JP5019352B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus, and more particularly to an imaging apparatus including an image display unit that displays a color image.

When the input luminance level signal is within a predetermined range as in the timing chart example shown in FIG. 5, the conventional video camera is about 70% in FIG. 5A and 100% in FIG. 5B. By outputting an output luminance level signal in which the input luminance level signal is replaced with a predetermined luminance level (40% in FIG. 5) at a predetermined interval (every four clocks in FIG. 5), the output luminance level signal is displayed on the viewfinder. As a mark image indicating that the input luminance level signal is within a predetermined range, a striped zebra pattern like the region Z shown in the image example of FIG. 1).
With this zebra pattern, a user looking through the viewfinder can easily grasp the luminance distribution of the captured image.
JP-A-11-313244

  However, in the conventional zebra pattern insertion method, the zebra pattern is displayed by replacing only the luminance level signal. For this reason, there was no problem even if an image with a zebra pattern inserted in a region where the color saturation is large was displayed in monochrome, but there was no problem in color display, but because the zebra pattern replaced only the luminance level signal, the saturation was Only the brightness changes without change, and it becomes a striped pattern of the color before insertion and the color with blackness on the color, the inserted zebra pattern is not noticeable, and the color of the area gives a dull impression, There is a problem that it is difficult for the photographer to set the white balance adjustment as intended.

  The present invention has been made in view of such circumstances, and an object of the present invention is to determine the color of the original image even if the photographer visually confirms the color image in which the mark image is inserted in an area where the color saturation is large. An object of the present invention is to provide an imaging apparatus that can insert a mark image that is easy to confirm without changing the impression.

  The present invention has been made to solve the above-described problems, and the imaging apparatus of the present invention outputs an imaging signal obtained as an imaging result of a subject and displays a display image based on the imaging signal on a display unit. A determination unit configured to determine whether or not a luminance level of each pixel forming the captured image based on the imaging signal is within a preset upper and lower threshold values, and the captured image The display image portion displayed on the display unit corresponding to each pixel, for each pixel that is determined by the determination unit to have a luminance level within the threshold value range Image switching means for switching to a mark image having an achromatic color and a display pattern and display timing set in advance. .

  The imaging apparatus of the present invention outputs an imaging signal obtained as a result of imaging an object, and forms a captured image based on the imaging signal in an imaging apparatus that displays a display image based on the imaging signal on a display unit. Determining means for determining whether or not the luminance level of each pixel is within a range of preset upper and lower thresholds, and white balance for adjusting white balance for the color signal separated from the imaging signal Among the pixels forming the captured image, the adjustment unit and each pixel determined by the determination unit to have a luminance level within the threshold range are displayed on the display unit corresponding to the pixel. The image switching means for switching the display image portion to a mark image in which a display pattern and display timing are set in advance. Wherein the image switching means, the color level of each pixel forming the mark image displayed on the display unit, and sets the white level adjusted by the white balance adjusting means.

  According to the present invention, since the mark image having an achromatic color is displayed, the photographer is not recognized as an unnatural color by being influenced by the mark image even if the color image is displayed. Without overlooking the mark image, the color of the original image including the area displaying the mark image can be correctly visually confirmed. Furthermore, since the photographer can correctly confirm the color of the original image, the white balance adjustment can be easily set even when the mark image is displayed.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing the configuration of a digital video camera according to an embodiment of the present invention.

A camera unit 101 images a subject and outputs an analog image signal.
Reference numeral 102 denotes an A / D converter that converts an analog image signal output from the camera unit 101 into a digital image signal of three primary colors of red, green, and blue.

Reference numeral 103 denotes an image processing unit that performs image processing on the digital image signal converted by the A / D conversion unit 102 and converts it into a luminance level signal S1 and a color signal S2 in a so-called YCrCb signal format. The image processing unit 103 also converts the value of each color component based on the adjustment instruction signal WB input from the control unit 105 before converting the digital image signal converted by the A / D conversion unit 102 into a luminance level signal and a color signal. Perform white balance adjustment processing to adjust the size of. The control unit 105 receives a value input by the user using an input unit (not shown), and uses the value as the value of the adjustment instruction signal WB. It is possible to change to an image, for example, to an image with reddishness.
In the present embodiment, the image processing unit 103 functions as a white balance adjustment unit, and the color level after white balance adjustment of a white pixel is the white level before white balance adjustment.

