Image acquisition system and method for acquiring variable sized objects

• US 6,970,182 B1
• Filed: 10/20/1999
• Issued: 11/29/2005
• Est. Priority Date: 10/20/1999
• Status: Expired due to Term

• Current Assignee: National Instruments Corporation (Emerson Electric Company)
• Original Assignee: National Instruments Corporation (Emerson Electric Company)
• Inventors: Hall, Mike, Schroeder, Charles, Odom, B. Keith, Schultz, Kevin L.
• Primary Examiner(s): VO, TUNG T
• Application Number:
  US09/421,963
• Time in Patent Office: 2,232 Days
• Field of Search: 348/552, 348/553, 348/554, 348/42, 348/86, 356/237, 356/379, 382/8, 382/101, 382/162, 250/563, 250/222.1, 700/217, 209/580
• US Class Current: 348/86
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30164 Workpiece; Machine component
• CPC Class Codes: G06T 7/0008 checking presence/absence

Abstract

A system and method for acquiring images of variably sized objects. An object detector provides an indication of the presence or absence of objects as they pass by. An image sensing device acquires image data for the objects. An image acquisition device starts an activity counter, and initiates storage of image data for an object in response to detecting presence of the object. The image data is stored into an on-board memory. The activity counter counts a number of acquired scan lines for the object. In response to detecting absence of the object, the image acquisition device terminates the activity counter, and discontinues storage of the image data for the object. The final activity counter value, which reflects the number of scan lines acquired for the object, is recorded in an on-board FIFO. The image data is transferred to a system memory image buffer in a system memory. Host software routines may read the on-board FIFO. The image acquisition device is configured to rearm for acquisition of another object by resetting the activity counter, and initializing a write pointer to the on-board memory so that it points to the top of a next on-board memory buffer. After rearming, the image acquisition device may acquire image data for a second object in response to detecting presence of the second object.

Claims

1. A method for acquiring images of variable sized objects in an image acquisition system, wherein the image acquisition system comprises an image sensing device and an image acquisition device, wherein the objects are moving relative to the image sensing device, wherein the method acquires images independent of spacing between the objects, the method comprising:

(a) the image acquisition device physically detecting presence of a first object;

(b) the image sensing device generating image data corresponding to the first object;

(c) the image acquisition device initiating storage of the image data corresponding to the first object in response to the image acquisition device detecting the presence of the first object;

(d) the image acquisition device physically detecting absence of the first object after detecting presence of the first object;

(e) the image acquisition device discontinuing storage of the image data corresponding to the first object in response to the image acquisition device detecting the absence of the first object;

wherein an amount of the stored image data substantially corresponds to a size of the first object;

the image acquisition device initiating a counter of scan lines in response to the image acquisition device detecting the presence of the first object;

the image acquisition device terminating the counter of the scan lines in response to the image acquisition device detecting an absence of the first object;

the image acquisition device recording a final value of the counter after said terminating of the counter.

2. The method of claim 1, further comprising:

the image acquisition device rearming after the image acquisition device detects the absence of the first object, after the image acquisition device discontinues storage of the image data corresponding to the first object, and after the image acquisition device records the final value of the counter;

wherein the image acquisition device acquires more image data for a second object after said rearming and in response to detecting presence of the second object.

3. The method of claim 2, wherein the image acquisition system further comprises an object detector configured to provide a signal indicating the presence and absence of objects including the first object to the image acquisition device, wherein said rearming comprises:

resetting the counter; and

initializing a pointer to an on-board image buffer on the image acquisition device.

4. The method of claim 3, further comprising the image acquisition device transferring the image data to a system memory image buffer in a memory of a computer system.

5. A system for acquiring images of variable sized objects, the system comprising:

an image sensing device, wherein the objects are moving relative to the image sensing device;

an object detector for detecting a presence and absence of the objects including a first object, wherein the object detector detects the presence and absence of the objects by transmission of at least one of electromagnetic energy or acoustic energy;

an image acquisition device coupled to the image sensing device and the object detector, wherein the image acquisition device comprises an on-board memory;

wherein the image sensing device generates image data corresponding to the first object, wherein the image acquisition device initiates storage of the image data corresponding to the first object into the on-board in response to the object detector detecting the presence of the first object, wherein the image acquisition device discontinues storage of the image data corresponding to the first object in response to the object detector detecting absence of the first object; and

wherein an amount of the stored image data substantially corresponds to a size of the first object;

wherein the image acquisition device further comprises a counter for counting a number of scan lines corresponding to the first object, wherein the image acquisition device is configured (a) to start the counter in response to the object detector detecting the presence of the first object, and (b) to terminate the counter in response to the object detector detecting the absence of the first object;

wherein the image acquisition device records a final value of the counter after the counter terminates counting.

6. The system of claim 5, wherein the image acquisition device is further configured to rearm for acquisition of a second object after the image acquisition device discontinues storage of the image data corresponding to the first object, and after the image acquisition device records the final value of the counter;

wherein the image acquisition device acquires more image data for the second object after said rearming and in response to detecting presence of the second object.

7. The system of claim 6, wherein the image acquisition device is configured to rearm for acquisition of the second object by resetting the counter, and initializing a pointer to an on-board image buffer on the image acquisition device.