selected when two points are selected by the selecting means. After the user selects the first feature point that is the starting point for measuring the point, the second feature point that is the end point is selected, and the selection restricting unit selects the second feature point by the selecting unit , And limits the range that can be selected to select the information indicating the feature points from the position of the first feature points previously selected by said selection means within a predetermined range.

  Further, for example, as described in claim 2, the detection unit detects a feature point evaluation value indicating the likelihood of a feature point from within the image obtained by the image acquisition unit, and the detected feature point A point whose evaluation value is within the first range may be detected as a feature point.

  For example, as described in claim 3, the display control unit may display information indicating the feature point based on the feature point evaluation value of the feature point detected by the detection unit. Good.

  Further, for example, as described in claim 4, the display control means may display a point where the feature point evaluation value is within a second range as a feature point.

  For example, as described in claim 5, the display control unit displays a predetermined number of feature points in descending order of the feature point evaluation value among the feature points detected by the detection unit. You may make it control a display means to do.

  For example, as described in claim 6, the display control unit ranks the feature points in descending order of the feature point evaluation values among the feature points detected by the detection unit. The display means may be controlled so as to identify and display the information to be displayed based on the ranking of the feature point evaluation values.

  Further, for example, as described in claim 7, the display control unit indicates a feature point whose feature point evaluation value is within a third range among the feature points displayed by the display unit. The display means may be controlled so as to identify and display information and information indicating feature points that are out of the third range.

  Further, for example, as described in claim 8, the display control means indicates the feature point by changing at least one of the display color, size, and shape of the information indicating the feature point. Information may be identified and displayed.

  Further, for example, as described in claim 9, the display control unit includes a position within a predetermined range in the image obtained by the image acquisition unit among the feature points detected by the detection unit. Control may be performed so that information indicating the feature point is displayed on the display means for the feature point detected in step (b).

Further, for example, as described in claim 10 , the selection unit selects a first feature point that is a starting point when the distance measurement unit measures a distance between two points, and then selects an end point. The feature point of the feature point detected by the detection unit when the second feature point is selected and the first feature point is selected by the selection unit and when the second feature point is selected. You may make it further provide the feature point evaluation value range change means which changes the predetermined range of the evaluation value, or the predetermined range of the feature point evaluation value of the information indicating the feature point to be displayed and controlled by the display control means.

For example, as described in claim 11 , the display control means further includes a distance display means for displaying a distance between two feature points measured by the distance measuring means on the display means. It may be.

Further, for example, as described in claim 12 , the display control unit displays the image obtained by the image acquisition unit on the display unit, and the position where the feature point is detected by the detection unit. Information indicating the feature point may be displayed at the same position.

Further, for example, as described in claim 13 , the distance measuring unit measures an actual distance between two feature points corresponding to information indicating the feature point selected by the selection unit. May be.

To achieve the above object, a program according to a fourteenth aspect of the present invention is directed to a computer having a display unit, detecting means for detecting a plurality of feature points from an image, and displaying the information indicating the feature points detected by the detecting means. Display control means to be displayed on the part, selection means to allow the user to select two from the information displayed on the display part, distance between two feature points corresponding to information indicating the feature point selected by the selection means A distance measuring means for obtaining a point, and a selection restricting means for restricting selectable feature points when selecting two points by the selecting means. The selecting means measures a distance between the two points by the distance measuring means. After the user selects the first feature point that is the starting point for the selection, the second feature point that is the end point is selected, and the selection restricting unit selects the second feature point by the selecting unit. In this case, the selection unit is made to function so as to limit a selectable range so as to select information indicating a feature point within a predetermined range from the position of the first feature point previously selected by the selection unit. A distance measurement program.

  ADVANTAGE OF THE INVENTION According to this invention, the distance measurement apparatus which can perform the distance measurement which gave priority to the measurement with high precision by simple operation, and its program can be provided.

