Image pickup apparatus with function of rate conversion processing and control method therefor

• US 20060114334A1
• Filed: 09/21/2005
• Published: 06/01/2006
• Est. Priority Date: 09/21/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Watanabe, Yoshinori, Rengakuji, Hideyuki
• Granted Patent: US 7,860,321 B2
• Time in Patent Office: Days
• US Class Current: 348/222.100
• CPC Class Codes: H04N 23/633 for displaying additional information relating to control or operation of the camera
• CPC Class Codes: H04N 5/772 the recording apparatus and the television camera being placed in the same enclosure

Abstract

A rate conversion unit determines a frame thinning-out rate to thin out frames on the basis of a recording rate at the time of photographing and a display rate for display on a display apparatus so that a temporal updating interval of a video image between continuous fields becomes constant. After that, a frame is repeatedly inserted so that a frame rate becomes equal to the display rate.

Claims

1. An image pickup apparatus, comprising:

image pickup means for picking up an object image;

recording means for recording image data obtained by the image pickup means onto a recording medium;

display means for selectively displaying an image related to any one of the image data obtained by the image pickup means and the image data recorded on the recording medium on a display apparatus;

thinning-out rate determination means for determining a thinning-out rate for the image to be displayed by the display means on the basis of a rate at the time of photographing of the image to be displayed by the display means and a display rate in the display apparatus;

image thinning-out means for performing thinning-out processing on the image to be displayed by the display means on the basis of the thinning-out rate-determined by the thinning-out determination means; and

rate conversion means for inserting repeatedly output images to the image thinned out by the image thinning-out means to increase a rate so that the rate of the image thinned out by the image thinning-out means is made equal to the display rate in the display apparatus.

2. An apparatus according to claim 1,

wherein the thinning-out rate determination means includes:

comparison means for comparing the rate at the time of photographing and the display rate with each other; and

dividing value calculation means for calculating a dividing value k corresponding to thinning out k-1 frames after displaying one frame, on the basis of the result of comparison by the comparison means,

wherein the image thinning-out means thins out the frame in accordance with the dividing value k.

3. An apparatus according to claim 2, wherein the dividing value calculation means includes:

first initialization means for initializing the dividing value k to 1 to provide the initialized dividing value k to the image thinning-out means if the rate at the time of photographing is equal to or lower than the display rate as a result of comparison by the comparison means;

second initialization means for initializing the dividing value k to 2 to provide the initialized dividing value k if the rate at the time of photographing is higher than the display rate as a result of comparison by the comparison means; and

dividing value increment means for incrementing the dividing value k initialized by the second initialization means one by one until a frame rate obtained by dividing the rate at the time of photographing by k becomes equal to or lower than the display rate, to provide the dividing value k corresponding to the frame rate equal to or lower than the display rate to the frame thinning-out means.

4. An apparatus according to claim 1, wherein the recording means includes:

compression means for compression-encoding the image data obtained by the image pickup means to generate compressed image data;

rate information addition means for adding information related to the rate at the time of the photographing to the compressed image data; and

compressed image data recording means for recording the compressed image data onto the recording means.

5. An apparatus according to claim 4, wherein the display means includes:

expansion means for reading out and expanding the compressed image data recorded on the recording medium; and

rate information reading means for reading out the information related to the rate at the time of the photographing, which information is added to the compressed image data.

6. An apparatus according to claim 5, wherein the thinning-out rate determination means determines an image thinning-out rate on the basis of the information related to the rate at the time of the photographing which information is added to the compressed image data, and the display rate in the display apparatus, when a reproduced image on the recorded medium is displayed on the display apparatus by the display means.

7. An apparatus according to claim 1, further comprising operation means for setting a recording rate at the time of a photographing operation, wherein the thinning-out rate determination means determines the image thinning-out rate on the basis of the recording rate set by the operation means and the display rate in the display apparatus when the object image picked up by the pickup means is displayed by the display means on the display apparatus in parallel to the image pickup of the object image by the image pickup means.

8. An apparatus according to claim 1, wherein the thinning-out rate determination means determines the image thinning-out rate on the basis of the rate at the time of photographing, the display rate and a reproduction speed for displaying a reproduced image by the display means on the display apparatus.

