Apparatus and method for acquiring eccentric sight light point pixel coordinates based on distance sensor

Abstract

The application provides a device and method for obtaining pixel coordinates of a light point of an eccentric sight based on a distance sensor, which comprises a lens, a sight, a distance sensor and a control unit, the sight and the distance sensor are respectively arranged on two sides of the lens, the starting point of the field of view center of the lens and the starting point of the measurement of the distance sensor are located on the same horizontal installation surface, and the control unit is electrically connected with the lens, the sight and the distance sensor respectively. The application measures the distance between the installation surface and the imaging surface by using the distance sensor, and calculates the accurate pixel coordinates of the light point of the eccentric sight on the image according to the field of view angle of the lens, the resolution of the image, the horizontal physical distance between the sighting optical axis of the sight and the field of view center axis of the lens, and the distance between the installation surface and the imaging surface, so as to facilitate the prediction of the position of the bar code, ensure the effectiveness of the automatic exposure of the code scanner, and improve the decoding efficiency.

Description

Technical Field

[0001] This invention relates to the field of imaging aiming and positioning technology, and in particular to a device and method for obtaining the coordinates of an eccentric aiming point based on a distance sensor. Background Technology

[0002] A barcode scanner's aiming device is an optoelectronic device used to project aiming light onto a target object. The main function of the aiming device in a barcode scanner is to guide the user to align the center of the lens's field of view with the barcode during scanning, thus obtaining a centered image of the barcode. This facilitates the use of a pre-set algorithm to predict the approximate position of the barcode in the image, ensuring the effectiveness of automatic exposure and improving decoding efficiency. The approximate position of the barcode in the image needs to be calculated using the pixel coordinates of the aiming device's light spot within the image; therefore, obtaining the precise pixel coordinates of the aiming device's light spot is particularly important.

[0003] like Figure 3 As shown, in current barcode scanners, the aiming device 20 is generally offset, meaning it is positioned to the side of the lens 10, and the aiming light path projected by the aiming device 20 is not coaxial with the central axis of the lens 10's field of view. For the image on the imaging surface, the light spots (points A1 and A2) projected by the aiming device onto the image do not coincide with the image center points (points O1 and O2). Furthermore, the pixel positions of the light spots projected by the aiming device onto the image change with the shooting distance, and this change is more pronounced closer to the lens. The specific reason is that in the actual lens field of view, W1 and W2 represent different physical widths, but the two images have the same resolution, resulting in different pixel densities. Therefore, the light spots projected by the aiming device onto images at different shooting distances have different pixel coordinates. The algorithm cannot accurately obtain the pixel coordinates of the aiming device's light spots, leading to errors in barcode position prediction and affecting decoding efficiency. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a device and method for obtaining the coordinates of an eccentric aiming point based on a distance sensor. This method can obtain the precise pixel coordinates of the aiming point in an image, thereby facilitating the prediction of barcode positions, ensuring the effectiveness of automatic exposure of the barcode scanner, and improving decoding efficiency.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A device for obtaining the pixel coordinates of an eccentric aiming device based on a distance sensor includes a lens, an aiming device, a distance sensor, and a control unit. The aiming device and the distance sensor are respectively disposed on both sides of the lens. The aiming optical axis of the aiming device is parallel to the central axis of the field of view of the lens, and the starting point of the center of the field of view of the lens and the measurement starting point of the distance sensor are on the same horizontal mounting surface.

[0007] The lens is used to acquire an image corresponding to the imaging surface. The lens has a field of view α, and the resolution of the image is W×H; where W is the number of pixels in the width direction of the image, and H is the number of pixels in the height direction of the image.

[0008] The sight is used to project aiming light onto the imaging surface and form a light spot on the image; the horizontal physical distance between the aiming optical axis of the sight and the central axis of the field of view of the lens is d.

[0009] The distance sensor is used to measure the distance h between the mounting surface and the imaging surface.

[0010] The control unit is electrically connected to the lens, the aiming device, and the distance sensor respectively. The control unit is used to obtain the field of view angle α of the lens, the resolution W×H of the image, the horizontal physical distance d between the aiming optical axis of the aiming device and the center axis of the field of view of the lens, and the distance h between the mounting surface and the imaging surface, and to calculate the pixel coordinates of the light spot of the aiming device on the image according to the set algorithm.