Hereinafter, the first embodiment will be described in detail with reference to the drawings as an example in which the imaging apparatus of the present invention is applied to a digital camera.
[First embodiment]
A. 1 is a diagram showing the appearance of an embodiment of a digital stereo camera as an example of an image pickup apparatus according to the present invention. FIG. 1 (a) is a front view, and FIG. 1 (b) is a rear view. FIG. 1 (c) is a top view.
In FIG. 1, a stereo digital camera 1 has two imaging lenses 2 and 3 and a strobe 11 on the front side as shown in FIG. 1A. As shown in FIG. 1B, an LCD monitor 4, a cursor key 5, a SET key 6, a distance measuring key 7, a menu key 8 and the like are provided. Further, as shown in FIG. A shutter button 9 and a power button 10 are provided. Although not shown in the drawing, a USB terminal connection portion used when connecting to a personal computer or the like via a USB cable is provided on the side portion.
FIG. 2 is a diagram showing an embodiment of the electronic circuit configuration of the stereo digital camera 1 shown in FIG. In FIG. 2, the stereo digital camera 1 captures image data from the two CMOS camera modules 210 and 220.

The operation of the CMOS camera module 210 will be described. The light collected from the photographing lens 2 is photoelectrically converted and A / D converted in the CMOS sensor 212 and output as digital data. The output according to the color filter array (Bayer array) of the CMOS sensor 212 is obtained. The output of the CMOS sensor 212 is input to the ISP 213. The ISP 213 adjusts the color, and the ISP 213 outputs Y, Cb, and Cr at an 8-bit resolution.
The CMOS camera module 210 and the CMOS camera module 220 are the same. Outputs (Y, Cr, and Cb data) from the CMOS camera modules 210 and 220 are stored in the work memory 204 by the DMA 202. The work memory 204 is constituted by a DRAM or the like.

The CPU 201 controls the overall control operation of the stereo digital camera 1. The flash memory 203 stores an operation program for the CPU 201. The captured image data is also stored in the flash memory 203.
The CPU 201 takes out an imaging program and menu data corresponding to each mode stored in the flash memory 203 or the like in response to a status signal from the key input unit 209, and performs effective control of each function of the stereo digital camera 1. . For example, the function selection menu by the shooting operation when the shutter button 9 is pressed, the recording, the reproduction of the recorded image, the display, the operation when the distance measurement key 7 is pressed, the cursor key 5 when the menu key 8 is pressed, etc. Display control and setting screen display control.

The VRAM control unit 205 extracts display data from the VRAM 206 and displays it on the display unit 208. Display data in the VRAM 206 is written by the CPU 201.
Further, the CPU 201 calculates the distance between the two points by the method described later, based on the luminance signal Y from the two camera modules stored in the work memory 204.
It is possible to exchange image data with a personal computer using a USB cable connected to the USB connection terminal unit 214 via the USB control unit 211.

The distance measurement principle of the stereo digital camera will be described with reference to the perspective projection model of the camera shown in FIG.
A three-dimensional orthogonal coordinate system composed of X, Y, and Z will be referred to as camera coordinates. The camera coordinates have the optical center of the camera 302 as the origin, the Z axis coincides with the optical direction of the camera, and the X and Y axes are parallel to the horizontal and vertical directions of the image. The optical center corresponding to the stereo digital camera 1 becomes the optical center of the imaging lens 2 because the CMOS camera module 210 corresponds to the camera 302.
The coordinates of the camera axis and the length unit obtained by converting the pixel interval to the origin at the intersection of the optical axis and the image plane are the (u, v) coordinates on the camera 302 side, and (u ′) on the camera 3030 side. , V ′) coordinates.

  The camera 302 is installed so that the optical axis is parallel to the camera 303 and the image coordinate u-axis of 302 and the image coordinate u′-axis of the camera 303 are in the same straight line and in the same direction. Further, the focal length f and the pixel sensation of both are the same, and in both cases, the optical axis and the respective image coordinate planes intersect perpendicularly. Such a configuration is called parallel stereo, and the two camera modules of the stereo digital camera 1 have a parallel stereo configuration.

Assuming that the base line length (sense of two camera optical axes) is b, the camera coordinates (X1, Y1, Z1) of point A1 are expressed by the following equations. (U1, v1) represents a projection point of the image coordinates of the camera 302, and (u′1, v′1) represents a projection point of the camera 303 to the image coordinates.