  A recording unit 104 records the luminance level signal S1 and the color signal S2 converted by the image processing unit 103 on a medium such as a magnetic tape, a hard disk, or an optical disk.

  The control unit 105 controls the entire digital video camera. The control unit 105 outputs the adjustment instruction signal WB to the image processing unit 103, outputs the luminance level upper limit value signal S 5 and the luminance level lower limit value signal S 6 to the luminance level comparison unit 106, and outputs to the output selection unit 107. Outputs a zebra pattern luminance level setting value signal S3 and a zebra pattern color setting value signal S4. The control unit 105 receives an adjustment instruction, a luminance level upper limit value, a luminance level lower limit value, a zebra pattern luminance level setting value, and a zebra pattern color setting value input by the user using an input unit (not shown). The value is the value of each of these output signals.

  The luminance level comparison unit 106 determines whether or not the luminance level signal S1 converted by the image processing unit 103 is between the luminance level upper limit value signal S5 and the luminance level lower limit value signal S6 output by the control unit 105. . When the luminance level comparison unit 106 determines that the luminance level signal S1 is between the luminance level upper limit value signal S5 and the luminance level lower limit value signal S6 output by the control unit 105, the output selection signal S7 is displayed as a zebra pattern. “ON” instructing the insertion of the data is output to the output selection unit 107.

When the output selection signal S7 is “ON”, the output selection unit 107 converts the luminance level signal S1 and the color signal S2 into the zebra pattern luminance level setting value signal S3 and the zebra pattern color setting value signal S4 at regular intervals, respectively. Instead, the display luminance level signal S8 and the display color signal S9 are output to the viewfinder unit 108.
In the present embodiment, the output selection unit 107 functions as an image switching unit.

The viewfinder unit 108 includes display means such as a liquid crystal display, and displays a color image based on the display luminance level signal S8 and the display color signal S9. Note that the viewfinder unit 108 may be a display unit for confirming an image being captured, and may be a liquid crystal monitor or the like instead of a display unit for confirming by looking through like a viewfinder. .
In the present embodiment, the viewfinder unit 108 functions as a display unit, and the color level of the pixel displayed on the view fan inder unit 108 is determined by the display color signal S9.

FIG. 2 is a schematic block diagram illustrating the configuration of the luminance level comparison unit 106 according to the present embodiment. Reference numeral 111 denotes a luminance level upper limit storage unit that stores the value of the input luminance level upper limit signal S5. Reference numeral 112 denotes a luminance level lower limit storage unit that stores the value of the input luminance level lower limit signal S6.
113, the value of the input luminance level signal S1 is less than or equal to the luminance level upper limit value S21 (upper limit threshold value) read from the luminance level upper limit value storage unit 111, and is read from the luminance level lower limit value storage unit 112. The determination condition is that the luminance level lower limit value S22 (lower limit threshold value) is exceeded. When the determination condition is satisfied, the output selection signal S7 is set to "ON" and output. When the determination condition is not satisfied, The comparison unit outputs the output selection signal S7 with “OFF”.
In the present embodiment, the comparison unit 113 functions as a determination unit.

FIG. 3 is a schematic block diagram illustrating the configuration of the output selection unit 107 according to the present embodiment.
121, when the output selection signal S7 is “ON”, “ON” and “OFF” are switched at a predetermined interval (in this embodiment, every four clocks (one pixel is processed in one clock)). The zebra pattern generator outputs “OFF” when the output selection signal S7 is “OFF”.
When “ON” is input from the zebra pattern generator 121, the zebra pattern luminance level setting value signal S3 is output as a display luminance level signal S8. When “OFF” is input, the luminance level signal S1 is output. Is a switch unit that outputs as a display luminance level signal S8.
When “ON” is input from the zebra pattern generation unit 121, the zebra pattern color setting value signal S4 is output as the display color signal S9. When “OFF” is input, the color signal S2 is displayed. A switch unit that outputs the color signal S9.
In the present embodiment, the zebra pattern generator 121 switches between “ON” and “OFF” at a predetermined interval to generate a display pattern and display timing, and a zebra pattern luminance level setting value signal S3 and zebra pattern color setting. An image portion displayed based on the value signal S4 becomes a mark image.