[0011] In some preferred embodiments, the perpendicular line between the aiming optical axis of the sight and the central axis of the field of view of the lens is parallel to the wide side of the image, and the field of view angle α of the lens, the actual physical distance l1 between the two high sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following:

[0012]

[0013] In the image, the number of pixels N between the light spot of the sight and the center point of the image is:

[0014]

[0015] Expressing l1 using a relation containing α and h, and simplifying it, we get:

[0016]

[0017] The pixel coordinates of the sight's spot in the image are:

[0018]

[0019] Right now:

[0020]

[0021] In other preferred embodiments, the perpendicular line between the aiming optical axis of the sight and the central axis of the field of view of the lens is parallel to the high side of the image, and the field of view angle α of the lens, the actual physical distance l2 between the two wide sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following:

[0022]

[0023] In the image, the number of pixels N between the light spot of the sight and the center point of the image is:

[0024]

[0025] Expressing l2 using a relation containing α and h, and simplifying it, we get:

[0026]

[0027] The pixel coordinates of the sight's spot in the image are:

[0028]

[0029] Right now:

[0030]

[0031] According to another aspect of the present invention, a method for obtaining the pixel coordinates of an off-center sight based on a distance sensor is provided, comprising the following steps:

[0032] Step S1: Provide the device described above for obtaining the pixel coordinates of the eccentric aiming device based on the distance sensor, install the aiming device and the distance sensor on both sides of the lens respectively, and ensure that the aiming optical axis of the aiming device is parallel to the center axis of the field of view of the lens, and the starting point of the center of the field of view of the lens and the measurement starting point of the distance sensor are on the same horizontal mounting surface.

[0033] Step S2: Project the aiming light onto the imaging surface using the aiming device, acquire the image corresponding to the imaging surface using the lens, and acquire the field of view angle α of the lens, the resolution W×H of the image, and the horizontal physical distance d between the aiming optical axis of the aiming device and the center axis of the field of view of the lens;

[0034] Step S3: Use the distance sensor to obtain the distance h between the mounting surface and the imaging surface;

[0035] Step S4: Calculate the pixel coordinates of the aiming point on the image according to the set algorithm.

[0036] In some preferred embodiments, when the perpendicular line between the aiming optical axis of the sight and the central axis of the field of view of the lens is parallel to the wide side of the image, the field of view angle α of the lens, the actual physical distance l1 between the two high sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following:

[0037]

[0038] In the image, the number of pixels N between the light spot of the sight and the center point of the image is:

[0039]

[0040] Expressing l1 using a relation containing α and h, and simplifying it, we get:

[0041]

[0042] The pixel coordinates of the sight's spot in the image are:

[0043]

[0044] Right now:

[0045]

[0046] In other preferred embodiments, when the perpendicular line between the aiming optical axis of the sight and the central axis of the field of view of the lens is parallel to the high side of the image, the field of view angle α of the lens, the actual physical distance l2 between the two wide sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following:

[0047]

[0048] In the image, the number of pixels N between the light spot of the sight and the center point of the image is:

[0049]

[0050] Expressing l2 using a relation containing α and h, and simplifying it, we get:

[0051]

[0052] The pixel coordinates of the sight's spot in the image are:

[0053]

[0054] Right now:

[0055]

[0056] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses a distance sensor to measure the distance between the mounting surface and the imaging surface, and calculates the precise pixel coordinates of the light spot of the eccentric aiming device on the image based on the field of view of the lens, the resolution of the image, the physical distance between the aiming light starting point of the aiming device and the center starting point of the field of view of the lens, and the distance between the mounting surface and the imaging surface. This facilitates the prediction of the barcode position, ensures the effectiveness of the automatic exposure of the barcode scanner, and improves the decoding efficiency. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of a device for obtaining the pixel coordinates of an eccentric aiming device based on a distance sensor, according to an embodiment of the present invention.

[0058] Figure 2 This is a schematic diagram of a device for obtaining the pixel coordinates of an eccentric aiming device based on a distance sensor, according to another embodiment of the present invention.

[0059] Figure 3 This is a schematic diagram of the lens and aiming device in a conventional barcode scanner.

[0060] Figure 4 This is a flowchart illustrating a method for obtaining the pixel coordinates of an eccentric aiming device based on a distance sensor, according to an embodiment of the present invention.

[0061] In the diagram, 10 is the lens, 20 is the sight, 30 is the distance sensor, and 40 is the control unit. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It is understood that, without conflict, some technical means of the various embodiments described herein can be substituted for or combined with each other.