上記より平行ステレオの構成であれば、焦点距離ｆ、基線長ｂ、視差（ｕ１−ｕ’１）、画像座標（ｕ１，ｖ１）が判れば、２点間の距離が判ることになる、焦点距離ｆと基線長ｂを固定しておけば、撮像した２枚の画像により特定２点間の距離が判ることになる。 From the captured images from the two camera modules 210 and 220 of the stereo digital camera 1, the camera coordinates (for example, A1) projected onto the specific position (for example, u1 and u2) in the captured image are obtained. Similarly, A2 (not shown) on the camera coordinates is obtained as (X2, Y2, Z2). Therefore, the distance between A1 and A2 can be obtained as follows.

From the above, in the case of the parallel stereo configuration, if the focal length f, the base length b, the parallax (u1-u′1), and the image coordinates (u1, v1) are known, the distance between the two points can be known. If the distance f and the base line length b are fixed, the distance between two specific points can be determined from the two captured images.

  FIG. 4 shows two luminance images captured by the stereo digital camera 1. Processing such as feature point extraction and template matching, which will be described later, is performed on each luminance image. 4A shows a photographed image by the photographing lens 3 (camera module 220), and FIG. 4B shows a photographed image by the photographing lens 2 (camera module 210). Each pixel in the image of (a) is obtained by moving the pixel in the image of (b) in parallel in the desired amount u ′ direction.

  Here, FIG. 4B is referred to as a reference image, and FIG. 4A is referred to as a target image. FIG. 5 shows a state in which feature points 501 in the image are extracted from the reference image shown in FIG. 4B and plotted on the image. The feature point 501 is used to obtain the parallax from captured images in which the line of sight (light rays) of the reference image and the two target images are different. Parallax is the difference between the two image coordinates in the u direction when considering the same camera coordinate point. It is difficult to find an arbitrary position in the reference image from the corresponding target image. A characteristic position is found from the reference image, and the same position as the characteristic position is found from the corresponding target image.

行列Ｇの２個の固有値が大きいときにはその位置にコーナーが存在する事を示しているので、コーナー検出関数Ｒは以下となる。det（）は行列式を、tr（）はトレース（対角成分の和）を表す。ｋは所望の定数であり、例えば０．０４が用いられる。

Ｒ＿Ｈが閾値Ｈ１より大きければ、その位置にコーナーがあり特徴点とみなす。図５に、基準画像から特徴点検出をした結果をプロットしたものを示す。５０１で示される●が特徴点を示している。 First, the Harris corner detection function R_H is used as the feature point. A covariance direction tensor matrix G is considered when the pixel value at the position (u, v) of the reference image is I (u, v).

When the two eigenvalues of the matrix G are large, it indicates that a corner exists at that position, so the corner detection function R is as follows. det () represents a determinant, and tr () represents a trace (sum of diagonal components). k is a desired constant, for example, 0.04 is used.

If R_H is larger than the threshold value H1, there is a corner at that position and it is regarded as a feature point. FIG. 5 shows a plot of the result of feature point detection from the reference image. A black circle 501 indicates a feature point.

但し、テンプレートの大きさをＭ×Ｎ、基準画像のテンプレートの位置における画素値をＩ、テンプレートと重ね合わせたる対象画像の画素値をＴとする。基準画像の特徴点は（ｕ，ｖ）の座標点となる、対象画像の（ｕ’，ｖ’）は、ｕ’座標の方向のみに並行にずらしていき、それぞれＲ＿ＳＳＤを計算する。Ｒ＿ＳＳＤは完全に一致すれば０になり、相違度が大きければ大きな値になる、例えば、Ｒ＿ＳＳＤが一番小さい値が得られた（ｕ’，ｖ’）を対象画像での対応する位置とする。これにより視差（ｕ−ｕ’）が求まる。 The position in the target image corresponding to the feature point 501 on the reference image shown in FIG. 5 is searched by template matching using SSD (Sum of Squared Difference). Template matching is a process in which images are overlapped to check differences in order to check the degree of difference between two images. The dissimilarity by SSD is expressed by the following equation.