  FIG. 4 shows the color signal S2 and luminance level signal S1, which are outputs of the image processing unit 103, and the output of the output selection unit 107, and the display color signal S9 and the display luminance level displayed on the viewfinder unit 108. It is a timing chart which shows the signal corresponding to the pixel of the area | region which inserts a zebra pattern with signal S8. A clock C in FIG. 4 is a clock supplied to the image processing unit 103, the control unit 105, the luminance level comparison unit 106, the output selection unit 107, and the viewfinder unit 108. Processing for pixels is performed in synchronization.

  In FIG. 4A, the control unit 105 outputs “no white balance adjustment” as the adjustment instruction signal WB, and “75%” and “65%” are set as the luminance level upper limit value signal S5 and the luminance level lower limit value S6, respectively. , And “40%” and “0x80” are output to the zebra pattern luminance level setting value signal S3 and the zebra pattern color setting value signal S4, respectively. Here, the value “0x80” of the zebra pattern color setting value signal S4 output from the control unit 105 represents an achromatic color.

  Here, the values of the luminance level upper limit value signal S5, the luminance level lower limit value signal S6, the zebra pattern luminance level setting value signal S3, and the values of the luminance level signal S1 and the display luminance level signal S8 in FIG. However, when these values are expressed by 8 bits and take values from “0” to “255”, for example, “0%” is changed to “16”, “100”. “235” is assigned to “%”, and “75%” represents “180”. Also, the zebra pattern color set value signal S4 and the display color signal S9 in the figure are expressed as “0x80” or the like, but this means that “hexadecimal 80”, that is, “128”. To express.

  First, when the control unit 105 outputs the luminance level upper limit value signal S5 and the luminance level lower limit value S6 as described above, the luminance level upper limit value storage unit 111 and the luminance level lower limit value storage unit 112 are each set to “75%”. And “65%” are stored. Further, when the control unit 105 outputs the adjustment instruction signal WB as described above, the image processing unit 103 converts the input image into a color signal S2 and a luminance level signal S1, and outputs it.

At time ta1, the image processing unit 103 outputs “70%” as the luminance level signal S1 and an arbitrary value Cb (Cb represents a color difference from the luminance level signal S1 of the blue component) as the color signal S2. At this time, the comparison unit 113 of the luminance level comparison unit 106 has the value “70%” of the input luminance level signal S1 equal to or lower than “75%” of the luminance level upper limit storage unit 111 and the luminance level lower limit. It is determined whether or not “65%” of the value storage unit 112 is exceeded. Here, since the determination condition is satisfied, the comparison unit 113 outputs “ON” as the output selection signal S7. Further, the zebra pattern generation unit 121 of the output selection unit 107 counts up at the rising edge of the clock C, the value of the counter provided therein for counting 0 to 7 cyclically is 0 to 3, and the output selection signal S7 Is determined to be “ON”. Here, if the value of the counter is “0”, since the output selection signal S7 output from the comparison unit 113 is “ON” as described above, the determination condition is satisfied, so the zebra pattern generation unit 121 is “ON”. Is output.
It should be noted that a zebra pattern stripe pattern is generated by outputting “ON” and “OFF” from the zebra pattern generator 121 in accordance with the value of the counter.

  When the switch unit 122 receives “ON” from the zebra pattern generation unit 121, the switch unit 122 sets the value of the zebra pattern luminance level setting value signal S3 from the input luminance level signal S1 and the zebra pattern luminance level setting value signal S3. This is output as a display luminance level signal S8. Here, as described above, since the control unit 105 outputs “40%” as the zebra pattern luminance level setting value signal S3, the value of the display luminance level signal S8 is also “40%”.

  Upon receiving “ON” from the zebra pattern generator 121, the switch unit 123 displays the value of the zebra pattern color setting value signal S4 from the input color signal S2 and the zebra pattern color setting value signal S4. Output as signal S9. Here, as described above, since the control unit 105 outputs “0x80” as the zebra pattern color setting value signal S4, the value of the display color signal S9 is also “0x80”.

  Next, at time ta2, the image processing unit 103 outputs “70%” as the luminance level signal S1 and an arbitrary value Cr (Cr represents a color difference from the luminance level signal S1 of the blue component) as the color signal S2. And At this time, the comparison unit 113 of the luminance level comparison unit 106 outputs “ON” as the output selection signal S7, similarly to the time ta1. Further, the zebra pattern generation unit 121 of the output selection unit 107 has the counter value “1”, and the output selection signal S7 output from the comparison unit 113 is “ON” as described above. The generation unit 121 outputs “ON”.