[0063] In the description of this invention, the terms "first," "second," etc., are used only to distinguish the described objects and have no sequential or technical meaning. Therefore, objects specified with "first," "second," etc., may explicitly or implicitly include one or more of those objects. Furthermore, the words "one" or "a" do not indicate a quantity limitation, but rather indicate the presence of at least one, while "multiple" indicates at least two.

[0064] In the description of this invention, references to "one embodiment" or "some embodiments" mean that one or more embodiments of the invention include a particular feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "one embodiment," "some embodiments," "other embodiments," "and other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0065] Please see Figure 1 The present invention provides a device for obtaining the pixel coordinates of an eccentric aiming device based on a distance sensor. The device includes a lens 10, an aiming device 20, a distance sensor 30, and a control unit 40. The aiming device 20 and the distance sensor 30 are respectively disposed on both sides of the lens 10. The aiming optical axis of the aiming device 20 is parallel to the central axis of the field of view of the lens 10, and the starting point of the center of the field of view of the lens 10 and the measurement starting point of the distance sensor 30 are on the same horizontal mounting surface.

[0066] Lens 10 is used to acquire the image corresponding to the imaging plane. Lens 10 has a field of view α, and the resolution of the acquired image is W×H, where W is the number of pixels in the width direction of the image and H is the number of pixels in the height direction of the image.

[0067] The aiming device 20 is used to project aiming light onto the imaging surface and form a light spot on the image; the horizontal physical distance between the aiming optical axis of the aiming device 20 and the center axis of the field of view of the lens 10 is d.

[0068] Distance sensor 30 is used to measure the distance h between the mounting surface and the imaging surface.

[0069] The control unit 40 is electrically connected to the lens 10, the aiming device 20, and the distance sensor 30 respectively. The control unit 40 is used to acquire the field of view angle α of the lens 10, the resolution W×H of the image, the horizontal physical distance d between the aiming optical axis of the aiming device 20 and the center axis of the field of view of the lens 10, and the distance h between the mounting surface and the imaging surface. It also calculates the pixel coordinates of the light spot of the aiming device 20 on the image according to the set algorithm.

[0070] The calculation process of the pixel coordinates of the light spot of the aiming device 20 on the image also differs depending on the different positional relationships between the aiming device 20 and the lens 10.

[0071] See Figure 1 In some preferred embodiments, the perpendicular line between the aiming optical axis of the sight 20 and the central axis of the field of view of the lens 10 is parallel to the wide side of the image, and the field of view angle α of the lens 10, the actual physical distance l1 between the two high sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following:

[0072]

[0073] but:

[0074]

[0075] In the image, the number of pixels N between the spot (point A) of the aiming device 20 and the center point (point O) of the image is:

[0076]

[0077] Expressing l1 using a relation containing α and h, and simplifying it, we get:

[0078]

[0079] The pixel coordinates of the spot (point A) of the sight 20 in the image are:

[0080]

[0081] Right now:

[0082]

[0083] It should be noted that the above calculation process corresponds to the case where the sight 20 is located on the right side of the wide edge of the lens 10 (e.g., Figure 1 As shown), the origin of the image coordinates is located at the lower left corner of the image. It can be understood that when the sight 20 is positioned to the left of the wide side of the lens 10, similar to the calculation process described above, the pixel coordinates of the light spot of the sight 20 in the image are:

[0084]

[0085] See Figure 2 In some other preferred embodiments, the perpendicular line between the aiming optical axis of the sight 20 and the field-of-view center axis of the lens 10 is parallel to the high side of the image, and the field-of-view angle α of the lens 10, the actual physical distance l2 between the two wide sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following:

[0086]

[0087] but:

[0088]

[0089] In the image, the number of pixels N between the light spot (point B) of the aiming device 20 and the center point (point O) of the image is:

[0090]

[0091] Expressing l2 using a relation containing α and h, and simplifying it, we get:

[0092]

[0093] The pixel coordinates of the spot (point B) of the sight 20 in the image are:

[0094]

[0095] Right now:

[0096]

[0097] It should be noted that the above calculation process corresponds to the case where the sight 20 is located on the rear side of the high edge of the lens 10 (e.g., Figure 2 As shown), the origin of the image coordinates is located at the lower left corner of the image. It can be understood that when the sight 20 is positioned in front of the high edge of the lens 10, similar to the calculation process described above, the pixel coordinates of the light spot of the sight 20 in the image are:

