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US-20260127849-A1 - SIMILARITY DETECTION SYSTEM AND METHOD

US20260127849A1US 20260127849 A1US20260127849 A1US 20260127849A1US-20260127849-A1

Abstract

A similarity detection system includes at least one summation device that sums video data of a current frame, thereby generating a current sum associated with the current frame, the summation device applying a set of different weights for pixel values of the video data at different locations; at least one difference device that generates a difference between the current sum and a reference sum; and at least one comparator that compares the difference with a predetermined threshold, thereby generating a comparison result indicating similarity between the video data of the current frame and reference video data.

Inventors

  • Ming-Chih Wang

Assignees

  • HIMAX TECHNOLOGIES LIMITED

Dates

Publication Date
20260507
Application Date
20241106

Claims (20)

  1. 1 . A similarity detection system, comprising: at least one summation device that sums video data of a current frame, thereby generating a current sum associated with the current frame, the summation device applying a set of different weights for pixel values of the video data at different locations; at least one difference device that generates a difference between the current sum and a reference sum; and at least one comparator that compares the difference with a predetermined threshold, thereby generating a comparison result indicating similarity between the video data of the current frame and reference video data.
  2. 2 . The system of claim 1 , further comprising: a truncator that truncates at least one least significant bit (LSB) of each pixel value of the video data before the video data is received by the summation device.
  3. 3 . The system of claim 1 , further comprising: a validator that determines similarity of the video data according to the comparison result; wherein similarity of the video data is confirmed, if the difference is less than the predetermined threshold.
  4. 4 . The system of claim 1 , wherein the at least one summation device comprises a plurality of summation devices with different sets of weights, each configured to sum the video data of the current frame with a corresponding set of weights, thereby generating a corresponding current sum.
  5. 5 . The system of claim 4 , wherein the at least one difference device comprises a plurality of difference devices, each configured to generate a corresponding difference between the corresponding current sum and a corresponding reference sum.
  6. 6 . The system of claim 5 , wherein the at least one comparator comprises a plurality of comparators, each configured to compare the corresponding difference with a corresponding predetermined threshold, thereby generating a corresponding comparison result.
  7. 7 . The system of claim 6 , further comprising: a validator that determines similarity of the video data according to all comparison results; wherein similarity of the video data is confirmed, if every difference is less than the corresponding predetermined threshold.
  8. 8 . The system of claim 1 , further comprising: a dithering device that converts the video data from one color depth to another color depth and performs dithering on the video data before the video data is received by the summation device.
  9. 9 . The system of claim 8 , wherein a frozen screen is detected, if similarity is confirmed according to the comparison result.
  10. 10 . The system of claim 1 , further comprising: an on-screen display (OSD) element generator that generates an OSD element; a host mixer that overlays the OSD element on original video data, thereby resulting in mixed video data; and an OSD region device that generates a weighted sum of an OSD region of the mixed video data as the reference sum.
  11. 11 . The system of claim 10 , wherein correctness of the OSD element is detected, if similarity is confirmed according to the comparison result.
  12. 12 . The system of claim 11 , further comprising: at least one image processing device that processes the mixed video data, thereby resulting in processed video data; an OSD overwriter that generates a predetermined OSD element, the OSD overwriter being activated when similarity is not confirmed; and a display mixer that overlays the predetermined OSD element on the processed video data.
  13. 13 . The system of claim 1 , further comprising: a pseudorandom number generator that generates a sequence of random numbers as the set of different weights.
  14. 14 . A similarity detection method, comprising: summing video data of a current frame with a set of different weights for pixel values of the video data at different locations, thereby generating a current sum associated with the current frame; generating a difference between the current sum and a reference sum; and comparing the difference with a predetermined threshold, thereby generating a comparison result indicating similarity between the video data of the current frame and reference video data.
  15. 15 . The method of claim 14 , further comprising: truncating at least one least significant bit (LSB) of each pixel value of the video data before the current sum is generated.
  16. 16 . The method of claim 14 , further comprising: determining similarity of the video data according to the comparison result; wherein similarity of the video data is confirmed, if the difference is less than the predetermined threshold.
  17. 17 . The method of claim 14 , further comprising: converting the video data from one color depth to another color depth and performing dithering on the video data before the current sum is generated; wherein a frozen screen is detected, if similarity is confirmed according to the comparison result.