However, the size of the template is M × N, the pixel value at the template position of the reference image is I, and the pixel value of the target image to be superimposed on the template is T. The feature point of the reference image is the coordinate point of (u, v). (U ′, v ′) of the target image is shifted in parallel only in the direction of the u ′ coordinate, and R_SSD is calculated for each. R_SSD becomes 0 when it completely matches, and becomes a large value when the degree of dissimilarity is large. For example, (u ′, v ′) at which the smallest value of R_SSD is obtained is set as a corresponding position in the target image. . Thereby, the parallax (u−u ′) is obtained.

The method for measuring the distance between two points will be described in detail using the flowchart of FIG.
When the shutter button 9 is pressed, it is determined whether the current state is the normal shooting mode or the distance measurement mode (701). Switching between the distance measurement mode and the normal photographing mode is determined by the toggle operation of the distance measurement key 7 before the shutter button 9 is pressed. Which mode is currently in use is notified to the user by an icon or the like on the LCD monitor 4. In the normal shooting mode, two images captured by the two CMOS camera modules are stored in the flash memory (702). One image is displayed on the LCD monitor 4 (703).

  If the mode is the distance measurement mode, variables such as threshold values of feature points are initialized at 710. The maximum value of the feature point evaluation value when detecting the feature point is set to H1_MAX, and the upper limit of the threshold value of the evaluation function for obtaining the feature point is substituted for H1_MAX. For example, 20 is set. The minimum value of the feature point evaluation value when detecting the feature point is set as H1_MIN, and the lower limit is substituted into H1_MIN. For example, assume 2. The initial value of the determination threshold value of the feature point evaluation function is substituted for H1. Here, it is assumed that H1_MAX. The larger the value of H1_MIN, the smaller the number of feature points detected, and each feature point is a more characteristic point than the surroundings. Since the Harris corner detection function is used this time, a clear corner is detected when the threshold value H1 is larger. N is a variable used when two feature points are selected as distance measurement points, and is initialized to zero. When N is 0, a feature point is not selected for distance measurement. When N = 1, one distance measurement feature point is selected. S_C is a variable used when changing with the left and right cursors, and is initialized to 1. H1_K is a step unit value when changing the threshold value with the up and down cursors, and is set to 2 here. H1_B is a variable for storing H1 before one operation, and is initialized to be the same as H1.

Feature point detection is performed on the luminance value of the reference image using the Harris corner detection function value R_H. At this time, the point of R_H> H1 is used as a feature point, and the image coordinates of the feature point are substituted into the array variable FP (). The number of obtained feature points is pn (711).
The obtained feature point FP is displayed together with the reference image on the LCD monitor 4 (712). The reference image is written in the reference image layer, and the others are written in the feature point layer. Image data is read from each layer and displayed on the LCD monitor 4 such that the feature point layer overlaps the reference image layer. When the reference image layer and the feature point layer are overlapped and viewed from above, the reference image layer below can be seen through the coordinates where the feature point layer is not written. That is, when all the feature point layers are deleted, the image of the reference image layer itself is displayed. In the feature point layer, the feature point 601 indicated by FP is written with a mark ●, and the feature point 610 selected with the left and right cursors is written with a mark ■. The feature point 610 is a coordinate indicated by FP (S_C). FIG. 6A shows an image on the LCD monitor 4 displaying this state.

  Wait for key operation (713). If the distance measurement is to be cancelled, the long cursor key is pressed and the distance measurement mode is exited (719). If the feature point 610 of the image on the LCD monitor 4 shown in FIG. 6A is moved, the left and right cursor keys are used. If the left cursor key operation is detected, S_C is subtracted (715), and if it is the right cursor, S_C is increased (716). If it is below the minimum value of S_C, pn is assigned (731, 733), and if it exceeds pn, which is the maximum value of S_C, 1 is assigned (732, 734). Here, the value of S_C takes a value from 1 to pn which is the array element number of the array variable FP in which the feature points are stored. When S_C is updated, the display image on the LCD monitor 4 is also updated at 747. Here, only the feature point layer is rewritten. Once all feature point layers are deleted, the feature point indicated by FP is marked with ●, the feature point showing the point selected with the left and right cursors is marked with ■, and if N = 1, that is, the feature for distance measurement If a point has been selected, a large ● is written in the coordinates of SEL (0).