[0098]

[0099] According to another aspect of the present invention, a method for obtaining the pixel coordinates of an off-center sight based on a distance sensor is provided, comprising the following steps:

[0100] Step S1: Provide the device for obtaining the pixel coordinates of the eccentric aiming point based on the distance sensor as described above, install the aiming point 20 and the distance sensor 30 on both sides of the lens 10 respectively, and ensure that the aiming optical axis of the aiming point 20 is parallel to the center axis of the field of view of the lens 10, and the starting point of the center of the field of view of the lens 10 and the measurement starting point of the distance sensor 30 are on the same horizontal mounting surface.

[0101] Step S2: Project the aiming light onto the imaging surface using the aiming device 20, acquire the image corresponding to the imaging surface using the lens 10, and acquire the field of view angle α of the lens 10, the resolution W×H of the image, and the horizontal physical distance d between the aiming optical axis of the aiming device 20 and the center axis of the field of view of the lens 10; where W is the number of pixels in the width direction of the image and H is the number of pixels in the height direction of the image.

[0102] Step S3: Use distance sensor 30 to obtain the distance h between the mounting surface and the imaging surface;

[0103] Step S4: Calculate the pixel coordinates of the light spot of the aiming device 20 on the image according to the set algorithm.

[0104] The calculation process of the pixel coordinates of the light spot of the aiming device 20 on the image also differs depending on the different positional relationships between the aiming device 20 and the lens 10.

[0105] See Figure 1 In some preferred embodiments, when the perpendicular line between the aiming optical axis of the sight 20 and the center axis of the field of view of the lens 10 is parallel to the wide side of the image, the field of view angle α of the lens 10, the actual physical distance l1 between the two high sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following:

[0106]

[0107] but:

[0108]

[0109] In the image, the number of pixels N between the spot (point A) of the aiming device 20 and the center point (point O) of the image is:

[0110]

[0111] Expressing l1 using a relation containing α and h, and simplifying it, we get:

[0112]

[0113] The pixel coordinates of the spot (point A) of the sight 20 in the image are:

[0114]

[0115] Right now:

[0116]

[0117] It should be noted that the above calculation process corresponds to the case where the sight 20 is located on the right side of the wide edge of the lens 10, and the origin of the image coordinates is located at the lower left corner of the image. It can be understood that when the sight 20 is located on the left side of the wide edge of the lens 10, the calculation process is similar, and the pixel coordinates of the light spot of the sight 20 in the image are:

[0118]

[0119] In some other preferred embodiments, when the perpendicular line between the aiming optical axis of the sight 20 and the field-of-view center axis of the lens 10 is parallel to the high side of the image, the field-of-view angle α of the lens 10, the actual physical distance l2 between the two wide sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following:

[0120]

[0121] but:

[0122]

[0123] In the image, the number of pixels N between the light spot (point B) of the aiming device 20 and the center point (point O) of the image is:

[0124]

[0125] Expressing l2 using a relation containing α and h, and simplifying it, we get:

[0126]

[0127] The pixel coordinates of the spot (point B) of the sight 20 in the image are:

[0128]

[0129] Right now:

[0130]

[0131] It should be noted that the above calculation process corresponds to the case where the aiming device 20 is located behind the high edge of the lens 10, and the origin of the image coordinates is located at the lower left corner of the image. It can be understood that when the aiming device 20 is located in front of the high edge of the lens 10, the calculation process is similar, and the pixel coordinates of the light spot of the aiming device 20 in the image are:

[0132]

[0133] In application, the lens 10, aiming device 20, and distance sensor 30 can all be selected from existing related devices according to the actual situation, and the present invention does not impose further limitations on them.

[0134] In summary, this invention provides a device and method for obtaining the coordinates of an eccentric sight's light spot based on a distance sensor. The device utilizes a distance sensor to measure the distance between the mounting surface and the imaging surface. Based on the lens's field of view, image resolution, the physical distance between the sight's aiming light starting point and the lens's field of view center, and the distance between the mounting surface and the imaging surface, the precise pixel coordinates of the eccentric sight's light spot on the image are calculated. This facilitates barcode position prediction, ensures the effectiveness of the scanner's automatic exposure, and improves decoding efficiency.

