Combination of 2-D detector array with display for image processing

• US 5,917,464 A
• Filed: 10/18/1994
• Issued: 06/29/1999
• Est. Priority Date: 10/18/1994
• Status: Expired due to Term

• Current Assignee: Thomson Licensing (Vantiva SA)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Stearns, Richard G.
• Primary Examiner(s): WU, XIAO MIN
• Application Number:
  US08/325,008
• Time in Patent Office: 1,715 Days
• Field of Search: 345/205, 345/206, 345/207, 345/97, 345/104, 345/87, 345/98, 345/100, 382/312, 382/317, 382/318
• US Class Current: 345/87
• CPC Class Codes: G02F 1/1354 having a particular photoconducting structure or material
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: H04N 1/00127 Connection or combination of a still picture apparatus with another apparatus, e.g. for storage, processing or transmission of still picture signals or of information associated with a still picture
• CPC Class Codes: H04N 1/00129 with a display device, e.g. CRT or LCD monitor with a television apparatus H04N1/00283; arrangements for control of display devices G09G
• CPC Class Codes: H04N 1/028 for picture information pick-up
• CPC Class Codes: H04N 1/02805 with photodetectors arranged in a two-dimensional array
• CPC Class Codes: H04N 2201/0081 Image reader H04N2201/0091 - H04N2201/0094 take precedence

Abstract

An image display/processing apparatus which integrates as a single unit a two-dimensional (2-D) display, such as an LCD, with a two-dimensional (2-D) sensor array, such as a photodiode array. The arrays are aligned with a pixel corresponding to a single sensor element of the sensor array. Levels from the sensor elements which have been thresholded to predetermined threshold values are fed-back to the LCD for image display and processing. The LCD image may be moved in a pixel increment by control circuitry to implement morphological image processing.

Claims

1. An image display/processing apparatus for morphological image processing, the apparatus comprising:

a liquid crystal display (LCD) having an array of thin film transistors (TFTs) positioned in rows and columns, corresponding to a plurality of LCD pixels;

a sensor array integrated with the LCD as a single unit, the sensor array having a plurality of photodiodes positioned in rows and columns, the array of TFTs and the array of photodiodes aligned with each other to allow a given LCD pixel to project onto a single given photodiode of the array of photodiodes;

driving circuitry integrated with both the LCD and sensor array comprising addressing lines for independent addressing of the given LCD Pixel and the given photodiode, configured to operate the LCD and sensor array in synchronism;

a feedback circuit to feedback to the LCD data obtained by the photodiodes representative of a status of the LCD pixels; and

morphological image processing means to control operation of the integrated LCD and sensor array arrangement based upon said data obtained by the photodiodes.

2. An image display/processing apparatus comprising:

a liquid crystal display (LCD) having an array of switching elements, corresponding to a plurality of LCD pixels;

a sensor array integrated with the LCD to form a single unit, the sensor array having a plurality of sensor elements positioned in rows and columns in the array, the array of switching elements and the array of sensor elements aligned with each other to allow a given LCD pixel to project onto a corresponding sensor element of the array of sensor elements; and

driving circuitry in operative connection with both the LCD and sensor array comprising independent addressing lines to the given LCD pixel and the corresponding sensor element.

3. The apparatus according to claim 2 further including morphological image processing means to control operation of the integrated LCD and sensor array arrangement.

4. The apparatus according to claim 2 wherein the LCD and sensor array are formed on two separate substrates and are then integrated.

5. The apparatus according to claim 2 wherein the LCD and sensor array are formed on a single substrate.

6. The apparatus according to claim 4 wherein a gap between the sensor array and LCD is equal to or less than on the order of an LCD pixel pitch.

7. The apparatus according to claim 4 wherein the sensor elements include sensing capabilities on a first side and a second side, whereby scanning of a document placed on the second side of the sensor elements is achieved.

8. The apparatus according to claim 2 wherein the sensor array is a photodiode array.

9. The apparatus according to claim 2 wherein the sensor array further includes a means for dynamically programming the sensor array to integrate a sensing current.

