Time lapse recording apparatus having abnormal detecting function

• US 6,600,872 B1
• Filed: 06/21/1999
• Issued: 07/29/2003
• Est. Priority Date: 06/19/1998
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Yamamoto, Naoto
• Primary Examiner(s): NGUYEN, HUY THANH
• Application Number:
  US09/336,587
• Time in Patent Office: 1,499 Days
• Field of Search: 386/46, 386/111, 386/117, 386/67, 386/93, 386/68, 386/112, 360/5, 348/154
• US Class Current: 386/264
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/132 Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
• CPC Class Codes: H04N 19/139 Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• CPC Class Codes: H04N 19/14 Coding unit complexity, e.g. amount of activity or edge presence estimation H04N19/146 takes precedence
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/587 involving temporal sub-sampling or interpolation, e.g. decimation or subsequent interpolation of pictures in a video sequence
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding
• CPC Class Codes: H04N 5/76 Television signal recording
• CPC Class Codes: H04N 7/188 Capturing isolated or intermittent images triggered by the occurrence of a predetermined event, e.g. an object reaching a predetermined position signal generation from motion picture films H04N5/253
• CPC Class Codes: H04N 9/8042 involving data reduction

Abstract

A picture processing apparatus of moving picture coding type having a motion correcting circuit is disclosed. An abnormality detecting means 5 compares the unit time mean coding bit number of past frame and the coding bit number of the present frame and executes abnormality detection on the basis of the difference between the compared coding bit numbers. A recording interval control means 8 controls the number of frames outputted to a recording means such that the unit time recording frame interval is reduced in the abnormality detection state. A code quantity control means 6 controls the picture quality and/or the quantity of codes generated per frame correspondence to the complexity of input picture.

Claims

1. A time lapse recorder comprising:

a dividing means for dividing an input picture signal into signals corresponding to small area blocks each consisting of a plurality of pixels;

a motion estimate means for retrieving motion vectors of blocks most similar to each other in picture frames of different times;

a motion compensating means for obtaining a difference between a coding subject frame and a motion vector computation frame for each of the blocks on the basis of the motion vectors;

an orthogonal transform means for executing orthogonal transform of the blocks;

a quantizing means for quantizing transform coefficient values as the output of the orthogonal transform means;

a code quality control means for controlling picture quality and quantity of codes generated per frame in accordance with the complexity of the input picture;

a variable length coding means for variable length coding quantized coefficient data outputted from the quantizing means;

an abnormality detecting means for detecting abnormality of input picture;

a recording interval control means for changing recording frame number at a constant interval in the normal state and in unit times in the abnormality detection state; and

a recording means for recording the variable length coded data in a recording medium under control of the recording interval control means,

wherein the abnormality detecting means computes the coding bit number of the variable length coding means for each frame, compares the difference of this coding bit number from the coding bit number of the immediately preceding frame having the same predicted structure and executes abnormal detection when the compared difference is above a predetermined threshold value, and

wherein the recording interval control means adaptively controls the recording frame number according to a multiple-valued output of the abnormality detecting means.

3. The time lapse recorder according to claim 1, wherein when the output of the abnormality detecting means is abnormal, the recording interval control means controls the recording frame number.

5. The time lapse recorder according to claim 1, wherein the code quantity control means executes code quantity control on the basis of the output of the abnormality detecting means such as to provide an improved recording picture quality when the abnormality is detected.

21. The time lapse recorder according to claim 1, wherein when the output of the abnormality detecting means is abnormal, the recording interval control means controls the recording frame number to permit recording of all frames.

2. A time lapse recorder comprising:

a dividing means for dividing an input picture signal into signals corresponding to small area blocks each consisting of a plurality of pixels;

a motion estimate means for retrieving motion vectors of blocks most similar to each other in picture frames of different times;

a motion compensating means for obtaining a difference between a coding subject frame and a motion vector computation frame for each of the blocks on the basis of the motion vectors;

an orthogonal transform means for executing orthogonal transform of the blocks;

a quantizing means for quantizing transform coefficient values as the output of the orthogonal transform means;

a code quantity control means for controlling picture quality and quantity of codes generated per frame in accordance with the complexity of the input picture;

a variable length coding means for variable length coding quantized coefficient data outputted from the quantizing means;

an abnormality detecting means for detecting abnormality of input picture;

a recording interval control means for changing recording frame number at a constant interval in the normal state and in unit times in the abnormality detection state; and

a recording means for recording the variable length coded data in a recording medium under control of the recording interval control means,

wherein the abnormality detecting means computes statistical value of the distribution or amplitude values of the motion vectors for each frame, compares the statistical value of the motion vectors with a predetermined threshold value, and executes abnormality detection when the statistical value is above the threshold value.

17. The time lapse recorder according to claim 2, wherein the recording interval control means adaptively controls the recording frame number according to a multiple-valued output of the abnormality detecting means.

18. The time lapse recorder according to claim 2, wherein when the output of the abnormality detecting means is abnormal, the recording interval control means controls the recording frame number such as to permit recording of all frames.

19. The time lapse recorder according to claim 2, wherein the abnormality detecting means provides a multiple-valued output, and the recording interval control means decodes the value of the output of the abnormality detecting means, selects a recording time interval corresponding to the output value among a plurality of different recording times shorter than a recording time in a normal state and causes the recording means to record frames at the selected recording time interval.

20. The time lapse recorder according to claim 2, wherein the code quantity control means executes code quantity control on the basis of the output of the abnormality detecting means such as to provide an improved recording picture quality when the abnormality is detected.

4. A time lapse recorder comprising:

a dividing means for dividing an input picture signal into signals corresponding to small area blocks each consisting of a plurality of pixels;

a motion estimate means for retrieving motion vectors of blocks most similar to each other in picture frames of different times;

a motion compensating means for obtaining a difference between a coding subject frame and a motion vector computation frame for each of the blocks on the basis of the motion vectors;

an orthogonal transform means for executing orthogonal transform of the blocks;

a quantizing means for quantizing transform coefficient values as the output of the orthogonal transform means;

a code quality control means for controlling picture quality and quantity of codes generated per frame in accordance with the complexity of the input picture;

a variable length coding means for variable length coding quantized coefficient data outputted from the quantizing means;

an abnormality detecting means for detecting abnormality of input picture;

a recording interval control means for changing recording frame number at a constant interval in the normal state and in unit times in the abnormality detection state; and

a recording means for recording the variable length coded data in a recording medium under control of the recording interval control means,

wherein the abnormality detecting means computes the coding bit number of the variable length coding means for each frame, compares the difference of this coding bit number from the coding bit number of the immediately preceding frame having the same predicted structure and executes abnormal detection when the compared difference is above a predetermined threshold value, wherein the abnormality detecting means provides a multiple-valued output, and the recording interval control means decodes the value of the output of the abnormality detecting means, selects a recording time interval corresponding to the output value among a plurality of different recording times shorter than a recording time in a normal state and causes the recording means to record frames at the selected recording time interval.

6. In an image processing apparatus of moving picture coding type for detecting motion vectors from an input picture, variable length coding a motion corrected signal, and recording the coded signal in recording means, a time lapse recorder comprising:

means for comparing a unit time mean coding bit number of past frames and the coding bit number of the present frame and executing abnormality detection on the basis of the difference between the compared coding bit numbers; and

means for controlling the number of frames recorded in the recording means such that the recording interval per unit time is reduced when the abnormality is detected.

7. In an image recording apparatus for detecting motion vectors from an input picture, generating an inter-frame difference value between the input picture and a predicted frame from the motion vectors, executing orthogonal transform of the inter-frame difference, quantizing coefficients obtained by the orthogonal transformation, coding the quantized coefficients and recording the quantized coefficients in a recording means, a time lapse recorder comprising:

an abnormality detecting mean for comparing a unit time mean coding bit number of past frames and the coding bit number of the present frame and executing abnormality detection on the basis of the difference between the compared coding bit numbers; and

a recording interval control means for controlling the number of frames recorded in the recording means such that the recording interval per unit time is reduced when the abnormality is detected.

10. The time lapse recorder according to claim 7, wherein the abnormality detecting means includes:

means for selecting a frame having a predetermined predicted structure among input frames;

means for receiving frame coding bit number of the selected frame and computing the unit time least mean coding bit number; and

means for executing abnormality detection and providing an abnormality detection signal when the quotient of division of the mean coding bit number by the least mean coding bit number is greater than a predetermined threshold value and also when the quotient of division of the coding bit number of the selected present input frame by the unit time least mean coding bit number is greater than a predetermined threshold value.

12. The time lapse recorder according to claim 7, wherein the abnormality detecting means includes:

means for analyzing the motion vector over one frame; and

means for comparing the motion vector value distribution with a predetermined value, executing abnormality detection when it is larger than the predetermined value, and generating an abnormal detection signal.

13. The time lapse recorder according to claim 7, wherein the abnormality detecting means includes:

means for converting the motion vector amplitudes to corresponding scalar values;

means for accumulating the scalar values for each frame; and

means for comparing the accumulation value with a predetermined threshold value and outputting an abnormality detection signal when the accumulation value is greater than the threshold value.

14. The time lapse recorder according to claim 7, wherein:

the recording interval control means normally executes a control for recording frames at a predetermined recording time interval in the recording means; and

when the abnormality detecting means detects abnormality, the variable length coding means is controlled on the basis of the value of the output of the abnormality detecting means such that all frames are recorded continuously or at a recording time interval shorter than the recording time interval in the normal state.

15. The time lapse recorder according to claim 7, wherein an abnormal detection signal is outputted when it is determined from a motion vector value and coordinate data of a base block of the motion vector that motion coordinates of the motion vector are in a predetermined monitoring area.

8. In an image recording apparatus for detecting motion vectors from an input picture, generating an inter-frame difference value between the input picture and a predicted frame from the motion vectors, executing orthogonal transform of the inter-frame difference, quantizing coefficients obtained by the orthogonal transformation, coding the quantized coefficients and recording the quantized coefficients in a recording means, a time lapse recorder comprising:

an abnormality detecting means including means for computing the unit time least mean coding bit number on the basis of the frame coding bit number of each frame, and means for comparing the coding bit number of the present frame and the least mean coding bit number and determines that the frame is abnormal when the difference is greater than a predetermined threshold value; and

a recording interval control means for controlling the number of frames recorded in the recording means such that the recording interval per unit time is reduced when the abnormality is detected.

9. In an image recording apparatus for detecting motion vectors from an input picture, generating an inter-frame difference value between the input picture and a predicted frame from the motion vectors, executing orthogonal transform of the inter-frame difference, quantizing coefficients obtained by the orthogonal transformation, coding the quantized coefficients and recording the quantized coefficients in a recording means, a time lapse recorder comprising:

an abnormality detecting means including means for computing the unit time least mean coding bit number on the basis of the frame coding bit number of each frame, and means for comparing the coding bit number of the present frame and the least mean coding bit number and determines that the frame is abnormal when the difference is greater than a predetermined threshold value; and

a recording interval control means for controlling the number of frames recorded in the recording means such that the recording interval per unit time is reduced when the abnormality is detected,

wherein a plurality of threshold values are provided, and abnormality detection is executed by a multiple-valued state detection as a result of comparison between the difference and the plurality of threshold values.

11. The time lapse recorder according to claim 9, wherein the frame coding bit number is inputted when P picture frames alone or P and B picture frames are inputted.

16. The time lapse recorder according to claim 9, wherein when the abnormality detecting means detects abnormality, the code quantity control means controls the quantizing means and the variable length coding means for recording frames in the recording means at an increased coding rate and a reduced compression factor compared to the normal state.