Image sensing apparatus and analog-to-digital converter control method
By introducing offset control circuit and automatic exposure control into the optical mouse, adjusting the ADC offset according to image quality and average pixel value, the power consumption problem of the optical mouse when moving on a high-quality surface is solved, and energy saving and image quality improvement is achieved.
Patent Information
- Application Number
- CN202411385657.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-01-23
- Filing Date
- 2024-09-30
- Publication Date
- 2025-07-25
AI Technical Summary
When existing optical mice move on high-quality surfaces, the light emission time of the light source is not optimized, resulting in increased power consumption and failure to effectively improve image quality.
By introducing an offset control circuit into the image sensing device, the offset of the ADC is adjusted according to the image quality and average pixel value, and combined with automatic exposure control, the luminescence time of the light source is optimized to reduce unnecessary illumination.
While ensuring correct calculation of movement, the light emission time of the light source is reduced, thereby saving power consumption of the optical mouse, while improving the image quality of the image sensing device.
Smart Images
Figure CN120378764A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an image sensing device and an ADC (Analog to Digital Converter) offset control method, and particularly to an image sensing device and an ADC offset control method capable of automatically and dynamically adjusting the ADC offset of an image sensing device. Background Art
[0002] Existing optical mice usually include an ADC and use a fixed ADC offset to improve image quality. However, this mechanism does not take into account the issue of light source power consumption. In addition, when an optical mouse moves on a high-quality surface, the image of the high-quality surface does not need to have high brightness for the optical mouse to be used, but the light emission time of the light source in the existing optical mouse does not optimize in consideration of this point. Summary of the Invention
[0003] An object of the present invention is to disclose an image sensing device that can reduce power consumption while ensuring correct calculation of movement.
[0004] Another object of the present invention is to disclose an ADC control method that can reduce the power consumption of an image sensing device while ensuring correct calculation of movement.
[0005] An embodiment of the present invention discloses an image sensing device, including: a pixel array for generating an analog image sensing signal; an ADC for converting the analog image sensing signal into a digital image sensing signal; and an offset control circuit for adjusting the ADC offset of the ADC according to the image quality and the average pixel value of an image, the image being generated from the previous image sensing signals sensed by the pixel array.
[0006] Another embodiment of the present invention discloses an ADC control method used in an image sensing device including a pixel array and an ADC, including: (a) generating an analog image sensing signal with the pixel array; (b) converting the analog image sensing signal into a digital image sensing signal with the ADC; and (c) adjusting the ADC offset of the ADC according to the image quality and the average pixel value of an image, the image being generated from the previous image sensing signals sensed by the pixel array.
[0007] Another embodiment of the present invention discloses an electronic device, including: an image sensor for sensing a working surface on which the electronic device moves and judging the image quality of the working surface; and a light source for irradiating the working surface with a first light intensity when the image quality is higher than a first image quality threshold, and irradiating the working surface with a second light intensity when the image quality is lower than a second image quality threshold, the first light intensity being lower than the second light intensity.
[0008] According to the above embodiments, the light emitting time of the light source can be reduced while ensuring correct calculation of movement, so the power consumption of the optical mouse can be saved. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Figure 1 FIG. is a schematic diagram of an image sensing device according to an embodiment of the present invention.
[0010] Figure 2 FIG. is a schematic diagram of an optical mouse including the Figure 1 image sensing device shown.
[0011] Figure 3 FIG. is a schematic diagram of an ADC offset control method performed by the Figure 1 image sensing device shown according to an embodiment of the present invention.
[0012] Figure 4 FIG. shows a Figure 3 table of the actions shown.
[0013] Figure 5 FIG. is a schematic diagram of an ADC offset control method performed by the Figure 1 image sensing device shown according to another embodiment of the present invention.
[0014] Figure 6 FIG. is a flowchart of an ADC offset control method according to an embodiment of the present invention.
[0015] Among them, the reference numerals are explained as follows:
[0016] 100 Image sensing device
[0017] 101 Pixel array
[0018] 103 Read circuit
[0019] 105 ADC
[0020] 107 Offset control circuit
[0021] 200 Optical mouse
[0022] 201 Processing circuit
[0023] 601, 603, 605 Steps
[0024] AIS_1…AIS_n Analog image sensing signals
[0025] LS Light source
[0026] Sr Working surface DETAILED DESCRIPTION OF THE EMBODIMENTS
[0027] The content of the present invention will be described with multiple embodiments hereinafter. Please also note that the elements in each embodiment can be implemented by hardware (such as a device or a circuit) or firmware (such as writing at least one program in a microprocessor). In addition, the "first", "second" and similar descriptions in the following description are only used to define different elements, parameters, data, signals or steps, and are not used to limit their order. For example, the first device and the second device may have the same structure but be different devices.
[0028] In addition, in the following description, an optical mouse is taken as an example for illustration. However, the image sensing device and the ADC offset control method disclosed in the present invention can be applied to any other optical device.
[0029] Figure 1 FIG. is a schematic diagram of an image sensing device 100 according to an embodiment of the present invention. As Figure 1 shown, the image sensing device 100, or referred to as an image sensor, includes a pixel array 101, a read circuit 103, an ADC 105, and an offset control circuit 107. The pixel array 101 is used to generate analog image sensing signals AIS_1... AIS_n. In one embodiment, the pixel array 101 includes a plurality of pixel circuits, and the pixel circuits can generate corresponding charges according to the light received by the pixel circuits. In this embodiment, the read circuit 103 is used to read the charges from the pixel circuits to generate analog image sensing signals AIS_1... AIS_n.
[0030] The ADC 105 is used to convert the analog image sensing signals AIS_1... AIS_n into digital image sensing signals DIS_1... DIS_n. The offset control circuit 107 is used to adjust the ADC offset of the ADC 105 corresponding to the image quality and the average pixel value of the image generated according to the previous analog image sensing signals sensed by the pixel array. For example, the pixel array 101 senses the analog image sensing signals and generates a first image according to the analog image sensing signals. After the first image, the pixel array 101 senses other analog image sensing signals and generates a second image according to the analog image sensing signals. In this case, the offset control circuit 107 adjusts the ADC offset of the second image corresponding to the image quality and the average pixel value of the first image. In one embodiment, the image sensing device 100 further includes an ISP (Image Signal Processor) to generate the first image and the second image.
[0031] Figure 2 FIG. is a schematic diagram of an optical mouse including the Figure 1 image sensing device 100 shown according to an embodiment of the present invention. As Figure 2As shown, the optical mouse 200 includes a processing circuit 201, a light source LS, and an image sensing device 100. The optical mouse 200 is located on a working surface Sr, and the light source LS is used to emit light from the image sensing device 100 to the working surface Sr. The image sensing device 100 is used to sense an image based on the reflected light of the surface Sr. The processing circuit 201 is used to calculate the movement based on the image generated by the image sensing device 100.
[0032] Also note that the movement calculation can be performed by the image sensing device 100, and is not limited to being performed by the processing circuit 201 independent of the image sensing device 100. Additionally, in one embodiment, the processing circuit 201 is also used to control the optical mouse 200 based on the movement. For example, if the movement is low within a predetermined time interval, the processing circuit 201 can control the optical mouse 200 to switch to the standby mode, and if the movement changes from low to high, the processing circuit 201 returns to the active mode. Furthermore, in Figure 3 the embodiment, since the image sensed by the image sensing device 100 is the image of the working surface Sr, the image quality of the image corresponds to the surface quality of the working surface Sr. In one embodiment, the surface quality refers to whether the features (e.g., texture, markings, cracks) on the surface are obvious. The more obvious the features (i.e., the higher the feature degree), the easier it is for the processing circuit 201 to calculate the correct movement, so in this case the surface quality is higher. In this case, the image quality also represents the feature level of the image.
[0033] Figure 3 To illustrate the Figure 1 schematic diagram of the ADC offset control method performed by the image sensing device shown according to an embodiment of the present invention. In Figure 3 the embodiment, if the image quality is higher than the first image quality threshold and the average pixel value is lower than the first pixel value threshold, the offset control circuit 107 increases the ADC offset. A higher ADC offset means that the ADC 105 will increase the pixel value by a larger value when converting the analog image sensing signal into a digital image sensing signal. For example, if the ADC 105 initially converts the analog image sensing signal into pixel values 1, pixel values 2... pixel values n, if the ADC offset increases, the ADC 105 will convert the same analog image sensing signal into pixel values 1 + k, pixel values 2 + k... pixel values n + k. In other words, if the image quality of the previous image is higher than the first image quality threshold and the average pixel value of the previous image is lower than the first pixel value threshold, the image sensing device 100 will adjust the image to be brighter.
[0034] In Figure 3 the embodiment, the image sensing device 100 may have an automatic exposure control mechanism, so the emission time (i.e., the on - time) of the light source LS will decrease corresponding to the increase in the ADC offset amount, as Figure 3As shown. More specifically, the processing circuit 201 controls the light emission time of the light source LS corresponding to the luminance of the previous image. If the previous image is brighter, the next illumination time is reduced to avoid saturation of the pixel values of the image, that is, to avoid the pixel values of the image exceeding the saturation threshold. Therefore, since an increase in the ADC offset means an increase in the image luminance, the light emission time of the light source LS is reduced corresponding to the increase in the ADC offset.