  The switch unit 122 outputs “40%” as the display luminance level signal S8 in the same manner as at the time ta1. The switch unit 123 outputs “0x80” as the display color signal S9 in the same manner as the time ta1.

  Also at time ta3 and time ta4, similarly to time ta1 and time ta2, the switch unit 122 and the switch unit 123 of the output selection unit 107 output “40%” as the display luminance level signal S8, respectively. “0x80” is output as the color signal S9. However, the counter of the zebra pattern generation unit 121 is counted up at each time and becomes “3” at time ta4.

  As described above, the output of the output selection unit 107 at the times ta1 to ta4 is that the value of the display luminance level signal S8 and the value of the display color signal S9 are respectively “40%” of the zebra pattern luminance level setting value signal S3. And the value “0x80” of the zebra pattern color setting value signal S4. The value “40%” of the zebra pattern luminance level setting value signal S3 represents low brightness, and the value “0x80” of the zebra pattern color setting value signal S4 represents an achromatic color. The finder unit 108 displays dark achromatic colors, that is, dark gray, on the four pixels corresponding to the clocks at times ta1 to ta4.

  Next, at time ta5, the image processing unit 103 outputs “70%” as the luminance level signal S1 and an arbitrary value Cb as the color signal S2. At this time, the comparison unit 113 of the luminance level comparison unit 106 outputs “ON” as the output selection signal S7 in the same manner as at times ta1 to ta4. The zebra pattern generation unit 121 of the output selection unit 107 has a counter value of “4” and the output selection signal S7 output from the comparison unit 113 is “ON” as described above. 0 to 3 and the output selection signal S7 is not “ON”, and “OFF” is output.

  When the switch unit 122 receives “OFF” from the zebra pattern generation unit 121, the switch unit 122 sets the value of the luminance level signal S1 from the input luminance level signal S1 and the zebra pattern luminance level setting value signal S3. Output as signal S8. Here, as described above, since the image processing unit 103 outputs “70%” as the luminance level signal S1, the value of the display luminance level signal S8 is also “70%”.

  Upon receiving “OFF” from the zebra pattern generation unit 121, the switch unit 123 outputs the value of the color signal S2 as the display color signal S9 from the input color signal S2 and zebra pattern color setting value signal S4. To do. Here, as described above, since the image processing unit 103 outputs Cb as the color signal S2, the value of the display color signal S9 is also Cb.

  Also from time ta6 to ta8, similarly to time ta5, the switch unit 122 and the switch unit 123 of the output selection unit 107 output “70%” as the display luminance level signal S8, respectively, and as the display color signal S9. Cr or Cb is output. However, the counter of the zebra pattern generation unit 121 is incremented at each time and becomes “7” at time ta8.

  As described above, the output of the output selection unit 107 at times ta5 to ta8 is such that the value of the display luminance level signal S8 and the value of the display color signal S9 are the same as the luminance level signal S1 and the color signal S2, respectively. The viewfinder unit 108 that has received the color displays the color composed of the luminance level signal S1 and the color signal S2, that is, the color of the image captured by the camera unit 101, on the four pixels corresponding to the clocks at times ta5 to ta8. .

Since the value of the luminance level signal S1 continues to be “70%” at times ta9 to ta16, the same operation as at time ta1 is performed at time ta9, and between times ta2 to ta4 at time ta10 to ta12. The same operation is performed, and from time ta13 to ta16, the same operation as time ta5 to ta8 is performed.
As a result, the viewfinder unit 108 alternately represents dark gray and the color of the image captured by the camera unit 101 for every four pixels, so that the value of the luminance level signal S1 is “65%” to “75%”. If it is between, a zebra pattern is displayed.

  In FIG. 4B, the control unit 105 outputs “no white balance adjustment” as the adjustment instruction signal WB, and “100%” and “95%” are set as the luminance level upper limit signal S5 and the luminance level lower limit S6, respectively. , And “40%” and “0x80” are output to the zebra pattern luminance level setting value signal S3 and the zebra pattern color setting value signal S4, respectively.

  4B is different from FIG. 4A in that the value range of the luminance level signal S1 for displaying the zebra pattern is “100%” or more, but the viewfinder unit 108 has four pixels. Every time, the dark gray and the color of the image captured by the camera unit 101 are alternately displayed, so that a zebra pattern is displayed. At this time, the control unit 105 outputs “100%” as the luminance level lower limit value S6, and outputs the maximum value (for example, “109%”) that the luminance level signal can take as the luminance level upper limit value signal S5.

  As described above, the value of the zebra pattern color setting value signal S4 output from the control unit 105 is “0x80” representing an achromatic color, and the zebra pattern is a stripe between the achromatic gray and the color of the image captured by the camera unit 101. In order to form a pattern, the video camera of the present embodiment can display the zebra pattern conspicuously on the viewfinder unit 108 without blurring the color of the photographed image.

  The control unit 105 instructs the white balance adjustment so that the adjustment instruction signal WB is bluish, and the Cb value of the color signal S2 is increased by “4” in the image processing unit 103, and the Cr value is “4”. When the adjustment is made to decrease, the control unit 105 increases the value of the zebra pattern color setting value signal S4 to “0x84” by increasing “4” when the color signal S2 is Cb, and when the color signal S2 is Cr. “4” is decremented and “0x7c) is output.At this time, the control unit 105 counts the clock C with reference to the horizontal synchronization signal indicating the break of one line of the image, so that the clock C of the timing is output. Since it can be determined whether the color signal S2 at the time of rising is Cb or Cr, a value selected from “0x84” and “0x7c” based on the determination is used as the zebra pattern color setting value signal S4. That.

  As a result, the value of the zebra pattern color setting value signal S4 input to the output selection unit 107 becomes a value in which “0x84” and “0x7c” are alternately switched, and the output selection unit 107 outputs in the region where the zebra pattern is displayed. For the display color signal S9, “0x84” and “0x7c” are repeated twice, then the original color signal S2 is output by four pixels, and “0x84” and “0x7c” are repeated twice. Thereafter, the original color signal S2 is output by 4 pixels. The display luminance level signal S8 output from the output selection unit 107 is the same as when white balance adjustment is not performed. For this reason, since the viewfinder unit 108 alternately captures the dark gray with bluish color and the image of the white balance imaged by the camera unit 101 every four pixels, the blue color is adjusted by white balance adjustment. The zebra pattern can be displayed without changing the impression of the screen with the touch.

  The processing unit 30 may be realized by dedicated hardware. The processing unit 30 includes a memory and a CPU (central processing unit), and realizes the functions of the processing unit 30. This function may be realized by loading the program into a memory and executing it.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within a scope not departing from the gist of the present invention.

  The present invention is suitable for use in an imaging apparatus such as a digital still camera and a digital video camera provided with means for confirming a captured image by color display, but is not limited thereto.

1 is a schematic block diagram illustrating a configuration of an imaging apparatus according to an embodiment of the present invention. It is a schematic block diagram which shows the detailed structure of the luminance level comparison part 106 in the embodiment. It is a schematic block diagram which shows the detailed structure of the output selection part 107 in the embodiment. 5 is a timing chart showing a luminance level signal and a color signal output from the image processing unit 103 and a color signal and a luminance level signal output from the output selection unit 107 in the embodiment. It is the timing chart which showed the luminance level signal and color signal after the conventional luminance level signal and color signal, and zebra pattern insertion. It is a display example of the conventional zebra pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Camera part 102 ... A / D conversion part 103 ... Image processing part 104 ... Recording part 105 ... Control part 106 ... Luminance level comparison part 107 ... Output selection part 108 ... Viewfinder part 111 ... Luminance level upper limit storage part 112 ... Luminance level lower limit storage unit 113... Comparison unit 121... Zebra pattern generation unit 122, 123.

Claims (2)

  In an imaging apparatus that outputs an imaging signal obtained as a result of imaging an object and causes a display unit to display an image for display based on the imaging signal.
  Determining means for determining whether or not a luminance level of each pixel forming a captured image based on the imaging signal is within a preset upper and lower threshold values;
  White balance adjustment means for adjusting white balance for the color signal separated from the imaging signal;
  Of the pixels that form the captured image, the display that is displayed on the display unit corresponding to each pixel for each pixel that is determined by the determination unit to have a luminance level within the threshold range Image switching means for switching and displaying the image portion for a mark image with a display pattern and display timing set in advance,
  The image switching means is
  The color level of each pixel forming the mark image displayed on the display means is set to the white level adjusted by the white balance adjusting means.
  An imaging apparatus characterized by that.   In the image switching means,
  The image pickup apparatus according to claim 1, wherein the value of the color signal of each pixel displayed by switching to the mark image is further increased or decreased based on a value representing an achromatic color.

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