  When the set key 6 is pressed (714), the feature point selected by FP (S_C) becomes the selection point for distance measurement. When it becomes the selection point for distance measurement, it is displayed as the selection point 620 as shown in FIG. The selection point 620 stores the image coordinates of the reference image in the selection point array variable SEL (). It is determined whether two selected points have been selected (730). If there is still only one point, 1 is substituted for N (736). In FIG. 6B, there is one selection point 620, and the selection point 620 at this time is called a first selection point.

When the up / down cursor is operated, the current threshold value H1 is saved in the H1_B variable (717, 718). If the down cursor key is pressed, the threshold value H1_K is incremented (741). However, if it is equal to or higher than the upper limit H1_MAX (743), the saved threshold value H1_B is returned to H1 (745), and the key operation is again waited. When the up cursor key is pressed, the threshold value H1 is subtracted by H1_K (742). Here, if H1 is smaller than the minimum threshold value H1_MIN, the saved threshold value H1_B is returned to H1 to wait for a key operation again.
When the new threshold value H1 is determined, a new feature point is detected from the reference image using the threshold value H1 (746).
As described above, the feature point layer image is updated at 747. FIG. 6C shows the LCD monitor 4 at this time. A new feature point (for example, 602) that is not seen in FIGS. 6A and 6B is displayed.

The second selection point 630 is selected by the left / right cursor movement and the set key 6 in the same manner as the first selection point. The LCD monitor 4 image at this time is shown in FIG. Since two selection points have been selected, camera coordinates of the first selection point and the second selection point are obtained (750). The parallax of the distance measurement selection point is obtained between the reference image and the target image by the SSD template matching method shown in Equation 5, and the camera coordinates are obtained from Equation 1.
Using two camera coordinates, the distance between the two points is obtained by Equation 2 (751). A straight line 604 indicating the obtained distance between the two points and a calculated distance 603 are displayed on the LCD monitor. The LCD monitor image at this time is shown in FIG.

[Modification]
The following modifications are also conceivable for the above embodiment.

(1) In the above embodiment, the feature point within the range of the threshold value set by the feature point evaluation value is detected, and the detected feature point is displayed. It is also possible to display all the feature points obtained by the lowest possible threshold value, and further to identify and display the feature points within the threshold range set by the feature point evaluation value.
For example, referring to FIG. 8, all feature points detected on the reference image are displayed by x marks (801), and feature point evaluation values are previously selected from the feature points in the same manner as in the above embodiment. The mark ● is displayed at the feature point within the set threshold range, and the mark ■ is displayed at the feature point indicating the point selected by the left and right cursors. If the first selection point has already been determined, a large mark (810) is written in the coordinates of the first selection point. Similarly, if the second selection point has been determined, a large mark is also displayed at the second selection point. Write.
Alternatively, the feature point evaluation values of the feature points may be ranked in descending order, and information indicating the feature points may be identified and displayed in descending order. In addition, the method for identifying and displaying information indicating the feature points may change the display color of the information indicating the feature points to be identified and displayed, change the size, or change the shape. Good. In the case of ranking, a number indicating the ranking may be displayed.
As a result, the user can easily visually recognize the feature points that can be measured with high accuracy, and can easily perform the measurement with high accuracy by selecting the feature points.

(2) In the above embodiment, the feature point within the threshold set by the feature point evaluation value is detected and the information indicating the detected feature point is displayed, but the feature point to be displayed on the screen is indicated. The number of information may be limited to a predetermined number.
For example, among the detected feature points, N feature points are displayed on the screen in descending order of the feature point evaluation value.
As a result, only feature points with high feature point evaluation values can be selected, and the distance between the two points is measured between the two feature points with high feature point evaluation value accuracy, enabling high-precision measurement. It becomes.