10. The apparatus according to claim 2 wherein the single unit further includes:

a glass substrate having the switching elements fabricated thereon as thin film transistors (TFTs);

a layer of liquid crystal material applied on top of the TFTs;

a glass coverplate coated with a transparent coating placed over the liquid crystal material;

a thin polarizing plate bonded on a first side to the transparent conductive coating; and

said sensor elements having a first side and a second side with at least the first side having sensing capabilities, and the sensing elements bonded, by the first side, to a second side of the thin polarizing plate, whereby the first side of the sensing elements senses towards the LCD.

11. The apparatus according to claim 2 wherein the LCD is a ferroelectric display.

12. The apparatus according to claim 10 wherein the TFTs are poly-silicon TFTs.

13. The apparatus according to claim 2 wherein the sensing elements are a-Si:

H sensors.

14. The apparatus according to claim 2 further including a transferring means for transferring an output from the sensor array directly to the LCD, thereby eliminating intermediate storage of sensor element output.

15. The apparatus according to claim 2 wherein the array of switching elements include first addressing electrodes and the array of sensor elements include second addressing electrodes spaced from said first addressing electrodes.

16. A method for displaying and processing an image on an integrated display/processing apparatus comprising the steps:

loading a liquid crystal device (LCD) with image data, the LCD being in the form of an array with LCD switching elements positioned at rows and columns and with a pixel associated with each of the switching elements;

displaying an image by adjusting each of the pixels in accordance with the loaded image data;

sensing data of the displayed image by a sensor array comprised of a plurality of sensing elements located at rows and columns independently addressable from said LCD switching elements, the sensor array integrated as a single unit with the LCD, the sensor array and LCD aligned with each other to allow a given LCD pixel to project fully onto one sensing element of the sensing array;

feeding back data from the sensor array to the LCD based on the data of the displayed image; and

processing the feedback data of the displayed image.

17. The method according to claim 16 further including a step of driving the LCD and sensor array by a single driving circuit.

18. The method according to claim 17 wherein the driving step further includes driving the LCD and sensor array in synchronism.

19. The method according to claim 16 further including dynamically programming the sensor array to integrated data obtained by the sensing elements for predetermined length of time.

20. The method according to claim 19 wherein the predetermined length of time is for a specified number of LCD frames.

21. The method according to claim 18 wherein the driving step further includes shifting the image on the LCD.

22. The method according to claim 18 wherein the driving step further includes reading out a line of the sensor array at a same time as a corresponding LCD line is updated.

23. The method according to claim 16 further including morphologically processing the displayed image.

24. The method according to claim 23 wherein the morphologically processing includes:

defining a structuring element;

shifting the image as prescribed by the structuring element to generate multiple shifted images of the original; and

performing boolean operations using the original image and the multiple shifted images.

25. The method according to claim 23 wherein the morphologically processing includes,

integrating data obtained by the sensing elements over all translations of an original LCD image.

26. The method according to claim 23 wherein the morphologically processing for dilation includes,

zeroing the sensing elements;

sequentially loading LCD images at a rate of 1/Δ

T, where T equals time;

integrating the loaded LCD images;

reading the sensor array after time (N+1)Δ

T; and

thresholding the sensor array to a value of (1) when a sensor level corresponds to a pixel being in an ON state of the LCD for a period Δ

T or greater, with other signals being thresholded to (0).

27. The method according to claim 23 wherein the morphologically processing, for erosion, includes;

displaying on the LCD, at a rate of 1/Δ

T, a set of N images translated by a predetermined inverted shift;

reading out the sensor array after a time (N+1)Δ

T; and

thresholding the sensor array to a value of (1) when a sensor level corresponds to a pixel being in the ON state of the LCD for a period (N+1)Δ

T, with other signals thresholded to (0).

28. The method according to claim 16 wherein the displaying comprises addressing the LCD switching elements of the pixels by a first set of electrodes and said sensing comprises addressing the sensing elements by a second set of electrodes.