[0035] In addition, in Figure 3 , the image quality may also decrease corresponding to the increase in the ADC offset because the image becomes brighter. However, when the surface quality is high, even if the image becomes brighter, the features in the image may still be sufficiently obvious. And as mentioned above, the ADC offset means an increment of the pixel value, so the average pixel value increases corresponding to the increase in the ADC offset, as Figure 3 shown.
[0036] Figure 4 illustrates Figure 3 a table of the actions shown. Also note that Figure 4 is only an example for explanation, Figure 4 and the values shown in Figure 4 do not mean to limit any scope of the present invention. In addition, Figure 4 the numerical values shown in
[0037] are only for showing the trend of change, so Figure 4 the units of each parameter are not shown in Figure 4 shown. When the ADC offset increases, the AP also increases. On the contrary, when the ADC offset increases, the IQ and LT decrease. Therefore, Figure 4 the numerical values shown in Figure 3 follow the trend shown in the line graph of
[0038] In addition to increasing automatically, the ADC offset can also be automatically reduced according to specific conditions. Figure 5 is a schematic diagram illustrating an ADC offset control method performed by an image sensing device shown in Figure 1 according to another embodiment of the present invention. In Figure 5In an embodiment, if the image quality is lower than a second image quality threshold and the average pixel value is higher than a second pixel value threshold, the offset control circuit 107 reduces the ADC offset. The second image quality threshold may be the same as the first image quality threshold, but may also be different from the first image quality threshold. Additionally, the second pixel value threshold may be the same as the first pixel value threshold, but may also be different from the first pixel value threshold.
[0039] As described above, a higher ADC offset means that the ADC 105 increases the pixel value by a larger value when converting the analog image sensing signal into a digital image sensing signal. Therefore, a lower ADC offset means that the ADC 105 increases the pixel value by a smaller value when converting the analog image sensing signal into a digital image sensing signal. In other words, if the image quality is lower than the second image quality threshold and the average pixel value is higher than the second pixel value threshold, the image sensing device 100 adjusts the image to be darker.
[0040] As described above, the image sensing device 100 may have an automatic exposure control mechanism, so the light emission time (i.e., the on-time) of the light source LS increases corresponding to the reduction of the ADC offset, as Figure 5 shown. More specifically, the processing circuit 201 controls the light emission time of the light source LS corresponding to the brightness of the previous image. If the previous image is darker, the next illumination time is increased to control the image brightness close to a predetermined value. Therefore, since the reduction of the ADC offset means the reduction of the image brightness, the light emission time of the light source LS increases corresponding to the reduction of the ADC offset.
[0041] Additionally, in Figure 5 , if the image is already too bright, the image quality may also increase corresponding to the reduction of the ADC offset. Moreover, as described above, the ADC offset represents the increase amount of the pixel value, so the average pixel value decreases corresponding to the reduction of the ADC offset, as Figure 5 shown.
[0042] Figure 5 The steps shown in Figure 3 can follow the steps shown in Figure 3 . That is, if increasing the ADC offset through the steps shown in Figure 3 results in a higher average pixel value and a lower image quality, the ADC offset can be adjusted lower so that the average pixel value can be reduced to approach the desired value and the image quality can be improved to the desired level. However, Figure 5 's steps can also be applied independently without being limited to being combined with Figure 3 's steps.
[0043] The above illumination time can be replaced by light intensity. Additionally, Figure 3 's illumination time decreases, while Figure 5 's illumination time increases, soFigure 3 has a shorter illumination time than Figure 5 . Correspondingly, if the embodiments of Figure 3 and Figure 5 are combined, the electronic device disclosed in the present invention can be summarized as:
[0044] An electronic device including an image sensor (e.g., the image sensing device 100) and a light source. The image sensor is used to sense the working surface (e.g., Figure 2 the working surface Sr in) on which the electronic device moves, and to judge the image quality of the working surface. When the image quality is higher than the first image quality threshold, the light source irradiates the working surface with a first light intensity (e.g., Figure 3 the embodiment of), and when the image quality is lower than the second image quality threshold, the light source irradiates the working surface with a second light intensity (e.g., Figure 5 the embodiment in). The first light intensity is lower than the second light intensity.
[0045] According to the foregoing embodiments, an ADC control method can be obtained, which is applied to an image sensing device including a pixel array and an ADC. Figure 6 FIG. is a flowchart showing an ADC offset control method according to an embodiment of the present invention, including the following steps:
[0046] Step 601
[0047] Generate an analog image sensing signal with a pixel array (e.g., the pixel array 101 in Figure 1 ).