  18. 18 . The method of claim 14 , further comprising: generating an on-screen display (OSD) element; overlaying the OSD element on original video data, thereby resulting in mixed video data; and generating a weighted sum of an OSD region of the mixed video data as the reference sum.
  19. 19 . The method of claim 18 , wherein correctness of the OSD element is detected, if similarity is confirmed according to the comparison result.
  20. 20 . The method of claim 19 , further comprising: processing the mixed video data, thereby resulting in processed video data; generating a predetermined OSD element; and overlaying the predetermined OSD element on the processed video data only when similarity is not confirmed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to similarity detection, and more particularly to a similarity detection system and method capable of detecting frozen screen and on-screen display (OSD). 2. Description of Related Art The significance of frozen screen detection in in-vehicle display modules cannot be overstated, as it is a critical part of functional safety in modern vehicles. For example, the rearview mirror is a critical component for drivers to maintain awareness of their surroundings and traffic conditions. A frozen rearview mirror that becomes unresponsive and stops updating may potentially lead to dangerous misjudgment of distances and the positions of other vehicles. As another example, if the speedometer on the dashboard loses updates and remains unchanged, drivers may become confused and put themselves in danger. In the realm of video data processing, particularly when dealing with color depth conversion (for example, converting from 10-bit to 8-bit), as a generic concept of dithering, the converted 8-bit data will follow the least-significant-bit (LSB) change (or dithering) of the original 10-bit data. The dithering may introduce minor disturbances or errors. These slight alterations in pixel values necessitate robust frozen screen detection methods that can discern between these expected changes and actual screen freezing events, particularly for in-vehicle display modules without frame buffer for the purpose of reduced cost and simplified design. Traditional techniques like Cyclic Redundancy Check (CRC) may miss detection of a frozen screen due to disturbances or errors caused by dithering. Conversely, methods such as checksum can lead to false alarms due to distinct frames with the same sum. On the other hand, in a display module with frame buffer, screen freezing events can be easily detected by comparing video data of the current frame with video data of the previous frame stored in the frame buffer, but the chip cost will be higher due to the frame buffer. The accuracy of on-screen displays (OSD) in vehicles is indeed a critical component of functional safety, especially as we move towards higher levels of vehicular autonomy. As in-vehicle display technology advances, the integration of accurate and reliable OSDs becomes imperative to ensure that drivers and autonomous systems have precise information about the vehicle's status and the surrounding environment. This is crucial for preventing misjudgments, which could lead to accidents. The reliability of these systems directly impacts the effectiveness of OSDs in conveying critical information, thereby playing a substantial role in maintaining and improving road safety. A need has thus arisen to propose a novel scheme capable of improving the reliability of frozen screen detection and OSD correctness detection. The proposal of the novel scheme reflects the automotive industry's commitment to leveraging technology for safety and underscores the importance of reliable frozen screen and OSD detection mechanisms. SUMMARY OF THE INVENTION In view of the foregoing, it is an object of the embodiment of the present invention to provide a similarity detection system and method with enhanced and accurate detection of frozen screen or on-screen display (OSD) particularly adaptable to an in-vehicle display device without frame buffer. According to one embodiment, a similarity detection system includes at least one summation device, at least one difference device and at least one comparator. The summation device sums video data of a current frame, thereby generating a current sum associated with the current frame, the summation device applying a set of different weights for pixel values of the video data at different locations. The difference device generates a difference between the current sum and a reference sum. The comparator compares the difference with a predetermined threshold, thereby generating a comparison result indicating similarity between the video data of the current frame and reference video data. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A shows a block diagram illustrating a similarity detection system according to one embodiment of the present invention; FIG. 1B shows a block diagram illustrating a similarity detection system according to an alternative embodiment of the present invention; FIG. 1C shows a block diagram illustrating a similarity detection system according to an alternative embodiment of the present invention; FIG. 2 shows a block diagram illustrating a digital image processing system adopting the similarity detection system of FIG. 1A, FIG. 1B or FIG. 1C according to one exemplary embodiment of the present invention; and FIG. 3 shows a block diagram illustrating a digital image processing system adopting the similarity detection system of FIG. 1A, FIG. 1B or FIG. 1C according to another exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE I