Method of detection for a panoramic camera, camera for its implementation, and surveillance system equipped with such a camera

• US 5,262,852 A
• Filed: 04/03/1992
• Issued: 11/16/1993
• Est. Priority Date: 08/03/1990
• Status: Expired due to Fees

• Current Assignee: Thomson-CSF
• Original Assignee: Thomson-CSF
• Inventors: Eouzan, Jean-Yves, Heurteaux, Jean-Claude
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US07/844,660
• Time in Patent Office: 592 Days
• Field of Search: 358/87, 358/108, 358/109
• US Class Current: 348/39
• CPC Class Codes: G01S 3/784 using a mosaic of detectors
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 25/71 Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors
• CPC Class Codes: H04N 25/711 Time delay and integration [TDI] registers; TDI shift registers
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

The invention relates to a method of photodetection for a panoramic camera and to a system for implementation of such a method. A panoramic camera can incorporate a photodetector system of the charge transfer type, an optical system for focusing on a sector of the field of observation and a mechanical rotational drive system for the support having a vertical axis of the assembly. The camera incorporates a photodetection system including at least one module constituted by contiguous arrays (b₁ to b_n) arranged vertically, structure permitting the integration of the charges in synchronism with the rotation of the support, structure for varying the number of activated arrays and for comparing the luminance levels received successively by the elementary cells of the various arrays situated at the same height. The invention also applies to target seeking and to the rapid detection of false alarms due to noise peaks.

Claims

1. A panoramic camera comprising:

a cylindrical support tower;

at least one array of photosensitive cells mounted to the tower, including a preselected number of rows and n columns of cells, the sensitivity of the camera being a function of n;

at least one shift register mounted to the tower, adjacent a last column of cells of the array, and having a number of stages equal to the number of rows;

means for focusing the image of one sector of a field of view onto the area of a column of cells;

means for rotating the tower about its axis;

means for synchronizing the rotation of the tower with the transfer of integrated electrical charge from a cell in a particular row to a corresponding cell in the same row, in an adjacent column, until the charge is stored in a corresponding stage of the shift register;

luminance discrimination means for comparing the output from the shift register at successive moments in time; and

means connected to an output of the discrimination means for signaling an alarm comparison condition signifying the detection of a noise signal.

2. The camera set forth in claim 1 wherein each array and associated shift register form a photodetector module, the camera including a preselected number of identical modules mounted to the support tower;

and

clock means for enabling read out of the shift register, associated with each module, to the discrimination means.

3. The camera set forth in claim 2 together with:

comparator-selector means for measuring level deviations of the outputs from the shift register thereby ascertaining image contrast, the comparator-selector means generating, by comparison with a predetermined threshold, a control signal variably enabling a number of columns in each array of each module, thereby achieving a desired contrast; and

sequencing means for synchronizing operation of the clock means and the comparator-selector means.

4. The camera set forth in claim 2 together with:

a reference photosensitive cell mounted to the tower;

comparator-selector means for measuring level deviations of the outputs from the shift registers thereby ascertaining image contrast, the comparator-selector means generating, by comparison with a reference cell output, a control signal variably enabling a number of columns in each array of each module, thereby achieving a desired contrast; and

sequencing means for synchronizing operation of the clock means and the comparator-selector means.

5. The camera set forth in claim 2 wherein the luminance discrimination means stores outputs from each shift register and performs corresponding stage by stage comparisons to establish identity of the bits in respective stages of the shift registers.

6. A mobile panoramic camera comprising:

a vehicle;

a cylindrical support tower mounted to the vehicle;

a plurality of arrays of photosensitive cells mounted to the tower, each array including a preselected number of rows and n columns of cells, the sensitivity of the camera being a function of n;

a plurality of similar shift register mounted to the tower, each shift register located adjacent a last column of cells of a corresponding array, and having a number of stages equal to the number of rows;

means for focusing the image of one sector of a field of view onto the area of a column of cells;

means for rotating the tower about its axis;

means for synchronizing the rotation of the support tower with the transfer of integrated electrical charge from a cell in a particular row to a corresponding cell in the same row, in an adjacent column, until the charge is received and stored in a corresponding stage of the shift register;

luminance discrimination means for storing outputs from the shift registers and performing corresponding stage by stage comparisons to establish identity of the bits in respective stages of the shift registers;

a sensor for sensing vehicle movement;

a sensor for sensing camera tower rotational speed;

means for processing data received from the sensors and generating corrective coefficients therefrom;

means for obtaining a Fourier transform of an output from the discriminator means;

first means for obtaining an inverse Fourier transform of the coefficients combined with the Fourier transform; and

second means for obtaining an inverse Fourier transform of an output from the first inverse Fourier means and producing a corrected camera output signal.