9. An apparatus according to claim 8,

wherein the thinning-out rate determination means includes:

multiplication means for multiplying a magnification of the reproduction speed with respect to an image pickup speed by the rate at the time of the photographing to obtain a multiplied frame rate;

comparison means for comparing the multiplied frame rate and the display rate with each other; and

dividing value calculation means for calculating a dividing value k corresponding to thinning out k-1 frames after displaying one frame, on the basis of the result of comparison by the comparison means,

wherein the image thinning-out means thins out the frame in accordance with the dividing value k.

10. An apparatus according to claim 9, wherein the dividing value calculation means includes:

first initialization means for initializing the dividing value k to 1 to provide the initialized dividing value k to the frame thinning-out means if the multiplied frame rate is equal to or lower than the display rate as a result of comparison by the comparison means;

second initialization means for initializing the dividing value k to 2 to provide the initialized dividing value k if the multiplied frame is higher than the display rate as a result of comparison by the comparison means; and

dividing value increment means for incrementing the dividing value k initialized by the second initialization means one by one until a frame rate obtained by dividing the multiplied frame rate by k becomes equal to or lower than the display rate, to provide the dividing value k corresponding to the frame rate equal to or lower than the display rate to the frame thinning-out means.

11. An image pickup apparatus, comprising:

a camera for picking up an object image to generate image data;

a recording circuit for recording the image data generated by the camera onto a recording medium; and

a reproduction circuit for selectively displaying any one of the image photographed by the camera and the image recorded on the recording medium on a display apparatus,

wherein the camera, the recording circuit, and the reproduction circuit are configured in the same image pickup apparatus,

wherein the reproduction circuit includes;

a rate conversion controller for determining a thinning-out rate for an image to be displayed on the basis of a rate at the time of photographing of the image to be displayed on the display apparatus during photographing and a display rate in the display apparatus, thereby controlling rate conversion;

an image thinning-out circuit for performing thinning-out processing of data of the image to be displayed on the basis of the thinning-out rate determined by the rate conversion controller; and

a rate converter for inputting the data output from the image thinning-out circuit and inserting repeat image data in accordance with control of the rate conversion controller to make a rate of an image to be reproduced equal to the display rate in the display apparatus.

12. A method of controlling an image pickup apparatus including image pickup means for picking up an object image, recording means for recording image data obtained by the image pickup means onto a recording medium, and display means for selectively displaying any one of the image photographed by the image pickup means and the image recorded onto the recording medium on a display apparatus, the method comprising:

a thinning-out rate determination step of determining a thinning-out rate for the image to be displayed by the display means on the basis of a rate at the time of photographing of the image displayed by the display means and a display rate in the display apparatus;

an image thinning-out step of performing thinning-out processing on the image to be displayed by the display means on the basis of the thinning-out rate determined in the thinning-out rate determination step;

a rate conversion step of inserting repeatedly output images to the image thinned out in the image thinning-out step to increase a rate so that the rate of the image thinned out in the image thinning-out step is made equal to the display rate in the display apparatus; and

a display step of displaying the image whose rate is converted in the rate conversion step on the display apparatus.

13. A program for controlling an image pickup apparatus including image pickup means for picking up an object image, recording means for recording image data obtained by the image pickup means onto a recording medium, and display means for selectively displaying any one of the image photographed by the image pickup means and the image recorded onto the recording medium on a display apparatus, the program causing a computer to execute:

a thinning-out rate determination procedure of determining a thinning-out rate for the image to be displayed by the display means on the basis of a rate at the time of photographing of the image displayed by the display means and a display rate in the display apparatus;

an image thinning-out procedure of performing thinning-out processing on the image to be displayed by the display means on the basis of the thinning-out rate determined in the thinning-out rate determination procedure;

a rate conversion procedure of inserting repeatedly output images to the image thinned out in the image thinning-out procedure to increase a rate so that the rate of the image thinned out at the image thinning-out step is made equal to the display rate in the display apparatus; and

a display procedure of displaying the image whose rate is converted in the rate conversion procedure on the display apparatus.