[0135] The present invention has been described in the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. Conversely, any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

Claims

1. A device for acquiring pixel coordinates of an eccentric sight based on a distance sensor, characterized in that: It includes a lens, a sight, a distance sensor, and a control unit. The sight and the distance sensor are respectively located on both sides of the lens. The aiming optical axis of the sight is parallel to the center axis of the field of view of the lens, and the starting point of the center of the field of view of the lens and the measurement starting point of the distance sensor are on the same horizontal mounting surface. The lens is used to acquire an image corresponding to the imaging plane. The lens has a field of view α, and the resolution of the image is W×H; where W is the number of pixels in the width direction of the image, and H is the number of pixels in the height direction of the image. The sight is used to project aiming light onto the imaging surface and form a light spot on the image; the horizontal physical distance between the aiming optical axis of the sight and the central axis of the field of view of the lens is d; The distance sensor is used to measure the distance h between the mounting surface and the imaging surface; The control unit is electrically connected to the lens, the aiming device, and the distance sensor respectively. The control unit is used to obtain the field of view angle α of the lens, the resolution W×H of the image, the horizontal physical distance d between the aiming optical axis of the aiming device and the center axis of the field of view of the lens, and the distance h between the mounting surface and the imaging surface, and to calculate the pixel coordinates of the light spot of the aiming device on the image according to the set algorithm.

2. The device for obtaining the pixel coordinates of an eccentric sight based on a distance sensor as described in claim 1, characterized in that: The perpendicular line between the aiming optical axis of the sight and the central axis of the field of view of the lens is parallel to the wide side of the image. The field of view angle α of the lens, the actual physical distance l1 between the two high sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following: In the image, the number of pixels N between the light spot of the sight and the center point of the image is: Expressing l1 using a relation containing α and h, and simplifying it, we get: The pixel coordinates of the sight's spot in the image are: Right now:

3. The apparatus for obtaining the pixel coordinates of an eccentric sight based on a distance sensor as described in claim 1, characterized in that: The perpendicular line between the aiming optical axis of the sight and the central axis of the field of view of the lens is parallel to the high side of the image. The field of view angle α of the lens, the actual physical distance l2 between the two wide sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following: In the image, the number of pixels N between the light spot of the sight and the center point of the image is: Expressing l2 using a relation containing - and h, and simplifying it, we get: The pixel coordinates of the sight's spot in the image are: Right now:

4. A method for obtaining the pixel coordinates of an eccentric sight based on a distance sensor, characterized in that: Includes the following steps: Step S1: Provide an apparatus for obtaining the pixel coordinates of an eccentric sight based on a distance sensor as described in any one of claims 1-3, wherein the sight and the distance sensor are respectively mounted on both sides of the lens, and the aiming optical axis of the sight is parallel to the center axis of the field of view of the lens, and the starting point of the center of the field of view of the lens and the measurement starting point of the distance sensor are on the same horizontal mounting surface. Step S2: Project the aiming light onto the imaging surface using the aiming device, acquire the image corresponding to the imaging surface using the lens, and acquire the field of view angle α of the lens, the resolution W×H of the image, and the horizontal physical distance d between the aiming optical axis of the aiming device and the center axis of the field of view of the lens; Step S3: Use the distance sensor to obtain the distance h between the mounting surface and the imaging surface; Step S4: Calculate the pixel coordinates of the aiming point on the image according to the set algorithm.

5. The method for obtaining the pixel coordinates of an eccentric sight based on a distance sensor as described in claim 4, characterized in that: When the perpendicular line between the aiming optical axis of the sight and the center axis of the field of view of the lens is parallel to the wide side of the image, the field of view angle α of the lens, the actual physical distance l1 between the two high sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following: In the image, the number of pixels N between the light spot of the sight and the center point of the image is: Expressing l1 using a relation containing α and h, and simplifying it, we get: The pixel coordinates of the sight's spot in the image are: Right now:

6. The method for obtaining the pixel coordinates of an eccentric sight based on a distance sensor as described in claim 4, characterized in that: When the perpendicular line between the aiming optical axis of the sight and the center axis of the field of view of the lens is parallel to the high side of the image, the field of view angle α of the lens, the actual physical distance l2 between the two wide sides of the image, and the distance h between the mounting surface and the imaging surface satisfy the following: In the image, the number of pixels N between the light spot of the sight and the center point of the image is: Expressing l2 using a relation containing α and h, and simplifying it, we get: The pixel coordinates of the sight's spot in the image are: Right now:

Images