[0048] Step 603
[0049] Convert the analog image sensing signal into a digital image sensing signal with an ADC (e.g., the ADC 105 in Figure 1 ).
[0050] Step 605
[0051] Adjust the ADC offset of the ADC according to the image quality and the average pixel value of the image, which is generated from the previous image sensing signal sensed by the pixel array.
[0052] In one embodiment, the light emitting time of the light source decreases corresponding to the increase of the ADC offset, as shown in the embodiment of Figure 3 . In another embodiment, the light emitting time of the light source increases corresponding to the decrease of the ADC offset, as shown in the embodiment of Figure 5 . It should also be noted that, in addition to the light emitting time of the light source, the sensing time of the pixel array can also be controlled according to the same rule.
[0053] According to the above embodiments, the light-emitting time of the light source can be reduced while ensuring correct calculation of movement, so the power consumption of the optical mouse can be saved.
[0054] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. An image sensing device, characterized in that, Comprising: A pixel array for generating analog image sensing signals; An ADC for converting the analog image sensing signals into digital image sensing signals; And An offset control circuit for adjusting the ADC offset of the ADC according to the image quality and the average pixel value of an image, the image being generated from previous image sensing signals sensed by the pixel array. Wherein if the image quality is higher than a first image quality threshold and the average pixel value is lower than a first pixel value threshold, the offset control circuit increases the ADC offset.
2. The image sensing device according to claim 1, wherein Further comprising:
3. The image sensing device according to claim 2, wherein A light source for emitting light out of the image sensing device; Wherein the light emitting time of the light source decreases corresponding to the increase of the ADC offset. Wherein the image quality decreases corresponding to the increase of the ADC offset.
4. The image sensing device according to claim 2, wherein Wherein if the image quality is lower than a second image quality threshold and the average pixel value is higher than a second pixel value threshold, the offset control circuit decreases the ADC offset.
5. The image sensing device according to claim 1, characterized in that, Further comprising:
6. The image sensing device according to claim 5, wherein A light source for emitting light out of the image sensing device; Wherein the light emitting time of the light source increases corresponding to the decrease of the ADC offset. Wherein the image quality increases corresponding to the decrease of the ADC offset.
7. The image sensing device according to claim 5, wherein The image sensing device is located on a working surface, and the image quality corresponds to the surface quality of the working surface.
8. The image sensing device according to claim 1, wherein The image sensing device is an optical mouse.
9. The image sensing device according to claim 1, wherein Comprising:
10. A method for controlling an analog-to-digital converter, which is used in an image sensing device including a pixel array and an analog-to-digital converter (ADC), characterized in that, (a) Generating analog image sensing signals with the pixel array; (b) Converting the analog image sensing signals into digital image sensing signals with the ADC; And (c) Adjusting the ADC offset of the ADC according to the image quality and the average pixel value of an image, the image being generated from previous image sensing signals sensed by the pixel array. Wherein if the image quality is higher than a first image quality threshold and the average pixel value is lower than a first pixel value threshold, step (c) increases the ADC offset.
11. The ADC control method according to claim 10, wherein 12. The ADC control method according to claim 11, characterized in that Wherein the image sensing device includes a light source for emitting light out of the image sensing device; Wherein the ADC control method includes: Decreasing the light emitting time of the light source corresponding to the increase of the ADC offset. Wherein the image quality decreases corresponding to the increase of the ADC offset.
13. The ADC control method according to claim 11, wherein Wherein if the image quality is lower than a second image quality threshold and the average pixel value is higher than a second pixel value threshold, step (c) decreases the ADC offset.
14. The ADC control method according to claim 10, wherein, Further comprising:
15. The ADC control method according to claim 14, wherein Wherein the image sensing device includes a light source for emitting light out of the image sensing device; Wherein the ADC control method includes: Increasing the light emitting time of the light source corresponding to the decrease of the ADC offset. Wherein the image quality increases corresponding to the decrease of the ADC offset.
16. The ADC control method according to claim 14, characterized in that, The image sensing device is located on a working surface, and the image quality corresponds to the surface quality of the working surface.
17. The ADC control method according to claim 10, wherein The image sensing device is an optical mouse.
18. The ADC control method according to claim 10, wherein, Comprising:
19. An electronic device, characterized in that, An image sensor for sensing a working surface on which the electronic device moves and for judging the image quality of the working surface; And A light source that irradiates the working surface with a first light intensity when the image quality is higher than a first image quality threshold and irradiates the working surface with a second light intensity when the image quality is lower than a second image quality threshold, the first light intensity being lower than the second light intensity.