(3) In the above-described embodiment, the feature point evaluation value is detected within the set threshold value range, and the information indicating the feature point to be displayed is displayed by displaying the information indicating the detected feature point. Although the number is controlled, the selectable feature points may be limited by limiting the range in which the information indicating the feature points is displayed.
For example, information indicating a detected feature point within a predetermined range in the display screen among the detected feature points may be displayed, or a feature point within a predetermined range from the first selection point may be displayed. Information may be displayed as the second selection point.
Similarly, only the information indicating the feature points displayed within the predetermined range in the display screen among the information indicating the feature points being displayed may be selectable. Information indicating feature points detected within a predetermined range from the position of the first selected point previously selected in the captured image may be selected.
Similarly to the modification (1), the display color of information indicating selectable feature points may be changed, the size may be changed, or the shape may be changed.
This makes it possible to select feature points with fewer key operations by narrowing the range in which feature points can be selected.

(4) In the above embodiment, the feature points within the threshold range set by the feature point evaluation value are detected. However, the upper limit of the feature point evaluation value is not limited, and the feature point evaluation value is You may make it detect the feature point more than the set threshold value.
Further, the threshold range of the feature point evaluation value to be detected or displayed may be changed by the user, or may be a predetermined range determined in advance.

(5) In the above embodiment, the information indicating the feature point is displayed by marking the same position as the feature point detected from the captured image, but the display position of the information indicating the feature point is the feature It does not have to be the same position as the position where the point is detected, as long as it can indicate the position of the detected feature point. Further, the coordinates of feature points may be displayed.
In short, it is sufficient that the user can know the position where the feature point is detected, and the display of the information indicating the feature point is not limited in position, color, size, or shape.

(6) In the above embodiment, the distance between the two feature points is measured in three dimensions. However, the distance is not necessarily in three dimensions, and the distance in two dimensions is measured. Also good.
Further, the distance between two points on the LCD monitor may be used instead of the actual distance.

  (7) In the above embodiment, the distance measurement mode and the normal shooting mode are provided, and when the distance measurement mode is selected, the feature point is detected and the information indicating the feature point is displayed. Such a mode may not be provided, and feature point information may be recorded together with image data for each photographing, and the feature point may be displayed when the user instructs to measure the distance.

  (8) In the above embodiment, the information indicating the feature point displayed by the key operation is selected. However, the user provides the position of the information indicating the feature point displayed by providing the touch panel on the display screen. Selection may be made by touching with a finger or the like.

  (9) The embodiment described above may be an embodiment in which the above modifications (1) to (8) are arbitrarily combined.

  (10) Each of the above embodiments of the present invention is only an example as the best embodiment, and is described in order to better understand the principle and structure of the present invention. And is not intended to limit the scope of the appended claims. Accordingly, it should be understood that all the various variations and modifications that can be made to the above-described embodiments of the present invention are included in the scope of the present invention and protected by the appended claims. .

  Lastly, in each of the above embodiments, the case where the distance measuring device of the present invention is applied to the stereo digital camera 1 has been described. However, the present invention is not limited to the above embodiment, and the main point is that Any device that can detect feature points of a subject and measure the distance between the detected feature points is applicable.

1 is an external view of a stereo digital camera according to an embodiment of the present invention. 1 is a block diagram of a stereo digital camera according to an embodiment of the present invention. It is a perspective projection figure which shows the distance measurement principle of a stereo digital camera. It is a figure which shows two images imaged with the stereo digital camera 1 of embodiment of this invention. It is a figure which shows the example of a display of a feature point in the image imaged with the stereo digital camera 1 of embodiment of this invention. It is the figure which showed the example of the monitor display in the stereo digital camera 1 of embodiment of this invention. It is a flowchart which shows operation | movement of the stereo digital camera 1 of embodiment of this invention. It is the figure which showed the example of the monitor display of the stereo digital camera 1 of the modification of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stereo digital camera 2, 3 Imaging lens 4 LCD monitor 5 Cursor key 6 SET key 7 Distance measurement key 8 Menu key 9 Shutter button 10 Power button 11 Strobe 201 CPU
202 DMA
203 Flash memory 204 Work memory 205 VRAM control unit 206 VRAM
207 Digital video encoder 208 Display unit 209 Key input unit 211 USB control unit 214 USB connection terminal unit 210, 220 CMOS camera module 212, 222 CMOS sensor 213, 223 ISP

Claims (14)

Image acquisition means for acquiring images;
Detection means for detecting a plurality of feature points from the image obtained by the image acquisition means;
Display control means for displaying information indicating the characteristic points detected by the detection means on the display means;
Selection means for allowing the user to select two from the information displayed on the display means;
Distance measuring means for obtaining a distance between two feature points corresponding to information indicating the feature points selected by the selection means;
Selection restriction means for restricting selectable feature points when two points are selected by the selection means;
With
The selection means, after the user has selected a first feature point as a starting point when measuring the distance between two points by the distance measuring means, to select a second feature point as an end point,
The selection limiting unit selects information indicating a feature point within a predetermined range from the position of the first feature point previously selected by the selection unit when the second feature point is selected by the selection unit. A distance measuring device that limits a range that can be selected.   The detection means detects a feature point evaluation value indicating the likelihood of a feature point from within the image obtained by the image acquisition means, and uses the point where the detected feature point evaluation value is within a first range as a feature point The distance measuring device according to claim 1, wherein the distance measuring device is detected.   3. The distance measuring apparatus according to claim 2, wherein the display control unit displays information indicating the feature point based on the feature point evaluation value of the feature point detected by the detection unit.   4. The display control unit according to claim 3, wherein the display control unit controls the display unit to display a point indicating that the feature point evaluation value is within a second range as a feature point. Distance measuring device.   The display control unit controls the display unit to display information indicating a predetermined number of feature points in descending order of the feature point evaluation value among the feature points detected by the detection unit. The distance measuring device according to claim 3 or 4.   The display control means ranks the feature points detected by the detection means in descending order of the feature point evaluation values, and identifies and displays information indicating the feature points based on the ranks of the feature point evaluation values. The distance measuring apparatus according to claim 3, wherein the display unit is controlled as described above.   The display control unit includes information indicating a feature point whose feature point evaluation value is within a third range and information indicating a feature point outside the third range among the feature points displayed by the display unit. The distance measuring device according to claim 3, wherein the display unit is controlled so as to identify and display the information.   8. The display control means for identifying and displaying information indicating a feature point by changing at least one of a color, a size, and a shape of information indicating the feature point. The distance measuring device described in 1.   The display control means displays the information indicating the feature points of the feature points detected by the detection means for the feature points detected at a position within a predetermined range in the image obtained by the image acquisition means. The distance measuring device according to claim 3, wherein the distance measuring device is controlled to display on a means. The selection unit selects a first feature point that is a starting point when the distance measurement unit measures a distance between two points, and then selects a second feature point that is an end point.
A predetermined range of feature point evaluation values of the feature points detected by the detection means when the first feature points are selected by the selection means and when the second feature points are selected; or the display The feature point evaluation value range changing means for changing a predetermined range of the feature point evaluation value of the information indicating the feature point to be displayed and controlled by the control means is further provided. Distance measuring device. The said display control means is further provided with the distance display means to display the distance between the two feature points measured by the said ranging means on a display means. Distance measuring device.   The display control unit displays an image obtained by the image acquisition unit on the display unit, and displays information indicating the feature point at the same position as the position where the feature point is detected by the detection unit. The distance measuring device according to claim 1. The distance according to any one of claims 1 to 12, wherein the distance measuring unit measures an actual distance between two feature points corresponding to information indicating the feature point selected by the selection unit. Measuring device . A computer equipped with a display unit
Detecting means for detecting a plurality of feature points from the image;
Display control means for displaying information indicating the feature points detected by the detection means on the display unit;
Selection means for allowing the user to select two of the information displayed on the display unit;
Distance measuring means for obtaining a distance between two feature points corresponding to information indicating the feature points selected by the selection means;
Selection restriction means for restricting selectable feature points when selecting two points by the selection means;
Function as
The selection means, after the user has selected a first feature point as a starting point when measuring the distance between two points by the distance measuring means, to select a second feature point as an end point,
The selection limiting unit selects information indicating a feature point within a predetermined range from the position of the first feature point previously selected by the selection unit when the second feature point is selected by the selection unit. A distance measurement program that functions so as to limit a selectable range.

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